Patulin Contamination Control by Saccharomyces cerevisiae KD in Apple Juice

In the present study, the efficacy of a strain of food grade yeast Saccharomyces cerevisiae KD on patulin contamination control in medium and commercial 100% apple juice was evaluated. Patulin content was measured by HPLC, and the influences of initial patulin content, strain concentration and pH value on patulin reduction by S. cerevisiae KD were analyzed. The growth status of S. cerevisiae KD was detected by multiscan spectrum. Besides, the quality of the fermented apple juice, including the contents of soluble solids, titratable acid, total phenols and flavone, was evaluated. The results demonstrated that patulin was removed completely within 28 h by S. cerevisiae KD under aerobic incubation, and the mechanism of patulin reduction included physical adsorption, as well as enzymatic degradation. Lower initial patulin content and higher strain concentration contributed to higher patulin reduction ratio, however, the reduction rate of the treatments with different initial strain concentrations trended to come close to each other in the later stage of the reaction. Acidic condition was found to be conducive to patulin recluction. Furthermore, S. cerevisiae KD was tolerant to patulin, and could still grow well at patulin concentration as high as 100 mg/L. Moreover, patulin contamination in commercial 100% apple juice was also effectively controlled by S. cerevisiae KD. Patulin was undetectable in the apple juice after fermentation by S. cerevisiae KD and Lactococcus lactis MG1363 together for 2 days. Content of total phenol was significantly increased after fermentation (p<0.05), and the quality of the fermented product was also found satisfying. In summary, S. cerevisiae KD was a promising tool to effectively reduce patulin contamination in commercial food.