Effect of Ultra-high Pressure and Heat Treatment on Activity and Structure of Four Aroma Synthesis Enzymes in Fruits and Vegetables

The effects of ultra-high pressure and heat treatment on the activity,structure and their correlation of four key pure enzymes in aroma metabolism of fruits and vegetables were studied. The results showed that the activity of lipoxygenase(LOX),phospholipase A2(PLA2)and acyltransferase(AAT)decreased after different heat treatment and ultra-high pressure treatment,while that of ethanol dehydrogenase(ADH)increased. SDS-PAGE electrophoresis results showed that the primary structure of the four enzymes did not change,while the secondary and tertiary structures were different. After ultra-high pressure treatment of LOX,the contents of α-helix and β-fold were significantly reduced,and the fluorescence intensity was higher than that of the blank group. The secondary structural changes of ADH were mainly the increasing of irregular crimp,and the fluorescence intensity was lower than that of the blank group. LOX activity was correlated with alpha-helix and PLA2 activity was correlated with fluorescence intensity under the two different treatment.