Impact of postharvest methyl jasmonate treatment on the volatile composition and flavonol content of strawberries

[Background]: Although strawberry aroma is very complex, certain compounds have been described as main contributors, i.e. furanones, aldehydes, alcohols, sulfur compounds and particularly methyl and ethyl esters. In addition, strawberries possess potent antioxidant activity because of their high content of phenolic compounds. Among them, flavonols are highlighted as important antioxidant compounds in strawberry. The objective of this study was to assess the effect of methyl jasmonate (MJ) on the composition of the major contributors to aroma and on the content of certain flavonols in strawberry fruits.
[Results]: The levels of all studied volatile compounds were significantly affected by MJ treatment, though the individual effect differed according to the specific compound considered. Most of them increased significantly (P < 0.05), except methyl butanoate, which always showed higher levels in untreated strawberries. In contrast to aroma compounds, the change in the concentration of flavonols (i.e. myricetin, quercetin and kaempferol) was not significant in MJ-treated strawberries. Considering the health-promoting activity of these compounds, further investigations on the experimental conditions related to the treatment are required to control flavonol bioformation by means of MJ.
[Conclusion]: The exogenous application of MJ vapour to strawberry enhances, in general, the production of the most relevant aroma-active compounds. On the contrary, MJ treatment does not appear to influence the levels of myricetin, quercetin and kaempferol. Thus postharvest MJ treatment is proposed as an approach to obtain improved strawberry fruits in terms of sensory quality and health-promoting properties.
This work was financially supported by the Ministerio de Ciencia e Innovación (project AGL-2007-65772). Fernando de la Peña thanks CSIC for his I3P contract.