Deep eutectic solvent (DES)-assisted extraction of pectin from Ficus carica Linn. peel: optimization, partial structure characterization, functional and antioxidant activities.

BACKGROUND: The pectin from Ficus carica Linn. (fig) peels is a valuable and recyclable constituent that may bring huge economic benefits. To maximize the utilization of this resource, deep eutectic solvent (DES)-assisted extraction was applied to extract pectin from fig peels, and the extraction process was optimized with response surface methodology. RESULTS: When DES (choline chloride/oxalic acid = 1:1) content was 168.1 g kg-1, extraction temperature was 79.8 °C, liquid-solid ratio was 23.3 mL g-1, and extraction time was 120 min, the maximum yield of 239.6 g kg-1 was obtained, which was almost twice the extraction of hot water. DES-extracted fig peel pectin (D-FP) exhibited better nature than hot water-extracted fig peel pectin (W-FP) in terms of uronic acid content, particle size distribution, and solubility, but lower molecular weight and esterification degree. D-FP and W-FP had similar infrared spectra and thermodynamic peaks but differed in monosaccharide compositions. D-FP also showed good antioxidant capacities and exhibited better functional activities than W-FP. CONCLUSION: These results indicated that D-FP was of promising quality being utilized in food or medical industries and the optimal DES-assisted extraction method might be applied as a sustainable process for the effective extraction of bioactive pectin from fig peels with the excellence of low equipment requirements and simple operation. © 2024 Society of Chemical Industry.

Characterization of the (Poly)Phenolic Fraction of Fig Peel: Comparison among Twelve Cultivars Harvested in Tuscany.

(1) Background: The fig tree (Ficus carica L.) is widely cultivated in the Mediterranean area and it produces fruits largely consumed in the Mediterranean diet. Previous studies have shown that this fruit represents a rich source of (poly)phenols, which are mainly located in the peel rather than the pulp. In our study, fig peel derived from twelve different cultivars located in Tuscany was assessed for its (poly)phenol profile. (2) Methods: The (poly)phenol characterization was performed through ultra-high performance liquid chromatography coupled to multiple-stage mass spectrometry. (3) Results: Twenty-eight (poly)phenolic compounds were quantified in the investigated fig peel. It was possible to observe an interesting variability in the (poly)phenol content among the twelve cultivars of fig peel. Rutin and 5-caffeoylquinic acid were the main compounds in the greenish fig peel, while cyanidin-3-O-rutinoside was the main component in the dark-violet fig peel. (4) Conclusions: fig peel could be used as a (poly)phenol-rich ingredient in several food products to increase the bioactive compound content of foods. Moreover, dark-violet peel could be considered potentially suitable as a natural food colorant.