Investigating the role of alkaline pH shifting in modifying structure and fermentation-induced gelation properties of pea protein-casein binary composites

作者：Mei Yang, Nana Huang, Yuhan Tang, Y W Sun, Shuqi Zhang, Junjian Ran, Xueli Gao · 发表于：LWT · 年份：2026 · DOI：10.1016/j.lwt.2026.119642 · 研究领域：Proteins in Food Systems、Nanocomposite Films for Food Packaging、Collagen: Extraction and Characterization

This research investigated how alkaline pH shifting (pH 9–12) affects the structural characteristics and fermentation-induced gelation of pea protein (PP) as well as PP/ casein (CS) binary systems. The results showed that as pH increased from 9 to 12, the solubility of PP and PP/CS significantly increased by 37.04%–51.09%. Meanwhile, particle size initially decreased by 12.02%–32.32% as pH increased to 10, but subsequently increased at pH 11 and 12, accompanied by reduced homogeneity. This phenomenon could be attributed to the dissociation of legumin 11S and the formation of large protein aggregates. Secondary structure analysis further indicated that alkaline pH shifting treatment increased the proportion of random coils (5.90%–28.39%) and β-turns (18.47–49.67%). Regarding the gel properties induced by fermentation, moderate pH 10 treatment generated compact and ordered microstructures and superior elasticity in PP and PP/CS gels, as evidenced by enhanced hardness and water-holding capacity. In contrast, excessive alkaline treatment at pH 12 resulted in deteriorated gel performance and weakened structural integrity. This structural enhancement of PP and PP/CS gels triggered by pH 10 alkaline shifting was primarily attributed to strengthened hydrophobic interactions and hydrogen bonding.