Off-flavor caused by cold storage is related to induced activity of LOX and HPL in young coconut fruit

Abstract

Off-flavor after cold storage is the major consumer complaint relating to consumption of young coconut fruit. To understand its chemical basis, young coconut fruit were stored for up to 4 weeks at either 4 or 25 °C, followed by volatile analysis. Off-flavor was detected at 4 °C in both water and kernel tissue after one week of storage and then increased quickly thereafter. PatternHunter analysis showed that volatiles from the lipid oxidation pathway, heptanal, octanal, nonanal and heptanol, were positively correlated with the development of fruit off-flavor during cold storage. Lipoxygenase (LOX) and hydroperoxide lyase (HPL) were related to the formation of lipid-derived volatiles and activities of both of these enzymes were high in fruit during cold storage. Fruit wrapped with polyethylene (PE) film reduced LOX and HPL activities, reduced the concentrations of heptanal, octanal, nonanal and heptanol and inhibited off-flavor development relative to fruit wrapped with polyvinyl chloride (PVC) film.