Sustainable Versus Conventional Bioactive Extractions from Tunisian Carob Pulp: Evaluation of Polyphenol Profile by HPLC-HRMS, Antioxidant Capacity and Chemometric Analysis

Carob pulp is a Mediterranean by-product highlighted as an important source of bioactive compounds potentially used in different industrial applications. This paper deals with the comparison of methods elaborated with combinations of conventional (maceration-M, organic solvents and water) and non-conventional green (ultrasound-assisted extraction -UAE, and natural deep eutectic solvents -NADES) extraction approaches and using chemometric tools for screening the polyphenol profile by HPLC-HRMS and bioactive potential measured by Folin-Ciocalteu, DPPH and ABTS assays of carob pulp from two Tunisian ubications (North and South). Regarding the factors studied (extraction technique and solvent, and geographical location), the solvent marked the higher variability found for the different families of compounds studied. The highest yield of total phenolics was achieved by the conventional method ethanol 75%-M (5023.92 µg/g) and the green approaches water-UAE (5008.32 µg/g), followed by the NADES lactic acid: sodium acetate (3:1) (3117.23 µg/g). The latter standing out for its contents in flavonols and hydrolizable tannins and antioxidant potential. The two Tunisian locations studied showed differentiation in the phenolic content depending on the extraction method. However, in general, higher contents were observed in extracts from the southern region. The chemometric evaluation confirm the suitability of the proposed green methods as excellent powerful tools for bioactive extraction from carob pulp, with similar, improved or highly selective phenolic recoveries compared to the conventional methods assessed.