Effect Of Aging Methods On The Aroma Components Of Brandy

In recent years,the quality of China’s brewed brandy has reached the quality of international high-grade brandy.In order to further highlight the characteristics of brandy and improve the grade,there are still oak products,aging time and dissolved oxygen that need to be researched.This thesis relies on the technical center of Yantai Zhang Yu Grape Winery Co.,Ltd(Zhang Yu)to investigate the effects of oak products used in the aging process of brandy,aging time and micro-oxygenation technology on the aroma composition of brandy.The main results obtained in this paper are as follows:(1)The effect of oak products on the aroma of the original brandy.A total of 82 aromatic components were detected in the original brandy of Cabernet Gernisch,with an increase in the variety of aromas after aging in oak staves: French staves(OS1),American staves(OS2),and Saint-Go?n staves(OS3),and a decrease in the variety after aging in oak chips: Dinh Duong BXF42 chips(OC1),vanilla chips(OC2),Dinh Duong CXF32 chips(OC3),and oak barrels: Light toasted oak barrels(LT),Medium toasted oak barrels(MT),and Medium enhanced toasted oak barrels(MT+);The content of esters,alcohols,furans and lactones in the original brandy showed different degrees of increase after aging in oak products;the content of acids,aromatics and terpenes was decreasing overall;the content of aldehydes and ketones and acetals was the highest in OS1 aging,and the cumulative content of aroma components increased significantly after aging.The PCA was effective in identifying characteristic aromas in brandy and distinguishing between samples with high variability,and the results showed that,the original brandy was clustered with oak staves as one category,MT+ as one category;LT was clustered with MT as one category;OC1 and OC2 were clustered as one category and OC3 as one category.The oak products used in the top three brandies in the overall ranking of sensory evaluation are MT > OC3 >LT.(2)Effect of aging time on the aroma composition of brandy.Oak barrel(LT,MT,MT+)storage for 11～23 months for brandy: The content of esters,alcohols,acids,terpenes,aromatics,furans and lactones in LT-aged barrels tended to decrease and then increase,while the content of aldehydes and ketones and acetals tended to decrease in all three types of barrels;the content of esters in MT-aged barrels showed less variation,while the content of alcohols,acids and aromatics tended to increase,the content of furans and lactones in MT+ tended to increase,the content of esters and alcohols tended to decrease,and the content of acids,aromatics and terpenes tended to increase and then decrease.The heat map shows 45 key aroma components,with LT and MT aged wines showing a more pronounced variation in the type and amount of key aroma components than MT+,which has the highest content of furans,masking the flavor profile of the brandy itself.Oak Stave OS2,oak chips OC3 soaked in brandy for 3～9 months: As the aging time increases,the content of esters,alcohols and acids in OS2 brandy tends to increase,while the content of aromatics,terpenes,furans and lactones tends to increase and then decrease,the content of acetals and aldehydes and ketones showed a trend of decreasing and then increasing,The content of esters in OC3 brandy tends to increase,while the content of alcohols,acids,aromatics,terpenes,furans and lactones tends to increase and then decrease,and the content of acetals and aldehydes and ketones tends to decrease and then increase.Of the 48 key aroma components,18 in OS2 brandy and 15 in OC3 brandy had a good linear correlation with aging time.The PCA results showed that five samples,including original brandy,3-month OC3,3-month,6-month,and 9-month OS2,clustered into one category,9-month OC3 into one category and 6-month OC3 into one category.Oak barrels: 17 months LT,MT and 11 months MT,MT+ clustered into one category,23 months MT+ into one category,23 months LT into one category,11 months LT and 17 months MT+ had significant differences(3)Effect of micro-oxygen technology on brandy aroma components: The original brandy uses three different aging processes,and the content of various aroma components increases the most significantly with micro-oxygen aging,and the cumulative content of aroma components is ranked: micro-oxygen > oak barrel > non-oxygen > original brandy.PCA results showed that the four brandy samples were significantly different.The heat map presented 51 key aroma components,and the micro-oxygenated brandy had the highest content and variety of key aroma components,followed by the oak barrel and non-oxygenated.The overall ranking of sensory evaluation was micro-oxygen > oak barrel > non-oxygenated > original brandy.