Abstract: In this paper, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to compare the aroma-producing performance of different strains of Saccharomyces cerevisiae (CY3079, LA-FR, LA-RA, MST, and OFC) in model grape juice and to analyze the variation of aroma compounds produced under different fermentation conditions. The results showed that strain LA-FR had the strongest ability to produce esters and terpenes and displayed the best aroma-producing performance of the strains tested. Therefore, LA-FR was used to study the effects of nitrogen source, fermentation temperature, pH value and SO2 addition on the production of various aroma compounds. When the concentration of nitrogen source increased from 1.0 g/L to 2.0 g/L, the contents of alcohols and terpenes decreased by 36.41% and 42.56%, whereas the contents of esters and acids increased by 72.92% and 26.86%, respectively. In the range of 18–28 ℃, lower temperature fermentation was beneficial to the accumulation of esters and terpenes, but not to the synthesis of alcohols and acids. When the pH increased from 3.2 to 3.8, the contents of esters and terpenes increased by 19.50% and 67.43%, while the contents of alcohols and acids decreased by 30.24% and 34.16%, respectively. The addition of SO2 was positively correlated with the synthesis of alcohols and esters, but negatively correlated with the synthesis of acids and terpenes. The results of multiple regression analysis showed that nitrogen sources had the greatest influence on the contents of alcohol and ester, and that fermentation temperature and SO2 addition had the greatest influence on the content of acid and terpenes, respectively. The results of this study can provide theoretical support for further study of the effects of multiple factors on the production of aroma compounds during wine fermentation and the control of wine aroma quality.

Key words: fermentation aroma, Saccharomyces cerevisiae, winemaking conditions