Effect of post-processing radiation treatment on physico-chemical, microbiological and sensory quality of dried apple chips during storage

Abstract

In the present study dried apple chips packed in polyethylene packs were gamma irradiated in the dose range of 1.0–3.0 kGy. Irradiated samples including control were stored under ambient (10±2–15 ± 2 °C, RH 60–70%) conditions and evaluated at intervals of 2 months for physico-chemical, sensory and microbial quality parameters. Results revealed that dose levels of 2.5 kGy and 3.0 kGy proved significantly (p ≤ 0.05) beneficial in enhancing the nutritional quality besides maintaining color and texture attributes during storage. Post-drying irradiation treatment at 3.0 kGy increased the total phenol content by 6.6%, total and reducing sugars by 4.2% and 18.8% respectively. Results of the antioxidant activity revealed a significant (p ≤ 0.05) decrease in EC50 values of apple chips following post drying irradiation. EC50 values of apple chips irradiated at 2.5 kGy and 3.0 kGy were significantly (p ≤ 0.05) lower than standard antioxidants for hydroxyl radical scavenging activity. Data pertaining to Hunter color score indicated that during storage, percentage increase in browning was 40.4% in control compared to 21.9% in 3.0 kGy irradiated samples. The above irradiation treatments maintained significantly (p ≤ 0.05) higher overall acceptability of apple chips and resulted in about 2.5 log reduction in microbial load just after irradiation and 2.1 log reductions after 6 months of storage under ambient conditions.