Fermentation Kinetic Modeling and Antioxidant Evaluation of Suaeda salsa

The changes of yeast count, ethanol, reducing sugar, pH, titratable acidity and total phenols as well as antioxidant properties such as hydroxyl and superoxide anion radical scavenging activities and reducing power during Suaeda salsa fermentation by yeast were studied. The SGompertz, DoseResp, Logistic and Boltzmann models were used to investigate the fermentation kinetics. Meanwhile, a comprehensive evaluation index (CEI) system of S. salsa fermentation was developed by correlation analysis (CA) and principal component analysis (PCA). The growth kinetic model of yeast was established using the DoseResp and Boltzmann equations, the kinetic model of ethanol production was established using the SGompertz equation, and the kinetic model of reducing sugar consumption was established using the Logistic equation. The fitting coefficients (R2) of these models were 0.977, 0.995 and 0.982, respectively, indicating excellent goodness of fit. CA showed that total phenols and organic acid were the major contributors to the antioxidant capacity of fermented S. salsa. PCA showed that the CEI value increased first, then leveled off, and finally decreased. The fermentation endpoint was on the eighth day in overall consideration. The results of this study provide a theoretical basis for the precision preparation of fermented S. salsa.