Selenium and nano-selenium in horticultural produce: from preharvest biofortification to postharvest preservation

Postharvest losses of fruits and vegetables caused by microbial spoilage and physiological disorders remain a significant challenge to global food security. Selenium (Se), particularly ionic Se and selenium nanoparticles (SeNPs), has demonstrated significant potential for the preservation of postharvest fruits and vegetables. This review summarizes the roles of ionic Se and SeNPs in maintaining the postharvest quality of horticultural produce. Furthermore, it highlights recent advances in SeNPs synthesis and the fabrication of SeNPs-based edible coatings using natural polymers for postharvest preservation applications. Both ionic Se and SeNPs improve postharvest quality by inhibiting microbial decay, delaying fruit ripening, and maintaining the nutritional properties of stored fruits and vegetables. Compared with ionic forms, SeNPs offer greater stability, controllable Se release, and low toxicity, making them ideal candidates for edible coating fabrication. Integrating SeNPs into natural biopolymers, such as chitosan (CT), alginate, and starch, improves coating strength, gas barrier properties, and overall preservation performance. These coatings effectively suppress microbial growth, reduce oxidative damage, delay senescence, and extend shelf life while maintaining sensory quality. Notably, postharvest Se application is a valuable source of Se micronutrient biofortification, further enhancing the nutritional value of stored fruits and vegetables. In addition, green-synthesized SeNPs are safer and more sustainable compared with chemically synthesized SeNPs, minimizing potential environmental risk. Despite their potential as multifunctional nanotechnology for postharvest management, further studies on toxicity, safety regulations, and large-scale production are required to ensure their practical and commercial applicability.