Inulin enhances transglutaminase-induced peanut protein gel:Insights into gel and structural properties

Peanut protein is abundant in peanut meal. However, conventional processing often causes protein denaturation and the decrease of functional properties. Inulin, a well-recognized prebiotic, improves the gel properties, but the effects and mechanisms of inulin on peanut protein are not clear. This research aimed to compare the impact of short-chain (DP ≤ 10) and long-chain (DP ≥ 23) inulin on the properties of transglutaminase-crosslinked peanut protein gels. Results demonstrated that inulin significantly enhanced both gel strength and water-holding capacity, with 0.5% long-chain achieving optimal results -increasing these parameters by 26.6% and 14.09%, respectively, compared to the control group. Notably, long-chain inulin demonstrated superior enhancement effects compared to short-chain inulin. Mechanistically, inulin promotes hydrophobic group exposure, strengthens disulfide bonds and hydrogen bonds, increases β-sheet content, and forms a more compact three-dimensional network. Additionally, the in vitro gastric digestibility of composite gels was reduced. These findings provide valuable theoretical support for the application of inulin as a natural gel enhancer in peanut protein-based food systems.