Intelligent & edible biopolymer-based packaging technologies for postharvest shelf-life enhancement of litchi (Litchi chinensis) fruit: a comprehensive review

Abstract

Litchi (Litchi chinensis) is a sub-tropical fruit of high nutrition and commercial value, but its quality and safety deteriorate during storage due to physical, chemical, enzymatic, and microbial damage. The shelf-life can be improved by various methods such as sulfur (SO₂) fumigation, cold storage, gamma irradiation, high-pressure processing, edible packaging, etc. SO₂ fumigation is one of the most explored methods for preserving litchi fruit but due to its negative environmental and human health effects, its application is limited. Edible and intelligent coatings and films comprised of various biopolymers can be a promising solution to prolong the shelf-life of litchi and they help to achieve SDGs 12.3 (halve per capita global food waste at the retail and consumer levels), 13.2 (integrate climate change measures into national policies, strategies, and planning) and 14.1 (prevent and significantly reduce marine pollution of all kinds). This article reviews the recent advances in using different biopolymers to develop intelligent & edible films and coatings to improve the storage life of litchi fruit. Edible packaging based on polysaccharides, proteins, lipids, additives, nanoparticles, etc. has been examined. These protective layers reduce the respiration and transpiration rates, protect against mechanical stress, microbial contamination, enzymatic browning and UV light, and enhance the quality by adding bioactive agents, nanomaterials, probiotics, etc. The opportunities to use bioactive compounds, essential oils and plant extract in various biopolymeric edible coatings are explored. Finally, regulatory aspects associated with edible intelligent packaging have been discussed. Overall, the application of edible and intelligent packaging can be a potential alternative for delaying the degradative changes, extending the shelf-life, and reducing the economic losses caused by the spoilage of litchi.