Enhanced Extraction of Vitamin C from Orange Peels using Microwave Technology: A Comparative Study with Conventional Heated Maceration

Enhanced Extraction of Vitamin C from Orange Peels using Microwave Technology: A Comparative Study with Conventional Heated Maceration | 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 Enhanced Extraction of Vitamin C from Orange Peels using Microwave Technology: A Comparative Study with Conventional Heated Maceration Murtaza Sattar, Hussein Fallah This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9280173/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 Vitamin C (Ascorbic Acid) is an essential nutrient for human health, playing a vital role in immune system enhancement, collagen synthesis, and connective tissue support. While citrus fruits are primary sources, orange peels constitute approximately 15% of the total fruit weight and contain nearly three times the ascorbic acid concentration found in the pulp. Utilizing these peels—typically considered agricultural waste—presents a highly sustainable and economically viable opportunity for bio-resource recovery. This study focuses on a comparative performance analysis between Microwave-Assisted Extraction (MAE) and Conventional Heated Maceration (CHM). Our results demonstrate that MAE technology achieved a 38.3% increase in Vitamin C yield compared to conventional methods. Notably, the extraction time was drastically reduced from 45 minutes to just 2 minutes, reflecting a high energy efficiency with 94.1% savings. Furthermore, a stable thermal steady-state of 60°C was achieved within 180 seconds, effectively preventing the thermal degradation of the heat-sensitive ascorbic acid. These findings establish MAE as a superior, green engineering solution for the industrial valorization of citrus by-products. microwave-assisted extraction ascorbic acid orange peel waste green engineering energy efficiency bio-waste valorization Figures Figure 1 Figure 2 1. Introduction Vitamin C, chemically known as L-ascorbic acid (AA), is a vital water-soluble micronutrient and a potent antioxidant essential for human health. Since humans lack the L-gulono-gamma-lactone oxidase enzyme due to a genetic mutation, dietary intake of AA is mandatory for maintaining collagen synthesis, immune regulation, and iron absorption. Beyond its biological importance, the global market for Vitamin C was valued at 1.24 billion in 2022 and is projected to reach 1.97 billion by 2025, driven by a growing industrial shift toward "natural" and "clean label" ingredients . Currently, citrus fruits represent the primary source of AA. However, the citrus processing industry generates massive quantities of waste—peels and seeds—which constitute nearly 50% of the total fruit weight. Global citrus production rose from 105.9 million tons in 2000 to 161.8 million tons in 2021, leading to significant environmental and economic challenges regarding waste disposal. Interestingly, citrus peels are not merely "refuse" but a rich matrix containing bioactive compounds such as flavonoids (hesperidin and naringenin), pectin, and essential oils (D-limonene). Critically, studies indicate that orange peels contain approximately three times the concentration of ascorbic acid found in the pulp (ranging from 10–100 mg/100 g), making them a superior substrate for bio-resource recovery. Despite this potential, extracting AA remains a chemical engineering challenge due to its inherent susceptibility to thermal degradation and oxidation. Traditional methods such as Maceration and Soxhlet Extraction are widely used but suffer from significant drawbacks, including excessive time consumption (hours to days), high energy requirements, and potential degradation of the heat-sensitive AA during prolonged exposure to high temperatures. Furthermore, chemical synthesis via the Reichstein process or two-step fermentation involves complex multi-step reactions and hazardous solvents . To address these limitations, "Green Extraction" technologies have emerged as sustainable alternatives. Microwave-Assisted Extraction (MAE) stands out as a highly efficient technique that utilizes a unique heat transfer mechanism—heating the plant matrix directly and instantly without preheating tube walls. This allows for achieving optimal extraction temperatures in a fraction of the time required by conventional heating, significantly reducing energy consumption and preserving the biological activity of the AA. While other green methods like Supercritical Fluid Extraction (SFE) and Pressurized Fluid Extraction (PLE) offer high yields, they often require high initial capital investment and complex high-pressure equipment . The primary aim of this research is to develop an optimized engineering process for extracting high-quality ascorbic acid from orange peel waste. This study focuses on comparing the efficiency of Microwave-Assisted Extraction (MAE) against conventional Maceration, evaluating parameters such as yield, time, and energy efficiency. Additionally, the research investigates a novel stabilization approach using Licorice extract (rich in glycyrrhizin) to enhance the chemical stability and solubility of the final AA extract. By integrating waste valorization with green engineering, this work contributes to a circular economy and provides a cost-effective solution for the nutraceutical industry. 2. Materials and Methods This section describes the experimental procedures, materials, and analytical protocols used to evaluate the efficiency of microwave-assisted extraction (MAE) compared to conventional thermal maceration (CHM). 2.1. Materials and Sample Preparation Fresh oranges (Citrus sinensis) were obtained from a local market in Diwaniyah, Iraq. The peels were manually separated. The sample was dried by exposure to room temperature for two days. The dried peels were then ground into a very fine powder. 2.2. Extraction method 2.2.1. Microwave-Assisted Extraction (MAE) Microwave-assisted extraction was performed using a domestic microwave system (rated maximum power 800 W) modified for laboratory observation. Mixture: 50.0 g of peel powder was mixed with 100 ml of acidified deionized water and 0.5 g of citric acid as a stabilizer to create an acidic environment and prevent the oxidation of ascorbic acid, which oxidizes in alkaline solutions. Operating Parameters: Extraction was performed at a medium power setting (effective power ≈ 400 W) using pulsed irradiation (30 seconds on/10 seconds off) to prevent localized overheating. Duration: The process took 2 minutes, with a constant temperature of 60°C reached in the third minute. 2.2.2. Conventional Thermal Soaking (CHM) For comparison, a conventional extraction was performed using a magnetic stirrer with a heating plate. Standards: 50.0 g of powder in 100 mL of deionized water. Conditions: The mixture was stirred at 550 rpm at a constant temperature of 60°C for 45 minutes to ensure a fair comparison with the thermal stability of the microwave-assisted extraction method. 2.3. Analytical Procedures: Iodinated Titration The concentration of the extracted ascorbic acid was determined using iodine titration, an analytical method based on redox reactions. Preparation: 10 mL of the filtered extract was diluted, and 2 mL of a 1% starch solution was added as an internal indicator. Titration: A titrant iodine solution (0.005 mol/L) was used. Endpoint Determination: The titration continued until a sudden and sustained dark blue-black color appeared, indicating the complete oxidation of ascorbic acid and the formation of the starch-iodine complex. Calculation: The mass of ascorbic acid (mAA) was calculated using the standard relationship (weight of ascorbic acid (mg) = volume of iodine × 0.8806). 2.4. Energy Balancing and Sustainability Indicators: Mass and energy balances were performed to determine the sustainability of the two processes. Energy consumption (E) was calculated as the product of power (P) and time (t), while the energy savings ratio was calculated to assess the environmental impact of the ultrasonic extraction technique. 3. Results analyzes the experimental data obtained from Microwave-Assisted Extraction (MAE) and Conventional Heated Maceration (CHM), focusing on yield intensification and energy sustainability. 