Changes in carbohydrate and organic acid composition of the mesocarp of `carabao' and `pico' mango (Mangifera indica L.) during ripening

The chemical changes during ripening of carabao and Pico mangoes were determined. The moisture, titratable acidity and starch content of Carabao mango decreased by 0.25%, 0.30%, and 3.93% per day, respectively while pH, total sugars and reducing sugars increased by 0.23%, 4.52% and 1.67% per day, respectively. A similar trend was observed in ripening Pico mango. Its moisture, titratable acidity and starch content decreased by 0.28%, 0.22% and 2.78% per day, respectively while pH, total sugars and reducing sugars increased by 0.22%, 4.07% and 4.25% per day, respectively. HPLC analysis of the organic acid components of unripe (2 days after harvest), mid-ripe (6 days after harvest) and ripe (10 days after harvest) Carabao and Pico mangoes showed the presence of oxalic, tartaric, malic, citric, and ascorbic acid and were found to decrease during ripening. The predominant organic acids were ascorbic (2.27%, Pico; 2.10%, Carabao) and citric acid (0.58%, Pico; 0.65%, Carabao). The polysaccharide components of mango fruits at three ripening stages (unripe, mid-ripe, and ripe) were fractionated, quantified and partially characterized. HEPES buffer soluble fraction increased while hot water soluble, KOH soluble and KOH insoluble fractions decreased as the fruit ripened. Glucose and galactose were the predominant monosaccharides determined in the HEPES soluble fractions of unripe Carabao and Pico mangoes; concentrations of which decreased as the fruits ripened. Glucose is the predominant monosaccharide detected from the hot water soluble fractions of unripe Carabao (68%), unripe Pico (76.98%), mid-ripe Carabao (28.40%), mid-ripe Pico (88.82%) and ripe Pico (1.40%). On the other hand, in ripe Carabao mango, galactose (36.0%) was found to be more abundant than glucose (17.80%). The KOH soluble fractions of both cultivars were found to contain rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose. Similar set of monosaccharides was detected in KOH insoluble fractions or residues with glucose and rhamnose in abundance