Foods

Umami peptides were screened and identified from yak bone collagen for the first time by in silico analysis, molecular docking, and electronic tongue. Twenty proteases with known cleavage sites were used for the simulated proteolysis, and results indicated that “pepsin + papain” was the optimal enzymatic strategy for yak bone collagen to generate peptides with potential umami taste. Moreover, 82 novel unreported peptides with umami taste were found from the simulated hydrolysate, among which 9 peptides exhibited high binding affinity with the T1R1/T1R3 receptor (both -CDOCKER energy and CDOCKER interaction energy > 40 kcal/mol) via molecular docking. Subsequently, six novel umami peptides were identified through sensory evaluation and electronic tongue analysis, including VY, VM, SL, SN, VN, and IS (umami sensory score > 5). These peptides were also in silico characterized with high hydrophobicity, good water solubility, non-toxicity, non-allergenicity, good intestinal absorption, and good oral bioavailability. Furthermore, the identified peptides could bind with the key residues (such as HIS281 and LEU304) within the Venus flytrap domain of the T1R3 subunit of receptor T1R1/T1R3 through hydrogen bonds and electrostatic attractions to generate umami perception. This study revealed the mechanism of umami peptides identified from yak bone collagen and provides a novel approach for the development of umami peptides from animal sources.

Partial or total replacement of pork fat with homologous functional oils may meet consumer demand for healthy meat products while preserving their sensory quality. This study investigated the use of lard-derived diacylglycerol (DG) as a fat replacer on the flavor characteristics of frankfurters. The results revealed that substituting pork fat with purified glycerolized lard (PGL) at different levels (25%, 50%, and 100%) increased the water content and water activity, improved the L* and b* values, and protein thermal stability, while decreasing the a* value of frankfurters. Meanwhile, electronic nose results showed that replacing pork fat with PGL affected the aroma of frankfurters. Furthermore, gas chromatography–mass spectrometry detected 50 volatile compounds in all the frankfurters (such as aldehydes, alcohols, terpenes, and aromatic hydrocarbons, etc.). Replacing lard with PGL significantly increased the variety and content of flavor compounds in frankfurters (p < 0.05). According to the approximate odor activity values (OAV) > 1 and variable importance in projection (VIP) > 1, the distinct flavor of the frankfurters with different levels of PGL mainly resulted from aldehydes, alcohols, and terpenes. Generally, this study provided a valuable theoretical foundation for substituting fat with lard-derived DG to improve the flavor characteristics of frankfurters.

Brewer’s spent grain (BSG), the primary by-product of beer production, represents a promising and sustainable source of plant-based protein. This review provides a comprehensive overview of extraction techniques for brewer’s spent grain protein (BSGP), encompassing conventional methods—such as alkaline, hydrothermal, ethanol, and enzymatic extraction—as well as emerging green approaches, including ultrasound-assisted, microwave-assisted, subcritical water, and deep eutectic solvent extraction. The influence of key extraction parameters on protein yield, purity, and structural integrity is critically examined, along with the resultant alterations in functional properties such as solubility, emulsifying capacity, foaming ability, and gelation behavior. Although through parameter optimization and the application of novel technology, the existing research has been able to increase the protein extraction rate and achieve better functional properties, the challenges of obtaining higher protein purity and extracting proteins on a larger scale remain. Collectively, these findings underscore the considerable potential of BSGP as a multifunctional ingredient in next-generation sustainable food formulations.