Effects Of Grape Varieties,Aging Time And Oak Products On Aroma Components Of Brandy

The application of grape varieties,aging time and oak products is an indispensable link in the brewing of brandy,which is crucial to the formation and development of brandy’s flavor.The research uses Ugni Blanc,Munage,and Cabernet Sauvignon grape raw materials provided by Yantai Changyu Group Co.,Ltd.(Changyu Company),after de-stemming,crushing,and water sac squeezing,adding 0.2 g/L yeast to ferment the brandy raw wine.After the fermentation is completed using a 30 L copper Charente pot distiller for secondary distillation,the original brandy was obtained.The original brandy of Ugni Blanc and Cabernet Sauvignon obtained by distillation process were aged for 3 to 18 months in 5 L small oak barrels respectively,and the aroma components of brandy with different aging time were analyzed;the original brandy of Ugni Blanc and Cabernet Sauvignon obtained by distillation process were aged for 1 month with oak boards with different baking degrees respectively,and the aroma components of brandy with different oak boards were analyzed.The aroma components of brandy aged for 6 years,10 years and 15 years provided by Keya brandy of Yantai Changyu Group Co.,Ltd.were analyzed.In this research,the head space solid phase micro extraction(HS-SPME)technology and gas chromatography-mass spectrometry(GC-MS)technology were used to analyze the aroma components,and the conditions of HS-SPME-GC-MS analysis were optimized.The main research contents and conclusions are as follows:(1)The optimized HS-SPME-GC-MS conditions for the determination of brandy aroma were as follows: Sample preparation: Dilute the alcohol content of brandy to10%(v/v),add into a 100 m L volumetric flask,then add 50 μL of internal standard3-octanol,and fix the volume with brandy diluent;HS-SPME conditions: Take 5 m L sample into a 20 m L head space flask,add 1.5 g Na Cl,add agitator,cover,and place at50℃ 500 r/min water bath equilibration for 20 min,extraction with DVB/CAR/PSMS extraction head for 5 min;GC-MS conditions: Resolution at the injection port for 5 min,using DB-Wax chromatographic column,carrier gas is helium,flow rate is 1.17 m L/min,split ratio is 5:1;heating program: Column temperature is 40℃ for 2 min,then 6℃/min to 100℃,then 5℃/min to 200℃,then 10℃/min to 240℃,keep 6 min;scanning mode is Scan,ionization mode is EI,ion source temperature is 200 ℃,interface temperature is 250℃,solvent is not delayed,scanning range is 30 m/z ～ 500m/z.(2)A total of 80 aroma components were identified by HS-SPME-GC-MS,including esters 34 kinds(42.5%),alcohols 16 kinds(20%),aromatics 8 kinds(10%),terpenes 8 kinds(10%),acids 6 kinds(7.5%),furans 3 kinds(3.8%),aldehydes 3 kinds(3.8%)and acetals There were 2 species(2.5%).(3)The results of cluster analysis are as follows: Cluster analysis can effectively distinguish and classify brandy with different grape varieties,different aging time and different oak baking.aging 6 months and aging 9 months are the key nodes of Ugni Blanc brandy aging,and there are significant differences in the aroma components of Ugni Blanc brandy in the two stages;aging 6 months,aging 9 months and aging 12 months are the key nodes of Munage brandy aging,and there are significant differences in the aroma components of Munage brandy in the three stages;as the key points of Keya brandy aging,there was significant difference in aroma components between Keya brandy aged for 6 years and more than 10 years;the effect of heavy baking on brandy aroma was higher than that of grape varieties,the effect of light baking and moderate baking on brandy aroma was lower than that of grape varieties,there was significant difference between heavy baking and light and moderate baking on brandy aroma.(4)Data visualization technology was used to normalize brandy with different aging times and draw heat-map.The relationship between the type and content of aroma substances and aging time was directly reflected by the heat-map.The type and content of aroma substances in brandy were positively correlated with aging time,and the most obvious one was the increase of esters,especially ethyl esters.The type and content of terpenes and esters in Ugni Blanc brandy were higher than those in Cabernet Sauvignon brandy.With the increase of oak baking degree,the content of terpenes decreased,the content of esters did not change significantly,and the content of alcohols increased.(5)Principal component analysis(PCA)conclusion: Principal component analysis can effectively determine the characteristic components of brandy aroma,aroma components can be effectively used to identify the variety differences between Ugni Blanc and Munage brandy,the variety differences between Ugni Blanc and Cabernet Sauvignon brandy,the age of Keya brandy,and the baking degree of oak board used in brandy aging.