不同皮渣浸渍发酵时间对葡萄酒中缩合单宁构成及感官品质的影响

为明确不同皮渣浸渍时间对葡萄酒中缩合单宁的影响，以赤霞珠和西拉为材料，进行不同浸渍发酵时间处理，对葡萄皮和葡萄籽以及葡萄酒中缩合单宁的含量、组成、缩合单宁以及相关口感指标等进行了分析。结果表明，不同葡萄品种中缩合单宁的初始含量、聚合度及没食子酰化率都有显著差异（P<0.05）。葡萄皮中缩合单宁的平均聚合度显著高于葡萄籽（P<0.05），而葡萄皮缩合单宁的没食子酰化率则显著低于葡萄籽缩合单宁（P<0.05）。葡萄皮和葡萄籽中缩合单宁组成的最大差异是葡萄籽缩合单宁中不含有（?）-表棓儿茶素亚单元，而且末端单元主要是由（+）-儿茶素、（?）-表儿茶素和（?）-表儿茶素没食子酸酯组成。皮渣浸渍时间对葡萄酒中缩合单宁的组成及含量都有明显影响。随着浸渍时间的延长，葡萄酒中缩合单宁的总含量呈上升趋势，而平均聚合度则呈下降趋势。不同品种的葡萄酒之间缩合单宁含量也存在显著差异（P<0.05），这与不同葡萄品种中酚类物质的可浸提率有关。葡萄酒中葡萄皮缩合单宁的占比一直显著高于籽粒缩合单宁的占比（P<0.05），说明葡萄皮中缩合单宁比葡萄籽缩合单宁更容易浸提到葡萄酒中。相对于苦味和酸味，不同浸渍时间处理对葡萄酒的涩味影响更为显著（P<0.05），综合考虑酒体的丰满度和口感的平衡，皮渣浸渍时间选择14 d左右更好一些。

Effect of Different Maceration Times on the Composition of Condensed Tannins and Sensory Quality of Wines

In order to study the effects of different maceration times on the condensed tannin profiles of wine,the content,composition of condensed tannins and mouth-feel attributes related with condensed tannins in grape berries and resulting wines were analyzed with Cabernet Sauvignon and Syrah as materials.The results showed that the initial concentration,degree of polymerization,extent of galloylation of condensed tannins in different grape varieties were different significantly(P<0.05).The mean degree of polymerization of condensed tannins in grape skin was significantly higher than that in grape seed(P<0.05),while the extent of galloylation of condensed tannins in skin was lower than that in seed(P<0.05).The major difference between the composition of condensed tannins in grape skin and seed was the absence of(-)-epigallocatechin units,with(+)-catechin,(-)-epicatechin and(-)-epicatechin-3-O-gallate as terminal units.The different maceration times affected the profile of condensed tannins in resulting wines.With the prolongation of maceration time,the total content of condensed tannin in wine tended to increase,while the polymerization degree decreased.There was also significant difference in condensed tannin content among different grape varieties(P<0.05),which was related to the extraction rate of phenols in different grape varieties.The percentages of skin-derived condensed tannins were always higher than that of seed-derived condensed tannins in two variety wines(P<0.05),suggesting that skin condensed tannins were more readily extracted than seed condensed tannins.The maceration time affected the astringency more significant than bitterness and acidity(P<0.05).Considering the fullness of the wine body and the balance of taste,14 days of the maceration time was recommended.