The effect of weak-acid preservatives and other additives on growth of Zygosacchromyces bailii

學生姓名: 黃毓棻
指導教授: 劉昌樹
學　　號: 10332023
學期: 103上
摘　　要: Zygosaccharomyces bailii is an effective spoiler of many food and beverages, particularly those with low pH and high sugar content. It is notorious for its extreme resistance to preservatives and ability to grow in excess of legally-permitted concentrations of preservatives. The aim of this study was to estimated and used to establish the effect of weak-acid preservatives and other additives on the growth and survival of Z. bailli. Extreme resistance was confirmed in 38 strains of Z. bailii to several weak acids. The re-inoculation of resistant sub-populations into weak-acid-containing media showed the all cells possessed extreme resistance. Aspartame addition increased the population of the stationary phase of the systems containing glucose or xylitol, which suggests that Z. bailii metabolizes aspartame. Glucose and xylitol addition to the system containing aspartame and sorbate increased the heat sensitivity of Z. bailii. The metabolism pathway of acetic acid was established by in vivo 13C-NMR experiment. Acetate was metabolised throught Kerbs cycle and the metabolic products involved lipid biosynthesis.