Exogenous calcium nitrate application delays senescence, enhance nutraceutical properties and antioxidant defense system during storage

In recent year, the demand for guava fruit has been increasing in domestic and international markets. However, guava fruit is extremely perishable due to the short shelf life and rapid over-ripening of the fruits suggesting the need for practical tools to extend their shelf-life. In the present study, the efficiency of calcium nitrate treatment was investigated on Golla guava fruit. Fruits were treated with different concentrations (0, 1%, 2%, 3% and 4%) for 12 days storage at ambient condition. Among the dipping treatments, 4% calcium nitrate significantly reduced fruit weight loss (FWL), decay percentage, and suppressed the increase of soluble solids content (SSC). Moreover, 4% calcium-treated fruits had higher total titratable acidity (TA), and lower ripening index (SSC: TA ratio) and pH during the storage period. Higher ascorbic acid, total phenolic content (TPC) and higher reducing, non-reducing and total sugars along with retained higher activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes were observed in (4%) calcium nitrate treated guava fruits. Calcium nitrate (4%) also exhibited higher aroma, taste and flavour among the other treatments. Generally, the pre-storage calcium nitrate dipping treatment of guava fruit-maintained fruit quality for up to 12 days at ambient storage condition and could be suggested as practical solution at commercial levels in extending the shelf life of fresh guava fruits.