Comparing soilless and non-chemical farming food production systems: Nutritional and environmental aspects for food security and sustainability

Comparing soilless and non-chemical farming food production systems: Nutritional and environmental aspects for food security and sustainability | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comparing soilless and non-chemical farming food production systems: Nutritional and environmental aspects for food security and sustainability Wannaporn Hatongkham, Kitti Sranacharoenpong, Unchalee Suwanmanee, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4894455/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Plant factory with artificial light (PFAL) technology is a soilless cultivation system that designed to optimize plant growth, productivity, and product quality, as well as ensure efficient use of water and fertilizer. Non-chemical farming (N-CF) systems are a traditional agricultural cultivation method. Both agricultural systems can serve as commodity production methods for ensuring food security. However, concerns about nutritional value and environmental sustainability remain. This study compares the nutritional compositions, antioxidant contents, environmental impacts, and carbon footprint of kale ( Brassica oleracea L.) in PFAL and N-CF systems. The proximate values of kale in PFAL and N-CF systems were not significantly different (p < 0.05). However, the results revealed that antioxidant contents, determined by polyphenol, oxygen radical absorbance capacity (ORAC) assay and ferric reducing antioxidant power (FRAP) assay were significantly lower in PFAL-harvested kale than in N-CF-harvested kale after three months. The polyphenol, ORAC and FRAP of PFAL kale were 68.95 mg GAE/100 g, 1,321.25 and 111.95 μmol TE/100 g fresh weight, respectively, while those of N-CF kale were136.06 mg GAE/100 g, 3,519.87 and 220.17 μmol TE/100 g fresh weight, respectively. The carbon dioxide (CO 2 ) emissions of 3 month-kale from PFAL and N-CF productions were 168.61 and 14.75 Kg CO 2 eq./kg of kale, respectively. Consequently, new policies should be oriented toward reducing environmental pressure by introducing process certification of low environmental impacts. However, not only environmental aspects but also the adequacy of nutritive values of products should be a concern for farming food production systems. Food security Environmental impacts Nutritive values Carbon footprints Figures Figure 1 Figure 2 Figure 3 Introduction Climate change has become a global concern in recent decades. It causes ozone depletion, impacts agriculture yield, water supply, and transportation, and create several other problems. Climate change may impact food systems in various aspects, increasing crop disease, lowering nutritional quality and reducing crop yield e.g., changes in rainfall patterns can cause drought or flood, or warmer or cooler temperatures can lead to changes in the length of the growing season (Gregory et al., 2005 ). The world populations are predicted to get larger by over a third or 2.3 billion people in 2050. These trends indicate that food market demand will continue to rise. According to studies, feeding the world's population in 2050 would require a 50 percent increase in overall grain production (Alexandratos & Bruinsma, 2012 ). As the world faces the challenge of feeding a growing global population while preserving environmental integrity, two contrasting agricultural systems have gained prominence: Plant Factory with Artificial Lighting (PFAL) and Non-chemical farming (N-CF). PFAL is a soilless close production system characterized by a controlled environment, hydroponics, and artificial lighting, making it a high-tech approach to crop cultivation. Meanwhile, N-CF is a traditional agriculture. The advancement of PFAL technology could be considered an optional intervention for addressing these concerns. It is claimed that PFAL could lower greenhouse gas emissions by the potential reductions of air pollution, water use, fertilisers, and pesticides. A few reports suggest that PFAL can reduce greenhouse gas emissions (Orsini et al., 2020 ). There is a report indicating that an improved vertical farm, a type of indoor farm, could emit 0.16 to 0.33 kg of CO 2 equivalents per kg of lettuce (Milestad et al., 2020 ). Apart from eco-friendly benefits, PFAL could be related to the quality of plants (Butryee, 2020 ). For example, light is a key factor in phytochemical synthesis, growth, development, and nutritional composition in plants. Myung Jin Lee (2016) found that red, blue, and far-red LEDs at ratios of 0.7 and 1.2 significantly increased total phenolic levels, antioxidant activity, chlorogenic acid contents, and caffeic acid contents in intervention plant groups compared to the control. It was presumed that the appropriate quality and intensity of light can increase the quantity and quality of phytochemicals in plants (Lee et al., 2016 ). N-CF is an alternative agriculture system that attempts to deliver sustainable and safe foods. It also protects resources and the environment by avoiding synthetic pesticides and using the on-farm resources in the most efficient ways. Kale ( Brassica oleracea L.) is a highly nutritious leafy green vegetable known for its rich content of vitamins, minerals, and antioxidants. It contains high levels of vitamins A, C, and K, as well as calcium, potassium, and fibre. These nutrients promote various health benefits, including improved vision, immune function, bone health, and cardiovascular health (Satheesh & Workneh Fanta, 2020 ). The consumption of kale has been associated with reduced risks of chronic diseases such as heart disease, diabetes, and cancer due to its high levels of antioxidants and anti-inflammatory compounds (Sikora & Bodziarczyk, 2012 ). Additionally, kale has gained significant popularity in the health and wellness market, leading to increased demand and market value. It is commonly used in salads, smoothies, and as a cooked vegetable, making it an adjustable ingredient in many diets. The economic value of kale is also crucial, as it has become a profitable crop for farmers, especially those focusing on organic and health food markets (Samec et al., 2018 ). Studying the environmental impact and carbon footprint related to the nutritive values of plants should be considered as a benefit for addressing the food shortage problem. Thus, the purpose of this study is to compare the nutritive values in terms of nutritional compositions and antioxidant contents, and carbon footprints of Kale ( Brassica oleracea L.) between PFAL and N-CF systems. Materials and Methods Planting materials, sample collection and preparation PFAL kale trials were conducted at the Agrowlab plant factory in Bangkok, Thailand. The samples were collected 3 months after planting. A total of 32 buckets of kale were separated into 3 parts; 12:8:12, three varieties of PFAL kale were randomly collected from each part. N-CF kale trials were conducted at a farm in Pathum Thani province, Thailand. There were 180 kale plants in the experimental plot. The N-CF kale samples were collected at 3, 6, and 12 months after planting. The kale plot was divided into three parts; three varieties of N-CF kale were randomly collected from each part of the plot. An identical quantity of kale seeds was utilised in each agricultural system. In addition, leaf samples for the assessment of nutrition were collected throughout the same growth phases. The sets of kale samples were washed individually with water to remove dirt and contaminants. After washing, the edible part of each set will be cut into small pieces and homogenized. The homogenized samples are going to be divided into two portions for nutritional compositions and antioxidant contents analysis and stored at − 20°C until analysis. Proximate Analysis The proximate analysis of kale samples followed standardized methods according to the AOAC (George W. Latimer, 2019). The Kjeldahl method (AOAC 981.10) was used to determine protein content, and fat content following the Soxhlet method (AOAC 922.06). Moisture content was assessed by drying the samples at 100°C in a hot air oven, according to AOAC 925.45 A. Ash content was determined through incineration at 550°C in a muffle furnace (AOAC 920.153). Total dietary fibre analysis was determined by Enzymatic-Gravimetric Method (AOAC 985.29). The total carbohydrate content of the dry mass was calculated using the following formula: Total carbohydrates (%) = 100 − (protein + total fat + moisture + ash + total dietary fibre) Total Polyphenol Content Total phenolic concentration (TPC) was determined according to the method described by Kongkachuichai et al. ( 2015 ), with slight modifications based on Brune et al. ( 1991 ). Two grams of samples were extracted with 20 ml of 50% dimethylformamide (Sigma–Aldrich, St. Louis, MO, USA) in 0.1 M acetate buffer for 16 h by constant shaking at room temperature. After extraction, samples were centrifuged (20 min, 25°C, 3000 rpm) and then supernatants were collected. The supernatants were diluted to 25 µl with water. Then the samples were added to a 96-well plate, followed by 125 µl of 10% Folin–Ciocalteau reagent (Merck, Darmstadt, Germany) and 100 µl 0.5 M sodium hydroxide to each well and mixed. Absorbance was measured at 750nm using an automated microplate reader (SunriseTM Tecan, Victory, Australia) after standing for 15 min at 25°C. Gallic acid (Sigma–Aldrich, St. Louis, MO, USA) was used as the standard with concentrations ranging from 0.00 to 80.00 ppm. Results were expressed as in milligram gallic acid (GAE) equivalents per 100 g of fresh weight (mg GAE/100 g). (Brune et al., 1991 ; Kongkachuichai et al., 2015 ) Antioxidant activity Antioxidant activity was analyzed by two methods, oxygen radical absorbance capacity (ORAC) assay and ferric reducing antioxidant power (FRAP) assay. The FRAP solution was freshly prepared before analzing a sample. The solution consists of 0.3 M sodium acetate buffer solution (pH 3.6), 10 mM 2,4,6-tripyridyl-s-triazine (TPTZ, Sigma–Aldrich, St. Louis, MO, USA) in 40 mM of concentrated HCl and 20 mM FeCl 3 (Sigma–Aldrich, St. Louis, MO, USA) at the ratio 10:1:1 (v/v/v). The sample was added to the FRAP solution and incubated at 37°C for 4 min. The absorbance of each sample was measured at 593 nm using a spectrophotometer (UV-1601 Shimadzu, Kyoto, Japan). The standard curve of Trolox (6-hydroxy-2,5,7,8 tetramethychroman-2-carboxylic acid, Sigma–Aldrich, St. Louis, MO, USA) was used to calculate the FRAP values of the samples. The results were expressed as micromole Trolox equivalents per 100 g of fresh weight (µmol TE/100 g). (Benzie & Strain, 1996 ; Kongkachuichai et al., 2015 ). The ORAC assay was performed using a spectrofluorometer (PerkinElmer LS 55 luminescence spectrofluorometer, Perkin Elmer, Waltham, MA, USA) with excitation and emission wavelengths set to 493 nm and 515 nm, respectively. 