Shalit M, Katzir N, Tadmor Y, Larkov O, Burger Y, Shalekhet F, Lastochkin E, Ravid U, Amar O, Edelstein M, Karchi Z, Lewinsohn E
Department of Vegetable Crops, Agricultural Research Organization (ARO), Newe Ya'ar Research Center, P.O. Box 1021, Ramat Yishay 30-095, Israel.
J Agric Food Chem. 2001 Feb;49(2):794-9. doi: 10.1021/jf001075p.
Melon varieties (Cucumis melo L.) differ in a range of physical and chemical attributes. Sweetness and aroma are two of the most important factors in fruit quality and consumer preference. Volatile acetates are major components of the headspace of ripening cv. Arava fruits, a commercially important climacteric melon. In contrast, volatile aldehydes and alcohols are most abundant in cv. Rochet fruits, a nonclimacteric melon. The formation of volatile acetates is catalyzed by alcohol acetyltransferases (AAT), which utilize acetyl-CoA to acetylate several alcohols. Cell-free extract derived from Arava ripe melons exhibited substantial levels of AAT activity with a variety of alcohol substrates, whereas similar extracts derived from Rochet ripe melons had negligible activity. The levels of AAT activity in unripe Arava melons were also low but steadily increased during ripening. In contrast, similar extracts from Rochet fruits displayed low AAT activity during all stages of maturation. In addition, the benzyl- and 2-phenylethyl-dependent AAT activity levels seem well correlated with the total soluble solid content in Arava fruits.
甜瓜品种（甜瓜属）在一系列物理和化学特性上存在差异。甜度和香气是果实品质和消费者偏好的两个最重要因素。挥发性乙酸酯是成熟的阿瓦拉品种甜瓜（一种商业上重要的跃变型甜瓜）顶空的主要成分。相比之下，挥发性醛类和醇类在罗谢特品种甜瓜（一种非跃变型甜瓜）中含量最为丰富。挥发性乙酸酯的形成由醇乙酰转移酶（AAT）催化，该酶利用乙酰辅酶A将多种醇乙酰化。源自阿瓦拉成熟甜瓜的无细胞提取物对多种醇底物表现出较高水平的AAT活性，而源自罗谢特成熟甜瓜的类似提取物活性可忽略不计。未成熟的阿瓦拉甜瓜中AAT活性水平也较低，但在成熟过程中稳步增加。相比之下，罗谢特果实的类似提取物在成熟的所有阶段均表现出较低的AAT活性。此外，阿瓦拉果实中依赖苄基和2-苯乙基的AAT活性水平似乎与总可溶性固形物含量密切相关。
