A structural explanation for protein digestibility changes in different food matrices

This study was conducted to investigate the protein digestibility changes in different food matrices. A structural description of proteins responding to nanocrystalline cellulose (NCC) treatment was also proposed. The conformational alterations of various samples were verified by variable-temperature X-ray diffraction (VT-XRD) and multi-spectroscopic methods. The results implied that NCC induced moderate unfolding and aggregation of distinct protein samples. Notably, the original state of the modified myofibrillar protein (MP) was disrupted by pepsin catalysis, resulting in a rheological behavior similar to that of the rigid ovalbumin (Ova) system. According to digestion kinetic parameters and proteomics analyses, when treated with NCC, the flexible MP sample had higher gastric digestibility than the rigid Ova system, but they varied in the intestinal digestion stage. A potential shielding action of the flexible protein system on the inhibitory effect of NCC was also demonstrated. These findings show that protein digestibility is linked to matrix structures and composition.