Nam Seonghyeon, Ozturk Oguz K, Lim Jongbin
Department of Food Bioengineering, Jeju National University, Jeju 63243, Republic of Korea.
Department of Food Science and Human Nutrition, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
Foods. 2025 Jan 13;14(2):233. doi: 10.3390/foods14020233.
In this study, we explored the binding mechanism between tannic acid (TA) and gluten to apply TA as an ingredient in bread-making to evaluate its baking performance and starch digestion. The interaction was systematically investigated by analyzing binding affinity, binding mode, and matrix structure of the TA-gluten complex using fluorescence quenching, molecular docking, and confocal laser scanning microscopy. TA strongly interacted with gluten via non-covalent interactions, mainly hydrogen bonds, and formed the major hydrogen bonds with six different glutamines (Q32, Q108, Q313, Q317, Q317, and Q349), which play a critical role in gluten network construction among amino acid residues of gluten. Additionally, TA showed lower binding affinity toward glutenin (-10.4 kcal/mol) compared to gliadin (-8.9 kcal/mol), implying stronger binding with glutenin. Consequently, the interaction between TA and gluten created a dense and compact gluten network structure. It influenced baking performance, causing a decrease in bread loaf volume while an increase in firmness and lowering the starch digestion rate, increasing slowly digestible starch and resistant starch fractions. This study identified the binding mechanism of TA toward gluten and provides better insights into how to apply TA or perhaps other polyphenols to design functional bakery products to control starch digestion rate.
在本研究中，我们探究了单宁酸（TA）与面筋之间的结合机制，以便将TA用作面包制作的一种成分，评估其烘焙性能和淀粉消化情况。通过使用荧光猝灭、分子对接和共聚焦激光扫描显微镜分析TA-面筋复合物的结合亲和力、结合模式和基质结构，对这种相互作用进行了系统研究。TA通过非共价相互作用（主要是氢键）与面筋强烈相互作用，并与六种不同的谷氨酰胺（Q32、Q108、Q313、Q317、Q317和Q349）形成主要氢键，这些谷氨酰胺在面筋氨基酸残基间的面筋网络构建中起关键作用。此外，与醇溶蛋白（-8.9 kcal/mol）相比，TA对谷蛋白（-10.4 kcal/mol）的结合亲和力较低，这意味着与谷蛋白的结合更强。因此，TA与面筋之间的相互作用形成了致密紧凑的面筋网络结构。它影响了烘焙性能，导致面包体积减小，同时硬度增加，并降低了淀粉消化率，增加了慢消化淀粉和抗性淀粉组分。本研究确定了TA与面筋的结合机制，并为如何应用TA或其他多酚来设计功能性烘焙产品以控制淀粉消化率提供了更好的见解。