3.1. Comparative Yield Analysis The recovery of Ascorbic Acid (AA) was significantly enhanced by the application of microwave energy. As detailed in Table 1 , MAE achieved a concentration of 9.74 mg/100mL, whereas CHM yielded only 7.04 mg/100mL, representing a 38.35% increase in extraction efficiency. 3.2. Thermal Gradient and Dielectric Heating Dynamics The core advantage of MAE lies in its unique heating mechanism. Unlike CHM, which relies on slow thermal conduction, MAE utilizes Dipole Rotation. At a frequency of 2450 MHz, the electric field oscillates 2.45 billion times per second, causing water molecules inside the orange peel cells to rotate frantically. 3.2.1. The "Inside-Out" Heating Phenomenon As illustrated in the thermal profile (Fig. 1), a steep Thermal Gradient is established. The localized friction generates heat "from the inside out," creating a rapid increase in intracellular pressure. This pressure exceeds the mechanical strength of the cellulose cell walls, leading to their rupture—a process termed "micro-explosions." This allows the solvent to penetrate the matrix instantly, explaining why MAE reached the maximum yield in 2 minutes, while CHM required 45 minutes. 3.2.2. Thermal Steady-State and Degradation Prevention Vitamin C is highly sensitive to the "Thermal History" of the process. In CHM, the 45-minute exposure to the hot plate caused significant oxidation of the furanose ring. In contrast, the MAE system reached a Steady-State at 60°C within 180 seconds, minimizing the residence time at high temperatures and preserving the chemical integrity of the Ascorbic Acid. 3.3. Mass and Energy Balance (Sustainability Metrics) The engineering efficiency of the process was quantified through a global energy balance. Conventional Energy (E_conv): 400 W \times 2700 s = 1080 kJ. Microwave Energy (E_MAE): 400 W \times 120 s = 48 kJ. Energy Savings: 95.5%. The 95.5% reduction in energy consumption confirms that MAE is not just a faster alternative, but a foundational technology for "Green Engineering" in the Iraqi agricultural sector. By heating the target molecules directly rather than the surrounding environment (glassware and air), MAE decouples high-yield production from high-carbon intensity. 3.4. Stoichiometric Validation The 1:1 stoichiometric relationship was validated by the sharp transition to a deep blue-black color at the endpoint. The consumption of 8.3 mL of Iodine for the MAE sample confirms the high density of recovered bioactive molecules, validating the accuracy of the proposed mass balance . Table 1 titration results Experiment V(SAMPLE) V(Titrant) Extracted mass in the flask Concentration in each 100 ml Microwave assisted extraction (MAE) 75mL 8.3mL 7.31mg 9.74 mg/100 ml Conventional Heated Maceration (CHM) 50mL 4mL 3.52mg 7.04 mg/100 ml ( a ) ( b ) Figure(a). Thermal gradient and kinetic heating profile of Microwave-Assisted Extraction (MAE). The plot illustrates the rapid transition phase reaching the target steady-state temperature of 60°C within 180 seconds, showcasing the efficiency of dipole rotation heating. Figure 2. Temperature profile during Conventional Heated Maceration (CHM). The graph depicts the extended time required to reach the extraction temperature (60°C) and the thermal stability maintained over the 45-minute extraction duration. 3.3. Formatting of Mathematical Components The weight of ascorbic acid in the tested sample is calculated using the following formula : Weight of ascorbic acid (mg) = Volume of iodine solution (mL) × Iodine concentration (mol/L) × Molecular weight of ascorbic acid (g/mol) ………(1) Where : Volume of iodine solution: The volume of iodine solution drawn from the burette (mL). Iodine concentration: The molar concentration of the iodine solution (0.005 mol/L). Molecular weight of ascorbic acid: The molecular weight of ascorbic acid (176.12 g/mol). (Substituting the constants) Weight AA (mg) = Volume of iodine × 0.005 × 176.12 ……. (2) Weight AA (mg) = Volume of iodine × 0.8806 …… (3) 4.2. Calculating Concentration (mg/100 ml) To standardize results and facilitate comparison between different extraction methods, the final concentration is expressed in mg per 100 ml of extract : Concentration (mg/100 ml) = (Weight (mg) × 100) / (Sample Volume (ml) …. (4) 4.2. Sample Calculation (Microwave-Assisted Extraction Method) For a sample extracted by microwave-assisted extraction (MAE), where the sample volume is 75 mL and the volume of iodine is 8.3 mL : Mass in the flask: 8.3 × 0.8806 = 7.309 mg Concentration: (7.309 / 75) × 100 = 9.74 mg/100 mL …. (5) 4.2. Example Calculation (Traditional Method) For a sample heated using the traditional method, where the sample volume is 50 mL and the volume of iodine is 4 mL : Mass in the flask: 4 × 0.8806 = 3.522 mg …. (6) Concentration: (3.522 / 50) × 100 = 7.04 mg/100 mL …. (7) The weight of ascorbic acid in the tested sample is calculated using the following formula : Weight of ascorbic acid (mg) = Volume of iodine solution (mL) × Iodine concentration (mol/L) × Molecular weight of ascorbic acid (g/mol) ………(1) Where : Volume of iodine solution: The volume of iodine solution drawn from the burette (mL). Iodine concentration: The molar concentration of the iodine solution (0.005 mol/L). Molecular weight of ascorbic acid: The molecular weight of ascorbic acid (176.12 g/mol). (Substituting the constants) Weight AA (mg) = Volume of iodine × 0.005 × 176.12 ……. (2) Weight AA (mg) = Volume of iodine × 0.8806 …… (3) 4.2. Calculating Concentration (mg/100 ml) To standardize results and facilitate comparison between different extraction methods, the final concentration is expressed in mg per 100 ml of extract : Concentration (mg/100 ml) = (Weight (mg) × 100) / (Sample Volume (ml) …. (4) 4.2. Sample Calculation (Microwave-Assisted Extraction Method) For a sample extracted by microwave-assisted extraction (MAE), where the sample volume is 75 mL and the volume of iodine is 8.3 mL : Mass in the flask: 8.3 × 0.8806 = 7.309 mg Concentration: (7.309 / 75) × 100 = 9.74 mg/100 mL …. (5) 4.2. Example Calculation (Traditional Method) For a sample heated using the traditional method, where the sample volume is 50 mL and the volume of iodine is 4 mL : Mass in the flask: 4 × 0.8806 = 3.522 mg …. (6) Concentration: (3.522 / 50) × 100 = 7.04 mg/100 mL …. (7) Material balance was performed based on the experimental inputs (dried orange peel powder and distilled water) and outputs (liquid extract and wet residue). Basis: Single extraction batch (50 g solids / 100 mL solvent) Total Input (Min) : Mass of orange peel powder (S): 50.0 g Mass of distilled water (L): 100.0 g (assuming density = 1 g/cm³) Mass of stabilizer (citric acid): 0.5 g Total (Min) = 150.5 g Total Output (Mout) : Recovered liquid extract (E): 84.2 g (measured after filtration) Wet solid residue (R): 62.3 g (solvent remaining in pores) Experimental losses (Loss): 4.0 g (evaporation + handling) Total (Mout) = 150.5 g Process Efficiency : Extraction ratio = (Mass of extract / Mass of solvent) × 100 = 84.2 / 100 84.2% 4.2 Energy Balancing and Sustainability Assessment Based on the specifications provided for a domestic microwave (rated output power: 800 watts) and an electric hob, the energy consumption for each method was calculated. 1. Conventional Heating Power (Econv): (dup: abstract ?) Power (P): 400 W (medium hob setting) Time (t): 45 minutes (2700 seconds) Econv = P × t = 400 J/s × 2700 seconds = 1,080,000 J = 1080 kJ 2. Microwave Heating Power (EMAE): (dup: abstract ?) Rated Operating Power (P): 400 W (medium setting) Effective Radiation Time (t): 2 minutes (120 seconds) EMAE = P × t = 400 J/s × 120 seconds = 48,000 J = 48 kJ 3.Comparison and Energy Savings: (dup: abstract ?) The energy efficiency of the green extraction method is calculated as follows : Energy Saving % = (1080–48) / 1080 × 100 = 95.5%Basis: Single extraction batch (50 g solids / 100 mL solvent) Total Input (Min) : Mass of orange peel powder (S): 50.0 g Mass of distilled water (L): 100.0 g (assuming density = 1 g/cm³) Mass of stabilizer (citric acid): 0.5 g Total (Min) = 150.5 g Total Output (Mout) : Recovered liquid extract (E): 84.2 g (measured after filtration) Wet solid residue (R): 62.3 g (solvent remaining in pores) Experimental losses (Loss): 4.0 g (evaporation + handling) Total (Mout) = 150.5 g Process Efficiency : Extraction ratio = (Mass of extract / Mass of solvent) × 100 = 84.2 / 100 84.2% 4.4.2. Energy Balancing and Sustainability Assessment Based on the specifications provided for a domestic microwave (rated output power: 800 watts) and an electric hob, the energy consumption for each method was calculated. 