6.25 to 100 µM trolox (6-hydroxy-2,5,7,8-tetramethychroman-2-carboxylic acid) was used as the standard. Briefly, a 500 µl sample, a 3.0 ml fluorescein solution (8.16 × 10 − 2 µM), and 500 µl of AAPH (153 mM) were mixed in each tube. All dilutions were prepared using a 75 mM potassium phosphate buffer solution at pH 7.2. The ORAC value was calculated from a linear regression equation of net area under the curve (AUC) of the standard Trolox concentrations. Results were expressed as micromole Trolox (TE) equivalents per 100 g fresh weight (µmol TE/100 g fresh weight) (Huang et al., 2002 ; Kongkachuichai et al., 2015 ). Statistical analysis Statistical analysis was performed using Statistical Package for the Social Science (SPSS) program 18.0 (IBM Software, Chicago, II, USA). The significant differences are represented by P < 0.05. An independent t-test was used to compare the results for the quantitative data (nutritional compositions, antioxidant contents, environmental impact, and carbon footprints) between the two groups, kales in PFAL and N-CF systems, to determine whether there is a statistically significant difference. One-way analysis of variance (ANOVA) was used for the quantitative data (nutritional compositions, antioxidant contents, environmental impact, and carbon footprints) in the 4 sets of kale samples, kale grown in PFAL and three samples from N-CF systems with repeated observations at 3, 6, and 12 months. Carbon footprint calculation Goal and scope definition This study analyzed the carbon footprints of kale production in PFAL and N-CF production systems, whereby the seeding process started in January 2022. PFAL kale production occurred from February 2022 to May 2022 (3 months), and N-CF kale production occurred from February 2022 to January 2023 (12 months). The cultivation practices commonly applied to the kale fields in this study differed slightly between the two systems: PFAL: Kale was planted for around 3 months and harvesting occurred 45–55 days after planting. Subsequently, kales were collected around 3 times before being removed from the bucket. N-CF: Kale was typically planted for around 12 months, and harvesting took place 45–55 days after planting. Subsequently, kales were collected weekly until 12 months after planting, after which they were plowed away from the field. The production systems were analyzed from the gate-to-gate perspective. The functional unit (FU) in this study was a mass-balanced FU defined as 1 kg of edible kale during the planting cycle of PFAL and N-CF. Thus, the life cycle inventory included the material and energy requirements of agricultural activities, as well as the transportation of farm inputs. Figure 1 shows the system boundary as they were underpinned by different farm processes, except for seeding process which was similar in both harvest systems. (Added Fig. 1) Life cycle inventory The inventory analysis quantified the inputs and outputs of the agricultural systems. Inputs and outputs data for both farming systems, including water, fertilisers and manure, pesticides, on-farm electricity use, transportation, and other factors related to kale production, were collected from the experimental farm through questionnaires. All inputs and outputs data were collected through follow-up questionnaires over different periods: 3 months for the PFAL farm and 12 months for the N-CF farm. The agricultural compositions of kale production studied in this work are shown in Table 1. (Added Table 1) Description of sites: The study site of PFAL was located at the Agrowlab plant factory in Khlong Kum, Bueng Kum District, Bangkok, Thailand (Fig. 2). The study site of N-CF was located on an experimental non-chemical farm in Khlong Song, Khlong Luang District, Pathum Thani province, Thailand (Fig. 2). Data are collected from a 3 m 2 kale planting area. Although these two experimental sites were in different provinces, they have similar environmental conditions, including temperature and humidity. In this study, the following assumptions are summarized: Energy consumption and CO 2 emissions from manual labour are not included in this analysis. In FPAL, only direct N 2 O emission released into the atmosphere was considered, as the mixed-chemical fertiliser was not applied to the soil. Limitation of this study, N-CF was susceptible to flooding events due to the nature of open-field cultivation, which can damage or destroy the kale crop and impact production yields. Additionally, insect infestations pose a significant challenge in N-CF systems, potentially leading to crop damage and yield losses if not adequately managed, which may impact the overall carbon footprint analysis of the N-CF system. (Added Fig. 2) Calculation of Carbon Footprints from PFAL and N-CF The carbon footprints of kale grown in PFAL and N-CF systems were calculated following the Intergovernmental Panel on Climate Change (IPCC) guidelines (Pörtner et al., 2019 ). Data pertaining to both systems were collected and validated for accuracy and reliability. Emissions from various sources, including energy consumption, transportation, production processes, and waste management, were calculated in accordance with the IPCC guidelines and the Thai National Life Cycle Inventory (LCI) Database (Thailand Greenhouse Gas Management Organization (Public Organization), 2022). The Carbon footprint of kale farming systems was calculated using Eq. (1). Carbon Footprint (kgCO 2 e) = EF ​× Q ​ (1) ​ where EF is the emission factor for the activity (kgCO 2 e per unit) (Table 2) and Q is the quantity of the raw materials, chemicals, and other emissions (in units). (Added Table 2) Application of manure and synthetic fertiliser results in direct and indirect emissions of N 2 O. N 2 O emissions from N-CF came from nitrogen in non-chemical fertilisers applied in the field, including direct N 2 O emissions released into the atmosphere, indirect N 2 O emissions from atmospheric deposition of volatilized N, and indirect N 2 O emissions from nitrogen leaching and runoff. N 2 O emissions from the use of nitrogen fertiliser are represented by Eq. (2). N 2 O Emissions (kgN 2 O) = N 2 O direct -N inputs +N 2 O direct -N os +N 2 O indirect−volatilize +N 2 O indirect−leaching (2) where N 2 O direct -N inputs represent direct N 2 O emissions released into the atmosphere from organic N additions to soils, N 2 O direct -N os represent direct N 2 O emissions released from managed areas annually, N 2 O indirect − volatilize represent indirect N 2 O emissions from atmospheric deposition of volatilized N, and N 2 O indirect − leaching represent indirect N 2 O emissions form nitrogen leaching and runoff. (Eggleston et al., 2006 ) Results Nutritional values of kale The outcomes of the proximate analysis and antioxidant content for the kale samples were presented in Table 3 and Table 4. Total fat, protein and carbohydrate contents were similar to previous research conducted by Sikora and Bodziarczyk (Plassmann & Edwards-Jones, 2010 ). The study suggested that the fat content in kale leaves reported by different authors ranged between 0.26–0.74%, protein content between 3.28–11.67%, carbohydrate content between 2.36%-10.14%, ash content between 1.33–2.11%, and dietary fibre between 1.94–8.39%. However, the moisture content of the kale samples in this study was notably higher compared to the reviewed literature, which was 81.38–82.92%. (Added Tables 3 and 4) The influence of different farming systems on the levels of bioactive compounds in kale is shown in Table 3. The results showed that the levels of polyphenol, ORAC and FRAB were statistically lower in the 3 months kale harvested from PFAL compared to 3 months N-CF kale. Further analysis revealed significant differences in the levels of polyphenols, ORAC, and FRAB among the N-CF kale samples harvested at different periods (Table 4). The reactivity of the antioxidants studied was generally lower in the FRAP assay than in the ORAC assay. Among the N-CF kale samples, those harvested at 6 months showed the highest values of polyphenol, ORAC and FRAB. Conversely, the values were significantly lower in N-CF kale harvested at 3 months and 12 months. Carbon footprints The carbon footprints of the two farming systems are presented in Table 5, and divided into 4 phases: seeding, transportation, preparation, and plantation. Carbon footprints in a 3-month PFAL were higher than in a 3-month N-CF. The carbon footprint of PFAL was 168.61 kg CO 2 -eq/kg. The carbon footprint values of 3, 6, and 12 months of N-CF kale were 14.75 kg CO 2 -eq/kg, 4.51 kg CO 2 -eq/kg, and 1.96 kg CO 2 -eq/kg, respectively (Table 5). In N-CF, carbon footprints were decreased due to the period of plantation. (Added Table 5) Figure 3 shows the contributors in relative percentage from the different farming practices. The electricity part in FPAL including air conditioning, lighting, fan operation, etc. accounts for 99.06% of total emissions. Similarly, other studies have reported that in vertical farming (VF), a type of indoor farming system, electricity contributes over 90% of the total carbon footprint impacts. (Sandison et al., 2023 ; Sørensen et al., 2021 ). N-CF systems presented lower carbon footprints as expected since air-conditioning and lighting were not applied. In N-CF systems, electricity along with water usage and waste emissions, including waste management, gasoline combustion and N 2 O emissions, were the major contributors to carbon footprints. They contributed 47.87–60.15%, 14.84–25.47% and 