Hydration behaviour of food grains and modelling their moisture pick up as per Peleg's equation: Part II. Legumes.

Hydration behaviour of legumes with and without seed coat in split form at room temperature (28°C) was studied. Equilibrium moisture content (EMC) on soaking at room temperature of these legumes with seed coat varied from 53 to 65% (wb). Soybean hydrated fast while horse gram, black gram and green gram hydrated very slowly. Legumes in split form hydrated fast and completed their hydration in 3 h. EMC at room temperature varied from 52 to 58%. Peleg's equation could be fitted to the hydration of all legumes except green gram and horse gram. Coefficient of correlation for legume and splits (dhal) varied from 0.96 to 0.99, thus proving the validity of Peleg's equation. EMC of masur dhal fitted perfectly to the Peleg's equation. EMC predicted from average k1 and k2 values remained almost same in legume splits.

Hydration behaviour of food grains and modelling their moisture pick up as per Peleg's equation: Part I. Cereals.

Cereals and millets generally hydrate at a moderate rate and their hydration behaviour differs in native and in processed state. The study was on the hydration of paddy, milled rice, parboiled rice, wheat, millets and equilibrium moisture content (EMC) on soaking at room temperature. Paddy hydrated very slowly, hydration rate was slow in brown rice but fast in milled rice and highest in waxy rice. In most of the rice varieties, maximum absorption occurred at the end of 30 min. In wheat hydration rate was slow and its EMC was highest (43%). Maize grits of big size hydrated slowly compared to small grits. In coarse cereals EMC varied from 28 to 38%. Foxtail millet hydration was slow whereas that of finger millet was fast. The data were tested on the Peleg's equation, which gave a reasonable fit to experimental data. Peleg's constants k1 and k2 were calculated for the above grains and their hydration behaviour has been predicted. The model fitted very well to milled rice hydration data where the coefficient of variance ranged from 0.9982 to 0.9995. With exception in some millet the hydration data fitted well with the Peleg's equation. Generalized equations have been formulated for prediction of moisture content of cereals and millets.