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.

This study evaluated the positive effects of autumn olive berries (AOBs) extract on delaying aging by improving lipid metabolism in middle-aged Caenorhabditis elegans that had become obese due to a high-glucose (GLU) diet. The total phenolic content and DPPH radical scavenging abilities of freeze-dried AOBs (FAOBs) or spray-dried AOBs (SAOBs) were examined, and FAOBs exhibited better antioxidant activity. HPLC analysis confirmed that catechin is the main phenolic compound of AOBs; its content was 5.95 times higher in FAOBs than in SAOBs. Therefore, FAOBs were used in subsequent in vivo experiments. FAOBs inhibited lipid accumulation in both the young adult and middle-aged groups in a concentration-dependent manner under both normal and 2% GLU conditions. Additionally, FAOBs inhibited ROS accumulation in a concentration-dependent manner under normal and 2% GLU conditions in the middle-aged worms. In particular, FAOB also increased body bending and egg production in middle-aged worms. To confirm the intervention of genetic factors related to lipid metabolism from the effects of FAOB, body lipid accumulation was confirmed using worms deficient in the daf-16, atgl-1, aak-1, and akt-1 genes. Regarding the effect of FAOB on reducing lipid accumulation, the impact was nullified in daf-16-deficient worms under the 2% GLU condition, and nullified in both the daf-16- and atgl-1-deficient worms under fasting conditions. In conclusion, FAOB mediated daf-16 and atgl-1 to regulate lipogenesis and lipolysis in middle-aged worms. Our findings suggest that FAOB improves lipid metabolism in metabolically impaired middle-aged worms, contributing to its age-delaying effect.

This study aimed to evaluate the positive effect of autumn olive berries (AOB) extract on aging delay by improving the lipid metabolism of middle-aged C. elegans who became obese due to high glucose (GLU) diet. As a result of investigating the total phenol content and DPPH radical scavenging ability of freeze- or spray-dried AOB, freeze-dried AOB showed better antioxidant potential. Afterward, through HPLC analysis, it was confirmed that catechin was the main compound in the polyphenols of AOB. Therefore, we used freeze-dried AOB in subsequent in vivo experiments. AOB inhibited lipid accumulation in both the young adult and middle-aged groups in a concentration-dependent manner under both normal and 2% GLU conditions. Additionally, AOB inhibited ROS accumulation in a concentration-dependent manner under normal and 2% GLU conditions in the middle-aged worms. In particular, AOB also increased the number of body bending and egg production in middle-aged worms. To confirm the intervention of genetic factors related to lipid metabolism in the effect of AOB, body lipid accumulation was confirmed using worms deficient in the daf-16, atgl-1, aak-1, and akt-1. Regarding the effect of AOB on reducing lipid accumulation, the impact was nullified in daf-16 deficient worms under the 2% GLU condition and nullified in both daf-16 and deficient worms under fasting conditions. This means that AOB regulates lipogenesis and lipolysis by mediating daf-16 and atgl-1 in middle-aged worms. Our results suggest that AOB contributes to the aging delay effect by improving lipid metabolism in metabolic impaired middle-aged worms.