12.26–16.32%, respectively, covering 87.25–87.67% of the total carbon footprints of the N-CF system. Other contributors include trays, fertilizer packages, pipes and CO 2 , which contribute 6.59–9.10%, fertilisers and pesticides 1.27–4.19%, and transportation 1.96–2.38%. (Added Fig. 3) Discussion Nutritional aspect There were two main factors to be considered when studying antioxidant values and other factors. One is biotic factors, such as species, cultivar, and orthogenesis. Another is abiotic factors, such as climate, soil, environmental and agrotechnical conditions. (Biesiada & Tomczak, 2012 ) The impact of environmental factors such as temperature fluctuations and light intensity have a significant influence on the nutritional composition and antioxidant levels in plants. Recent studies have highlighted how these factors can influence the stress response and subsequent antioxidant production in kale, particularly in different cultivation systems. Environmental stress, such as temperature fluctuations and varying light intensity were possible reasons that affected the levels of polyphenol, ORAC and FRAB in PFAL and N-CF kale. Temperature fluctuation, the change of temperature during day and night, can lead to irreversible damage in plant cells and this is a stress condition response. On the other hand, light intensity, the key factor in plant photosynthesis and metabolites, significantly impacts plant growth and chemical composition. Previous studies by Islam et al. ( 2021 ) and Kacperska ( 2018 ) have demonstrated that kale exposed to these environmental stresses exhibits higher levels of antioxidants compared to kale grown under controlled conditions. Specifically, N-CF kale cultivated in an environment exposed to direct sunlight during the day and fluctuating temperatures, experienced more stress than PFAL kale, leading to increased production of bioactive chemicals and antioxidant content (Islam et al., 2021 ; Kacperska, 2018 ). Furthermore, the duration of exposure to environmental stressors influenced the nutritional composition and antioxidant levels of kale over time. These factors caused variations in the nutritional composition and antioxidant levels of N-CF kale across different harvest intervals (3 months, 6 months, and 12 months). These variations were attributed to seasonal changes in temperature and light exposure. For example, days are shorter in winter compared to summer, highlighting the dynamic nature of environmental influences on kale quality (Paolillo et al., 2023 ). Additionally, the age of the kale plant plays a crucial role in determining its nutritional composition and antioxidant levels. The nutritional composition and antioxidant properties of fruits and vegetables, including kale, can significantly change as the plant matures, often peaking at specific growth stages before declining (Jaiswal, 2020 ). This aligns with recent research, which suggested that younger kale plants tend to exhibit higher levels of certain antioxidants and nutrients compared to more mature plants. This is likely due to the plant's response to growth stages and environmental stressors, which vary throughout its life cycle (Islam et al., 2021 ). Carbon footprints The PFAL system relies on artificial lighting, environment control, and other electrical tools, electricity is the most significant source of carbon emissions, accounting for 99.06% of total emissions. Despite the high energy consumption, PFAL systems offer several advantages, including high productivity, consistent production quality, and efficient use of available resources due to its regulated environment, which uses less pesticide and water; up to 90% less than traditional methods (Kozai, 2013 ). Although PFAL systems are highly efficient in resource use, it has a high carbon footprint that needs to be reduced. Switching to renewable energy sources such as solar or wind power can significantly reduce greenhouse gas emissions associated with electricity consumption (Despommier, 2010 ). N-CF systems had a more balanced approach, emitting moderate amounts of carbon emissions, primarily from electricity used (47.87–60.15%). However, N-CF production in this study showed more electricity components than usual due to the air-conditioning required during the seeding process. N-CF often utilises less synthetic/chemical inputs compared to conventional farming, lowering emissions related to fertiliser production and use. According to a previous study, in conventional farming, the production and application of fertilisers is the largest contributor, responsible for 51% of total emissions. Transportation contributes 21% of the total emissions, associated with transporting produce to markets. Irrigation accounts for 19% of the emissions due to water pumping and distribution (Yuttitham, 2019 ). Food security and sustainability Sustainable food production should minimise pollution, lessen the loss of natural resources, and maintain the environment. Consequently, preserving the resilience and vitality of the ecosystem promotes long-term food security. (Foley et al., 2011 ) In our work, kale in the field were grown in the soil, while another was germinated and developed hydroponically in buckets in the growth experiment room. Over the same duration, PFAL kale not only had higher yield and carbon footprints than N-CF kale but also had lower antioxidant values (Table 1,3, 5). Some studies have shown that hydroponically grown lettuce and strawberries contain higher concentrations of bioactive components (ascorbic acid and α-tocopherol) than soil-grown types. The research emphasises the contributions of light and nutrient solutions in enhancing a plant's bioactive compounds. Expanding farm setups and focusing on comparative efficiency should provide greater insight into what to anticipate and emphasise excellent practices from a sustainability perspective. (Ashenafi et al., 2022 ). Conclusion In summary, this PFAL showed potential for sustainable food production with higher yields, although N-CF has higher nutritional value and lower carbon footprints. With continuous experiments in the sector, there is a trade-off between carbon footprint and electricity consumption under the possible future innovation. Furthermore, environmental factors (such as lighting, air temperature, and mineral content) can be greatly optimised for high output and nutritional quality, which is advantageous for agricultural operations as well as customers. Future research ought to examine the potential of certain environmental factors, such as light spectrum or intensity, to improve the quality of nutrition, including food safety of the PFAL system. Declarations Authorship KS was a principal investigator of the project. KS, WH, US, and KSU conceptualized the research design. WH and KS collected the data. WH, KS and US managed the sample analysis and analysed the data. KS and WH drafted the manuscript. All authors were involved in editing the manuscript. Acknowledgement This project is funded by the Office of National Higher Education Science Research and Innovation Policy Council by the “Program Management Unit for National Competitiveness Enhancement (PMU-C)”, Contract number C10F640135. Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article. Data availability The data that support the findings of this study are available from the corresponding author upon reasonable request. ORCID Kitti Sranacharoenpong. https://orcid.org/0000-0002-1692-9645 Wannaporn Hatongkham. https://orcid.org/0009-0000-2849-2682 References Alexandratos N, Bruinsma J (2012) World agriculture towards 2030/2050: the 2012 revision Ashenafi EL, Nyman MC, Holley JM, Mattson NS, Rangarajan A (2022) Phenotypic plasticity and nutritional quality of three kale cultivars (Brassica oleracea L. var. acephala) under field, greenhouse, and growth chamber environments. Environ Exp Bot 199:104895. https://doi.org/https://doi.org/10.1016/j.envexpbot.2022.104895 Benzie IFF, Strain JJ (1996) The Ferric Reducing Ability of Plasma (FRAP) as a Measure of Antioxidant Power: The FRAP Assay. Anal Biochem 239(1):70–76. https://doi.org/https://doi.org/10.1006/abio.1996.0292 Biesiada A, Tomczak A (2012) Biotic and Abiotic Factors Affecting the Content of the Chosen Antioxidant Compounds in Vegetables. Vegetable Crops Res Bull 76:55–78. https://doi.org/10.2478/v10032-012-0004-3 Brune M, Hallberg L, SKÅNBERG AB (1991) Determination of iron-binding phenolic groups in foods. J Food Sci 56(1):128–131 Butryee C (2020) Vegetables and Fruits Consumption at Least 400 g Per Day for Health: Evidence-based Approach. J Nutr Association Thail 55(1):53–65. https://he01.tci-thaijo.org/index.php/JNAT/article/view/235378 Despommier D (2010) The vertical farm: feeding the world in the 21st century. Macmillan Eggleston H, Buendia L, Miwa K, Ngara T, Tanabe K (2006) 2006 IPCC guidelines for national greenhouse gas inventories Foley JA, Ramankutty N, Brauman KA, Cassidy ES, Gerber JS, Johnston M, Mueller ND, O’Connell C, Ray DK, West PC (2011) Solutions for a cultivated planet. Nature 478(7369):337–342 George W, Latimer A, o. OACI (2019) Official methods of analysis of AOAC Internationa, 21st edn. ed.). AOAC Internationa Gregory PJ, Ingram JS, Brklacich M (2005) Climate change and food security. Philos Trans R Soc Lond B Biol Sci 360(1463):2139–2148. https://doi.org/10.1098/rstb.2005.1745 Huang D, Ou B, Hampsch-Woodill M, Flanagan JA, Prior RL (2002) High-Throughput Assay of Oxygen Radical Absorbance Capacity (ORAC) Using a Multichannel Liquid Handling System Coupled with a Microplate Fluorescence Reader in 96-Well Format. J Agric Food Chem 50(16):4437–4444. https://doi.org/10.1021/jf0201529 Islam MZ, Park BJ, Lee YT (2021) Influence of Temperature Conditions during Growth on Bioactive Compounds and Antioxidant Potential of Wheat and Barley Grasses. Foods , 10 (11), 2742. https://www.mdpi.com/2304-8158/10/11/2742 Jaiswal AK (2020) Nutritional composition and antioxidant properties of fruits and vegetables. Academic Kacperska A (2018) Metabolic consequences of low temperature stress in chilling-insensitive plants. Low temperature stress physiology in crops. Crc, pp 27–40 Kongkachuichai R, Charoensiri R, Yakoh K, Kringkasemsee A, Insung P (2015) Nutrients value