Effect of post-harvest salicylic acid treatments on fruit quality of peach cv. "Flordaprince" during cold storage

Peach [Prunus persica (L.) Bastch.] "cv. Flordaprince" fruits at commercial maturity were immersed in 0, 0.5, 1.0 and 1.5 mM salicylic acid (SA) solution for 10 min, stored at 0 ◦ C for 28 days, then moved to 20 ◦C for 3 days to simulate shelf life. Fruit weight losses, firmness, TSS, acidity, Vit.C, sugars, anthocyanin, total phenols and two enzymes namely peroxidase and polyphenol oxidase activities of fruit were measured at the end of shelf life. The results showed the interaction effects between salicylic acid and storage period, also the effect of salicylic acid treatments and effect of storage period. It was noticed that the highest values of fruit losses weight were achieved with increasing storage period to 28 days and decreasing SA concentrations from 1.5 to 0.5 mM, firmness of fruit treated with SA was significantly greater than that of control fruit after 28 days of cold storage. Fruits receiving all postharvest treatments produced the firmest fruits, while the control plants (without receiving SA) had the softest fruits. Moreover, Regarding SA treatments, data revealed that, decreasing in fruit T.S.S contents were observed with increasing SA concentration in both seasons. No significant difference was found between T2 and T3 treatments on fruit T.S.S contents in both seasons. The three salicylic acid treatments maintained a significantly lower reducing and total sugars, anthocyanin and enzymes activity( peroxidase and polyphenol oxidase) than control. Acidity, Vit. C, total phenols content in fruits increased gradually with increasing SA concentrations. In the same time, prolonging periods of storage in both seasons, generally decreased vit. C and total phenols. In contrast, reducing and total sugars, anthocyanin, peroxidase and polyphenol oxidase activities increased. In the first season only, fruit reducing sugar content at 0 day has significantly high value compared to 7 days.