Role of irradiated and un-irradiated alginate as edible coating in physicochemical and nutritional quality of cherry tomato.

Background: Fresh vegetables are commodities that have a high tendency to deteriorate after harvest, causing significant losses in economic and environmental costs associated with plant food loss. Therefore, this study was carried out to evaluate the effects of both un-irradiated (UISA) and irradiated sodium alginate (ISA) as an edible coating for preserving cherry tomato fruits under storage conditions. The FTIR, XRD, TGA, SEM, and TEM were used to characterize the UISA and ISA (25, 50, 75, and 100 kGy), which demonstrated that the alginate polymer was degraded and low molecular-weight polysaccharides were formed as a result of irradiation, particularly with the 100 kGy dose level. Sodium alginate irradiated at 100 kGy was used for the coating process, and the physico-chemical and nutritional quality of cherry tomatoes were analyzed.

Results: The results demonstrated that UISA and ISA treatments delayed changes in most of the ripening characteristics; weight and acidity losses, decay, and softening. The weight loss of the control was observed to be greater at the two keeping temperatures (4 and 25 °C) comparison with tomatoes coated with UISA. The ISA coatings gave the least weight loss at the two keeping temperatures (4 and 25 °C) (5.46 and 14.72%), respectively compared to the control (8.77 and 18.93%), respectively at the end of the storage period. In terms of antioxidant properties, significant results were obtained with the use of the alginate coating, specially irradiated sodium alginate. Over time, the majority of water-soluble vitamins in cherry tomatoes decreased, especially vitamin C, and the alginate-coated tomatoes showed the least decrease in vitamin C content, especially ISA.

Conclusions: The current findings suggest that ISA treatment efficiently extends the storage period of tomato fruits and maintains their quality through preservation and offers promising potential for successful commercialization of this eco-friendly eatable coating for fruit and vegetable growers and industries.