Combination of soy protein isolate and calcium chloride inhibits browning and maintains quality of fresh-cut peaches

Fresh-cut fruits are often more perishable and exhibit browning shortly after pulp is cut and exposed to natural atmosphere. In this study, fresh-cut peaches were treated with distilled water (control), 20 g L-1 soy protein isolate (SPI), 10 g L-1 calcium chloride (CaCl2) or 20 g L-1 soy protein isolate + 10 g L-1 calcium chloride (20 g L-1 SPI + 1.0 g L-1 CaCl2), respectively, and then stored at 0°C to assess the protective effects of these treatments on the qualities and the antioxidative system of fresh-cut peaches. The result showed that firmness, colour(∆E*) and soluble solid content (SSC) in fresh-cut peaches treated with 20 g L -1 SPI + 10 g L-1 CaCl2 were higher than control. Compared with other treatments, treatment with 20 g L-1 SPI + 10 g L-1 CaCl2 2 significantly decreased weight loss rate, bacterial growth, respiratory rate and ethylene emission of fresh-cut peaches. Treatment with 20 g L-1 SPI + 10 g L-1 CaCl2 also inhibited increase in browning degree, production of reactive oxygen species, malonaldehyde and total phenols, and maintained higher activities of superoxide dismutase and catalase, whereas inhibited the activities of peroxidase and polyphenol oxidase. These results suggest that treatment with 20 g L-1 SPI + 10 g L-1 CaCl2 enhanced antioxidant activities of fresh-cut peaches, inhibited browning, and was more effective in maintaining the quality of fresh cut peaches.
Keywords: Edible coating; Ethylene emission; Phenolic contents; Respiration rate; Active oxygen species