DISTRIBUTION OF IMPORTANT FLAVOUR PRECURSORS IN ACTINIDIA: LONG CHAIN FATTY ACIDS

Distribution of long chain fatty acids (FAs) was monitored in two of New Zealand's main commercial kiwifruit cultivars, Actinidia deliciosa 'Hayward' and A. chinensis 'Hort16A' using a single step methylesterification method followed by GC-MS analysis. The FAs in different tissues of ripe and over-ripe fruit were assessed in both fresh fruit and cooked fruit, in which enzyme activity was minimized. Cooked kiwifruit had higher concentrations of FAs than non-cooked samples. The main FAs found in both species of kiwifruit were linolenic acid, linoleic acid, oleic acid, and stearic acid. In both cultivars, the inner pericarp contained more than four times as much fatty acids as any other tissues. 'Hort16A', which exhibits fewer green/grassy odours, contained significantly less linolenic acid in the inner pericarp than did 'Hayward'. Linolenic acid is the FA that has been reported as the precursor of (E)-2-hexenal through the lipoxygenase pathway. Further data are presented, with discussion of the fatty acid degradation pathways and potential impacts on the aroma volatiles in kiwifruit.