2019 ASHS Annual Conference

The nutritional composition of watermelon is influenced by various preharvest and postharvest factors. While application of nanotechnology on nutritional composition and quality has potential benefits, limited studies are available to provide strong evidences. Nanoparticle (silver nanoparticle and turmeric nanoemulsion) treated and untreated watermelons, Riverside (diploid) and Maxima (triploid) were harvested from multi-locations in Texas during two years. The physico-chemical properties and health promoting compounds of watermelons were assessed at ambient temperature 0, 10 and 20 days after harvesting. The results demonstrated the alteration of secondary metabolites of fresh produce leading to the variation of phytochemical composition. It is possible that watermelons continue their metabolic activities after harvest and might have undergone various biotic and abiotic stresses. The physico-chemical characteristics and the levels of bioactive compounds (lycopene, β-carotene, L-citrulline and ascorbic acid) were maintained and/or enhanced in watermelons at 10 days of storage compared to the fresh watermelons. However, in both varieties, levels of all the parameters were significantly reduced in the watermelons held for 20 days. Combined analysis across all locations demonstrated non-significant treatment effect on the physico-chemical and the levels of bioactive compounds among the control and the nanopriming treated Maxima watermelons. Both nanoparticles treated Riverside had significantly enhanced physico-chemical parameters along with the level of L-citrulline and lycopene compared to the unprimed watermelons. No significant difference was observed in the level of b carotene and ascorbic acid level between the treated and untreated Riverside fruits. These observations suggest that seed priming with nanomaterials did not have any toxic effect in the fruit functional quality and that outcomes could depend on cultivar, ploidy level, as well as production location. Similarly, our results demonstrated that watermelon could be stored up to 10 days of harvest without loss of the nutritional quality.