In the process of cider fermentation,Saccharomyces cerevisiae will make metabolic responses to various stresses and environmental changes.Chlorogenic acid is a relatively high content of apple polyphenols in apples and cider.This study selected chlorogenic acid as a representative apple polyphenol to investigate the effects of different concentrations on the physiological characteristic of Saccharomyces cerevisiae.The results showed that Saccharomyces cerevisiae CICC 31084 improved the resistance to stress by changing the activity of superoxide dismutase (SOD),catalase (CAT) and the content of intracellular malondialdehyde (MDA) under the stress of chlorogenic acid.Among them,SOD activity gradually increased with the increase of chlorogenic acid's concentration.The stress of low concentration of chlorogenic acid(0.01 g/L)promoted the increase of CAT activity of Saccharomyces cerevisiae.The content of MDA was reduced in the early fermentation stage,and increased in the late fermentation stage under the stress of chlorogenic acid.With the extension of the fermentation time,the concentration of key aroma substances in cider gradually increased,which reached the maximum in the middle of fermentation,and then gradually decreased and stabilized.Correlation analysis showed that the concentration of key aroma substances,such as phenylethyl alcohol,phenylethyl acetate,isoamyl acetate,and ethyl caprate were positively correlated with the concentration of chlorogenic acid,the correlation coefficients respectively were 0.133,0.253,0.026,0.114;ethyl caprylate and ethyl caproate were negatively correlated with the concentration of chlorogenic acid,the correlation coefficients were -0.012 and -0.248.