Mechanism underlying the effect of soluble oat β-glucan and tea polyphenols on wheat gluten aggregation...

The mechanism of how the coexistence of oat β-glucan (OβG) and tea polyphenols (TP) impacts gluten aggregation properties was investigated. The OβG might form interchain hydrogen bondings and compete for water with gluten, which could increase gluten aggregation and the gluten network's expansion, leading to its increasing average particle size (by 17.23 %) with 5%OβG. The physicochemical characteristics of TP and OβG + TP groups showed similar changing trends, indicating the predominant effect of TP; however, the effect was, to some extent, enhanced with the presence of OβG. This might be because OβG induced a more expanded network of gluten, favoring the access and attack of TP to unfold or disrupt the gluten structure by breaking disulfide bonds, as confirmed by the red-shifts in fluorogram, increasing content of free sulfhydryl by 250 % (without OβG) and 312 % (with OβG), and decreasing particle size of gluten by 10.43 % (without OβG) and 21.08 % (with OβG) when the addition of TP was 2 %. Moreover, with the increasing of TP, the tremendous unfolding or disrupting gluten structure exposed more amino acids whereas decreased the intermolecular contacts and extended chains of gluten, consequently leading to the increasing hydrogen bonds and hydrophobic interactions while reducing the content of β-sheets, respectively.