COMBINING MAP, DEFICIT IRRIGATION AND ANTIBROWNING TREATMENT FOR KEEPING QUALITY OF FRESH-CUT PEACHES

Agriculture in semi-arid areas faces the scarcity of water resources. The effect of deficit irrigation (DI) on quality of ‘Flordastar’ peach slices stored in modified atmosphere packaging was studied. The DI was programmed according to signal intensity (SI) of the maximum daily trunk shrinkage (MDS); DI plants were irrigated to maintain MDS SI values close to 1.4 or 1.3 in the case of DI1 or DI2 plants, respectively (see details in material and methods). Results were compared to a non-DI (NDI) watered at 150% crop evapotranspiration. Once harvested, peaches were cut in 6-8 pieces and two groups were made: ‘Control’, packaged in polypropylene trays, and ‘Antibrowning’ in which pieces were treated with 9% ascorbic acid (AA) before packaging. In both cases, a passive modified atmosphere (16.5 kPa O₂ and 3.5 kPa CO₂) was generated throughout storage at 5°C. On days 0, 4 and 8, firmness, vitamin C, microbial counts and sensory quality were evaluated. As results, DI₁ and DI₂ peaches showed higher firmness on the initial day than NDI fruits but no differences between irrigation treatments during storage were found. Initially, samples treated with AB solution showed higher AA content than control. During shelf life, no differences in AA content were registered between both kinds of treatments, following a decreasing trend with time. In general, the dehydroascorbic acid content tended to increase during storage, without differences among treatments. AA treated peaches reached the best rating by the sensory panel. In all treatments, microbial counts (mesophilic, yeast, moulds, Salmonella spp., Listeria spp. and E. coli) were below the legal European limits. The main conclusions obtained were that the use of DI strategies saved an important water amount, providing similar quality fresh-cut fruits. The use of AA kept the appearance of the slices allowing a shelf life of 8 days.