Fresh-cut produce are exposed to pre- and postharvest abiotic stresses during the production chain.Scientists at University of Milan, partner in EU project QUAFETY, evaluated the use of stress associated genes activated during postharvest as quality markers for rocket salad and melon by means of quantitative real time PCR (qRT-PCR).
The use of qRT-PCR in respects to other destructive methods has the advantage to be more sensitive and specific since it detects variations at molecular level and requires lower amounts of starting material. The expression of these genes was further linked to the evaluation of biochemical and physiological markers in order to predict the quality or reduced nutritional value in stored produce.
Stress responsive genes associated with quality losses were isolated in fresh-cut rocket and melon and their expression levels were analyzed by qRT-PCR at different time points after harvest at 20°C and 4°C.
Eleven stress responsive genes were selected as putative markers of quality in both species. The markers encode proteins associated with senescence, stress and degenerative processes, mechanisms that are not mutually exclusive and that drastically induce quality losses.
Results revealed a good association between some molecular markers and physiological and nutritional quality. In rocket the majority of the genes showed correlations with chlorophyll a fluorescence and sugars production, while in melon some of the genes were highly and significantly correlated to ascorbic acid content, sugars, O2- and ethylene biosynthesis.
The best quality markers were represented by DtNAC3 and DtStAR in rocket and CmASN and CmHPD in melon. These markers can be taken into consideration for the further development of new quality predictive technologies as well as quality monitoring systems on fresh produce markets.
Scientists conclude that these innovative markers can be adopted in support and integration of those already in use in order to implement the overall assessing and monitoring systems of quality at any point of the distribution chain.
Source: Cavaiuolo M., Cocetta G., Bulgari R., Spinardi A., Ferrante A. 2015, 'Identification of innovative potential quality markers in rocket and melon fresh-cut produce', May 2015, Food Chemistry, Vol. 188, pages 225 - 233.
http://www.sciencedirect.com/science/article/pii/S030881461500713X