POSTHARVEST STORAGE IMPROVEMENT IN PINEAPPLES BY IRRADIATION

摘要

Pineapple fruit (Ananas comosus L. Merr) of Order Farinosae and Family Bromeliaceae constitutes the major commercial fruit crop cultivated widely in Manipur state (India) (23 °83-25 °68 N.L.; 93 °03-94 °78 E.L.; 22, 356 sq.km. area; average annual rainfall 132 cm; 800-3000 m above M.S.L.). Two major commercial varieties, viz. Kew and Queen, are extensively grown in the hilly slopes of the state. Kew, a late-maturing variety, ripening in August-September, has a shy suckering habit (sucker- best planting material). The leaf margin is smooth (entire) and the fruit is large size. The skin is greenish-yellow, the eyes flush with the skin and not deeply seated. The pulp is juicy, soft, and very light yellow in color. It is ideally suited for canning. Queen is an early-maturing type, ripening in June-July. It has a good suckering habit and the leaves are serrated. The fruits have rich quality in terms of sweetness (total soluble sugar) and ascorbic acid content, and are of high commercial value. Off-season fruits are harvested in October, and the winter crop during December. Fruits are generally smaller than that of the Kew variety. The eyes are distinctly raised on the surface and are deeply seated. The skin is yellow when fully ripe. The pulp is very sweet with good flavor and golden-yellow in color. It has good keeping quality and can be preserved as canned rings or slices, jam or jelly, and squash. The succulent fleshy fruit of pineapple is a collection of small fruitlets. The edible flesh comprises mainly ovaries, the bases of sepals and bracts, and the nectary glands. Since flowering begins at the base of the inflorescence and progresses spirally to the apex, at a given time an entire fruit represents many discrete stages of physicochemical development. As long as the fruit is attached to the plant, the sugar content increases through senescence. There is no starch accumulation in pineapples. When three-fourth of the skin becomes yellow, the fruit attains its full development and maximum aesthetic and edible quality. Therefore, fruits are harvested after they reach the optimal stage of maturity or ripeness.