Moisture sorption isotherm of Amrakhand (Mango shrikhand)

The static gravimetric method was used to analyse the moisture sorption isotherm of Amrakhand at temperatures of 15°C, 25°C and 35°C. The purpose of this study was to understand the moisture behaviour of amrakhand and to evaluation models for prediction behaviour. Four models (GAB, BET, Halsey and Caurie) were tested for predicting the sorption data and best fit as indicated by% RMSE, %RE and R2 values. The isotherm plots had a sigmoid form and were classed as type II isotherms according to the BET classification. The equilibrium moisture content progressively increased at lower water activities before rising sharply at higher water activities. The BET monolayer fell from 7.3 g of water /100g of solid at 15°C to 6.2 g of water /100g of solid at 35°C. The Caurie monolayer decreased from 6.9 g of water /100g of solid at 15°C to 5.8 g of water /100g of solid at 35°C. The bound water in amrakhand decreased from 30.98% at 15°C to 25.30% at 35°C. According to the study the GAB model as the most effective in predicting the moisture sorption behaviour at water activity range of 0.07 to 0.977 for amrakhand.