Green synthesized nanomaterials as an alternative to restricted chemicals in postharvest preservation of horticultural crops: a review

Postharvest Research Laboratory, Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg 2006, South Africa.

^* Corresponding author: nxumalokwaneleandy@gmail.com

Abstract

Synthetic chemicals have been successfully used to control economic postharvest pathogens such as Botrytis cinerea, Penicillium spp., Rhizopus spp., etc., thus reducing postharvest losses. However, their active ingredient and co-formulants have resulted in their use being restricted internationally due to health concerns and consumers’ requests for safe and natural alternatives. As an alternative to chemicals, green synthesized nanomaterials incorporated with edible coatings in a polymer matrix have been successfully applied on horticultural crops to improve their shelf-life Due to their known antimicrobial activities, plant extracts and nanoparticles such as silver and zinc oxide have been successfully used in food processing applications. Green sources are used as stabilizer and reducing agents to synthesize shape and sizecontrolled metal and metal oxide nanoparticles. Thus, eco-friendly nanoparticles are produced without using toxic materials and are cost-effective. Edible coatings form a thin layer that prevents oxidation, maintains the product quality, can be safely eaten as part of the product, and does not add unfavourable properties. Studies showed that edible coatings with or without green nanomaterials have been successfully used to control postharvest losses and improve the shelf-life of fruit crops such as plums, raspberries, etc.