The enzymatic demethylation and depolymerization of protopectin, such as pectin methylesterases and polygalacturonase, lead to the formation of low molecular weight compound with less methoxyl groups. Softening of the fruit observed during ripening is due to the hydrolytic change of protopectin to pectin. The most common changes in the cell wall structure during ripening are related to pectins, which are the major components of primary cell wall and middle lamella. The cells in the pulp of the fruit are large and can lose their integrity due to cell wall hydrolysis during fruit ripening. Increases in the total soluble solids and total soluble sugars have also been reported in ripening Alphonso mangoes, which correlated with a similar observation in ripening Keitt mangoes. Also, carbohydrates and starch converted into sugars, resulting in an increase in sweetness. Carotenoid levels increased during ripening whereas anthocyanin levels gradually decreased. ![]() observed a rapid destruction of chlorophyll in the Tommy Atkins cultivar. The change in color during the ripening process is caused by the degradation of chlorophyll and the accumulation of carotenoids. The ripening process of the mango fruit involves both physical and biochemical changes, which alters respiration, ethylene production, flavor, texture, aroma, and nutritional values. ![]() This generates additional income for farmers by reducing the labor peak at harvest. In contrast to most mango cultivars, the Chok Anan cultivar has the ability to produce off-season flowering without chemical induction. It is a fiberless mango with smooth flesh and a deliciously unique flavor. Nam Dok Mai cultivar is a famous export mango of Thailand. Many mango cultivars are commercially grown in Thailand. It is a good source of nutrients, particularly rich in vitamin A and contains reasonable amounts of vitamins B and C and dietary fiber. Mango is an important fruit from the tropics and subtropical regions. The cheaper Chok Anan cultivar was more resistant to freezing damage than Nam Dok Mai. Tissue and cell wall damage in Nam Dok Mai were the greatest, which contributed to the large drip loss. The cell walls of fully ripe mangoes were dramatically damaged, which explained the low firmness values. The microstructure found using light microscopy and transmission electron microscopy showed that all frozen-thawed mangoes exhibited a swelling and folding of the cell wall due to freezing damage. After thawing, the partially ripe mango samples exhibited the highest firmness, lowest drip loss, lowest water-soluble pectin, and the highest sensory firmness scores. Mangoes from the three final ripening stages were frozen until the temperature of the samples reached –25☌. ![]() During ripening, titratable acidity, alcohol-insoluble residues, and firmness significantly decreased while total soluble solids, total pectin, and water-soluble pectin levels increased. ![]() Two mango cultivars (Nam Dok Mai and Chok Anan) were allowed to ripen for four ripening stages. Since freezing can cause severe textural damage to fruit, the proper selection of a ripening stage and cultivar can reduce such damage. The aim of this work was to investigate the quality and microstructure of different frozen mango cultivars.
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