Combined effect of chemical preservative and different doses of irradiation on green onions to enhance shelf life

Abstract

Trade of fresh, healthy, easy to cook and ready to use food products have been increased due to change in consumer trends. It is crucial to retain the freshness of produce. Aim of this study was to optimize effective dose of irradiation and/or chemical preservatives on shelf-life extension of green onions and to check its efficacy on physiochemical, phytochemical, sensorial and microbial quality. Freshly-cut green onions were washed with 0.001 mol sodium hypochlorite, irradiated at 0.5 kGy, 1.0 kGy, and 1.5 kGy and/or 0.1% sodium benzoate treated. The treated samples were stored at 5 °C for 16 days. Physicochemical analysis like weight loss, pH, moisture content, phytochemical analysis like chlorophyll and beta-carotenoid content, trolox equivalent antioxidant capacity, total phenolic content, color and texture analysis, sensory evaluation and microbial studies were done. Irradiation 0.5 kGy when compared to other treatments didn’t show better results in terms of appearance, nutrient content and storage life. In addition, irradiation 1.5 kGy showed more beta-carotenoid content but it also caused electrolytic leakage due to cellular membrane damage. The combined treatment of irradiation 1.0 kGy and sodium benzoate was found to be most effective in terms of texture, color, radical scavenging activity, polyphenols, chlorophyll content and microbial safety during the storage of 16 days. Keywords: Green onion, Sodium hypochlorite, Irradiation, Sodium benzoate, Shelf-life