1. Conventional Heating Power (Econv): Power (P): 400 W (medium hob setting) Time (t): 45 minutes (2700 seconds) Econv = P × t = 400 J/s × 120 seconds = 1,080,000 J = 1080 kJ 2. Microwave Heating Power (EMAE): Rated Operating Power (P): 400 W (medium setting) Effective Radiation Time (t): 2 minutes (120 seconds) EMAE = P × t = 400 J/s × 120 seconds = 48,000 J = 48 kJ 3.Comparison and Energy Savings: The energy efficiency of the green extraction method is calculated as follows : Energy Saving % = (1080–48) / 1080 × 100 = 95.5% 4. Discussion The enhanced performance of the MAE system is attributed to the following engineering phenomena: Disruption of Cellular Matrix: Unlike conventional heating which relies on thermal conduction, microwaves cause localized high-pressure buildup within the plant cells. This "micro-explosion" effect shatters the cell walls, providing an unobstructed pathway for the ascorbic acid to dissolve into the solvent. Selective Heating: Water molecules (the solvent) have a high dielectric constant, absorbing microwave energy directly. This creates a "thermal driving force" where the temperature inside the peel particles rises faster than the surrounding bulk liquid, significantly accelerating the mass transfer rate. Preservation Effect: The total processing time for MAE was 88.8% lower than the conventional method (2 min vs. 45 min). This drastic reduction in thermal residence time prevented the secondary oxidation of Vitamin C, which is highly unstable at sustained temperatures of 60°C. 5. Conclusions 5.1.1 Efficiency of Microwave-Assisted Extraction (MAE) and Cell Rupture Theory: The high yield is attributed to the 'localized heating' effect, where microwave radiation interacts with the polar water molecules inside the orange peel cells. This interaction causes a rapid increase in internal pressure, leading to the rupture of cell walls, a process known as the 'Cell Rupture'. 5.1.2 Thermal Degradation and Exposure Time Optimization: In conventional heating, a 45-minute exposure leads to the oxidation of the furanose ring in ascorbic acid. In contrast, the microwave-assisted extraction (MAE) cycle, which lasts only 5 minutes, reduces the thermal residence time, thereby maintaining the integrity of the vitamin. 5.1.3 Stabilization and Antioxidant Synergy of Citric Acid: The addition of 0.5g of citric acid successfully lowered the pH, acting as a chelating agent that inhibits the catalytic oxidation of the extract. 5.1.4 Dielectric Properties and Dipole Rotation of Deionized Water: Water, by its nature, is one of the most efficient solvents for microwave response due to its exceptionally high dipole moment. Water molecules are highly receptive to absorbing microwave energy, rotating at immense speeds, which generates rapid heating 5.1.5 Analytical Validation and Benchmarking: Quantitative Dominance: The titration results confirmed that the sample treated with MAE required 8.3 mL of Iodine (V Sample = 75 mL), resulting in a calculated concentration of 9.74 mg/100mL. This remains the highest recorded value in this study, proving that the chemical integrity of the Ascorbic Acid molecules was preserved despite the high-energy microwave pulses. Sensitivity to Thermal History: The lower Iodine consumption in conventional samples (4.0 mL) directly correlates with the "Thermal History" of the sample. Long-term exposure to heat (45 min) initiated the degradation of the Ene-diol group in Ascorbic Acid, making it less reactive with the Iodine titrant. Declarations Author Contribution M.S. and H.A. conceived and designed the research. M.S. performed the laboratory experiments, including extraction processes and titration analysis, and conducted the mathematical calculations and data processing. H.F. was responsible for the theoretical formulation, literature review, and drafting the initial manuscript documents. H.A. supervised the study, provided critical academic feedback, and revised the final manuscript. All authors have read and approved the final manuscript. Data Availability The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request Funding Statement: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Conflict of Interest: The authors have no relevant financial or non-financial interests to disclose References Ali, A., Riaz, S., Khalid, W., Fatima, M., Mubeen, U., Babar, Q., Manzoor, M. F., Zubair Khalid, M., & Madilo, F. K. (2024). Potential of ascorbic acid in human health against different diseases: an updated narrative review. In International Journal of Food Properties (Vol. 27, Number 1, pp. 493–515). Taylor and Francis Ltd. https://doi.org/10.1080/10942912.2024.2327335 Ali Anwar, S. R. W. K. M. F. (n.d.). Potential of ascorbic acid in human health against different diseases: an updated narrative review. Ascorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies. (n.d.). Belayneh Asfaw, T., Getachew Tadesse, M., Beshah Tessema, F., Woldemichael Woldemariam, H., V. Chinchkar, A., Singh, A., Upadhyay, A., & Mehari, B. (2024). Ultrasonic-assisted extraction and UHPLC determination of ascorbic acid, polyphenols, and half-maximum effective concentration in Citrus medica and Ziziphus spina-christi fruits using multivariate experimental design. Food Chemistry: X, 22. https://doi.org/10.1016/j.fochx.2024.101310 Calder, P. C., Kreider, R. B., & McKay, D. L. (2025a). Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults. In Nutrients (Vol. 17, Number 2). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/nu17020279 Calder, P. C., Kreider, R. B., & McKay, D. L. (2025b). Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults. In Nutrients (Vol. 17, Number 2). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/nu17020279 Chapter 4 - Vitamin C: The Metabolism and Functions of Ascorbic Acid in Plants. (n.d.). Ghorbani, M., Aboonajmi, M., Ghorbani Javid, M., & Arabhosseini, A. (n.d.). Optimization of ultrasound-assisted extraction of ascorbic acid from fennel (Foeniculum vulgare) seeds and evaluation its extracts in free radical scavenging. In Agricultural Engineering International: CIGR Journal (Vol. 19, Number 4). Retrieved http://www.cigrjournal.org Gita Rizkasari, R. I. (n.d.). Determination of Vitamin C Levels in Limes (Citrus aurantifolia Swingle) and Lemon (Citrus limon (L.) Burm. f.) Using the UV Vis Spectrophotometric Method. Gomez-Urios, C., Mbuy, I., Esteve, M. J., Blesa, J., Frigola, A., & Lopez-Malo, D. (2022). Reusing Food Waste: Ascorbic Acid Extraction from Orange Peel Using Ultrasound-Assisted Extraction and Natural Deep Eutectic Solvents. 29. https://doi.org/10.3390/foods2022-12976 Hancock, R. D., & Viola, R. (2001). The use of micro-organisms for L-ascorbic acid production: Current status and future perspectives. In Applied Microbiology and Biotechnology (Vol. 56, Numbers 5–6, pp. 567–576). https://doi.org/10.1007/s002530100723 Jain, S., Yadav, A. S., & Gothalwal, R. (2021a). ASSESSMENT OF TOTAL PHENOLIC, FLAVONOID CONTENT AND IN VITRO ANTIOXIDANT PROPERTIES OF ALCHEMILLIA VULGARIS (LADY’S MANTLE). In Journal of Advanced Scientific Research (Vol. 12, Number 4). http://www.sciensage.info Jain, S., Yadav, A. S., & Gothalwal, R. (2021b). ASSESSMENT OF TOTAL PHENOLIC, FLAVONOID CONTENT AND IN VITRO ANTIOXIDANT PROPERTIES OF ALCHEMILLIA VULGARIS (LADY’S MANTLE). In Journal of Advanced Scientific Research (Vol. 12, Number 4). http://www.sciensage.info Mazurek, A., & Włodarczyk-Stasiak, M. (2023). A New Method for the Determination of Total Content of Vitamin C, Ascorbic and Dehydroascorbic Acid, in Food Products with the Voltammetric Technique with the Use of Tris(2-carboxyethyl)phosphine as a Reducing Reagent. Molecules, 28(2). https://doi.org/10.3390/molecules28020812 Memnune Şengül. (n.d.). Vitamin C, Sugar Content, Color Intensity and Some Physicochemical Properties of Watermelon and Orange Peels. Salar, F. J., Díaz-Morcillo, A., Fayos-Fernández, J., Monzó-Cabrera, J., Sánchez-Bravo, P., Domínguez-Perles, R., Fernández, P. S., García-Viguera, C., & Periago, P. M. (2024). Microwave Treatment vs. Conventional Pasteurization: The Effect on Phytochemical and Microbiological Quality for Citrus–Maqui Beverages. Foods, 13(1). https://doi.org/10.3390/foods13010101 Skrovankova, S., Mlcek, J., Sochor, J., Baron, M., Kynicky, J., & Jurikova, T. (2015). Determination of ascorbic acid by electrochemical techniques and other methods. International Journal of Electrochemical Science, 10(3), 2421–2431. https://doi.org/10.1016/s1452-3981(23)04857-5 Susa, F., & Pisano, R. (2023). Advances in Ascorbic Acid (Vitamin C) Manufacturing: Green Extraction Techniques from Natural Sources. In Processes (Vol. 11, Number 11). