Effect of potassium fertilizers associated with cold storage on peach (Prunus persica L.) quality

Potassium (K) fertilization may affect peach quality and preservation. This study aimed at evaluating the effect of doses of K on physico-chemical and functional characteristics of "Sensacao" peaches in the postharvest period. Mass loss, pulp color, total solublesolids, titratable acidity, pH, pulp and skin firmness, total concentrations of phenolic compounds and carotenoids and antioxidant activity were evaluated in fruits. The experiment was a randomized block design in a 5x3 factorial scheme, five doses of fertilizers (0, 40, 80, 120 and 160 Kg ha-1K2O) and three storage periods (harvest day, 10 days and 20 days in cold storage at 1±1oC, followed by a day of simulated commercialization at 20±1oC). Mass loss, pulp firmness, phenolic compounds, antioxidant activity and carotenoids decreased when fruit underwent cold storage, independent of the dosage of K fertilization. Doses of40 and160 kg ha-1K2O applied to the soil lead to a larger number of phenolic compoundsand higher antioxidant activity in fruits at harvest time. After cold storage, fertilization with160 kg ha-1K2O exhibited the highest antioxidant activity and the lowest mass loss in fruits. Increase in doses of K strengthened the color of peach pulp.