Effect of a combined treatment of rice bran protein film packaging with aqueous chlorine dioxide washing and ultraviolet-C irradiation on the postharvest quality of ‘Goha’ strawberries

To investigate the effects of postharvest treatments on strawberry (Fragaria × ananassa Duch.) quality, a combination of non-thermal treatments was investigated as a potential hurdle technique. Specifically, ‘Goha’ strawberry samples were treated with 50 ppm aqueous chlorine dioxide (ClO₂) and 5 kJ/m² ultraviolet-C (UV-C) irradiation and packed with rice bran protein (RBP) film containing 1% grapefruit seed extract (GSE). The initial population of total aerobic bacteria in the strawberries was 3.15 log CFU/g, while that of samples treated with ClO₂/UV-C and packed with RBP film containing GSE was 1.64 log CFU/g. In terms of yeast and mold populations, the control had 2.98 log CFU/g, while the samples treated with the combined non-thermal processing and packed with the RBP film had 1.09 log CFU/g. In addition, after 11 days of storage, combined non-thermal treatment with RBP film packaging reduced the initial populations of total aerobic bacteria and of yeast and molds in the strawberries by 2.63 and 2.84 log CFU/g, respectively. Titratable acidity (TA) in the strawberries decreased during storage, but there was no significant difference among treatments. Postharvest treatments employed in this study produced a negligible change in the color of the strawberries, and sensory evaluation results indicated that the combined postharvest treatments provided better sensory scores compared with the control group. Therefore, these results suggest that a postharvest treatment consisting of 50 ppm ClO₂/5 kJ/m² UV-C with RBP film packaging containing GSE may be useful for maintaining the quality of ‘Goha’ strawberries.