Moisture Sorption Behavior and Shelf Life Prediction of Teff Seed and Flour.

Moisture sorption isotherms of Teff seed and its flour were determined over the range of relative humidity
(11–92%) using a gravimetric technique at constant temperature (27°C). The results obtained showed that
the moisture sorption isotherm of both is almost similar and sigmoid with increasing equilibrium water
content at the constant temperature. The curves start raising high above 64% RH indicating the products
deteriorates faster above 64% RH. Hence the moisture content equilibrating to 64% RH was taken as
critical for both Teff seed and flour variants. The sorption isotherm fits the GAB equation as per GAB
generalized equation for sorption phenomena (Bioprocess Technol, 2008) with R2>0.96. A nonlinear
regression analysis method was used to evaluate the constants of sorption equation and the values of
GAB constants of which Mo=7.5075, C=14.3886, K=0.7051 for Teff seed and Mo=6.9656, C=10.4012,
K=0.7255 for Teff flour respectively. The shelf life of the product was predicted using, Mpack software
developed in-house to “prediction of the shelf life of moisture sensitive products” using GAB parameters
and packaging Schedule.