Effect of Physical and Chemical Properties of Kombucha‐Fermented Soy Whey on the Quality of Tofu

ABSTRACT Background and Objectives This study investigated the coagulation of soymilk using fermented soy whey (FSW), a traditional natural coagulant for tofu production. We comprehensively evaluated the effects of key parameters of FSW pH, FSW addition amount, and FSW temperature on the physicochemical properties of the resulting tofu. Analyses included tofu yield, moisture content, water‐holding capacity, textural, sensory profile, and protein subunit composition via SDS‐PAGE. Experiments were conducted under controlled conditions, varying the FSW pH (3.78–4.50; 25% addition, 75°C), the FSW addition amount (17.5%–30% v/v; pH 4.0, 75°C), and the FSW temperature (35°C–85°C; pH 4.0, 25%). Findings Protein aggregation efficiency increased markedly as FSW pH decreased, reaching a maximum at pH 4.02. Increasing the FSW concentration enhanced tofu yield and water retention up to 22.5% (v/v), while higher levels caused slight declines. Similarly, coagulation improved with rising FSW temperature, peaking at 65°C, where a cohesive gel with optimal texture was formed. Conclusions Therefore, the optimal parameters were identified as an FSW pH of 4.02, a concentration of 22.5% (v/v), and an FSW addition temperature of 65°C. Significance and Novelty These parameters provide a scientific foundation for standardizing the traditional FSW tofu‐making process, offering crucial benchmarks for quality control and future product development.