EFFECT OF EDIBLE SURFACE COATINGS ON POSTHARVEST QUALITY AND SHELF LIFE OF GUAVA ( PSIDIUM GUAJAVA L . CV . PANT PRABHAT ) FRUITS

Guava (Psidium guajava L.) ‘The apple of the tropics’ is one of the most delicious and nutritious fruit crops grown in India. Guava is considered to be superior to several other fruits by virtue of its commercial and nutritional value (Menzel, 1985). It is rich in vitamin C (260 mg/100g) and a fair source of calcium, phosphorus, iron and vitamin A. Calcium chloride dipping treatment slow down and delayed the changes in ascorbic acid in fig fruit (Irfan et al., 2013). Guava fruits treated with calcium chloride @1% and wrapped in newspaper recorded minimum reduction in fruit weight during storage period (Kumar et al., 2014). Chitosan @2.5% increased the shelf-life of (Mutiara) guava fruits (Widodo et al., 2015). Kumari et al. (2015) observed that chitosan alone or in combination were found highly effective in minimizing weight loss of litchi fruit during storage at 4°C. An increase of three days shelf life of mexican guava was observed when fruits were coated with sodium alginate @10% (Gallo et al., 2003). Valero et al. (2013) reported that alginate treatments significantly decreased weight loss for all plum cultivars. Azarakhsh et al. (2014) observed a decrease in softening for fresh-cut pineapple coated with alginate, while firmness of 0.5% was found in control. Dip treatment of sapota fruit in Aloe vera gel coating 1:2 for 7 minutes had best retained the physico-chemical characteristics (Padmaja et al., 2015). Vieira et al. (2016) reported that application of an edible coating containing Aloe vera on the blueberry surface after harvesting provides an additional barrier to reduce postharvest contamination by fungi and also by reducing the rate of water loss. Due to highly perishable nature, guava fruits undergo rapid postharvest ripening in few days under ambient conditions (Hashem and Alamri, 2009). The fruit ripening in guava is characterized by loss of green colour, softening, shrinkage, loss of brightness and rot development (Ali and Lazan, 1997). The post harvest losses can be minimized by extension of shelf life through checking the rate of transpiration and respiration, microbial infection. The perishability of fruits requires the development of technologies that reduce their postharvest deterioration and extend their shelf life (Gonzalez Aguilar et al., 2009). In a country like India where sufficient refrigeration facilities are not available, the alternative means for increasing shelf life of fruits for a short period are likely to prove more beneficial. Edible coatings can provide an alternative means for extending keeping life of fresh fruits. Several types of edible coatings such as carbohydrate, protein, lipid and combination of these are in practice nowadays to extend the shelf life and quality of fruits. Among these, chitosan, calcium chloride, sodium alginate and Aloe vera gel has been known to protect perishable fruits from deterioration by reducing transpiration, respiration and maintaining textural quality. Edible coatings play an important role in the quality, safety, transportation, storage and display of a wide range of fresh and processed foods (Daniel et al., 2007; Elizabeth et al., 1995). They act as barriers to moisture and oxygen during handling (Olivas et al., 2005) and storage. They do not solely retard food deterioration but also enhance its safety due to their natural biocide activity or by incorporating antimicrobial compounds (Maria et al., 2008). For maintaining the quality and shelf life of guava fruits, ABSTRACT The main aim of the study was to assess the efficacy of different edible coating treatments like calcium chloride (1.0, 1.5, 2.0%), chitosan (0.5, 1.0, 1.5%), sodium alginate (0.5, 1.0, 1.5%) and Aloe vera gel (1:1, 1:2, 1:3) at varying concentrations on the post harvest quality attributes of fruits of guava cultivar ‘Pant Prabhat’. After treatment, fruits were kept at ambient temperature of 27-29°C till 12 days and analysed for various physicochemical parameters while the uncoated fruits serve as control. In all treatments, chitosan (1.5%) coating was effective in reducing physiological loss in weight (4.83%), decay (9.38%) and maintaining physical qualities than other treatments while Aloe vera 1:1 gel coating was also equally effective. Significant effect on minimum shrinkage in fruit length (7.37%), breadth (6.70%), total soluble solids (10.37%), titratable acidity (0.17%), ascorbic acid (156 mg/100g flesh), total sugars (6.94%), reducing sugars (3.50%) and non-reducing sugar (3.44%) were recorded with chitosan 1.5% coating. Hence, it was concluded that coating treatment of 1.5% chitosan followed by Aloe vera 1:1 gel coating can be used for enhancing the shelf life and maintaining postharvest quality in fruits of guava cultivar ‘Pant Prabhat’.