Comparative efficacy of natural seed coats in regulating protein aggregation in pre-roasted pine kernels and enhancing associated techno-functionality

To investigate the regulatory effect of pine nut seed coats on protein techno-functionality during pre-roasting, proteins from kernels subjected to various treatments, including de-shelling, de-skinning, and roasting with or without seed coat, were compared in terms of gelation behavior and interfacial properties. Results indicated that roasting without the seed coat caused disordered unfolding of proteins and the formation of heterogeneous, blocky protein aggregates. In contrast, skin-coating facilitated polyphenol binding with proteins by 2.5-fold, promoting ordered aggregation. Solubility, emulsification activity, emulsion stability, and foaming capacity increased by 34.52 %, 210.46 %, 59.51 %, and 55.54 %, respectively, while the gel network formed uniformly. Shell-coating promoted the formation of heat-stable aggregates, characterized by strong hydrogen bonds, disulfide bonds, and α-helical conformation. The seed coat was found to mediate roasting-induced modifications in protein spatial conformations and aggregate morphological transformations. This study proposes a novel strategy for modulating the functionality of nut proteins.