基于主成分分析的酿酒葡萄梅鹿辄的最佳采收期

The Optimal Harvest Time of Merlot Grape Based on Principal Component Analysis

在葡萄酒酿造过程中,酿酒葡萄采收期的确定是影响葡萄与葡萄酒质量的重要因素。通过研究梅鹿辄葡萄在不同采收期果实基本理化指标和多酚指标(皮总酚、皮单宁、皮花色苷、皮类黄酮、皮黄烷醇、籽总酚、籽单宁、籽类黄酮、籽黄烷醇)的变化,并运用主成分分析法对这些指标进行综合评价,为确定梅鹿辄葡萄的最佳采收期提供试验依据。结果表明:在2012年和2013年,梅鹿辄葡萄果皮各多酚物质的含量在成熟前期都呈缓慢上升趋势,至9月3日后,它们各自的变化都较小并趋于稳定(果皮单宁除外);而葡萄籽各多酚物质的含量在成熟前期的变化趋势虽存在差异,但都在9月3日达到最大值,之后又呈下降趋势,并且在成熟过程中,葡萄籽中多酚物质的含量始终高于果皮。主成分分析结果表明:梅鹿辄葡萄的最佳采收期在9月10日。该分析方法将基本理化指标与多酚指标相结合,能够更客观、全面地确定该地区梅鹿辄葡萄的最佳采收期,为酿造优质干红葡萄酒提供理论参考。

Determination of the harvest time has an effect on the quality of grape and wine. The optimal harvest time of Merlot in Jia Yuguan city, Gansu Province, were confirmed using the principal component analysis by studying the variation of basic physical and chemical indexes and polyphenols indexes（total phenols, tannins, anthocyanins,flavonoids and Flavanols in grape skins and total phenols, tannins, flavonoids and Flavanols in grape seeds） of grape berries in different harvest time. The results showed that the polyphenols content in skins increased at the earlier stage of ripeness, and then remained stabilized after September 3, 2012 and 2013（except for tannins）. However, There were some differences in polyphenols content in seeds at the earlier stage of ripeness, but all the highest values were reached on September 3. Additionally, the polyphenols content in seeds was always higher than that in skins during ripening. It was confirmed that the optimal harvest time of Merlot grape in this region is on September10. This analytical method can make the basic physical and chemical indexes combined with polyphenols indexes, which can determine the optimal harvest time of Merlot objectively and comprehensively, and provide some theoretical references for wine-making.