and antioxidant content of indigenous vegetables from Southern Thailand. Food Chem 173:838–846. https://doi.org/https://doi.org/10.1016/j.foodchem.2014.10.123 Kozai T (2013) Resource use efficiency of closed plant production system with artificial light: concept, estimation and application to plant factory. Proc Jpn Acad Ser B Phys Biol Sci 89(10):447–461. https://doi.org/10.2183/pjab.89.447 Lee MJ, Son KH, Oh MM (2016) Increase in biomass and bioactive compounds in lettuce under various ratios of red to far-red LED light supplemented with blue LED light. Hortic Environ Biotechnol 57(2):139–147 Milestad R, Carlsson-Kanyama A, Schaffer C (2020) The Högdalen urban farm: A real case assessment of sustainability attributes. Food Secur 12(6):1461–1475 Orsini F, Pennisi G, Zulfiqar F, Gianquinto G (2020) Sustainable use of resources in plant factories with artificial lighting (PFALs). Eur J Hortic Sci 85:297–309. https://doi.org/10.17660/eJHS.2020/85.5.1 Paolillo I, Costanzo G, Delicato A, Villano F, Arena C, Calabrò V (2023) Light Quality Potentiates the Antioxidant Properties of Brassica rapa Microgreen Extracts against Oxidative Stress and DNA Damage in Human Cells. Antioxidants , 12 (10), 1895. https://www.mdpi.com/2076-3921/12/10/1895 Plassmann K, Edwards-Jones G (2010) 15 - Carbon footprinting and carbon labelling of food products. In U. Sonesson, J. Berlin, & F. Ziegler (Eds.), Environmental Assessment and Management in the Food Industry (pp. 272–296). Woodhead Publishing. https://doi.org/https://doi.org/10.1533/9780857090225.3.272 Pörtner H-O, Roberts DC, Masson-Delmotte V, Zhai P, Tignor M, Poloczanska E, Mintenbeck K, Nicolai M, Okem A, Petzold J (2019) IPCC special report on the ocean and cryosphere in a changing climate. IPCC Intergovernmental Panel Clim Change: Geneva Switz, 1 (3) Samec D, Urlić B, Salopek-Sondi B (2018) Kale (Brassica oleracea var. acephala) as a superfood: Review of the scientific evidence behind the statement. Crit Rev Food Sci Nutr 59:1–37. https://doi.org/10.1080/10408398.2018.1454400 Sandison F, Yeluripati J, Stewart D (2023) Does green vertical farming offer a sustainable alternative to conventional methods of production? A case study from Scotland. Food Energy Secur 12(2):e438. https://doi.org/https://doi.org/10.1002/fes3.438 Satheesh N, Workneh Fanta S (2020) Kale: Review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products. Cogent Food Agric 6(1):1811048. https://doi.org/10.1080/23311932.2020.1811048 Sikora E, Bodziarczyk I (2012) Composition and antioxidant activity of kale (Brassica oleracea L. var. acephala) raw and cooked. Acta Sci Pol Technol Aliment 11(3):239–248. https://www.ncbi.nlm.nih.gov/pubmed/22744944 Sørensen MG, Olsen SI, Colley T (2021) Comparing the Environmental Sustainability of Vertical and Conventional Wheat Farming Using Life Cycle Assessment. In Preprints : Preprints Thailand Greenhouse Gas Management Organization (Public Organization), T (2022) Emission Factor for Carbon Footprint of Organization http://thaicarbonlabel.tgo.or.th/admin/uploadfiles/emission/ts_578cd2cb78.pdf Yuttitham M (2019) Comparison of Carbon Footprint of Organic and Conventional Farming of Chinese Kale. Environ Nat Resour J 17:78–92. https://doi.org/10.32526/ennrj.17.1.2019.08 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4894455","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":338673863,"identity":"32b3eb66-80da-4cbd-9450-b7ad044b5b4b","order_by":0,"name":"Wannaporn Hatongkham","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wannaporn","middleName":"","lastName":"Hatongkham","suffix":""},{"id":338673864,"identity":"8dfa2ade-f73c-4754-9b01-57ceb07b5abb","order_by":1,"name":"Kitti Sranacharoenpong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYBACCSidwA8mC0jRItkAIg1I0WJwAEQRo0Wy/+zDzwU1dnnG51cnfnhgwCDPL3YAvxZpiXRj6RnHkovNbrzdLAF0mOHM2Qn4tchJsDFI87AdSNx24+wGkJYEg9uEtPAfY/7N8+9A4uYZZzf/IEqLNEMamzRv24HEDfy924izRXJGGps1b19y4owbvNssEgwkCPtF4vwx5ts83+wS+/vPbr75o8JGnl+agBYkzWCVEgRUoQD+A6SoHgWjYBSMgpEEAB8xQa6UENMsAAAAAElFTkSuQmCC","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Kitti","middleName":"","lastName":"Sranacharoenpong","suffix":""},{"id":338673865,"identity":"2c2c1093-2191-4e7e-aad0-0345ce050397","order_by":2,"name":"Unchalee Suwanmanee","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Unchalee","middleName":"","lastName":"Suwanmanee","suffix":""},{"id":338673866,"identity":"de2803e0-db60-4158-8c88-d7c169661dca","order_by":3,"name":"Kanyaratt Supaibulwatana","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Kanyaratt","middleName":"","lastName":"Supaibulwatana","suffix":""}],"badges":[],"createdAt":"2024-08-11 08:57:52","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-4894455/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4894455/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":62351806,"identity":"397a7f2d-ba44-45da-b00d-2407118fba9d","added_by":"auto","created_at":"2024-08-13 08:20:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":93676,"visible":true,"origin":"","legend":"\u003cp\u003eSystem boundaries and flow chart of the (a) PFAL and (b) N-CF kale life cycle\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4894455/v1/5e10086ffa49b01ce0cf2cc6.png"},{"id":62352525,"identity":"ad90038a-dc54-4805-a4d3-c6da9e413b63","added_by":"auto","created_at":"2024-08-13 08:28:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":236631,"visible":true,"origin":"","legend":"\u003cp\u003eThe study sites located in Bangkok and Pathum Thani, Thailand\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4894455/v1/647abfc8941a8b62b43cc394.png"},{"id":62352526,"identity":"a015dc51-5e11-455d-9270-408a1a1572de","added_by":"auto","created_at":"2024-08-13 08:28:15","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":38210,"visible":true,"origin":"","legend":"\u003cp\u003eContribution (%) of inputs to carbon footprints (kgCO\u003csub\u003e2\u003c/sub\u003e-eq) of each farming system; PFAL, N-CF (3, 6, 12 months)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4894455/v1/b3a221bf37c842138c47d31d.png"},{"id":62352527,"identity":"3fe8fb99-50db-4809-abef-dc14208b7a82","added_by":"auto","created_at":"2024-08-13 08:28:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":722741,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4894455/v1/217c5dda-b763-4136-b2c5-5eb7efebdedf.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eComparing soilless and non-chemical farming food production systems: Nutritional and environmental aspects for food security and sustainability\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eClimate change has become a global concern in recent decades. It causes ozone depletion, impacts agriculture yield, water supply, and transportation, and create several other problems. Climate change may impact food systems in various aspects, increasing crop disease, lowering nutritional quality and reducing crop yield e.g., changes in rainfall patterns can cause drought or flood, or warmer or cooler temperatures can lead to changes in the length of the growing season (Gregory et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). The world populations are predicted to get larger by over a third or 2.3\u0026nbsp;billion people in 2050. These trends indicate that food market demand will continue to rise. According to studies, feeding the world's population in 2050 would require a 50 percent increase in overall grain production (Alexandratos \u0026amp; Bruinsma, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs the world faces the challenge of feeding a growing global population while preserving environmental integrity, two contrasting agricultural systems have gained prominence: Plant Factory with Artificial Lighting (PFAL) and Non-chemical farming (N-CF). PFAL is a soilless close production system characterized by a controlled environment, hydroponics, and artificial lighting, making it a high-tech approach to crop cultivation. Meanwhile, N-CF is a traditional agriculture.\u003c/p\u003e \u003cp\u003eThe advancement of PFAL technology could be considered an optional intervention for addressing these concerns. It is claimed that PFAL could lower greenhouse gas emissions by the potential reductions of air pollution, water use, fertilisers, and pesticides. A few reports suggest that PFAL can reduce greenhouse gas emissions (Orsini et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). There is a report indicating that an improved vertical farm, a type of indoor farm, could emit 0.16 to 0.33 kg of CO\u003csub\u003e2\u003c/sub\u003e equivalents per kg of lettuce (Milestad et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Apart from eco-friendly benefits, PFAL could be related to the quality of plants (Butryee, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). For example, light is a key factor in phytochemical synthesis, growth, development, and nutritional composition in plants. Myung Jin Lee (2016) found that red, blue, and far-red LEDs at ratios of 0.7 and 1.2 significantly increased total phenolic levels, antioxidant activity, chlorogenic acid contents, and caffeic acid contents in intervention plant groups compared to the control. It was presumed that the appropriate quality and intensity of light can increase the quantity and quality of phytochemicals in plants (Lee et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). N-CF is an alternative agriculture system that attempts to deliver sustainable and safe foods. It also protects resources and the environment by avoiding synthetic pesticides and using the on-farm resources in the most efficient ways.