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

Highlights: • Post-drying irradiation at 2.5–3.0 kGy significantly retained the nutritional content during storage. • Irradiation modified the antioxidant potential of dried apple chips particularly the hydroxyl radical scavenging activity. • Radiation processing maintained crispy texture, color attributes and overall acceptability during storage. • Post-drying radiation treatment offers opportunity for merchandizing of product and satisfying consumer health concerns. 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.