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Rheology and microstructure of gels based on wheat arabinoxylans enzymatically modified in arabinose to xylose ratio
Author(s) -
MarquezEscalante Jorge A,
CarvajalMillan Elizabeth,
Yadav Madhav P,
Kale Madhuvanti,
RasconChu Agustín,
Gardea Alfonso A,
ValenzuelaSoto Elisa M,
LopezFranco Yolanda L,
LizardiMendoza Jaime,
Faulds Craig B
Publication year - 2018
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.8537
Subject(s) - microstructure , arabinose , ferulic acid , rheology , polysaccharide , covalent bond , xylose , crystallinity , chemistry , morphology (biology) , scanning electron microscope , polymer , materials science , chemical engineering , crystallography , chromatography , organic chemistry , composite material , fermentation , biology , engineering , genetics
BACKGROUND Arabinoxylans (AX) are polysaccharides consisting of a backbone of xyloses with arabinose substituents ester‐linked to ferulic acid (FA). The arabinose to xylose ratio (A/X) in AX may vary from 0.3 to 1.1. AX form covalent gels by cross‐linking of FA but physical interactions between AX chains also contribute to the network formation. The present study aimed to investigate the rheological and microstructural characteristics of gels based on AX enzymatically modified in A/X. RESULTS Tailored AX presented A/X ranging from 0.68 to 0.51 and formed covalent gels. Dimers of FA content and elasticity ( G ′) increased from 0.31 to 0.39 g kg –1 AX and from 106 to 164 Pa when the A/X in the polysaccharide decreased from 0.68 to 0.51. Atomic force microscopy images of AX gels showed a sponge‐like microstructure at A/X = 0.68, whereas, at lower values, gels presented a more compact microstructure. Scanning electron microscopy analysis of AX gels show an arrangement of different morphology, passing from an imperfect honeycomb (A/X = 0.68) to a flake‐like microstructure (A/X = 0.51). CONCLUSION Lower A/X values favor the aggregation of AX chains resulting in an increase in di‐FA content, which improves the rheological and microstructural characteristics of the gel formed. © 2017 Society of Chemical Industry