\u003c/p\u003e \u003cp\u003eKale (\u003cem\u003eBrassica oleracea\u003c/em\u003e L.) is a highly nutritious leafy green vegetable known for its rich content of vitamins, minerals, and antioxidants. It contains high levels of vitamins A, C, and K, as well as calcium, potassium, and fibre. These nutrients promote various health benefits, including improved vision, immune function, bone health, and cardiovascular health (Satheesh \u0026amp; Workneh Fanta, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The consumption of kale has been associated with reduced risks of chronic diseases such as heart disease, diabetes, and cancer due to its high levels of antioxidants and anti-inflammatory compounds (Sikora \u0026amp; Bodziarczyk, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Additionally, kale has gained significant popularity in the health and wellness market, leading to increased demand and market value. It is commonly used in salads, smoothies, and as a cooked vegetable, making it an adjustable ingredient in many diets. The economic value of kale is also crucial, as it has become a profitable crop for farmers, especially those focusing on organic and health food markets (Samec et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eStudying the environmental impact and carbon footprint related to the nutritive values of plants should be considered as a benefit for addressing the food shortage problem. Thus, the purpose of this study is to compare the nutritive values in terms of nutritional compositions and antioxidant contents, and carbon footprints of Kale (\u003cem\u003eBrassica oleracea\u003c/em\u003e L.) between PFAL and N-CF systems.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePlanting materials, sample collection and preparation\u003c/h2\u003e \u003cp\u003ePFAL kale trials were conducted at the Agrowlab plant factory in Bangkok, Thailand. The samples were collected 3 months after planting. A total of 32 buckets of kale were separated into 3 parts; 12:8:12, three varieties of PFAL kale were randomly collected from each part.\u003c/p\u003e \u003cp\u003eN-CF kale trials were conducted at a farm in Pathum Thani province, Thailand. There were 180 kale plants in the experimental plot. The N-CF kale samples were collected at 3, 6, and 12 months after planting. The kale plot was divided into three parts; three varieties of N-CF kale were randomly collected from each part of the plot.\u003c/p\u003e \u003cp\u003eAn identical quantity of kale seeds was utilised in each agricultural system. In addition, leaf samples for the assessment of nutrition were collected throughout the same growth phases. The sets of kale samples were washed individually with water to remove dirt and contaminants. After washing, the edible part of each set will be cut into small pieces and homogenized. The homogenized samples are going to be divided into two portions for nutritional compositions and antioxidant contents analysis and stored at \u0026minus;\u0026thinsp;20\u0026deg;C until analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eProximate Analysis\u003c/h2\u003e \u003cp\u003eThe proximate analysis of kale samples followed standardized methods according to the AOAC (George W. Latimer, 2019). The Kjeldahl method (AOAC 981.10) was used to determine protein content, and fat content following the Soxhlet method (AOAC 922.06). Moisture content was assessed by drying the samples at 100\u0026deg;C in a hot air oven, according to AOAC 925.45 A. Ash content was determined through incineration at 550\u0026deg;C in a muffle furnace (AOAC 920.153). Total dietary fibre analysis was determined by Enzymatic-Gravimetric Method (AOAC 985.29). The total carbohydrate content of the dry mass was calculated using the following formula:\u003c/p\u003e \u003cp\u003eTotal carbohydrates (%)\u0026thinsp;=\u0026thinsp;100 \u0026minus; (protein\u0026thinsp;+\u0026thinsp;total fat\u0026thinsp;+\u0026thinsp;moisture\u0026thinsp;+\u0026thinsp;ash\u0026thinsp;+\u0026thinsp;total dietary fibre)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eTotal Polyphenol Content\u003c/h2\u003e \u003cp\u003eTotal phenolic concentration (TPC) was determined according to the method described by Kongkachuichai et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), with slight modifications based on Brune et al. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1991\u003c/span\u003e). Two grams of samples were extracted with 20 ml of 50% dimethylformamide (Sigma\u0026ndash;Aldrich, St. Louis, MO, USA) in 0.1 M acetate buffer for 16 h by constant shaking at room temperature. After extraction, samples were centrifuged (20 min, 25\u0026deg;C, 3000 rpm) and then supernatants were collected. The supernatants were diluted to 25 \u0026micro;l with water. Then the samples were added to a 96-well plate, followed by 125 \u0026micro;l of 10% Folin\u0026ndash;Ciocalteau reagent (Merck, Darmstadt, Germany) and 100 \u0026micro;l 0.5 M sodium hydroxide to each well and mixed. Absorbance was measured at 750nm using an automated microplate reader (SunriseTM Tecan, Victory, Australia) after standing for 15 min at 25\u0026deg;C. Gallic acid (Sigma\u0026ndash;Aldrich, St. Louis, MO, USA) was used as the standard with concentrations ranging from 0.00 to 80.00 ppm. Results were expressed as in milligram gallic acid (GAE) equivalents per 100 g of fresh weight (mg GAE/100 g). (Brune et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Kongkachuichai et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eAntioxidant activity\u003c/h2\u003e \u003cp\u003eAntioxidant activity was analyzed by two methods, oxygen radical absorbance capacity (ORAC) assay and ferric reducing antioxidant power (FRAP) assay.\u003c/p\u003e \u003cp\u003eThe FRAP solution was freshly prepared before analzing a sample. The solution consists of 0.3 M sodium acetate buffer solution (pH 3.6), 10 mM 2,4,6-tripyridyl-s-triazine (TPTZ, Sigma\u0026ndash;Aldrich, St. Louis, MO, USA) in 40 mM of concentrated HCl and 20 mM FeCl\u003csub\u003e3\u003c/sub\u003e (Sigma\u0026ndash;Aldrich, St. Louis, MO, USA) at the ratio 10:1:1 (v/v/v). The sample was added to the FRAP solution and incubated at 37\u0026deg;C for 4 min. The absorbance of each sample was measured at 593 nm using a spectrophotometer (UV-1601 Shimadzu, Kyoto, Japan). The standard curve of Trolox (6-hydroxy-2,5,7,8 tetramethychroman-2-carboxylic acid, Sigma\u0026ndash;Aldrich, St. Louis, MO, USA) was used to calculate the FRAP values of the samples. The results were expressed as micromole Trolox equivalents per 100 g of fresh weight (\u0026micro;mol TE/100 g). (Benzie \u0026amp; Strain, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Kongkachuichai et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe ORAC assay was performed using a spectrofluorometer (PerkinElmer LS 55 luminescence spectrofluorometer, Perkin Elmer, Waltham, MA, USA) with excitation and emission wavelengths set to 493 nm and 515 nm, respectively. 6.25 to 100 \u0026micro;M trolox (6-hydroxy-2,5,7,8-tetramethychroman-2-carboxylic acid) was used as the standard. Briefly, a 500 \u0026micro;l sample, a 3.0 ml fluorescein solution (8.16 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e \u0026micro;M), and 500 \u0026micro;l of AAPH (153 mM) were mixed in each tube. All dilutions were prepared using a 75 mM potassium phosphate buffer solution at pH 7.2. The ORAC value was calculated from a linear regression equation of net area under the curve (AUC) of the standard Trolox concentrations. Results were expressed as micromole Trolox (TE) equivalents per 100 g fresh weight (\u0026micro;mol TE/100 g fresh weight) (Huang et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Kongkachuichai et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using Statistical Package for the Social Science (SPSS) program 18.0 (IBM Software, Chicago, II, USA). The significant differences are represented by P\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003cp\u003eAn independent t-test was used to compare the results for the quantitative data (nutritional compositions, antioxidant contents, environmental impact, and carbon footprints) between the two groups, kales in PFAL and N-CF systems, to determine whether there is a statistically significant difference.\u003c/p\u003e \u003cp\u003eOne-way analysis of variance (ANOVA) was used for the quantitative data (nutritional compositions, antioxidant contents, environmental impact, and carbon footprints) in the 4 sets of kale samples, kale grown in PFAL and three samples from N-CF systems with repeated observations at 3, 6, and 12 months.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eCarbon footprint calculation\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003eGoal and scope definition\u003c/h2\u003e \u003cp\u003eThis study analyzed the carbon footprints of kale production in PFAL and N-CF production systems, whereby the seeding process started in January 2022. PFAL kale production occurred from February 2022 to May 2022 (3 months), and N-CF kale production occurred from February 2022 to January 2023 (12 months). The cultivation practices commonly applied to the kale fields in this study differed slightly between the two systems:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003ePFAL: Kale was planted for around 3 months and harvesting occurred 45\u0026ndash;55 days after planting. Subsequently, kales were collected around 3 times before being removed from the bucket.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eN-CF: Kale was typically planted for around 12 months, and harvesting took place 45\u0026ndash;55 days after planting. Subsequently, kales were collected weekly until 12 months after planting, after which they were plowed away from the field.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eThe production systems were analyzed from the gate-to-gate perspective. The functional unit (FU) in this study was a mass-balanced FU defined as 1 kg of edible kale during the planting cycle of PFAL and N-CF. Thus, the life cycle inventory included the material and energy requirements of agricultural activities, as well as the transportation of farm inputs. Figure\u0026nbsp;1 shows the system boundary as they were underpinned by different farm processes, except for seeding process which was similar in both harvest systems.\u003c/p\u003e \u003cp\u003e(Added Fig.\u0026nbsp;1)\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eLife cycle inventory\u003c/h2\u003e \u003cp\u003eThe inventory analysis quantified the inputs and outputs of the agricultural systems. Inputs and outputs data for both farming systems, including water, fertilisers and manure, pesticides, on-farm electricity use, transportation, and other factors related to kale production, were collected from the experimental farm through questionnaires. All inputs and outputs data were collected through follow-up questionnaires over different periods: 3 months for the PFAL farm and 12 months for the N-CF farm. The agricultural compositions of kale production studied in this work are shown in Table\u0026nbsp;1.