Influence of Environmental Conditions and Physical Modifications on the Gelation Behavior of Spent Brewers’ Yeast Protein

Single cell protein from spent brewer’s yeast is a promising alternative food protein. However, its techno-functional properties, such as gelation, remain insufficiently characterized due to strong raw material dependency. This study investigated the gelation behavior of spent brewer’s yeast protein (YP) under various environmental conditions, as NaCl and pH. Moreover, the potential of modification approaches, such as ultrasonication and thermal treatment, to enhance gel strength and rupture force was evaluated. In addition, amino acid composition and solubility were assessed. Untreated YP gelling temperature at pH 7 was determined at 53.17 ± 0.20 °C. Gel strength was increased by 34% via 0.25 M NaCl addition at pH 7. Together with adjusting the YP concentration, this allows tailoring of the gelation behavior for specific food applications with these parameters. Furthermore, ultrasonication was identified as a suitable modification approach to increase the gelation properties. Ultrasonication treatment (5 min, 20 kHz, 73 W) resulted in a gel strength of 2.15 ± 0.03 N compared to 1.63 ± 0.06 N for untreated YP (15% concentration, pH 7). Overall, these findings provide novel insights into the modulation of YP gelation behavior via environmental factors and modification approaches and consequently about its application potential as a functional food ingredient.