Research Projects

Litchi (Litchi chinensis Sonn.) is a high-value, non-climacteric subtropical fruit that holds significant commercial importance in India. According to the National Horticulture Board and recent horticultural statistics, India is the second-largest producer of litchi in the world, with an estimated cultivation area of 93,300 hectares, yielding nearly 720,000 metric tons annually. Eastern India, particularly Bihar is the leading litchi-producing state, contributing over 40% of the country’s litchi area and production, due to favorable agro-climatic conditions and cultivar diversity. Despite its economic and nutritional value, the commercial potential of litchi is largely restricted by its short postharvest life (2–3 days at ambient conditions). The most critical issue affecting litchi fruit after harvest is pericarp browning a physiological disorder primarily caused by rapid moisture loss, oxidative stress, and polyphenol oxidase (PPO) activity, which converts phenolic compounds into brown pigments. Even a 2–3% loss of pericarp moisture can lead to visible discoloration, making the fruit unattractive to consumers and significantly reducing its market value. Moreover, in many cases 100% loss in litchi fruit has been reported. Currently, sulfur dioxide (SO₂) fumigation is the most widely practiced commercial technique to prevent pericarp browning and microbial spoilage. However, SO₂ is a toxic chemical that often leaves residual levels far above international permissible limits (10 ppm). Studies show that up to 30–60% of sulfur used during fumigation is absorbed into the fruit. This poses serious health risks and has led to stringent regulatory restrictions by major importing countries like the European Union, Australia, and the USA, thereby limiting export potential. Moreover, SO₂ may cause off-flavor development, nutritional degradation, and consumer rejection in the global market. To address these limitations, this project aims to develop a novel active packaging system using biodegradable aerogel materials that can be functionalized with plant-derived signaling molecules such as hydrogen sulfide (H₂S- precursor sodium hydrosulfide), methyl jasmonate (MeJA- precursor Jasmonic acid), nitric oxide (NO- precursor Sodium Nitroprusside), and their comparative study with sulfur dioxide (SO₂-KMS) in trace, controlled-release forms. These signaling molecules are known to delay senescence, inhibit PPO activity, enhance antioxidant defense, and modulate ethylene response, thereby offering a safer and sustainable alternative to chemical fumigation. Aerogels, due to their ultra-lightweight, porous, and high-surface-area structure, provide an excellent matrix for the sustained release of bioactive compounds and moisture regulation. Natural biopolymers like starch, chitosan, cellulose, or pectin will be used to fabricate the aerogel matrix via sol-gel synthesis and freeze-drying. The aerogels will be tailored to litchi-specific packaging requirements, characterized for morphological, physicochemical, mechanical (to retain optimum moisture) and absorption properties, and optimized for controlled gas transmission and active molecule release. This multifunctional approach integrates postharvest physiology, materials science, and packaging technology to address one of the most pressing issues in litchi export and domestic trade. The outcome is expected to provide a non-toxic, biodegradable, consumer-safe packaging solution, enhance the marketability and export readiness of Indian litchi, and reduce dependence on sulfur fumigation.