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One stage hydrothermal treatment: A green strategy for simultaneous extraction of food hydrocolloid and co-products from sweet lime (Citrus Limetta) peels
Journal
Food Hydrocolloids
ISSN
0268005X
Date Issued
2023-01-01
Author(s)
Das, Ipsita
Arora, Amit
Abstract
The potential of a one-stage hydrothermal (HT) process using water as an extraction medium was investigated for the simultaneous extraction of pectin and phenols from Citrus limetta peels (CLP). A statistical experimental design based on response surface methodology was applied to evaluate the effect of temperature (100–120 °C), time (5–25 min), and liquid-to-solid ratio (10–20 mL/g) on extraction yield and optimize the process. The optimal conditions for the highest extraction yield (23.8% pectin and 1.2% phenol) were obtained at 112.2 °C, 17.1 min, and 14.3 mL/g. Experimental results were well matched with predicted values (p > 0.05). The pectin obtained under optimal HT conditions was evaluated for its physicochemical, structural, and thermal properties and the phenolic extract for its antioxidant potential and individual phenolic. The results indicated that the HT extract was rich in galacturonic acid (70.6 ± 1.3%), high in degree of esterification (71.2 ± 1.0%), and molecular weight (330.9 kDa), and the values were comparable to commercial pectin. Further, spectroscopy analysis (FT-IR and 1H NMR) confirmed the purity of pectin. Thermo-gravimetric analysis revealed the optimum degradation temperature of HT extract (227.3 °C) to be similar to the commercial pectin (231.3 °C) indicating its thermal stability. The higher antioxidant activity of the phenolic extract was indicated by lower IC50, higher FRAP, and ABTS values. The major flavonoids (mg/g dw) identified were kaempferol (0.84), rutin (0.82), quercetin (0.71), ferulic acid (0.46), caffeic (0.4) and gallic acid (0.31). These results suggested the suitability of HT as a one-step green extraction process for co-extracting pectin and phenols from CLP.
Volume
134
Subjects