The effect of heat treatment on post-harvest quality of fresh-cut nectarine

The work investigate the effect of short-term heat treatment on quality of fresh-cut nectarines, cv Orion. This treatment may have effects on the fruit beyond their stated purpose because a high temperature stress can trigger changes in plant tissue that affect many physiological processes. These processes include inhibition of ethylene production and other ripening and senescence related processes, induction of defense compounds against pathogens, attack and induction of resistance to other stresses, including low temperature stress. The result of the treatment is to maintain fruit quality following the heat treatment. In this work, a pre-cutting heat treatment at 40°C for 50 min and modified atmosphere packaging (5 kPa O2 and 5 KPa CO2) storage was evaluated. The quality-affecting parameters were evaluated by physical and chemical methods (firmness, colour, pH, soluble solids content and titratable acidity) and by the evaluation of physiological aspects (PPO activity) as well as the changes in headspace gas composition during storage for 11 days at 4°C. Significantly lower concentrations of O2 in the package atmosphere were recorded for heat-treated slices. In contrast, hot water treatment did not reduced firmness loss. Moreover an insignificant effect of heat treatment and modified atmosphere on chemical composition (total soluble solids and titratable acidity) and colour parameters was observed. Also for the polyphenoloxidase activity no significant changes was recorded.