Effect of Sunning as Post Harvest Treatment for Insect Pests on Antioxidants and Physicochemical Properties of Date Fruit

Date fruit from three date palm (Phoenix dactylifera) cultivars namely Khalas, Shiashy and Rizez were selected for study. Freshly harvested date fruit is prone to insect-pest infestation. It is, therefore, important to preserve it properly to maintain fruit quality and enhance shelf life for human consumption. The main aim of this study was to evaluate the effect of sunning as insect-pest post-harvest control treatment on the quality characteristics and the antioxidants of mature date fruit before and after sunning treatment. Dates treatments of exposure to direct sun light for two days (48 h) significantly increased the level of total phenolic compounds to more than 175% in all cultivars. The trend was found in both assays for total phenolics and total flavonoids with the same percentage in Khalas, Rizez than Shiashy. The FRAP value of fresh (control) Shiashy (151.14 mg/100 g) was significantly higher than fresh Rizez and Khalas dates (145.31 mg/100 g; 79.33 mg/100 g, respectively). Khalas cultivar showed highest antiradical activity (240%) than Shiashy (178%) and Rizez (171%), respectively. The results suggested that treatment of date fruit by exposing to direct sunlight is an excellent substitute to chemical fumigation for safety and to maintain quality characteristics for human consumption.