Study On Changes In Flavor Components In Kiwifruit During Storage

For understanding the physiological mechanism of volatile components metabolism in kiwifruit,changes in quality,the main volatile components,contents of different fatty acids,and the activities of key enzymes and the relative expression of encoding genes involved in fatty acid pathway of kiwifruit(Actinidia deliciosa.cv.Bruno)were investigated during storage at room temperatures(20?)and lower temperature(1?).The main results were as follows:1.Compared to room temperature,lower temperature effectively inhibited the increase trend of soluble solid content(SSC),fructose,glucose,sucrose content,delayed the decrease trend of firmness,titratable acid(TA)and Vitamin C(Vc)content in kiwifruit.The results showed that lower temperature delayed the ripeness and maintained the quality of kiwifruit during storage.2.A total of 80 volatile compounds were identified in kiwifruit during storage at room temperature,among which aldoketones and esters were the dominant components.Then a total of 59 volatile compounds were detected in kiwifruit during storage at lower temperature,and aldoketones were the major components.The fatty acid pathway acted as the primary pathway for biosynthesis of volatile components.Compared to room temperature,lower temperature effectively reduced the kinds and relative content of esters,inhibited the decrease in the kinds and relative contents of aldoketones and alcohols,delayed the increase trend of ethanol and acetaldehyde content in kiwifruit.Theresults showed that lower temperature reduced the accumulation of esters and ethanol,which contributed to inhibiting of the off-flavor.Odor activity value indicated 9 compounds were the characteristic flavor compounds in kiwifruit,including ethyl butyrate,ethyl hexanoate,2-hexenal,ethyl acetate,hexanal,methyl butyrate,ethanol,2-hexen-l-ol,and butyl butyrate.3.The lower temperature delayed the decrease in contents of different fatty acids,and inhibited the activities of key enzymes in fatty acid pathway,including lipoxygenase(LOX),hydroperoxide lyse(HPL),alcohol dehydrogenase(ADH),and alcohol acyltransferase(AAT)in kiwifruit.It indicated that lower temperature could regulated the fatty acid pathway in kiwifruit.4.Thelower temperature significantly reduced the relative expression of encoding genes involved in fatty acid pathway,including LOX,HPL,ADH,AT1,AT2 and AT 17 in kiwifruit.It suggested that lower temperature inhibited increases in the activities of key enzymes and the relative expressive of encoding genes involved in fatty acid pathway,which contributed to inhibiting biosynthesis of volatile components and maintaining the flavor quality in kiwifruit during storage.