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/pr11113167 Tucaliuc, A., Cîșlaru, A., Kloetzer, L., & Blaga, A. C. (2022). Strain Development, Substrate Utilization, and Downstream Purification of Vitamin C. In Processes (Vol. 10, Number 8). MDPI. https://doi.org/10.3390/pr10081595 Weiqing Zhang Mei Lin Hongju He Yuling Wang Jingru Wang and Hongjie Liu. (n.d.). Toward Achieving Rapid Estimation of Vitamin C in Citrus Peels by NIR Spectra Coupled with a Linear Algorithm. Wychowański, P., Starzyńska, A., Jereczek-Fossa, B. A., Iwanicka-Grzegorek, E., Kosewski, P., Adamska, P., & Woliński, J. (2020). The Effects of Smoking Cigarettes on Immediate Dental Implant Stability—A Prospective Case Series Study. Applied Sciences, 11(1), 27. https://doi.org/10.3390/app11010027 Additional Declarations No competing interests reported. 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9280173","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":615297491,"identity":"a6e25ae2-008e-4588-b7fd-f82737352265","order_by":0,"name":"Murtaza Sattar","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYBAC/gYYi7354AMgxcNHSIvEARCZAFJ7LNkARLER0mLgANMikWMmAWIT1sLee/Bz5Y/DcgY3cswqv+bYybAxMD98dAOfFp5zyZJnEg4bG5x5VnZbdlsy0GFsxsY5+LRI5BhINiQcTtxwPHnbbcltzEAtPGzSBLQY/wRrOZBgViy5rZ4ILRE5ZhBbTqSYMX7cdpiwFokz59IsG9LSjSXPHEuWZtx2nIeNmYBf+Nt7D99ssLGW4zvefPDjz23V9vzszQ8f49MCjDsQ0QxmMoPZzHiVw7XUgZmMPwiqHgWjYBSMgpEIAAxkSrosN32ZAAAAAElFTkSuQmCC","orcid":"","institution":"University of Al- Qadisiya","correspondingAuthor":true,"prefix":"","firstName":"Murtaza","middleName":"","lastName":"Sattar","suffix":""},{"id":615297492,"identity":"abb27447-e89d-4418-ac3c-2e7315923c90","order_by":1,"name":"Hussein Fallah","email":"","orcid":"","institution":"University of Al- Qadisiya","correspondingAuthor":false,"prefix":"","firstName":"Hussein","middleName":"","lastName":"Fallah","suffix":""}],"badges":[],"createdAt":"2026-03-31 12:57:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9280173/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9280173/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105877527,"identity":"77db057a-b109-47f1-9730-e244cf617858","added_by":"auto","created_at":"2026-04-01 06:05:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":37153,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(a).\u003c/strong\u003e Thermal gradient and kinetic heating profile of Microwave-Assisted Extraction (MAE). The plot illustrates the rapid transition phase reaching the target steady-state temperature of 60°C within 180 seconds, showcasing the efficiency of dipole rotation heating.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9280173/v1/f8487bf7d18ab120fe84bcb1.png"},{"id":105905394,"identity":"9d99aa09-d128-4b2e-95e3-d42ea402319d","added_by":"auto","created_at":"2026-04-01 10:12:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":33924,"visible":true,"origin":"","legend":"\u003cp\u003eTemperature profile during Conventional Heated Maceration (CHM). The graph depicts the extended time required to reach the extraction temperature (60°C) and the thermal stability maintained over the 45-minute extraction duration.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9280173/v1/2b5110ccab8259abe61336a4.png"},{"id":106401870,"identity":"9f73a361-8b03-4bc6-9ffa-25f4a2ae1440","added_by":"auto","created_at":"2026-04-08 09:10:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1053707,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9280173/v1/db9da85a-8f3b-4af6-a3db-c5a27139eccf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Enhanced Extraction of Vitamin C from Orange Peels using Microwave Technology: A Comparative Study with Conventional Heated Maceration","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003e \u003c/p\u003e\u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eVitamin C, chemically known as L-ascorbic acid (AA), is a vital water-soluble micronutrient and a potent antioxidant essential for human health. Since humans lack the L-gulono-gamma-lactone oxidase enzyme due to a genetic mutation, dietary intake of AA is mandatory for maintaining collagen synthesis, immune regulation, and iron absorption. Beyond its biological importance, the global market for Vitamin C was valued at 1.24\u0026nbsp;billion in 2022 and is projected to reach 1.97\u0026nbsp;billion by 2025, driven by a growing industrial shift toward \"natural\" and \"clean label\" ingredients .\u003c/p\u003e \u003cp\u003eCurrently, citrus fruits represent the primary source of AA. However, the citrus processing industry generates massive quantities of waste—peels and seeds—which constitute nearly 50% of the total fruit weight. Global citrus production rose from 105.9\u0026nbsp;million tons in 2000 to 161.8\u0026nbsp;million tons in 2021, leading to significant environmental and economic challenges regarding waste disposal. Interestingly, citrus peels are not merely \"refuse\" but a rich matrix containing bioactive compounds such as flavonoids (hesperidin and naringenin), pectin, and essential oils (D-limonene). Critically, studies indicate that orange peels contain approximately three times the concentration of ascorbic acid found in the pulp (ranging from 10–100 mg/100 g), making them a superior substrate for bio-resource recovery.\u003c/p\u003e \u003cp\u003eDespite this potential, extracting AA remains a chemical engineering challenge due to its inherent susceptibility to thermal degradation and oxidation. Traditional methods such as Maceration and Soxhlet Extraction are widely used but suffer from significant drawbacks, including excessive time consumption (hours to days), high energy requirements, and potential degradation of the heat-sensitive AA during prolonged exposure to high temperatures. Furthermore, chemical synthesis via the Reichstein process or two-step fermentation involves complex multi-step reactions and hazardous solvents .\u003c/p\u003e \u003cp\u003eTo address these limitations, \"Green Extraction\" technologies have emerged as sustainable alternatives. Microwave-Assisted Extraction (MAE) stands out as a highly efficient technique that utilizes a unique heat transfer mechanism—heating the plant matrix directly and instantly without preheating tube walls. This allows for achieving optimal extraction temperatures in a fraction of the time required by conventional heating, significantly reducing energy consumption and preserving the biological activity of the AA. While other green methods like Supercritical Fluid Extraction (SFE) and Pressurized Fluid Extraction (PLE) offer high yields, they often require high initial capital investment and complex high-pressure equipment .\u003c/p\u003e \u003cp\u003eThe primary aim of this research is to develop an optimized engineering process for extracting high-quality ascorbic acid from orange peel waste. This study focuses on comparing the efficiency of Microwave-Assisted Extraction (MAE) against conventional Maceration, evaluating parameters such as yield, time, and energy efficiency. Additionally, the research investigates a novel stabilization approach using Licorice extract (rich in glycyrrhizin) to enhance the chemical stability and solubility of the final AA extract. By integrating waste valorization with green engineering, this work contributes to a circular economy and provides a cost-effective solution for the nutraceutical industry.\u003c/p\u003e \u003c/div\u003e "},{"header":"2. Materials and Methods","content":"\u003cp\u003eThis section describes the experimental procedures, materials, and analytical protocols used to evaluate the efficiency of microwave-assisted extraction (MAE) compared to conventional thermal maceration (CHM).\u003c/p\u003e\u003ch2\u003e2.1. Materials and Sample Preparation\u003c/h2\u003e\u003cp\u003eFresh oranges (Citrus sinensis) were obtained from a local market in Diwaniyah, Iraq. The peels were manually separated. The sample was dried by exposure to room temperature for two days. The dried peels were then ground into a very fine powder.