Postharvest application of gamma irradiation affects fruit quality and antioxidant enzymes activities of ‘kinnow’ mandarin fruits during cold storage

Abstract

Food safety with maintained fruit quality is an important challenge for postharvest industry of citrus fruits. The present study was designed to check the effects of gamma irradiation on postharvest fruit quality of ‘Kinnow’ mandarin stored at 5 ± 1 °C and 90 ± 5% Relative Humidity. In the first experiment, fruits were exposed to different doses of gamma radiation (100-500 Gy), while after analyzing the results of first experiment, in the second experiment fruits were treated with 500, 600, 800 and 1000 Gy of gamma radiation. It was observed that higher doses of gamma irradiation exhibited lower weight loss and disease incidence as well as inhibiting the increase of soluble solid content (SSC) and retained higher titratable acidity (TA) and lower SSC: TA ratio. After 90 days of storage, maximum levels ascorbic acid, total phenolic contents and total antioxidants along with catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activities were recorded higher in fruits treated with 800 Gy. These fruit also exhibited higher score of taste, aroma and texture during storage. Overall results suggest that pre-storage treatment of 800 Gy is the most effective treatment and have potential application for quality management of ‘Kinnow’ mandarin under long term cold storage.

Keywords:
citrus; food irradiation, total phenolic contents; catalase; peroxidase antioxidant activity