\u003c/p\u003e \u003cp\u003e(Added Table\u0026nbsp;1)\u003c/p\u003e \u003cp\u003eDescription of sites: The study site of PFAL was located at the Agrowlab plant factory in Khlong Kum, Bueng Kum District, Bangkok, Thailand (Fig.\u0026nbsp;2). The study site of N-CF was located on an experimental non-chemical farm in Khlong Song, Khlong Luang District, Pathum Thani province, Thailand (Fig.\u0026nbsp;2). Data are collected from a 3 m\u003csup\u003e2\u003c/sup\u003e kale planting area. Although these two experimental sites were in different provinces, they have similar environmental conditions, including temperature and humidity. In this study, the following assumptions are summarized:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eEnergy consumption and CO\u003csub\u003e2\u003c/sub\u003e emissions from manual labour are not included in this analysis.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIn FPAL, only direct N\u003csub\u003e2\u003c/sub\u003eO emission released into the atmosphere was considered, as the mixed-chemical fertiliser was not applied to the soil.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eLimitation of this study, N-CF was susceptible to flooding events due to the nature of open-field cultivation, which can damage or destroy the kale crop and impact production yields. Additionally, insect infestations pose a significant challenge in N-CF systems, potentially leading to crop damage and yield losses if not adequately managed, which may impact the overall carbon footprint analysis of the N-CF system.\u003c/p\u003e \u003cp\u003e(Added Fig.\u0026nbsp;2)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eCalculation of Carbon Footprints from PFAL and N-CF\u003c/h2\u003e \u003cp\u003eThe carbon footprints of kale grown in PFAL and N-CF systems were calculated following the Intergovernmental Panel on Climate Change (IPCC) guidelines (P\u0026ouml;rtner et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Data pertaining to both systems were collected and validated for accuracy and reliability. Emissions from various sources, including energy consumption, transportation, production processes, and waste management, were calculated in accordance with the IPCC guidelines and the Thai National Life Cycle Inventory (LCI) Database (Thailand Greenhouse Gas Management Organization (Public Organization), 2022).\u003c/p\u003e \u003cp\u003eThe Carbon footprint of kale farming systems was calculated using Eq.\u0026nbsp;(1).\u003c/p\u003e \u003cp\u003eCarbon Footprint (kgCO\u003csub\u003e2\u003c/sub\u003ee)\u0026thinsp;=\u0026thinsp;\u003cem\u003eEF\u003c/em\u003e​\u0026times;\u003cem\u003eQ\u003c/em\u003e​ (1)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e​\u003c/h2\u003e \u003cp\u003ewhere EF is the emission factor for the activity (kgCO\u003csub\u003e2\u003c/sub\u003ee per unit) (Table\u0026nbsp;2) and Q is the quantity of the raw materials, chemicals, and other emissions (in units).\u003c/p\u003e \u003cp\u003e(Added Table\u0026nbsp;2)\u003c/p\u003e \u003cp\u003eApplication of manure and synthetic fertiliser results in direct and indirect emissions of N\u003csub\u003e2\u003c/sub\u003eO. N\u003csub\u003e2\u003c/sub\u003eO emissions from N-CF came from nitrogen in non-chemical fertilisers applied in the field, including direct N\u003csub\u003e2\u003c/sub\u003eO emissions released into the atmosphere, indirect N\u003csub\u003e2\u003c/sub\u003eO emissions from atmospheric deposition of volatilized N, and indirect N\u003csub\u003e2\u003c/sub\u003eO emissions from nitrogen leaching and runoff. N\u003csub\u003e2\u003c/sub\u003eO emissions from the use of nitrogen fertiliser are represented by Eq.\u0026nbsp;(2).\u003c/p\u003e \u003cp\u003eN\u003csub\u003e2\u003c/sub\u003eO Emissions (kgN\u003csub\u003e2\u003c/sub\u003eO)\u0026thinsp;=\u0026thinsp;N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003edirect\u003c/sub\u003e-N\u003csub\u003einputs\u003c/sub\u003e+N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003edirect\u003c/sub\u003e-N\u003csub\u003eos\u003c/sub\u003e+N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003eindirect\u0026minus;volatilize\u003c/sub\u003e+N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003eindirect\u0026minus;leaching\u003c/sub\u003e (2)\u003c/p\u003e \u003cp\u003ewhere N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003edirect\u003c/sub\u003e-N\u003csub\u003einputs\u003c/sub\u003e represent direct N\u003csub\u003e2\u003c/sub\u003eO emissions released into the atmosphere from organic N additions to soils, N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003edirect\u003c/sub\u003e-N\u003csub\u003eos\u003c/sub\u003e represent direct N\u003csub\u003e2\u003c/sub\u003eO emissions released from managed areas annually, N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003eindirect\u0026thinsp;\u0026minus;\u0026thinsp;volatilize\u003c/sub\u003e represent indirect N\u003csub\u003e2\u003c/sub\u003eO emissions from atmospheric deposition of volatilized N, and N\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003eindirect\u0026thinsp;\u0026minus;\u0026thinsp;leaching\u003c/sub\u003e represent indirect N\u003csub\u003e2\u003c/sub\u003eO emissions form nitrogen leaching and runoff. (Eggleston et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2006\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eNutritional values of kale\u003c/h2\u003e \u003cp\u003eThe outcomes of the proximate analysis and antioxidant content for the kale samples were presented in Table\u0026nbsp;3 and Table\u0026nbsp;4. Total fat, protein and carbohydrate contents were similar to previous research conducted by Sikora and Bodziarczyk (Plassmann \u0026amp; Edwards-Jones, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). The study suggested that the fat content in kale leaves reported by different authors ranged between 0.26\u0026ndash;0.74%, protein content between 3.28\u0026ndash;11.67%, carbohydrate content between 2.36%-10.14%, ash content between 1.33\u0026ndash;2.11%, and dietary fibre between 1.94\u0026ndash;8.39%. However, the moisture content of the kale samples in this study was notably higher compared to the reviewed literature, which was 81.38\u0026ndash;82.92%.\u003c/p\u003e \u003cp\u003e(Added Tables\u0026nbsp;3 and 4)\u003c/p\u003e \u003cp\u003eThe influence of different farming systems on the levels of bioactive compounds in kale is shown in Table\u0026nbsp;3. The results showed that the levels of polyphenol, ORAC and FRAB were statistically lower in the 3 months kale harvested from PFAL compared to 3 months N-CF kale.\u003c/p\u003e \u003cp\u003eFurther analysis revealed significant differences in the levels of polyphenols, ORAC, and FRAB among the N-CF kale samples harvested at different periods (Table\u0026nbsp;4). The reactivity of the antioxidants studied was generally lower in the FRAP assay than in the ORAC assay. Among the N-CF kale samples, those harvested at 6 months showed the highest values of polyphenol, ORAC and FRAB. Conversely, the values were significantly lower in N-CF kale harvested at 3 months and 12 months.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eCarbon footprints\u003c/h2\u003e \u003cp\u003eThe carbon footprints of the two farming systems are presented in Table\u0026nbsp;5, and divided into 4 phases: seeding, transportation, preparation, and plantation. Carbon footprints in a 3-month PFAL were higher than in a 3-month N-CF. The carbon footprint of PFAL was 168.61 kg CO\u003csub\u003e2\u003c/sub\u003e-eq/kg. The carbon footprint values of 3, 6, and 12 months of N-CF kale were 14.75 kg CO\u003csub\u003e2\u003c/sub\u003e-eq/kg, 4.51 kg CO\u003csub\u003e2\u003c/sub\u003e-eq/kg, and 1.96 kg CO\u003csub\u003e2\u003c/sub\u003e-eq/kg, respectively (Table\u0026nbsp;5). In N-CF, carbon footprints were decreased due to the period of plantation.\u003c/p\u003e \u003cp\u003e(Added Table\u0026nbsp;5)\u003c/p\u003e \u003cp\u003eFigure 3 shows the contributors in relative percentage from the different farming practices. The electricity part in FPAL including air conditioning, lighting, fan operation, etc. accounts for 99.06% of total emissions. Similarly, other studies have reported that in vertical farming (VF), a type of indoor farming system, electricity contributes over 90% of the total carbon footprint impacts. (Sandison et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; S\u0026oslash;rensen et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). N-CF systems presented lower carbon footprints as expected since air-conditioning and lighting were not applied. In N-CF systems, electricity along with water usage and waste emissions, including waste management, gasoline combustion and N\u003csub\u003e2\u003c/sub\u003eO emissions, were the major contributors to carbon footprints. They contributed 47.87\u0026ndash;60.15%, 14.84\u0026ndash;25.47% and 12.26\u0026ndash;16.32%, respectively, covering 87.25\u0026ndash;87.67% of the total carbon footprints of the N-CF system. Other contributors include trays, fertilizer packages, pipes and CO\u003csub\u003e2\u003c/sub\u003e, which contribute 6.59\u0026ndash;9.10%, fertilisers and pesticides 1.27\u0026ndash;4.19%, and transportation 1.96\u0026ndash;2.38%.\u003c/p\u003e \u003cp\u003e(Added Fig.\u0026nbsp;3)\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eNutritional aspect\u003c/h2\u003e \u003cp\u003eThere were two main factors to be considered when studying antioxidant values and other factors. One is biotic factors, such as species, cultivar, and orthogenesis. Another is abiotic factors, such as climate, soil, environmental and agrotechnical conditions. (Biesiada \u0026amp; Tomczak, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) The impact of environmental factors such as temperature fluctuations and light intensity have a significant influence on the nutritional composition and antioxidant levels in plants. Recent studies have highlighted how these factors can influence the stress response and subsequent antioxidant production in kale, particularly in different cultivation systems.