\u003c/p\u003e\u003ch2\u003e2.2. Extraction method\u003c/h2\u003e\u003ch2\u003e2.2.1. Microwave-Assisted Extraction (MAE)\u003c/h2\u003e\u003cp\u003eMicrowave-assisted extraction was performed using a domestic microwave system (rated maximum power 800 W) modified for laboratory observation. Mixture: 50.0 g of peel powder was mixed with 100 ml of acidified deionized water and 0.5 g of citric acid as a stabilizer to create an acidic environment and prevent the oxidation of ascorbic acid, which oxidizes in alkaline solutions.\u003c/p\u003e\u003cp\u003eOperating Parameters: Extraction was performed at a medium power setting (effective power ≈ 400 W) using pulsed irradiation (30 seconds on/10 seconds off) to prevent localized overheating.\u003c/p\u003e\u003cp\u003eDuration: The process took 2 minutes, with a constant temperature of 60°C reached in the third minute.\u003c/p\u003e\u003ch2\u003e2.2.2. Conventional Thermal Soaking (CHM)\u003c/h2\u003e\u003cp\u003eFor comparison, a conventional extraction was performed using a magnetic stirrer with a heating plate.\u003c/p\u003e\u003cp\u003eStandards: 50.0 g of powder in 100 mL of deionized water.\u003c/p\u003e\u003cp\u003eConditions: The mixture was stirred at 550 rpm at a constant temperature of 60°C for 45 minutes to ensure a fair comparison with the thermal stability of the microwave-assisted extraction method.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003ch2\u003e2.3. Analytical Procedures: Iodinated Titration\u003c/h2\u003e\u003cp\u003eThe concentration of the extracted ascorbic acid was determined using iodine titration, an analytical method based on redox reactions.\u003c/p\u003e\u003cp\u003ePreparation: 10 mL of the filtered extract was diluted, and 2 mL of a 1% starch solution was added as an internal indicator.\u003c/p\u003e\u003cp\u003eTitration: A titrant iodine solution (0.005 mol/L) was used.\u003c/p\u003e\u003cp\u003eEndpoint Determination: The titration continued until a sudden and sustained dark blue-black color appeared, indicating the complete oxidation of ascorbic acid and the formation of the starch-iodine complex. Calculation: The mass of ascorbic acid (mAA) was calculated using the standard relationship (weight of ascorbic acid (mg) = volume of iodine × 0.8806).\u003c/p\u003e\u003cp\u003e2.4. Energy Balancing and Sustainability Indicators: Mass and energy balances were performed to determine the sustainability of the two processes. Energy consumption (E) was calculated as the product of power (P) and time (t), while the energy savings ratio was calculated to assess the environmental impact of the ultrasonic extraction technique.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eanalyzes the experimental data obtained from Microwave-Assisted Extraction (MAE) and Conventional Heated Maceration (CHM), focusing on yield intensification and energy sustainability.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Comparative Yield Analysis\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe recovery of Ascorbic Acid (AA) was significantly enhanced by the application of microwave energy. As detailed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, MAE achieved a concentration of 9.74 mg/100mL, whereas CHM yielded only 7.04 mg/100mL, representing a 38.35% increase in extraction efficiency.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Thermal Gradient and Dielectric Heating Dynamics\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe core advantage of MAE lies in its unique heating mechanism. Unlike CHM, which relies on slow thermal conduction, MAE utilizes Dipole Rotation. At a frequency of 2450 MHz, the electric field oscillates 2.45\u0026nbsp;billion times per second, causing water molecules inside the orange peel cells to rotate frantically.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1. The \"Inside-Out\" Heating Phenomenon\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eAs illustrated in the thermal profile (Fig.\u0026nbsp;1), a steep Thermal Gradient is established. The localized friction generates heat \"from the inside out,\" creating a rapid increase in intracellular pressure. This pressure exceeds the mechanical strength of the cellulose cell walls, leading to their rupture\u0026mdash;a process termed \"micro-explosions.\" This allows the solvent to penetrate the matrix instantly, explaining why MAE reached the maximum yield in 2 minutes, while CHM required 45 minutes.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2. Thermal Steady-State and Degradation Prevention\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eVitamin C is highly sensitive to the \"Thermal History\" of the process. In CHM, the 45-minute exposure to the hot plate caused significant oxidation of the furanose ring. In contrast, the MAE system reached a Steady-State at 60\u0026deg;C within 180 seconds, minimizing the residence time at high temperatures and preserving the chemical integrity of the Ascorbic Acid.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Mass and Energy Balance (Sustainability Metrics)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe engineering efficiency of the process was quantified through a global energy balance.\u003c/p\u003e \u003cp\u003eConventional Energy (E_conv): 400 W \\times 2700 s\u0026thinsp;=\u0026thinsp;1080 kJ.\u003c/p\u003e \u003cp\u003eMicrowave Energy (E_MAE): 400 W \\times 120 s\u0026thinsp;=\u0026thinsp;48 kJ.\u003c/p\u003e \u003cp\u003eEnergy Savings: 95.5%.\u003c/p\u003e \u003cp\u003eThe 95.5% reduction in energy consumption confirms that MAE is not just a faster alternative, but a foundational technology for \"Green Engineering\" in the Iraqi agricultural sector. By heating the target molecules directly rather than the surrounding environment (glassware and air), MAE decouples high-yield production from high-carbon intensity.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Stoichiometric Validation\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe 1:1 stoichiometric relationship was validated by the sharp transition to a deep blue-black color at the endpoint. The consumption of 8.3 mL of Iodine for the MAE sample confirms the high density of recovered bioactive molecules, validating the accuracy of the proposed mass balance\u003c/p\u003e \u003cp\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003etitration results\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExperiment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eV(SAMPLE)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eV(Titrant)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eExtracted mass in the flask\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eConcentration in each 100 ml\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMicrowave assisted extraction (MAE)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.3mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.31mg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.74 mg/100 ml\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConventional Heated Maceration (CHM)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.52mg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.04 mg/100 ml\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e(\u003cb\u003ea\u003c/b\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(\u003cb\u003eb\u003c/b\u003e)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure(a).\u003c/b\u003e Thermal gradient and kinetic heating profile of Microwave-Assisted Extraction (MAE). The plot illustrates the rapid transition phase reaching the target steady-state temperature of 60\u0026deg;C within 180 seconds, showcasing the efficiency of dipole rotation heating.\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure 2.\u003c/b\u003e Temperature profile during Conventional Heated Maceration (CHM). The graph depicts the extended time required to reach the extraction temperature (60\u0026deg;C) and the thermal stability maintained over the 45-minute extraction duration.