Characteristic Aroma Of Light Aroma Style Chinese Rice Wines And Effects Of Wheat Qu By GC-O Coupled With GC-MS

The volatile trace compounds in Chinese rice wines were considered the major components of the particular aroma of Chinese rice wines. In this paper, the volatile aroma compounds of Chinese typical rice wines and fresh rice wines were analyzed by gas chromatography–olfactometry; new and fast analysis method that detects the volatile aroma compounds in Chinese rice wine was established; the volatile aroma compounds of Chinese rice wines and fresh rice wines which brewing with different quantity of wheat Qu were quantitative analyzed by new constructed method. The main contents are as follows:Total of 63 volatile aroma compounds were identified by gas chromatography–olfactometry (GC–O) and total of 53 these compounds were identified in light aroma style Chinese rice wine. The aroma intensities of fatty acids and alcohols in light aroma style Chinese rice wine were weaker than these in Shaoxing rice wine. Aromatic compounds were the most number of volatile aroma compounds in Chinese rice wines, in which benzaldehyde, phenylacetaldehyde and 2-phenylethanol had the strongest aroma intensities. Furfural andγ-nonalactone had the strongest aroma intensities among all furans and lactones, respectively. Dimethyl trisulfide and 3-methylthiopropanol were the main sulfides in Chinese rice wines, and the intensity of 3-methylthiopropanol was stronger in light style aroma rice wine.A new method for the quantification of volatile compounds in Chinese rice wine was developed using headspace solid phase microextraction followed by gas chromatographymass–spectrometry. The sample ethanol content was adjusted to 6 % for the HS–SPME analysis and total of 8 mL diluted sample was extracted at 50°C for 45 min. The results indicate that this method is effective to extract the volatile compounds in Chinese rice wines, like alcohols, esters, fatty acids, and so on. Under the conditions described above, the method linearity was satisfactory, with correlation coefficients higher than 0.99 in all cases. The detection limits of this method ranged from 0.04μg/L to 955.22μg/L. Meanwhile the recoveries of analyzed compounds varied between 75.46% and 117.74%. The relative standard deviations were all below 10%. The similar results were found in samples.Total of 56 volatile aroma compounds were quantitative analysed by HS–SPME-GC–MS. The total concentrations of volatile aroma compounds in rice wines from Shanghai and Jiangsu were lower than these from Shaoxing, but similar with these from north. The quantification data was applied to principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA). These rice wines from Shanghai and Jiangsu were correlative with esters and alcohols. These 20 samples were well classified according to producing areas. Compared with odour active values (OAVs) of these identified aroma compounds, the concentrations of over 17 compounds were higher than their aroma threshold in these samples from Shanghai and Jiangsu.The OAVs ofγ-nonalactone, acetophenone, 3-methylthiopropanol and butanoic acid had obvious differences among 20 samples.Total of 49 volatile aroma compounds were identified by GC–O. The aroma intensities of fatty acids and alcohols were similar in fresh rice wines which were brewed with or without wheat Qu. The aroma intensities of aromatic compounds were increased along with the quantity of wheat Qu. The aroma intensity of 2-phenylethanol was the strongest in all aromatic compounds. The aroma intensities of phenols had obvious differences among all fresh rice wines, and the intensities of these compounds were increased along with the quantity of wheat Qu.Total of 46 volatile aroma compounds were quantitative analysed by HS–SPME–GC– MS. The total concentrations of volatile aroma compounds were increased along with the uantity of wheat Qu. The concentrations of 2-phenylethanol and benzylalcohol were higher than other aromatic compounds. The content of aromatic compounds in fresh rice wine which brewed with 15% wheat Qu was highest among all samples. These compounds contents in fresh rice wines which brewed with wheat Qu were higher than that brewed without wheat Qu. The contents of sulfides in fresh rice wine which marinated with wheat Qu were higher than that brewed without wheat Qu.Compared with OAVs of these identified aroma compounds, the concentrations of about 18-22 compounds were higher than their aroma threshold in these samples. The OAVs of dimethyl trisulfide, ethyl octanoate, 1-octen-3-ol, ethyl butanoate, ethyl hexanoate and 3-methylbutyl acetate were high in the fresh rice wine which brewed without wheat Qu. In the fresh rice wines which brewed with wheat Qu, 3-methylthiopropanol, guaiacol and ethyl 2-methylpropanoate had high OAVs except the same compounds in which brewed without wheat Qu. The OAVs of guaiacol and acetophenone had obvious differences among these samples. The OAVs of aromatic compounds were increased in fresh rice wine brewed with wheat Qu.