Received: 23 November, 2010. Accepted: 19 March, 2011. Original Research Paper Fresh Produce ©2011 Global Science Books Effect of Pre-Storage Treatments of Calcium Chloride and Gibberellic Acid on Storage Behaviour and Quality of Guava Fruits Bal Vipan Chandar Mahajan * • Kulbir Singh Brar • Birinder Singh Ghuman • Rajbir Singh Boora Punjab Horticultural Postharvest Technology Centre, Punjab Agricultural University, Ludhiana, Punjab, 141 004 India Corresponding author: * bvc_mahajan@rediffmail.com ABSTRACT Guava fruits of cultivar ‘Allahabad Safeda’ were harvested at the green mature stage. The fruits were given postharvest treatments of calcium chloride (CaCl 2 : 1, 2, 3%), gibberelic acid (GA 3 : 25, 50, 75 ppm) each for 5 min. The fruits were air dried and packed in corrugated fibre board boxes and stored in a walk-in cold-room maintained at 6 ± 1°C and 90-95% relative humidity. A control lot of fruit (without any treatment) was also stored under same conditions. The fruits were analysed for various quality attributes at different storage intervals until 4 weeks. The postharvest application of CaCl 2 (2%) extended the storage life of guava fruits up to 4 weeks with minimum weight loss, desirable firmness and highly acceptable quality. _____________________________________________________________________________________________________________ Keywords: firmness, postharvest, quality, storage Abbreviations: CaCl 2 , calcium chloride; GA 3 , gibberellic acid; RH, relative humidity INTRODUCTION Guava (Psidium guajava L.) is believed to have been intro- duced to India since the early 17 th century (Anonymous 2011). In India, it is the 5 th most widely grown fruit, oc- cupying an area of 220,000 ha, with an annual production of 2.27 million MT (Anonymous 2008). Guava is a climac- teric fruit (Akamine and Goo 1979), ripens rapidly after harvest and therefore has a short shelf-life. It is a highly perishable fruit and loses its texture and quality in 3-4 days at ambient temperature. Therefore, guava fruits are required to be managed appropriately in order to get a regulated mar- ket supply through judicious use of post-harvest treatments followed by storage at appropriate temperature and relative humidity. Calcium retards tissue softening and delays ripen- ing (Goncalves et al. 2000; Serrano et al. 2004). Similarly, the application of gibberellic acid (GA 3 ) has been reported to delay senescence in fruits and vegetables (Osman and Abu-Goukh 2008; Pila et al. 2010). This study was thus conducted to determine the most suitable post-harvest treat- ment for improving the storage life and quality of guava fruits cv. ‘Allahabad Safeda’, which is known for its excel- lent size, appearance and pleasant flavour and is grown commercially by fruit growers in the Northern parts of India. MATERIALS AND METHODS Uniform, medium-sized (60-80 mm) fruits, apparently free from diseases and bruises, were harvested at the physiological mature stage and divided into lots for further handling. Postharvest treatments, packaging and storage The fruits were dip treated with an aqueous solution of different concentrations of CaCl 2 (1, 2 and 3%) and GA 3 (25, 50 and 75 ppm) separately each for 5 min. Control fruits were dipped in tap water for 5 min. The surface of fruits was air dried and thereafter packed in corrugated fibre board boxes. The fruits were stored in a walk-in cold-room maintained at 6 ± 1°C and 90-95% relative humidity. Analytical methods The physiological loss in weight (PLW) of fruit was calculated on an initial weight basis and expressed in per cent. The fruit firmness was measured with the help of a penetrometer (Model FT- 327, USA) using an 8-mm stainless steel probe and expressed in pounds force (lb force). The overall organoleptic rating of the fruits was performed by a panel of 10 judges on the basis of a 9- point Hedonic scale (Amerine et al. 1965). The total soluble solids (TSS) of the fruit juice were determined using a hand refrac- tometer and expressed as TSS% after correcting the temperature at 20°C. The total sugars, titratable acidity and ascorbic acid content of fruits were estimated according to AOAC (1990). Statistical analysis There were three replications for each treatment and each replica- tion comprised of 20 fruits. The experiment was laid out in a com- pletely randomized design (Snedecor and Cochran 1987). RESULTS AND DISCUSSION Physiological loss in weight PLW, in general, increased as the storage period advanced, rather slowly initially but more rapidly as the storage period advanced (Table 1). The lowest mean PLW (1.98%) was observed in fruits treated with 2% CaCl 2 closely followed by 3% CaCl 2 . On the other hand, the highest mean PLW (3.32%) was observed in control fruits. During different storage intervals, CaCl 2 (2%)-treated fruits showed lowest weight loss, which ranged between 0.66 to 2.66% from 7 days to 28 days of cold storage, respectively compared to control fruits in which PLW ranged between 0.96 to 5.16% during the same interval. The application of calcium has been reported to be effective in terms of membrane func- tionality and integrity maintenance with lower losses of phospholipids and proteins and reduced ion leakage which could be responsible for the lower weight loss in plums (Lester and Grusak 1999). Favourable effects of CaCl 2 (4– ®