The Flavor Components Analysis And Quality Identification Of Aged Shaoxing Rice Wine

The volatile flavor compounds are one of important flavor compounds in Chinese rice wine and also the main components to decide the flavor quality of aged Shaoxing rice wine.Three analytical methods,petroleum ether liquid-liquid extraction-HPLC, distillation-GC and dichloromethane liquid-liquid extraction-GC were established to analyze the volatile flavor compounds in Chinese rice wine.The optimal condition of petroleum ether extraction was 60 mL rice wine saturated by NaCl,petroleum ether 3×60 mL and extraction time 10 min.The optimal condition of distillation was at first,rice wine was distillated by boiling water and then,by decompression,the fraction was collected by cold trap under the condition of liquid nitrogen condensation.The optimal condition of dichloromethane extraction was 100 mL rice wine saturated by NaCl,dichloromethane 3×50 mL and extraction time 7 min.A main volatile flavor compound,β-phenylethyl alcohol,was identified by HPLC retention time and quantified in Shaoxing rice wine of different aging years but the same brand.The analytical data showed that the content ofβ-phenylethyl alcohol decreased with the increase of aging years.13 and 33 volatile compounds were respectively detected by GC/MS and retention time in the distillation fraction and dichloromethane liquid-liquid fraction respectively.8 and 12 main volatile flavor compounds were separately quantified by GC/FID in distillation fraction and extraction fraction of Shaoxing rice wine of 6 different aging years but the same brand.The analytic data all showed that the contents of two compounds,ethyl acetate and ethyl lactate,increased with the increase of the aging time of Shaoxing rice wine,and but the other two compounds,β-phenylethyl alcohol and iso-amyl alcohol decreased.The content of acetic acid increased from one to three aging years,and then kept basically unchanged with the increase of wine age.The contents of n-propyl alcohol and iso-amyl alcohol kept constant fundamentally during aging.In the aging process of Shaoxing rice wine,the contents of protein especially for high molecular weights,polyphenol and iron showed to decrease but other physiochemical data were basically unchanged.Cool turbidness test,intensified test,natural storage and ethanol-turbidity test all showed that the non-biological stabilities of rice wine were improved with the increase of aging time.It is suggested that the quantitative standard on judging the aging time of rice wine and the quality identification are possibly established in according to the contents and changing trend of 4 representative volatile flavor compounds,ethyl acetate,ethyl lactate,β-phenylethyl alcohol and iso-amyl alcohol,and some components leading sedimentation of rice wine such as high molecular weight proteins as well as rice wine's turbidity determined by ethanol-turbidity test.