Analysis And Identification Of Characteristic Flavor Compounds In Hongqu Glutinous Rice Wine

Hongqu glutinous rice wine with unique flavor is a popular wine in Fujian Province. Its characteristic flavor largely depends on the volatile aroma compounds. The objective of this thesis was to study the flavor characteristics of Hongqu glutinous rice wine using a combination of instrumental analysis and sensory analysis. The sensory characteristics of Hongqu glutinous rice wine were analyzed bu using quantitative descriptive analysis method. The important contributions of volatile aroma compounds to the overall flavor in Hongqu glutinous wines were also analyzed by both gas chromatography-olfactometry method coupled with odor activity values (OAVs). Subsequently, the correlations between quantitative descriptive analysis method and instrumental analysis method were explored. The main results are listed as follows:1. The sensory characteristics of Hongqu glutinous rice wine were analyzed using quantitative descriptive analysis method. The "Flavor wheel" and the flavor profile which liked a cobweb were profiled to describe the aroma and taste characteristics of Hongqu glutinous rice wines. Besides, the language bank including the definitions and references of the 20 sensory attributes of Hongqu glutinous rice wine was established. According to Duncan’s multiple comparison method, Pearson’s linear correlation method and principal component anylasis, the significant linear correlation was found among the 20 sensory attributes. Furthermore, the significant differences among different types of Hongqu glutinous rice wine were also found and the results showed that the established quantitative descriptive analysis methods could differentiate the types of Hongqu glutinous rice wines.2. The important contributions of volatile aroma compounds to the overall aroma in Hongqu glutinous rice wines were analyzed by both GC-OSME method and odor activity values (OAVs). The results showed that the characteristic flavor compounds in Hongqu glutinous rice wines were identified, including isobutanol, isoamylol, ethyl acetate, ethyl propionate, ethyl butyrate, isoamyl acetate, ethyl hexanoate, ethyl lactate, diethyl succinate, 2-nonanone, guaiacol, furfural, benzaldehyde, phenethanol and 3-methylthiopropanol.3. The odor activity values (OAVs) analysis coupled with principal component analysis was applied to analyze the changes of volatile aroma compounds with aging time and the correlation between the volatile aroma compounds and the types of Hongqu glutinous rice wine. Results indicated that the content of the esters, benzaldehyde, furfural and 5-methyl furfural increased with aging time, however, the content of the alcohols decreased. Besides, the characteristic flavor compounds varied in different types of Hongqu glutinous rice wine. The characteristic flavor compounds in dry Hongqu glutinous rice wine were identified, including hexanol, octanol, benzaldehyde, ethyl benzoate, butyl acetate. The characteristic flavor compounds in semi-dry Hongqu glutinous rice wine were identified, including isobutyl acetate, nonanol, diethyl succinate, phenethyl acetate, ethyl hexanoate, isoamyl acetate, ethyl lactate,3-methylthiopropanol and 4-ehtyl-2-methoxyphenol. The characteristic flavor compounds in sweet Hongqu glutinous rice wine were also identified, including 5-methyl furfural, isobutanol, isoamylol and furfural.4. According to the combination of quantitative descriptive analysis method and instrumental analysis. The aroma-active compounds not only had deep impacts on the flavor characteristics of Hongqu glutinous rice wine but also had closed relationships with sensory attributes.