发酵温度及果实成熟度对北红葡萄酒香气的影响

Effect of fermentation temperature and fruit ripeness on aroma of Beihong wine

以宁夏银川市平吉堡现代农业示范园区种植的北红葡萄为材料,采收成熟度为S1(可溶性固形物质量分数为25%)、S2(可溶性固形物质量分数为28%)、S3(可溶性固形物质量分数为31%)的果实,分别在发酵温度T1(20℃)、T2(24℃)、T3(28℃)下发酵,15 d后收集上清液于4℃冰箱冷藏保存备用。结果表明:①不同成熟度果实穗质量、10粒质量、纵径及横径均为S2最大,S3次之;可滴定酸质量比以S1最大,S3次之;总酚、单宁质量比以S3最大,S2次之;总糖质量比、糖酸比以S3最大,S2次之。②成熟度为S3的果实无辛辣、生青等气味,且果实的花香、果香比成熟度为S1、S2的果实更浓郁。③当发酵温度一定时酒样中的可滴定酸、挥发酸质量比随着果实成熟度的增长而增加,当果实成熟度为S3时酒样中的可滴定酸、挥发酸质量比更高。使用不同成熟度果实酿造的酒样中可滴定酸与挥发酸的质量比变化趋势不同,当果实成熟度为S1、S2时,酒样中可滴定酸与挥发酸的质量比随着发酵温度的增加先下降后升高,在T1时最高;当果实成熟度为S3时酒样中可滴定酸与挥发酸的质量比随着发酵温度的升高而下降,在T1时最高。④酒样中的香气物质主要有辛酸乙酯、乙酸乙酯、己酸乙酯、癸酸乙酯、乙酸异戊酯、异戊醇、苯乙醇、香叶醇、芳樟醇、正辛醇等。随发酵温度的升高果香、花香先减小再增大,当发酵温度为T3时,酒样中的果香、花香显著高于T1下发酵的酒样,同时酒样中的化学、脂肪等气味物质减少。

The Beihong grapes from Pingjibu Modern Agricultural Demonstration Park in Ningxia Hui Autonomous Region were used as the test material.The fruits with three levels of ripeness of S1(with 25%soluble solids),S2(with 28%soluble solids)and S3(with 31%soluble solids)were harvested,respectively,and then fermented at T1 of 20℃,T2 of 24℃,and T3 of 28℃,respectively,for 15 days.The supernatant was collected and stored in the refrigerator at 4℃.The test results reflect that①In terms of bunch weight,tengrain weight,longitudinal diameter and transverse diameter,S2 were the largest,followed by S3;in terms of titratable acid content,S1 the largest,followed by S3;in terms of total phenol content and tannin content,S3 the largest,followed by S2;and in terms of total sugar content and sugar-acid ratio,S3 the largest,followed by S2.②About fruit aroma substances,the S3 groups had no unpleasant aroma substances such as spicy taste and green taste,yet they had more intense floral and fruit aroma than the other two groups.③The titratable acid and volatile acid in wine samples increased with the increase of fruit ripeness when the fermentation temperature was fixed,and reached the maximum in S3 groups.But their contents in wine samples made from fruits with different ripeness showed different trends.When the fruit ripeness ranged from S1 to S2,the contents decreased first and then increased with the increase of fermentation temperature,and the highest value was found at 22℃.When the fruit ripeness reached 31%,the contents decreased with the increase of fermentation temperature,and reached the highest at 22℃.④The main aroma substances in wine samples include ethyl octanoate,ethyl acetate,n-caproic acid,ethyl quinoate,isoamyl acetate,isoamyl alcohol,phenylethanol,geraniol,linalol,noctanol,etc.About the influence of fermentation temperature on aroma substances of wine samples made from grapes with different ripeness,the fruit flavor and floral flavor decreased first and then increased with the increase of temperature.When the fermentation temperature reached 30℃,the fruit flavor and floral flavor in the wine sample were significantly higher than in the wine sample fermented at 22℃.At the same time,with the increase of fermentation temperature,the unpleasant odor substances such as chemical taste and fat taste could be effectively removed.