Effects of hot water treatment and modified Polypropylene packaging of Postharvest quality and shelf life of lime Citrus aurantifolia Swingle

Abstract

Hot water treatment is an effective method for prolonging shelf life of agricultural products. This method affects some physiological changes of the products and can also control diseases. In this experiment, hot water dipping of lime at 40, 45, 50 and 55 ºC for 2 and 5 min and stored at 10 and 25 ºC for 6 and 4 weeks, respectively, was conducted. The results showed that hot water treatment at 40 ºC for 5 min was the best temperature and duration for prolonging shelf life of limes in both 10 and 25 ºC storage temperatures. This condition could delay change of peel color, decrease percentage of weight loss and percentage of disease incidence compared with fruits dipped in distilled water at room temperature (control treatment) whereas treated fruits with too high temperatures resulted in hot water damage. Appropriate temperature and period of time (40 ºC for 5 min) with modified polypropylene packaging (HPCH and MPPCH) and normal polypropylene (PP) used as control was selected to test postharvest storage of lime. After four weeks storage at 25 ºC, hot water treatment with modified polypropylene packaging efficiently delayed the increase of L value and the decrease of Hue value more than controls which were significant difference in HPCH packaging compared with control. The combination of MPPCH and hot water treatment significantly increased total phenolic content, while HPCH significantly increased catalase (CAT) activity. In addition, HPCH packaging with hot water treatment could decrease respiration rate and percentage of disease incidence at the end of storage. However, hot water treatments with modified polypropylene packaging did not affect other postharvest qualities such as percentage of weight loss, ascorbic acid, total soluble solids and ascorbate peroxidase (APX) activity. For 10 ºC storage, hot water treatment with modified polypropylene packaging had no effect on postharvest qualities after storage except APX activity and percentage of disease incidence. Lime dipped in hot water treatment combined with HPCH and MPPCH could increase APX activity and reduced disease incidence after storage for 6 weeks. These results suggested that hot water with modified polypropylene packaging can maintain postharvest quality of lime fruits during storage at 25 ºC for 4 weeks, while no significantly affect was observed for the quality of lime stored at 10 ºC.