Changes of lipoxygenase and fatty acid hydroperoxide lyase activities in bell pepper fruits during maturation.

Developmental changes in fatty acid hydroperoxide lyase (HPO lyase) and lipoxygenase (LOX) during the maturation of bell pepper fruits (Capsicum annuum L. cv. Kyonami) were examined by means of activity measurements, immunological detection of both the enzymes, and analysis of the volatile compounds formed upon homogenization of the fruits. Both the enzyme activities decreased with maturation, and immunological studies showed that the amounts of the enzymes concomitantly decreased. The amounts of six-carbon aldehydes and alcohols formed from bell pepper fruits upon homogenization also decreased during maturation, and with the fully ripened red fruits, these volatile compounds were hardly detectable. These results suggest that the major factor contributing to the changes in the composition of volatile compounds during the maturation of bell pepper fruits was changes in the amounts of HPO lyase and LOX.