Effects of Patulin Stress on the Physiology, Fermentation Performance, and Aroma Profile of <i>Saccharomyces cerevisiae</i> During Fermentation

Patulin (PAT) is a mycotoxin commonly found in apples and their derived products, posing a significant threat to human health. Saccharomyces cerevisiae CICC 31084 exhibited excellent ability in removing PAT during fermentation. However, limited studies have addressed the physiological and fermentation-related responses of S. cerevisiae under PAT stress. This study investigated the effect of different concentrations of PAT on S. cerevisiae in simulated apple juice. The results revealed that the PAT removal process affected the growth and metabolism of S. cerevisiae. PAT stress increased the thickness and altered the structure of yeast cell walls while upregulating the expression of genes associated with cell wall biosynthesis. Furthermore, oxidative stress induced by PAT triggered elevated glutathione levels, catalase activity, and ATPase activity, suggesting a robust adaptive response. A total of 1 µg/mL PAT accelerated the changes of fermentation parameters, whereas 10 µg/mL impaired yeast performance. GC-MS analysis revealed that PAT influenced the content of key aroma compounds in the simulated juices. PAT concentration was positively correlated with the production of octanoic acid and ethyl octanoate and negatively correlated with the formation of phenylethyl alcohol, hexanoic acid, and esters. The results could provide a theoretical basis for the application of PAT detoxification by S. cerevisiae in cider, and the identified aroma compounds could serve as potential markers for PAT contamination.