Reduction of linolenic acid affects tomato leaf and fruit aroma
Canoles M., Li C., Howe G., Beaudry R.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004
2004
บทคัดย่อ
Reduction of linolenic acid affects tomato leaf and fruit aroma
Some of the most important aroma ‘impact compounds’ in tomato fruits are cis-3-hexanal, which are produced by linoleic (18:2) and linolenic (18:3) acid peroxidation.We evaluated C6-aldehyde and alcohol production in the tomato cv. Castlemart and is mutant Lefad7, which has a reduced amount of 18:3, and performed sensory evaluations to determine whether the aroma volatile differences could be perceived.Volatiles were analyzed by GC-MS.Lipid composition was determined using FID gas chromatography.Aroma differences were tested by Triangle Test and Preference Test.Fatty acids from leaves and fruit of Lefad7 mutant differed dramatically from those of the wild type plants.The 18:3 content of the leaves and fruit of the mutant line was 15 and 10% of wild type respectively.Mutant leaves produced 20% of the amounts of cis-3-hexenal, trans-2-hexenal, and cis-3-hexenol, relative to wild type, and 10-fold higher levels of hexanol and 1-hexanol.Mutant fruit produced very reduced amounts of cis-3-hexenal (3%), trans-2-hexenal (7%), but 5-fould higher levels of hexanal relative to the wild type.Differences in the volatiles between wild type and mutant leaves and fruits were perceived by untrained sensory panels with a high significance (p-value<0.0005), and more than 50% of the consumers preferred the aroma of wild type fruits having higher unsaturated C6-aldehyde levels.In conclusion, the ratios and amounts of C6 saturated and unsaturated aldehydes and alcohols produced by tomato are dependent on substrate levels, and these difference can be perceived by consumers, suggesting that altering the concentration of the hexenals or their precursors can influence tomato flavor.