Changes in structural and chemical composition of insoluble dietary fibers bound phenolic complexes from grape pomace by alkaline hydrolysis treatment

Abstract

This study was aimed at explanation of evolution process of bound phenolics from IDF through structural modifications after alkaline hydrolysis along with free phenolics and functional characteristics. SEM results depicted that IDF with bound phenolics exhibited denser, more compact and tubular shape whereas, the surface features of alkali-hydrolyzed residue exhibited clear fragmentation, wrinkling and porosity on outside surfaces. Microstructure changes due to alkaline hydrolysis caused disintegration of linkages among hemicellulose and cellulose microfibers. As evident from the FTIR spectra, both IDF samples (with phenolic) and alkali-soluble residue (IDF without phenolics) exhibited resemblance in FTIR spectral features and characteristics bonds. Overall, the peak positions of IDF samples and alkali-hydrolyzed residue did not show any significant change, which was indicative of the fact that no major alterations were occurred in crystalline structures of IDF due to alkali-hydrolysis treatment. IDF-bound phenolic complexes showed the highest TPC, ABTS and FRAP than SDF. In IDF alkaline extracts, total 6 phenolic compounds were detected through HPLC. The identified phenolic compounds were as; salicylic acid, chlorogenic acid, syringic acid, epigallocatechin, p-coumaric acid and ferulic acid. These results demonstrated that higher antioxidant activity of dietary fiber would be related to bound phenolics.

Effects of Dehydrated Moringa (Moringa oleifera) Leaf Powder Supplementation on Physicochemical, Antioxidant, Mineral, and Sensory Properties of Whole Wheat Flour Leavened Bread

“…Te results of the present study for calories content of whole wheat four and moringa leaf powder have been in close afrmation with the earlier studies, wherein the contents of the calories for whole wheat four and moringa leaf powder were seen in a similar range, i.e., 11.25% and 26.28%, [40,43]. In a report by Jiang et al [45], ginseng insoluble dietary fber (GSI) was added to the wheat bread. and up to the addition levels of GSI, the fortifed bread showed improvement in mineral, proteins, and fber contents as compared to that of control.…”

Comprehensive Physical and Chemical Characterization of Corncob and Nopal Fibers: Exploring Sustainable Alternatives for High-Value Applications

“…Additionally, a peak at 1510 cm –1 in corncob samples is attributed to the C–C stretch inside aromatic rings, which are present in phenolic acids and lignin . Corncob and nopal samples showed peaks at 1632 and 1621 cm –1 , respectively, associated with the adsorbed water . The woody ring samples exhibited a higher signal and variations in the position of peaks in the alkyl region, which ranged from 2800 to 3000 cm –1 .…”

“…44 Corncob and nopal samples showed peaks at 1632 and 1621 cm −1 , respectively, associated with the adsorbed water. 48 The woody ring samples exhibited a higher signal and variations in the position of peaks in the alkyl region, which ranged from 2800 to 3000 cm −1 . These differences can be attributed to the symmetry of alkyl groups.…”

Impact of water combined wet ball milling extraction and functional evaluation of dietary fiber from papaya (Carica papaya L)

“…Studies have shown that the signal peaks about 14–15°and 21–23.5° could be due to the presence of cellulose crystals. Furthermore, the presence of non-crystalline cellulose, hemicellulose and lignin is reported to cause amorphousness in DFs ( Jiang, Wu, Ramachandra, Zhao, & Ameer, 2021 ). With regards to AL-DF, front peaks were observed at 2θ angles of 32.56, 36.87° and 43.29°, whereas these peaks were not observed in case of W-DF and WB-DF.…”