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Formatting of Mathematical Components\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eThe weight of ascorbic acid in the tested sample is calculated using the following formula\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight of ascorbic acid (mg) = Volume of iodine solution (mL) \u0026times; Iodine concentration (mol/L) \u0026times; Molecular weight of ascorbic acid (g/mol) \u0026hellip;\u0026hellip;\u0026hellip;(1)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWhere\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eVolume of iodine solution: The volume of iodine solution drawn from the burette (mL).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eIodine concentration: The molar concentration of the iodine solution (0.005 mol/L).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMolecular weight of ascorbic acid: The molecular weight of ascorbic acid (176.12 g/mol).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003e(Substituting the constants)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight AA (mg) = Volume of iodine \u0026times; 0.005 \u0026times; 176.12 \u0026hellip;\u0026hellip;. (2)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight AA (mg) = Volume of iodine \u0026times; 0.8806 \u0026hellip;\u0026hellip; (3)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Calculating Concentration (mg/100 ml)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eTo standardize results and facilitate comparison between different extraction methods, the final concentration is expressed in mg per 100 ml of extract\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration (mg/100 ml) = (Weight (mg) \u0026times; 100) / (Sample Volume (ml) \u0026hellip;. (4)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Sample Calculation (Microwave-Assisted Extraction Method)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eFor a sample extracted by microwave-assisted extraction (MAE), where the sample volume is 75 mL and the volume of iodine is 8.3 mL\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass in the flask: 8.3 \u0026times; 0.8806\u0026thinsp;=\u0026thinsp;7.309 mg\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration: (7.309 / 75) \u0026times; 100\u0026thinsp;=\u0026thinsp;9.74 mg/100 mL \u0026hellip;. (5)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Example Calculation (Traditional Method)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eFor a sample heated using the traditional method, where the sample volume is 50 mL and the volume of iodine is 4 mL\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass in the flask: 4 \u0026times; 0.8806\u0026thinsp;=\u0026thinsp;3.522 mg \u0026hellip;. (6)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration: (3.522 / 50) \u0026times; 100\u0026thinsp;=\u0026thinsp;7.04 mg/100 mL \u0026hellip;. (7)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eThe weight of ascorbic acid in the tested sample is calculated using the following formula\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight of ascorbic acid (mg) = Volume of iodine solution (mL) \u0026times; Iodine concentration (mol/L) \u0026times; Molecular weight of ascorbic acid (g/mol) \u0026hellip;\u0026hellip;\u0026hellip;(1)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWhere\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eVolume of iodine solution: The volume of iodine solution drawn from the burette (mL).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eIodine concentration: The molar concentration of the iodine solution (0.005 mol/L).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMolecular weight of ascorbic acid: The molecular weight of ascorbic acid (176.12 g/mol).\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003e(Substituting the constants)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight AA (mg) = Volume of iodine \u0026times; 0.005 \u0026times; 176.12 \u0026hellip;\u0026hellip;. (2)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWeight AA (mg) = Volume of iodine \u0026times; 0.8806 \u0026hellip;\u0026hellip; (3)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Calculating Concentration (mg/100 ml)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eTo standardize results and facilitate comparison between different extraction methods, the final concentration is expressed in mg per 100 ml of extract\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration (mg/100 ml) = (Weight (mg) \u0026times; 100) / (Sample Volume (ml) \u0026hellip;. (4)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Sample Calculation (Microwave-Assisted Extraction Method)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eFor a sample extracted by microwave-assisted extraction (MAE), where the sample volume is 75 mL and the volume of iodine is 8.3 mL\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass in the flask: 8.3 \u0026times; 0.8806\u0026thinsp;=\u0026thinsp;7.309 mg\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration: (7.309 / 75) \u0026times; 100\u0026thinsp;=\u0026thinsp;9.74 mg/100 mL \u0026hellip;. (5)\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Example Calculation (Traditional Method)\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eFor a sample heated using the traditional method, where the sample volume is 50 mL and the volume of iodine is 4 mL\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass in the flask: 4 \u0026times; 0.8806\u0026thinsp;=\u0026thinsp;3.522 mg \u0026hellip;. (6)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eConcentration: (3.522 / 50) \u0026times; 100\u0026thinsp;=\u0026thinsp;7.04 mg/100 mL \u0026hellip;. (7)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eMaterial balance was performed based on the experimental inputs (dried orange peel powder and distilled water) and outputs (liquid extract and wet residue).\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eBasis: Single extraction batch (50 g solids / 100 mL solvent)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal Input (Min)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of orange peel powder (S): 50.0 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of distilled water (L): 100.0 g (assuming density\u0026thinsp;=\u0026thinsp;1 g/cm\u0026sup3;)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of stabilizer (citric acid): 0.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal (Min)\u0026thinsp;=\u0026thinsp;150.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal Output (Mout)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eRecovered liquid extract (E): 84.2 g (measured after filtration)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWet solid residue (R): 62.3 g (solvent remaining in pores)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eExperimental losses (Loss): 4.0 g (evaporation\u0026thinsp;+\u0026thinsp;handling)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal (Mout)\u0026thinsp;=\u0026thinsp;150.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eProcess Efficiency\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eExtraction ratio = (Mass of extract / Mass of solvent) \u0026times; 100\u0026thinsp;=\u0026thinsp;84.2 / 100 84.2%\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Energy Balancing and Sustainability Assessment\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eBased on the specifications provided for a domestic microwave (rated output power: 800 watts) and an electric hob, the energy consumption for each method was calculated.\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e1. Conventional Heating Power (Econv): (dup: abstract ?)\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003ePower (P): 400 W (medium hob setting)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTime (t): 45 minutes (2700 seconds)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEconv\u0026thinsp;=\u0026thinsp;P \u0026times; t\u0026thinsp;=\u0026thinsp;400 J/s \u0026times; 2700 seconds\u0026thinsp;=\u0026thinsp;1,080,000 J\u0026thinsp;=\u0026thinsp;1080 kJ\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e2. Microwave Heating Power (EMAE): (dup: abstract ?)\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eRated Operating Power (P): 400 W (medium setting)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEffective Radiation Time (t): 2 minutes (120 seconds)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEMAE\u0026thinsp;=\u0026thinsp;P \u0026times; t\u0026thinsp;=\u0026thinsp;400 J/s \u0026times; 120 seconds\u0026thinsp;=\u0026thinsp;48,000 J\u0026thinsp;=\u0026thinsp;48 kJ\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e3.Comparison and Energy Savings: (dup: abstract ?)