RESPONSE OF PHYSICAL AND PHYSIO-CHEMICAL ATTRIBUTES IN GUAVA FRUITS TO GUM ARABIC AND CALCIUM CHLORIDE TREATMENTS UNDER COLD STORAGE

This experiment was conducted during 2016 and 2017 seasons in Post-harvest Lab. Hort. Dept., Fac. Agric., Tanat University., Egypt to study the effects of Gum Arabic and /or calcium chloride on postharvest storage life and fruit quality of ‘Maamoura’ guavas during two consecutive seasons (2016 and 2017). Guava fruits were dipped for 3 min. into distilled water (control), Gum Arabic (GA, 10%), CaCl2 (CC1, 2%), CC2 (4%), GA (10%) + CC1 (2%) and GA (10%) + CC2 (4%). Treated and control fruits were stored at 7±1°C and 90±5% relative humidity (RH) for 24 days. The changes in physical and chemical characteristics of guava fruits were determined every eight days of cold storage. Results of this study indicated that, all postharvest treatments reduced the deterioration in physical and chemical characteristics compared to untreated fruits (control). In addition, combined treatments of 10 % of Gum Arabic with 2 or 4% of calcium chloride were superior to individual treatments. These treatments minimized the fruit weight loss and decay percentages and maximized fruit marketable percentage as well as maintained fruit firmness and visual appearance score during storage. Moreover, these applications delayed color development by retained total chlorophyll content as well as maintained fruit contents in ascorbic acid and total acidity and reduced the total soluble solids and total soluble solids/acid acidity ratio during cold storage period. Ultimately, these applications increase total phenolic and antioxidant contents; also, 706 USAMA EL-ABBASY et al. prolonged shelf life period of guava fruits at (25±2°C and 65±5% RH) after end of cold storage period (24 days) as compared to control. Conclusively, combined treatments of 10 % of Gum Arabic with 2 or 4% of calcium chloride reduced the deterioration in physical and chemical characteristics compared to untreated fruits (control).