Influence of selenium and chitosan on physico-chemical properties of guava (Psidium guajava) under storage

Guava (Psidium guajava L.) is an important fruit cultivated in tropical and sub-tropical countries. Being a climacteric fruit it has very high respiration and deterioration rates (shelf-life 3-4 days), making a challenge for storage. Therefore, the present experiment was conducted during 2016–17 to reduce the post-harvest losses and extension of shelf-life of guava fruits var. Hisar Surkha using the combination of selenium and chitosan treatments. The mature green freshly harvested guava fruits were treated with selenium solutions (0.01 ppm, 0.02 ppm, and 0.05 ppm) in combination with 1.5% chitosan containing 0.5% acetic acid for 5 min and stored at room temperature (20±2°C, 82±5% RH). The fruits were analyzed for physico-chemical attributes (physiological weight loss, fruit firmness, total soluble solids, and titratable acidity) and biochemical characteristics (total phenolic, flavonoid contents, and total antioxidant activity) at three days interval. The combined treatments of selenium and chitosan helped in delaying weight loss (9.66%), lower disease incidence, better retention of fruit firmness (4.70 kg/cm2), soluble solids (13.03 ºBrix), titratable acidity (0.38%) compared to control on 12th day of storage. Treatment of guava fruits with selenium and chitosan also maintained higher total phenols (24.99 mg GAE /g dry wt.), flavonoids (3.51 mg CE/g dry wt.) and exhibited higher antioxidant activity (54.32%) throughout storage. The present study showed that combination of Se (0.02 ppm) and chitosan (1.5%) was most effective in maintaining post-harvest quality and enhance the shelf life of guava fruits up to 12 days during storage at room temperature.