\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eThe energy efficiency of the green extraction method is calculated as follows\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eEnergy Saving % = (1080\u0026ndash;48) / 1080 \u0026times; 100\u0026thinsp;=\u0026thinsp;95.5%Basis: Single extraction batch (50 g solids / 100 mL solvent)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal Input (Min)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of orange peel powder (S): 50.0 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of distilled water (L): 100.0 g (assuming density\u0026thinsp;=\u0026thinsp;1 g/cm\u0026sup3;)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eMass of stabilizer (citric acid): 0.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal (Min)\u0026thinsp;=\u0026thinsp;150.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal Output (Mout)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eRecovered liquid extract (E): 84.2 g (measured after filtration)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eWet solid residue (R): 62.3 g (solvent remaining in pores)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eExperimental losses (Loss): 4.0 g (evaporation\u0026thinsp;+\u0026thinsp;handling)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTotal (Mout)\u0026thinsp;=\u0026thinsp;150.5 g\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eProcess Efficiency\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eExtraction ratio = (Mass of extract / Mass of solvent) \u0026times; 100\u0026thinsp;=\u0026thinsp;84.2 / 100\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e84.2%\u003c/h3\u003e\n\u003cdiv id=\"Sec26\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e4.4.2. Energy Balancing and Sustainability Assessment\u003c/div\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eBased on the specifications provided for a domestic microwave (rated output power: 800 watts) and an electric hob, the energy consumption for each method was calculated.\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e1. Conventional Heating Power (Econv):\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003ePower (P): 400 W (medium hob setting)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eTime (t): 45 minutes (2700 seconds)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEconv\u0026thinsp;=\u0026thinsp;P \u0026times; t\u0026thinsp;=\u0026thinsp;400 J/s \u0026times; 120 seconds\u0026thinsp;=\u0026thinsp;1,080,000 J\u0026thinsp;=\u0026thinsp;1080 kJ\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e2. Microwave Heating Power (EMAE):\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eRated Operating Power (P): 400 W (medium setting)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEffective Radiation Time (t): 2 minutes (120 seconds)\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eEMAE\u0026thinsp;=\u0026thinsp;P \u0026times; t\u0026thinsp;=\u0026thinsp;400 J/s \u0026times; 120 seconds\u0026thinsp;=\u0026thinsp;48,000 J\u0026thinsp;=\u0026thinsp;48 kJ\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e3.Comparison and Energy Savings:\u003c/h3\u003e\n\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eThe energy efficiency of the green extraction method is calculated as follows\u003c/em\u003e:\u003c/p\u003e \u003cp\u003e \u003cem\u003eEnergy Saving % = (1080\u0026ndash;48) / 1080 \u0026times; 100\u0026thinsp;=\u0026thinsp;95.5%\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe enhanced performance of the MAE system is attributed to the following engineering phenomena:\u003c/p\u003e \u003cp\u003eDisruption of Cellular Matrix: Unlike conventional heating which relies on thermal conduction, microwaves cause localized high-pressure buildup within the plant cells. This \"micro-explosion\" effect shatters the cell walls, providing an unobstructed pathway for the ascorbic acid to dissolve into the solvent.\u003c/p\u003e \u003cp\u003eSelective Heating: Water molecules (the solvent) have a high dielectric constant, absorbing microwave energy directly. This creates a \"thermal driving force\" where the temperature inside the peel particles rises faster than the surrounding bulk liquid, significantly accelerating the mass transfer rate.\u003c/p\u003e \u003cp\u003ePreservation Effect: The total processing time for MAE was 88.8% lower than the conventional method (2 min vs. 45 min). This drastic reduction in thermal residence time prevented the secondary oxidation of Vitamin C, which is highly unstable at sustained temperatures of 60\u0026deg;C.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003e5.1.1 Efficiency of Microwave-Assisted Extraction (MAE) and Cell Rupture Theory: The high yield is attributed to the \u0026apos;localized heating\u0026apos; effect, where microwave radiation interacts with the polar water molecules inside the orange peel cells. This interaction causes a rapid increase in internal pressure, leading to the rupture of cell walls, a process known as the \u0026apos;Cell Rupture\u0026apos;.\u003c/p\u003e\n\u003cp\u003e5.1.2 Thermal Degradation and Exposure Time Optimization: In conventional heating, a 45-minute exposure leads to the oxidation of the furanose ring in ascorbic acid. In contrast, the microwave-assisted extraction (MAE) cycle, which lasts only 5 minutes, reduces the thermal residence time, thereby maintaining the integrity of the vitamin.\u003c/p\u003e\n\u003cp\u003e5.1.3 Stabilization and Antioxidant Synergy of Citric Acid: The addition of 0.5g of citric acid successfully lowered the pH, acting as a chelating agent that inhibits the catalytic oxidation of the extract.\u003c/p\u003e\n\u003cp\u003e5.1.4 Dielectric Properties and Dipole Rotation of Deionized Water: Water, by its nature, is one of the most efficient solvents for microwave response due to its exceptionally high dipole moment. Water molecules are highly receptive to absorbing microwave energy, rotating at immense speeds, which generates rapid heating\u003c/p\u003e\n\u003cp\u003e5.1.5 Analytical Validation and Benchmarking:\u003c/p\u003e\n\u003cp\u003eQuantitative Dominance: The titration results confirmed that the sample treated with MAE required 8.3 mL of Iodine (V Sample = 75 mL), resulting in a calculated concentration of 9.74 mg/100mL. This remains the highest recorded value in this study, proving that the chemical integrity of the Ascorbic Acid molecules was preserved despite the high-energy microwave pulses.\u003c/p\u003e\n\u003cp\u003eSensitivity to Thermal History: The lower Iodine consumption in conventional samples (4.0 mL) directly correlates with the \u0026quot;Thermal History\u0026quot; of the sample. Long-term exposure to heat (45 min) initiated the degradation of the Ene-diol group in Ascorbic Acid, making it less reactive with the Iodine titrant.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.S. and H.A. conceived and designed the research. M.S. performed the laboratory experiments, including extraction processes and titration analysis, and conducted the mathematical calculations and data processing. H.F. was responsible for the theoretical formulation, literature review, and drafting the initial manuscript documents. H.A. supervised the study, provided critical academic feedback, and revised the final manuscript. All authors have read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eFunding Statement:\u003c/strong\u003e\u0026nbsp; The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e\u0026nbsp; \u0026nbsp;The authors have no relevant financial or non-financial interests to disclose\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAli, A., Riaz, S., Khalid, W., Fatima, M., Mubeen, U., Babar, Q., Manzoor, M. F., Zubair Khalid, M., \u0026amp; Madilo, F. K. (2024). Potential of ascorbic acid in human health against different diseases: an updated narrative review. In International Journal of Food Properties (Vol. 27, Number 1, pp. 493\u0026ndash;515). Taylor and Francis Ltd. https://doi.org/10.1080/10942912.2024.2327335\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAli Anwar, S. R. W. K. M. F. (n.d.). Potential of ascorbic acid in human health against different diseases: an updated narrative review.