STUDIES IN MATURITY STANDARDS FOR MANGIFERA INDICA L. VAR. 'BOMBAY YELLOW'

Several methods of determining maturity of fruits on the basis of their external appearance have been described, but these methods are subject to error in judgement and vary from fruit to fruit. Harkness and Cobin (3) suggested that specific gravity is a good index for predicting maturity in mango. Leley et al (6) reported main chemical activity in carbohydrates during development and ripening of Alphonso fruits. Lombard (8) observed that total soluble solids/acid ratio is a good index for fixing maturity in mango. The maturity standard in Avocado used to be fixed by maturity dates according to the varieties (5) but that method did not work satisfactorily. Later on, the laboratory tests were applied and it was fixed on the basis of the oil content (1). Hatton and Reeder (4) fixed picking time of several minor varieties of Avocado on the basis of their physical qualities and palatability. Popenoe et al (8) correlated starch content with the maturity stage of mango. Harding et al (2) observed too much variability in specific gravity in several varieties of mango and concluded that it cannot be utilized as criterion to predict the stage of maturity.

Teaotia and Bhan (10) working with pineapple have established direct correlation with T.S.S./acid ratio and sugar content.

However, no maturity standards have been fixed for mango varieties under Indian conditions. This study was therefore, conducted at this Research Station to evaluate certain effective indices for judging the maturity and quality of fruit.

The study was conducted in the year 1969 in randomized block design with three replications on ten years-old mango trees receiving uniform cultural practices. The dates of picking were taken as treatments. A large number of fruits were tagged at fruit setting stage to maintain uniformity of the material. Picking and testing of fruits was started from 30 April, 1969, and continued up to 5 June, 1969. The fruits were picked at five days interval. At each sampling date twenty fruits from each replication were picked and divided in two sub-samples of which one sub-sample of 10 fruits was analysed as fresh and the remaining were kept for ripening in an incubator at 35°C. During the course of ripening, fruits were individually inspected daily and those attaining desired degree of softness were removed from the incubator. The chemical and organoleptic tests were performed when at least 50 per cent fruits of the sample had ripened. A panel of three judges rated the fruits in the grades, poor obtaining below 70 per cent marks, fair obtaining 70–80 per cent marks, and good obtaining more than 80 per cent marks, keeping in mind the general appearance, taste and flavour of the fruits.