Preparation, physicochemical properties, and formation mechanism of quinoa self-assembled peptide-based hydrogel

Currently, self-assembly peptides with hydrogel properties that are used in various applications are being chemically synthesized. These peptides not only have safety and environmental problems but are also expensive and cumbersome to prepare. The present study established a convenient and efficient method for producing plant-based peptides with decent gel-forming ability from quinoa proteins. After alkaline protease treatment, hydrogels made with quinoa protein hydrolysis exhibited potent self-assembly capacity, enhanced gel hardness, and improved rheological properties. Moreover, the microstructure results revealed that the quinoa peptide hydrogels had regular, uniform, and interconnected porous structures. These observations were primarily attributed to the hydrogen bonding force and hydrophobic aggregation caused by hydrophobic group exposure. Amino acid and proteomics analysis suggested that the amino acid composition and sequence of quinoa peptides significantly influenced the formation of self-assembled hydrogels. Overall, this study provided a cost-effective approach to improve the gelling ability of quinoa protein and could potentially replace the use of chemically synthesized peptides in various applications, laying the theoretical basis for the development of novel natural plant-based foods.