Effect of ozonated water combined with sodium bicarbonate on microbial load and shelf life of cold stored clementine (Citrus clementina Hort. ex Tan.)

Abstract

The effect of 3 mg L−1 ozonated water (O3) in combination with 3% sodium bicarbonate (SBC), on the microbial control and the postharvest quality of cold stored Clementine fruit (C. clementina Hort. ex Tan.), compared to the single treatments and the water wash, was evaluated. After treatments fruits were stored for 30 days at 5 ± 1 °C and relative humidity (RH) 90 % followed by seven days at 20 ± 2 °C and RH 75 %, to simulate retail conditions (shelf life). Microbial reduction, decay incidence, physiological disorders, weight loss, rheological properties (deformation and firmness) physical-chemical parameters (colour, total soluble solids, titratable acidity, ascorbic acid) and sensory quality were evaluated soon after treatments during fruit cold storage (T10, T20, T30) and after 7 days of shelf-life (T30 + 7).The results showed that integrated treatments (O3+SBC) greatly reduced the total viable count (more than 1 log unit), during the first 10 days of storage (T10), if compared to the other treatments. Moreover, O3+SBC reduced significantly the decay incidence during the whole storage (2.6 % at T30; 10.9 % at T30 + 7) with respect to the control (27.3 % at T30; 45.5 % at T30 + 7). In particular, the control of sour rots (Galactomyces citri-aurantii E.E. Butler) in treated fruits was observed. Our findings did not highlight noticeable changes among treatments concerning fruits weight loss, physiological disorders, chemical composition and sensory analysis.