Mineral composition and anatomical changes in Alphonso mango during storage with reference to internal breakdown

Abstract

The investigations were made on (i) Physico-chemical changes, mineral composition, histological and histochemical changes, during growth, development, storage and ripening and (ii) the effect of pre-harvest spray and post harvest spray and post harvest infiltration with calcium chloride on the above mentioned changes and also on the occurrence of internal breakdown (spongy tissue) in Alphonso mango. Fruit length, diameter, weight of fruit, pulp and peel increased gradually up to 45 days, followed by a sudden increase to maximum of 90days and pre harvest spray of calcium at 5000 and 10000 ppm significantly enhanced this increase. The effect of post harvest calcium infiltration was more prounced in delaying ripening, reducing the weight loss and firmness, increase of peel colour, pulp colour (carotenoids), sugars and decrease of acidity during storage as compared to pre harvest sprays. Analysis of calcium (Ca), Potassium (K), Sodium (Na) and Phosphorus (P) during growth and development, in general indicated reduction in the concentrations from 15 days to 90days after fruit set both in the peel in the pulp. The distribution of minerals in 6 different pulp tissues during ripening indicated that Ca content was maximum in the basal pulp portion as compared to middle and apical parts. The distribution of minerals in 6 different pulp tissues during ripening indicated that Ca content was maximum in the basal pulp portion as compared to middle and apical parts. Further, the pulp towards the peel showed more Ca than in the pulp towards endocarp. In case of K & P, it was more in the pulp nearer to endocarp and no change was seen from base to apical portion of the pulp. Spongy tissue affected pulp showed low Ca (19.25 mg), high K (726 mg), P (135.6 mg) & Na (45 mg) as compared to 41.8 mg Ca, 501 mg K, 85 mg P & 37 mg Na in the healthy tissue. Both the pre & post harvest Ca treatments had no effect on spongy tissue development. Histochemical studies indicated the appearance of starch granules after 60 days of fruit set in all the tissues of the fruit & maximum accumulation was found after 90 days of fruit set. In pre harvest sprays of Ca, the cell of the fruit were bigger in size with more starch grains & degradation of these grains was delayed during ripening. Ripening process was initiated in mesocarp region. Development of spongy tissue was found in pulp near endocarp. The cells in this were small, globular & thick walled with numerous starch grains