\u003c/p\u003e \u003cp\u003eEnvironmental stress, such as temperature fluctuations and varying light intensity were possible reasons that affected the levels of polyphenol, ORAC and FRAB in PFAL and N-CF kale. Temperature fluctuation, the change of temperature during day and night, can lead to irreversible damage in plant cells and this is a stress condition response. On the other hand, light intensity, the key factor in plant photosynthesis and metabolites, significantly impacts plant growth and chemical composition. Previous studies by Islam et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) and Kacperska (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) have demonstrated that kale exposed to these environmental stresses exhibits higher levels of antioxidants compared to kale grown under controlled conditions. Specifically, N-CF kale cultivated in an environment exposed to direct sunlight during the day and fluctuating temperatures, experienced more stress than PFAL kale, leading to increased production of bioactive chemicals and antioxidant content (Islam et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kacperska, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFurthermore, the duration of exposure to environmental stressors influenced the nutritional composition and antioxidant levels of kale over time. These factors caused variations in the nutritional composition and antioxidant levels of N-CF kale across different harvest intervals (3 months, 6 months, and 12 months). These variations were attributed to seasonal changes in temperature and light exposure. For example, days are shorter in winter compared to summer, highlighting the dynamic nature of environmental influences on kale quality (Paolillo et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAdditionally, the age of the kale plant plays a crucial role in determining its nutritional composition and antioxidant levels. The nutritional composition and antioxidant properties of fruits and vegetables, including kale, can significantly change as the plant matures, often peaking at specific growth stages before declining (Jaiswal, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This aligns with recent research, which suggested that younger kale plants tend to exhibit higher levels of certain antioxidants and nutrients compared to more mature plants. This is likely due to the plant's response to growth stages and environmental stressors, which vary throughout its life cycle (Islam et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eCarbon footprints\u003c/h2\u003e \u003cp\u003eThe PFAL system relies on artificial lighting, environment control, and other electrical tools, electricity is the most significant source of carbon emissions, accounting for 99.06% of total emissions. Despite the high energy consumption, PFAL systems offer several advantages, including high productivity, consistent production quality, and efficient use of available resources due to its regulated environment, which uses less pesticide and water; up to 90% less than traditional methods (Kozai, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Although PFAL systems are highly efficient in resource use, it has a high carbon footprint that needs to be reduced. Switching to renewable energy sources such as solar or wind power can significantly reduce greenhouse gas emissions associated with electricity consumption (Despommier, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). N-CF systems had a more balanced approach, emitting moderate amounts of carbon emissions, primarily from electricity used (47.87\u0026ndash;60.15%). However, N-CF production in this study showed more electricity components than usual due to the air-conditioning required during the seeding process. N-CF often utilises less synthetic/chemical inputs compared to conventional farming, lowering emissions related to fertiliser production and use. According to a previous study, in conventional farming, the production and application of fertilisers is the largest contributor, responsible for 51% of total emissions. Transportation contributes 21% of the total emissions, associated with transporting produce to markets. Irrigation accounts for 19% of the emissions due to water pumping and distribution (Yuttitham, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eFood security and sustainability\u003c/h2\u003e \u003cp\u003eSustainable food production should minimise pollution, lessen the loss of natural resources, and maintain the environment. Consequently, preserving the resilience and vitality of the ecosystem promotes long-term food security. (Foley et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) In our work, kale in the field were grown in the soil, while another was germinated and developed hydroponically in buckets in the growth experiment room. Over the same duration, PFAL kale not only had higher yield and carbon footprints than N-CF kale but also had lower antioxidant values (Table\u0026nbsp;1,3, 5). Some studies have shown that hydroponically grown lettuce and strawberries contain higher concentrations of bioactive components (ascorbic acid and α-tocopherol) than soil-grown types. The research emphasises the contributions of light and nutrient solutions in enhancing a plant's bioactive compounds. Expanding farm setups and focusing on comparative efficiency should provide greater insight into what to anticipate and emphasise excellent practices from a sustainability perspective. (Ashenafi et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, this PFAL showed potential for sustainable food production with higher yields, although N-CF has higher nutritional value and lower carbon footprints. With continuous experiments in the sector, there is a trade-off between carbon footprint and electricity consumption under the possible future innovation. Furthermore, environmental factors (such as lighting, air temperature, and mineral content) can be greatly optimised for high output and nutritional quality, which is advantageous for agricultural operations as well as customers. Future research ought to examine the potential of certain environmental factors, such as light spectrum or intensity, to improve the quality of nutrition, including food safety of the PFAL system.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthorship\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKS was a principal investigator of the project. KS, WH, US, and KSU conceptualized the research design. WH and KS collected the data. WH, KS and US managed the sample analysis and analysed the data. KS and WH drafted the manuscript. All authors were involved in editing the manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgement\u003c/p\u003e\n\u003cp\u003eThis project is funded by the Office of National Higher Education Science Research and Innovation Policy Council by the \u0026ldquo;Program Management Unit for National Competitiveness Enhancement (PMU-C)\u0026rdquo;, Contract number C10F640135.\u003c/p\u003e\n\u003cp\u003eConflict of interest\u003c/p\u003e\n\u003cp\u003eThe authors have stated explicitly that there are no conflicts of interest in connection with this article.\u003c/p\u003e\n\u003cp\u003eData availability\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eORCID\u003c/p\u003e\n\u003cp\u003eKitti Sranacharoenpong. https://orcid.org/0000-0002-1692-9645\u003c/p\u003e\n\u003cp\u003eWannaporn Hatongkham. https://orcid.org/0009-0000-2849-2682\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlexandratos N, Bruinsma J (2012) World agriculture towards 2030/2050: the 2012 revision\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAshenafi EL, Nyman MC, Holley JM, Mattson NS, Rangarajan A (2022) Phenotypic plasticity and nutritional quality of three kale cultivars (Brassica oleracea L. var. acephala) under field, greenhouse, and growth chamber environments. Environ Exp Bot 199:104895. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/https://doi.org/10.1016/j.envexpbot.2022.104895\u003c/span\u003e\u003cspan address=\"10.1016/j.envexpbot.2022.104895\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenzie IFF, Strain JJ (1996) The Ferric Reducing Ability of Plasma (FRAP) as a Measure of Antioxidant Power: The FRAP Assay. Anal Biochem 239(1):70\u0026ndash;76. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/https://doi.org/10.1006/abio.1996.0292\u003c/span\u003e\u003cspan address=\"10.1006/abio.1996.0292\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBiesiada A, Tomczak A (2012) Biotic and Abiotic Factors Affecting the Content of the Chosen Antioxidant Compounds in Vegetables. Vegetable Crops Res Bull 76:55\u0026ndash;78. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2478/v10032-012-0004-3\u003c/span\u003e\u003cspan address=\"10.2478/v10032-012-0004-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrune M, Hallberg L, SK\u0026Aring;NBERG AB (1991) Determination of iron-binding phenolic groups in foods. J Food Sci 56(1):128\u0026ndash;131\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eButryee C (2020) Vegetables and Fruits Consumption at Least 400 g Per Day for Health: Evidence-based Approach. J Nutr Association Thail 55(1):53\u0026ndash;65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://he01.tci-thaijo.org/index.php/JNAT/article/view/235378\u003c/span\u003e\u003cspan address=\"https://he01.tci-thaijo.org/index.php/JNAT/article/view/235378\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDespommier D (2010) The vertical farm: feeding the world in the 21st century. Macmillan\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEggleston H, Buendia L, Miwa K, Ngara T, Tanabe K (2006) 2006 IPCC guidelines for national greenhouse gas inventories\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFoley JA, Ramankutty N, Brauman KA, Cassidy ES, Gerber JS, Johnston M, Mueller ND, O\u0026rsquo;Connell C, Ray DK, West PC (2011) Solutions for a cultivated planet. Nature 478(7369):337\u0026ndash;342\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeorge W, Latimer A, o. OACI (2019) Official methods of analysis of AOAC Internationa, 21st edn. ed.). AOAC Internationa\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGregory PJ, Ingram JS, Brklacich M (2005) Climate change and food security. Philos Trans R Soc Lond B Biol Sci 360(1463):2139\u0026ndash;2148. