Kinetic models of quality changes of sukiyaki sauce during thermal processing

Thai-style sukiyaki sauce is an acidified product that requires pasteurization to ensure microbiological safety while maintaining desirable color quality. This study investigated the changes in microbiological quality, including total viable count (TVC) and yeast and mold count (YM), as well as color properties ( L* , a* , b *, total color difference (ΔE), browning index (BI) and hue angle) of sukiyaki sauce during thermal treatment at 70, 80, 90, and 100 °C for 30–40 min. Kinetic models describing changes in quality indices were also developed. The reductions in TVC and YM, as well as the changes in color parameters ( L* , a *, ΔE and BI), were strongly influenced by increasing heating temperature and time, particularly at 100 °C. Meanwhile, significant changes in the b * value and hue angle were observed only at 100 °C ( p ≤ 0.05). TVC inactivation followed first-order kinetics, while changes in color indices, including ΔE, BI and hue angle, were best described by zero-order kinetics. The temperature dependence of reaction rate constants for microbial inactivation and changes in color indices was adequately explained by the Arrhenius, Ball and Eyring models. According to the Arrhenius equation, the activation energy for TVC inactivation was 145.54 kJ/mol. The activation energies associated with increases in ΔE and BI (70–100 °C) and the decrease in hue angle (70–90 °C) ranged from 51.22 to 71.91 kJ/mol. The Arrhenius, Ball and Eyring models demonstrated good predictive capability for estimating TVC reduction and color changes (ΔE, BI and hue angle) of sukiyaki sauce during isothermal thermal processing.