Phenolic composition of wine from 'Cabernet Sauvignon' grapes subjected to leaf removal at different timing in Southern Brazil

Abstract: The objective of this work was to evaluate the phenolic composition of wine from 'Cabernet Sauvignon' (Vitis vinifera) grapes subjected to leaf removal management at different timing, in a high-altitude region. The experiment was carried out in the 2015 and 2016 vintages, in a vineyard located in the municipality of São Joaquim, in the state of Santa Catarina, Brazil. The treatments consisted of different periods of leaf removal in the clusters, at five phenological stages ‒ full bloom, buckshot berries, pea-sized berries, veraison, and 15 days after veraison ‒, and of a control without leaf removal. At harvest, 50 kg of each treatment were collected for winemaking. The contents of gallic acid, catechin, p-coumaric acid, vanillic acid, resveratrol, quercetin, rutin, and kaempferol were evaluated. The results showed the importance of leaf removal before veraison, to obtain wine with a higher concentration of phenolic compounds, which favors wine quality. The leaf removal management promotes the increase of gallic acid, vanillic acid, p-coumaric acid, resveratrol, quercetin, and kaempferol in wine. The early leaf removal before veraison results in increases in vanillic acid, p-coumaric acid, resveratrol, quercetin, and kaempferol. The wine made from grapes not subjected to leaf removal shows higher values of catechin and rutin.

摘要：本研究旨在评估巴西高海拔产区经不同时期摘叶（leaf removal）处理的赤霞珠（Cabernet Sauvignon，Vitis vinifera）葡萄所酿葡萄酒的酚类物质组成。本实验于2015和2016两个葡萄采收年份，在巴西圣卡塔琳娜州圣若阿基姆市的一处葡萄园开展。试验设置5个葡萄物候期（phenological stages）的果穗摘叶处理，分别为盛花期（full bloom）、豆粒果期（buckshot berries）、豌豆粒果期、转色期（veraison）及转色后15天，另设不进行摘叶的对照组。采收期时，每个处理组采集50 kg葡萄用于酿酒。本研究检测了葡萄酒中没食子酸（gallic acid）、儿茶素（catechin）、对香豆酸（p-coumaric acid）、香草酸（vanillic acid）、白藜芦醇（resveratrol）、槲皮素（quercetin）、芦丁（rutin）及山奈酚（kaempferol）的含量。结果表明，转色前进行摘叶处理对提升葡萄酒中酚类物质浓度具有重要意义，可改善葡萄酒品质。摘叶管理可提高葡萄酒中没食子酸、香草酸、对香豆酸、白藜芦醇、槲皮素及山奈酚的含量。转色前早期摘叶可提升香草酸、对香豆酸、白藜芦醇、槲皮素及山奈酚的含量。而未进行摘叶处理的葡萄所酿葡萄酒中儿茶素与芦丁的含量更高。