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rstb.2005.1745\u003c/span\u003e\u003cspan address=\"10.1098/rstb.2005.1745\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang D, Ou B, Hampsch-Woodill M, Flanagan JA, Prior RL (2002) High-Throughput Assay of Oxygen Radical Absorbance Capacity (ORAC) Using a Multichannel Liquid Handling System Coupled with a Microplate Fluorescence Reader in 96-Well Format. J Agric Food Chem 50(16):4437\u0026ndash;4444. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1021/jf0201529\u003c/span\u003e\u003cspan address=\"10.1021/jf0201529\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIslam MZ, Park BJ, Lee YT (2021) Influence of Temperature Conditions during Growth on Bioactive Compounds and Antioxidant Potential of Wheat and Barley Grasses. \u003cem\u003eFoods\u003c/em\u003e, \u003cem\u003e10\u003c/em\u003e(11), 2742. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.mdpi.com/2304-8158/10/11/2742\u003c/span\u003e\u003cspan address=\"https://www.mdpi.com/2304-8158/10/11/2742\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJaiswal AK (2020) Nutritional composition and antioxidant properties of fruits and vegetables. Academic\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKacperska A (2018) Metabolic consequences of low temperature stress in chilling-insensitive plants. Low temperature stress physiology in crops. Crc, pp 27\u0026ndash;40\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKongkachuichai R, Charoensiri R, Yakoh K, Kringkasemsee A, Insung P (2015) Nutrients value and antioxidant content of indigenous vegetables from Southern Thailand. Food Chem 173:838\u0026ndash;846. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/https://doi.org/10.1016/j.foodchem.2014.10.123\u003c/span\u003e\u003cspan address=\"10.1016/j.foodchem.2014.10.123\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKozai T (2013) Resource use efficiency of closed plant production system with artificial light: concept, estimation and application to plant factory. Proc Jpn Acad Ser B Phys Biol Sci 89(10):447\u0026ndash;461. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2183/pjab.89.447\u003c/span\u003e\u003cspan address=\"10.2183/pjab.89.447\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee MJ, Son KH, Oh MM (2016) Increase in biomass and bioactive compounds in lettuce under various ratios of red to far-red LED light supplemented with blue LED light. Hortic Environ Biotechnol 57(2):139\u0026ndash;147\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMilestad R, Carlsson-Kanyama A, Schaffer C (2020) The H\u0026ouml;gdalen urban farm: A real case assessment of sustainability attributes. Food Secur 12(6):1461\u0026ndash;1475\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOrsini F, Pennisi G, Zulfiqar F, Gianquinto G (2020) Sustainable use of resources in plant factories with artificial lighting (PFALs). Eur J Hortic Sci 85:297\u0026ndash;309. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.17660/eJHS.2020/85.5.1\u003c/span\u003e\u003cspan address=\"10.17660/eJHS.2020/85.5.1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePaolillo I, Costanzo G, Delicato A, Villano F, Arena C, Calabr\u0026ograve; V (2023) Light Quality Potentiates the Antioxidant Properties of Brassica rapa Microgreen Extracts against Oxidative Stress and DNA Damage in Human Cells. \u003cem\u003eAntioxidants\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e(10), 1895. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.mdpi.com/2076-3921/12/10/1895\u003c/span\u003e\u003cspan address=\"https://www.mdpi.com/2076-3921/12/10/1895\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePlassmann K, Edwards-Jones G (2010) 15 - Carbon footprinting and carbon labelling of food products. In U. Sonesson, J. Berlin, \u0026amp; F. Ziegler (Eds.), \u003cem\u003eEnvironmental Assessment and Management in the Food Industry\u003c/em\u003e (pp. 272\u0026ndash;296). Woodhead Publishing. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/https://doi.org/10.1533/9780857090225.3.272\u003c/span\u003e\u003cspan address=\"10.1533/9780857090225.3.272\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eP\u0026ouml;rtner H-O, Roberts DC, Masson-Delmotte V, Zhai P, Tignor M, Poloczanska E, Mintenbeck K, Nicolai M, Okem A, Petzold J (2019) IPCC special report on the ocean and cryosphere in a changing climate. IPCC Intergovernmental Panel Clim Change: Geneva Switz, \u003cem\u003e1\u003c/em\u003e(3)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSamec D, Urlić B, Salopek-Sondi B (2018) Kale (Brassica oleracea var. acephala) as a superfood: Review of the scientific evidence behind the statement. Crit Rev Food Sci Nutr 59:1\u0026ndash;37. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/10408398.2018.1454400\u003c/span\u003e\u003cspan address=\"10.1080/10408398.2018.1454400\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSandison F, Yeluripati J, Stewart D (2023) Does green vertical farming offer a sustainable alternative to conventional methods of production? A case study from Scotland. Food Energy Secur 12(2):e438. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/https://doi.org/10.1002/fes3.438\u003c/span\u003e\u003cspan address=\"10.1002/fes3.438\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSatheesh N, Workneh Fanta S (2020) Kale: Review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products. Cogent Food Agric 6(1):1811048. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/23311932.2020.1811048\u003c/span\u003e\u003cspan address=\"10.1080/23311932.2020.1811048\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSikora E, Bodziarczyk I (2012) Composition and antioxidant activity of kale (Brassica oleracea L. var. acephala) raw and cooked. Acta Sci Pol Technol Aliment 11(3):239\u0026ndash;248. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.ncbi.nlm.nih.gov/pubmed/22744944\u003c/span\u003e\u003cspan address=\"https://www.ncbi.nlm.nih.gov/pubmed/22744944\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eS\u0026oslash;rensen MG, Olsen SI, Colley T (2021) Comparing the Environmental Sustainability of Vertical and Conventional Wheat Farming Using Life Cycle Assessment. In \u003cem\u003ePreprints\u003c/em\u003e: Preprints\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThailand Greenhouse Gas Management Organization (Public Organization), T (2022) \u003cem\u003eEmission Factor for Carbon Footprint of Organization\u003c/em\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://thaicarbonlabel.tgo.or.th/admin/uploadfiles/emission/ts_578cd2cb78.pdf\u003c/span\u003e\u003cspan address=\"http://thaicarbonlabel.tgo.or.th/admin/uploadfiles/emission/ts_578cd2cb78.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYuttitham M (2019) Comparison of Carbon Footprint of Organic and Conventional Farming of Chinese Kale. Environ Nat Resour J 17:78\u0026ndash;92. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.32526/ennrj.17.1.2019.08\u003c/span\u003e\u003cspan address=\"10.32526/ennrj.17.1.2019.08\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"ASEAN Institute for Health Development, Mahidol University, Thailand","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Food security, Environmental impacts, Nutritive values, Carbon footprints","lastPublishedDoi":"10.21203/rs.3.rs-4894455/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4894455/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePlant factory with artificial light (PFAL) technology is a soilless cultivation system that designed to optimize plant growth, productivity, and product quality, as well as ensure efficient use of water and fertilizer. Non-chemical farming (N-CF) systems are a traditional agricultural cultivation method. Both agricultural systems can serve as commodity production methods for ensuring food security. However, concerns about nutritional value and environmental sustainability remain. This study compares the nutritional compositions, antioxidant contents, environmental impacts, and carbon footprint of kale (\u003cem\u003eBrassica oleracea\u003c/em\u003e L.) in PFAL and N-CF systems. The proximate values of kale in PFAL and N-CF systems were not significantly different (p \u0026lt; 0.05). However, the results revealed that antioxidant contents, determined by polyphenol, oxygen radical absorbance capacity (ORAC) assay and ferric reducing antioxidant power (FRAP) assay were significantly lower in PFAL-harvested kale than in N-CF-harvested kale after three months. The polyphenol, ORAC and FRAP of PFAL kale were 68.95 mg GAE/100\u0026nbsp;g, 1,321.25 and 111.95 μmol TE/100 g fresh weight, respectively, while those of N-CF kale were136.06 mg GAE/100\u0026nbsp;g, 3,519.87 and 220.17 μmol TE/100 g fresh weight, respectively. The carbon dioxide (CO\u003csub\u003e2\u003c/sub\u003e) emissions of 3 month-kale from PFAL and N-CF productions were 168.61 and 14.75 Kg CO\u003csub\u003e2\u003c/sub\u003e eq./kg of kale, respectively. Consequently, new policies should be oriented toward reducing environmental pressure by introducing process certification of low environmental impacts. However, not only environmental aspects but also the adequacy of nutritive values of products should be a concern for farming food production systems.\u003c/p\u003e","manuscriptTitle":"Comparing soilless and non-chemical farming food production systems: Nutritional and environmental aspects for food security and sustainability","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-13 08:20:11","doi":"10.21203/rs.3.rs-4894455/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"067dc0fe-fe8e-4f7d-8301-1cc6fafde39c","owner":[],"postedDate":"August 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-08-13T08:20:11+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-13 08:20:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4894455","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4894455","identity":"rs-4894455","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}