Effects of lower temperature on flavor components and fatty acid pathway in harvested kiwifruit (Actinidia deliciosa. cv. Bruno)

For understanding the effects of storage temperatures on flavor quality of kiwifruit fruit (Actinidia deliciosa. cv. Bruno), changes in the main volatile components, the contents of linolenic acid and linoleic acid, and the activities of key enzymes along with the relative expression of their encoding genes involved in fatty acid pathway in kiwifruit were investigated during storage at room (20 ± 0.5℃) and lower temperatures (1 ± 0.5℃), respectively. The results showed that as compared with room temperature, lower temperature reduced the types and relative contents of esters in kiwifruit, and maintained the types and relative contents of aldehydes and ketones. Odor activity value and principal component analysis (PCA) indicated that the flavor components of kiwifruit changed dramatically during storage at room temperature, but the characteristic flavor components of kiwifruit maintained during storage at lower temperature. Also, lower temperature reduced the activities of key enzymes, including lipoxygenase (LOX), hydroperoxide lyse (HPL), alcohol dehydrogenase (ADH), and alcohol acyltransferase (AAT), and inhibited the expression of their encoding genes associated with fatty acid pathway compared to room temperature, which might contribute to accumulating linolenic acid and linoleic acid, reducing the contents of esters, and maintaining high levels of aldehydes and ketones in kiwifruit during postharvest. Our present work might provide useful information for regulating the synthesis of flavor components and maintaining the characteristic flavor of kiwifruit during storage at low temperature. (authors)