The Effect of Different Waxing Technologies on Shelf Life of ‘Apple’ Mango Fruits Stored Under Different Storage Conditions

Abstract

Beneficial effect of Shellac and Mango wax of different formulations was studied on shelf life of apple mango fruits which were harvested at mature green stage and stored in various storage conditions including ambient (25^ºC) and simulated commercial cold storage (12^ºC).  Mango wax (one mixed with a fungicide and another without) was obtained from United Phosphorous Limited, while Shellac wax was purchased from a commercial trader in flakes form and dissolved in 0.1N Sodium hydroxide to make two concentrations (3% and 5%). The two waxes were applied by dipping the fruits in a bowl of wax and placing them on wire mesh for air drying using fans. Upon drying the fruits were packed in open cotton boxes and stored in ambient (25^ºC) and cold storage (12^ºC). Three fruits from each treatment and different storage conditions were sampled after every 3 and 7 days (ambient and cold storage respectively) for measurement of attributes associated with ripening including weight loss, respiration rate, peel firmness and pulp hue angle.  Results indicated that waxing whether with Shellac or Mango wax was effective in extending shelf life of mango fruits for 4 and 6 more days in ambient and cold storage respectively. At the end of observation period, un waxed fruits in ambient and cold storage had lost 12.4% (day10) and 5.5% (day 22) compared to an average of 7.6% (day14) and 3.7% (day 28) for the waxed fruits respectively.  Waxed fruits exhibited low respiration peak of 49.39 and 30.38 ml/kg/hr compared to un waxed fruits that had a high peak of 85.09 and 43.15 ml/kg/hr for ambient and cold storage respectively signifying high respiratory activity in the un waxed fruits. Other ripening related parameters had a positive correlation to respiration and water loss. This study shows that coating of mango fruit with wax is effective in delaying ripening thereby extending its postharvest life.

Keywords: Mango wax, Shellac wax, Shelf life, Mango, Postharvest technologies, Storage