摘叶和挪叶处理对‘赤霞珠’葡萄种子黄烷-3-醇类物质的影响

Effect of leaf removing and moving on Flavan-3-ols composition in seeds of Cabernet Sauvignon

【目的】研究摘叶和挪叶处理对葡萄种子中黄烷-3-醇类物质的影响,为提高酿酒葡萄品质提供参考依据。【方法】以‘赤霞珠’(Vitis vinifera L.cv.Cabernet Sauvignon)葡萄为供试材料,于果实成熟的不同时期(转色50%、转色100%和采收前2周)分别进行半摘叶、全摘叶和挪叶处理,研究葡萄种子中黄烷-3-醇含量及组成的变化。【结果】葡萄种子黄烷-3-醇以表儿茶素(EC)和表儿茶素没食子酸酯(ECG)为主要组成单体,儿茶素(C)的含量最低。种子黄烷-3-醇含量从坐果期的13.7mg/g上升至转色开始时的78.3mg/g,之后呈下降趋势,至果实采收时黄烷-3-醇的含量为51.6mg/g。3个处理中,仅采收前全摘叶处理显著增加了采收时种子的黄烷-3-醇含量,增幅为7.6%。在黄烷-3-醇类物质的组成单元中,延伸单元的含量最高,其次为起始单元,游离单体的含量最低,采收时其含量分别为36.4,14.2和1.1 mg/g。摘叶和挪叶处理可显著降低采收时种子黄烷-3-醇的起始单元含量,降幅为11.2%~38.7%。此外,黄烷-3-醇类物质的平均聚合度(mDP)随葡萄生长发育呈先下降后上升趋势,转色期后逐渐升高,至采收时为2.9,而没食子酸化程度(G)的变化规律不明显,摘叶和挪叶处理可增大采收时种子黄烷-3-醇的mDP,并保持G值在42%左右。【结论】采收前全摘叶处理可显著增加采收时葡萄种子黄烷-3-醇的含量,而采收前半摘叶处理可显著降低G值,因此采收前半摘叶和全摘叶的栽培措施更有利于改善酿酒葡萄的酿酒品质。

【Objective】The effect of leaf removing and moving on flavan-3-ols composition in grape seeds were examined to provide basis for improvement of grape quality.【Method】The cultural practices including half leaf removing,leaf removing and leaf moving during ripening（50% véraison,100% véraison and 2 weeks before harvest）of‘Cabernet Sauvignon＇were conducted to study the effect of leaf removingand moving on concentration and composition of flavan-3-ols in grape seeds.【Result】The main components of flavan-3-ols were epicatechin（EC）and epicatechin-3-O-gallate（ECG）,while the lowest component was catechin（C）.The concentration of flavan-3-ols in grape seeds increased from 13.7 mg/g at fruit setting stage to 78.3 mg/g at the beginning of véraison,followed by a decrease trend with 51.6 mg/g at harvest.The leaf removing before harvest treatment increased the content by 7.6%.Extension subunit was the main unit of flavan-3-ols,followed by terminal subunit and monomer,and their concentrations in harvested grape seeds were 36.4,14.2 and 1.1 mg/g,respectively.Leaf removing and leaf moving significantly decreased terminal subunits concentration by 11.2%-38.7%.Meanwhile,the mean degree of polymerization（mDP）decreased gradually from beginning to véraison,followed by an increase to 2.9 at harvest.The galloylation（G）remained unchanged with little fluctuations.Leaf removing and leaf moving increased mDP and maintained Gat 42%.【Conclusion】Leaf removing and half leaf removing at pre-harvest could significantly increase flavan-3-ols content and decrease Gvalue in harvested grape seeds,respectively.Thus,the two cultural practices are beneficial to the improvement of grape quality from the winemaking perspective.