This study investigated the impact of different preheat treatments on the emulsifying and gel textural properties of soy protein with varying 11S/7S ratios. A mixture of 7S and 11S globulins, obtained from defatted soybean meal, was prepared at different ratios. The mixed proteins were subjected to preheating (75 °C, 85 °C, and 95 °C for 5 min) or non-preheating, followed by spray drying or non-spray drying. The solubility of protein mixtures rich in the 7S fraction tended to decrease significantly after heating at 85 °C, while protein mixtures rich in the 11S fraction showed a significant decrease after heating at 95 °C. Surprisingly, the emulsion stability index (ESI) of protein mixtures rich in the 7S fraction significantly improved twofold during processing at 75 °C. This study revealed a negative correlation between the emulsifying ability of soy protein and the 11S/7S ratio. For protein mixtures rich in either the 7S or the 11S fractions, gelling proprieties as well as emulsion activity index (EAI) and ESI showed no significant changes after spray drying; however, surface hydrophobicity was significantly enhanced following heating at 85 °C post-spray drying treatment. These findings provide insights into the alterations in gelling and emulsifying properties during various heating processes, offering great potential for producing soy protein ingredients with enhanced emulsifying ability and gelling property. They also contribute to establishing a theoretical basis for the standardized production of soy protein isolate with specific functional characteristics.

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.