Developmental and varietal differences in volatile ester formation and Acetyl-CoA:: Alcohol acetyl transferase activities in apple (Malus domestica Borkh.) fruit
Developmental and varietal differences in volatile ester formation and Acetyl-CoA:: Alcohol acetyl transferase activities in apple (Malus domestica Borkh.) fruit
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DOI：
10.1021/jf050519k
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发表时间：
2005-09-07
影响因子：
6.1
通讯作者：
Lewinsohn, E
中科院分区：
文献类型：
--
作者：
Holland, D;Larkov, O;Lewinsohn, E
苹果(Malus home tica Borkh.)不同品种的香气和果实、果肉和果皮中挥发性乙酸酯的组成不同。简历。富士果肉含有大量的2-甲基乙酸丁酯(水果香蕉味)，而富士果肉则含有丰富的醋酸甲酯。史密斯奶奶的苹果没有这种化合物。史密斯奶奶苹果的果皮中主要积聚着醋酸己酯(苹果梨的气味)。饲养实验表明，富士苹果在体内能够将己醇和2-甲基丁醇转化为各自的乙酸酯衍生物，而格林史密斯苹果只能将外源己醇转化为乙酸己酯。不同品种间乙酰-辅酶A：乙醇乙酰转移酶(AAT)活性的底物特异性也不同。在Granny Smith苹果中，AAT活性仅在果皮中检测到，其特异性几乎仅限于己醇和顺式-3-己烯醇。在富士苹果中，AAT活性在果皮和果肉中都被检测到，而且显然比Granny Smith酶活性接受更广泛的酒精作为底物。我们的数据有力地表明，不同的AAT活性在苹果组织和品种中是可操作的，这些差异有助于观察到挥发性乙酸酯积累的差异。
Apple (Malus domestica Borkh.) cultivars differ in their aroma and composition of volatile acetates in their fruit flesh and peel. Cv. Fuji flesh contains substantial levels of 2-methyl butyl acetate (fruity banana-like odor), while the flesh of cv. Granny Smith apples lacks this compound. Granny Smith apples accumulate mainly hexyl acetate (apple-pear odor) in their peel. Feeding experiments indicated that Fuji apples were able to convert hexanol and 2-methyl butanol to their respective acetate derivatives in vivo, while Granny Smith apples could only convert exogenous hexanol to hexyl acetate. Differential substrate specificities of the in vitro acetyl-CoA:alcohol acetyl transferase (AAT) activities were also detected among cultivars. In Granny Smith apples, the AAT activity was detected only in the peel, and its specificity was almost exclusively restricted to hexanol and cis-3-hexenol. In Fuji apples, the AAT activity was detected in both peel and flesh and apparently accepted a broader range of alcohols as substrates than the Granny Smith enzyme activity. Our data strongly suggest that different AAT activities are operational in apple tissues and cultivars and that these differences contribute to the variation observed in the accumulation of volatile acetates.