Storability, Ripening Behaviour and Physiological Disorder of Alphonso Mango Fruits in Relation to Maturity Stage

Abstract

Alphonso mango fruits were harvested at different stages of maturity and grouped according to their specific gravity to determine the relationship between specific gravity and fruit maturity stage. Fruit quality characteristics; a* value, the stage of ripening, ripening %, TSS and total acidity percentage; proved that the specific gravity was a simple and reliable indicator to assess the maturity stages of Alphonso mango fruits. Fruits should be harvested at a specific gravity 1.01-1.02 (optimum mature fruits) followed by 1.0-1.01 (just mature fruits) in order to solve the problem of uneven ripening and to keep fruit quality, with minimum physiological disorder (internal breakdown). At 10°C, Alphonso mango fruits should not be stored more than three weeks to avoid the appearance of sever symptoms of chilling injury or internal breakdown during marketing period. MATERIALS AND METHODS Preliminary Experiment:Since mango fruit ripening mainly depends on reaching maturity stage, a preliminary experiment was carried out to determine the best maturity degree. Hence, Alphonso mango fruits were obtained from Al-Khatatba region in August 1998 and 1999, washed, weighed individually, volume was taken and specific gravity was calculated; then grouped according to specific gravity as follows:(1) 0.8-0.9(2) More than 0.9-1.0 (3) More than 1.0-1.01 (4) More than 1.01-1.02 (5)More than 1.02-1.03 (6) More than 1.03 Each group contained 15 fruits and replicated 3 times. Fruits were placed at 22°C and 90% relative humidity for 5 days including 2 days for ripening by acetylene gas (released from calcium carbide 2 g./ kg. fruit according to Kumar et al, 1996 ). Fruit characteristics were measured at harvest time and after 5 days from ripening treatment as follows:Physical Properties: Percentage of weight loss: Fruits were periodically weighed and the percentage of weight loss was calculated by the difference between the initial weight and that recorded at the date of sampling. Peel Colour Measurement (L, a & b values): was determined by using a Hunter colorimeter type (DP-9000) for the estimation of L, a, b values. The instrument was calibrated with white and black standards.