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 15 h at 25 degrees C using sucrose solutions of 45 degrees 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 degrees C or 70 degrees 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-beta-carotene was significantly lower in all OD treated mango samples dried at 50 degrees C but remained unchanged in OD-treated mango samples with calcium or vitamin C dried at 70 degrees C. Moreover, osmotic dehydration with and without additives reduced the ratio of 13-cis-beta-carotene to all-trans-beta-carotene. The results showed that the addition of calcium or vitamin C to the osmotic solution can improve the nutritional value of dried mango. (C) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.