Retention of Β-Carotene and Vitamin C in Dried Mango Osmotically Pretreated with Osmotic Solutions Containing Calcium or Ascorbic Acid

The retention of vitamin C and carotenoids was studied in the cv. ‘Tommy Atkins’ mango as affected by osmotic dehydration prior to hot air drying. Osmotic dehydration (OD) was carried out over 15h at 25°C using sucrose solutions of 45 °BRIX with and without 1% (w/w) calcium chloride or 1% ascorbic acid with a fruit to solution ratio of 1:10 (w/w), and the OD-treated mango samples were then dried in an air convection oven at 50°C or 70°C. An osmotic pretreatment before drying significantly reduced the drying time and prevented colour change in dried mango. Addition of calcium in the OD solution significantly improved vitamin C retention, on average from 44% to 57%. However, the addition of ascorbic acid to the osmotic solution highly increased the retention of vitamin C content in the dried mango. The retention of all-trans-β-carotene was significantly lower in all OD treated mango samples dried at 50°C but remained unchanged in OD-treated mango samples with calcium or vitamin C dried at 70°C. Moreover, osmotic dehydration with and without additives reduced the ratio of 13-cis-β-carotene to all-trans-β-carotene. The results showed that the addition of calcium or vitamin C to the osmotic solution can improve the nutritional value of dried mango.