High CO2 concentrations could contribute to maintain high levels of phenolic compounds, involved in the counteracting the development of grey mould in table grape

Poscosecha, postcosecha, postharvest, uva, grape, moho gris, gray mould, Botrytis Grey mould diseases caused by Botrytis cinerea are one of the main factors reducing table grape quality during post - harvest cold storage. The fungus infect bunches on field and remain latent for a long time, showing its damaging potential within the postharvest cold storage period. High CO2 concentrations were proved to reduce diseases caused by the fungus. Nevertheless, scarce information is available about the mechanism by which this positive effect is exerted. In the aim to evaluate the effect of high CO2 concentrations on some fruit biochemical parameters in the presence of a high disease pressure, bunches of table grapes cv Italia were artificially infected by spraying with a conidial suspension of B. cinerea, packed in polyamide/polyethylene bags in three different initial MA conditions (air = control, 5% O2 + 10% CO2, and air + 20% CO2), and stored at 3 ?C for 18 days. Every 6 days within the storage, some biochemical parameters (i.e. titratable acidity, pH, total soluble solids, changes in characteristic phenolic compounds in both skin and flesh, glucose and fructose content, polygalacturonase activity) and the incidence of grey mould rots were evaluated. Moreover, the gas composition inside packages was measured at each sampling. The results showed that high CO2 concentrations did not significantly affect the polygalacturonase activity, a biochemical parameter connected to the softening, which, on the contrary, was found higher in the grey mould-infected samples than in corresponding non-inoculated samples. Moreover, in Botrytis - infected samples, a positive correlation between high CO2 levels associated to the lowest disease incidence and the high concentration of caftaric acid (the most representative phenolic compound) in the skin, was found. So, it can be supposed that high CO2 concentrations could contribute to maintain high levels of phenolic compounds in the table grape skin, which, in turn, might be involved in counteracting the disease development. Original tittle, full list of authors and sourcesTHE ROLE OF CO2 IN REDUCING GREY MOULD -CAUSED DISEASES ON STORED TABLE GRAPESGatto, M.A., Sergio, L., Pieralice, M., Linsalata, V., Cascarano, N.A. and Di Venere, D.(*)donato.divenere@ispa.cnr.itInstitute of Sciences of Food Production, National Research Council (CNR), Via G. Amendola 122/O, 70126 Bari, Italy CA MA 2013, XI International Controlled & Modified Atmosphere Research Conference, Trani (Italy), 3-7 June 2013 The picture is by vitivinicultura.net