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAscorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies. (n.d.).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBelayneh Asfaw, T., Getachew Tadesse, M., Beshah Tessema, F., Woldemichael Woldemariam, H., V. Chinchkar, A., Singh, A., Upadhyay, A., \u0026amp; Mehari, B. (2024). Ultrasonic-assisted extraction and UHPLC determination of ascorbic acid, polyphenols, and half-maximum effective concentration in Citrus medica and Ziziphus spina-christi fruits using multivariate experimental design. Food Chemistry: X, 22. https://doi.org/10.1016/j.fochx.2024.101310\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCalder, P. C., Kreider, R. B., \u0026amp; McKay, D. L. (2025a). Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults. In Nutrients (Vol. 17, Number 2). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/nu17020279\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCalder, P. C., Kreider, R. B., \u0026amp; McKay, D. L. (2025b). Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults. In Nutrients (Vol. 17, Number 2). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/nu17020279\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChapter\u0026nbsp;4 - Vitamin C: The Metabolism and Functions of Ascorbic Acid in Plants. (n.d.).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGhorbani, M., Aboonajmi, M., Ghorbani Javid, M., \u0026amp; Arabhosseini, A. (n.d.). Optimization of ultrasound-assisted extraction of ascorbic acid from fennel (Foeniculum vulgare) seeds and evaluation its extracts in free radical scavenging. In Agricultural Engineering International: CIGR Journal (Vol. 19, Number 4). Retrieved http://www.cigrjournal.org\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGita Rizkasari, R. I. (n.d.). Determination of Vitamin C Levels in Limes (Citrus aurantifolia Swingle) and Lemon (Citrus limon (L.) Burm. f.) Using the UV Vis Spectrophotometric Method.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGomez-Urios, C., Mbuy, I., Esteve, M. J., Blesa, J., Frigola, A., \u0026amp; Lopez-Malo, D. (2022). Reusing Food Waste: Ascorbic Acid Extraction from Orange Peel Using Ultrasound-Assisted Extraction and Natural Deep Eutectic Solvents. 29. https://doi.org/10.3390/foods2022-12976\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHancock, R. D., \u0026amp; Viola, R. (2001). The use of micro-organisms for L-ascorbic acid production: Current status and future perspectives. In Applied Microbiology and Biotechnology (Vol. 56, Numbers 5\u0026ndash;6, pp. 567\u0026ndash;576). https://doi.org/10.1007/s002530100723\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJain, S., Yadav, A. S., \u0026amp; Gothalwal, R. (2021a). ASSESSMENT OF TOTAL PHENOLIC, FLAVONOID CONTENT AND IN VITRO ANTIOXIDANT PROPERTIES OF ALCHEMILLIA VULGARIS (LADY\u0026rsquo;S MANTLE). In Journal of Advanced Scientific Research (Vol. 12, Number 4). http://www.sciensage.info\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJain, S., Yadav, A. S., \u0026amp; Gothalwal, R. (2021b). ASSESSMENT OF TOTAL PHENOLIC, FLAVONOID CONTENT AND IN VITRO ANTIOXIDANT PROPERTIES OF ALCHEMILLIA VULGARIS (LADY\u0026rsquo;S MANTLE). In Journal of Advanced Scientific Research (Vol. 12, Number 4). http://www.sciensage.info\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMazurek, A., \u0026amp; Włodarczyk-Stasiak, M. (2023). A New Method for the Determination of Total Content of Vitamin C, Ascorbic and Dehydroascorbic Acid, in Food Products with the Voltammetric Technique with the Use of Tris(2-carboxyethyl)phosphine as a Reducing Reagent. Molecules, 28(2). https://doi.org/10.3390/molecules28020812\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMemnune Şeng\u0026uuml;l. (n.d.). Vitamin C, Sugar Content, Color Intensity and Some Physicochemical Properties of Watermelon and Orange Peels.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSalar, F. J., D\u0026iacute;az-Morcillo, A., Fayos-Fern\u0026aacute;ndez, J., Monz\u0026oacute;-Cabrera, J., S\u0026aacute;nchez-Bravo, P., Dom\u0026iacute;nguez-Perles, R., Fern\u0026aacute;ndez, P. S., Garc\u0026iacute;a-Viguera, C., \u0026amp; Periago, P. M. (2024). Microwave Treatment vs. Conventional Pasteurization: The Effect on Phytochemical and Microbiological Quality for Citrus\u0026ndash;Maqui Beverages. Foods, 13(1). https://doi.org/10.3390/foods13010101\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSkrovankova, S., Mlcek, J., Sochor, J., Baron, M., Kynicky, J., \u0026amp; Jurikova, T. (2015). Determination of ascorbic acid by electrochemical techniques and other methods. International Journal of Electrochemical Science, 10(3), 2421\u0026ndash;2431. https://doi.org/10.1016/s1452-3981(23)04857-5\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSusa, F., \u0026amp; Pisano, R. (2023). Advances in Ascorbic Acid (Vitamin C) Manufacturing: Green Extraction Techniques from Natural Sources. In Processes (Vol. 11, Number 11). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/pr11113167\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTucaliuc, A., C\u0026icirc;șlaru, A., Kloetzer, L., \u0026amp; Blaga, A. C. (2022). Strain Development, Substrate Utilization, and Downstream Purification of Vitamin C. In Processes (Vol. 10, Number 8). MDPI. https://doi.org/10.3390/pr10081595\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeiqing Zhang Mei Lin Hongju He Yuling Wang Jingru Wang and Hongjie Liu. (n.d.). Toward Achieving Rapid Estimation of Vitamin C in Citrus Peels by NIR Spectra Coupled with a Linear Algorithm.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWychowański, P., Starzyńska, A., Jereczek-Fossa, B. A., Iwanicka-Grzegorek, E., Kosewski, P., Adamska, P., \u0026amp; Woliński, J. (2020). The Effects of Smoking Cigarettes on Immediate Dental Implant Stability\u0026mdash;A Prospective Case Series Study. Applied Sciences, 11(1), 27. https://doi.org/10.3390/app11010027\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":"","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":"microwave-assisted extraction, ascorbic acid, orange peel waste, green engineering, energy efficiency, bio-waste valorization","lastPublishedDoi":"10.21203/rs.3.rs-9280173/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9280173/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eVitamin C (Ascorbic Acid) is an essential nutrient for human health, playing a vital role in immune system enhancement, collagen synthesis, and connective tissue support. While citrus fruits are primary sources, orange peels constitute approximately 15% of the total fruit weight and contain nearly three times the ascorbic acid concentration found in the pulp. Utilizing these peels\u0026mdash;typically considered agricultural waste\u0026mdash;presents a highly sustainable and economically viable opportunity for bio-resource recovery.\u003c/p\u003e \u003cp\u003eThis study focuses on a comparative performance analysis between Microwave-Assisted Extraction (MAE) and Conventional Heated Maceration (CHM). Our results demonstrate that MAE technology achieved a 38.3% increase in Vitamin C yield compared to conventional methods. Notably, the extraction time was drastically reduced from 45 minutes to just 2 minutes, reflecting a high energy efficiency with 94.1% savings. Furthermore, a stable thermal steady-state of 60\u0026deg;C was achieved within 180 seconds, effectively preventing the thermal degradation of the heat-sensitive ascorbic acid. These findings establish MAE as a superior, green engineering solution for the industrial valorization of citrus by-products.\u003c/p\u003e","manuscriptTitle":"Enhanced Extraction of Vitamin C from Orange Peels using Microwave Technology: A Comparative Study with Conventional Heated Maceration","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-01 06:04:57","doi":"10.21203/rs.3.rs-9280173/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":"9c083619-2744-4473-87a5-28441b4cf15e","owner":[],"postedDate":"April 1st, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-14T17:11:43+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-01 06:04:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9280173","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9280173","identity":"rs-9280173","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}