SORPTION ISOTHERMS OF FORTIFIED MANGO BARS

Sorption isotherms of plain mango bar (86.9% total sugars, 2.7% protei n and 0.54% fat, db), mango-coconut bar (81.8% total sugars, 3.0% prot ein and 5.0% fat, db) and mango-soya protein concentrate bar (75.2% to tal sugars, 13.1% protein and 0.40% fat, db) were of a sigmoid shape h aving long second local isotherms. Their colour and texture were adver sely affected during storage at RH less than or equal to 54.1%, and mo uld growth was observed after 13-43 days storage at RH greater than or equal to 75.5%; the bars retained their quality best at RH 64.8%. The sorption data were fitted to five (BET, GAB, Henderson, Oswin and Smi th) models of sorption isotherms. The BET and GAB models were found to predict well the moisture content only for the plain mango bar (R(2) 0.9067 and 0.9325, E % 5.59 and 10.76) whereas the Oswin model was app licable to all the three types of bars (R(2) 0.9201-0.9731, E % 22.65- 31.44).