Foxtail millet is one of the commonly cultivated, nutritionally competitive 10 source of protein, fibre, phytochemicals and other micronutrients, as compared to major 11 cereals like wheat and rice. Considering the potential of these grains, the high pressure 12 processed flours of germinated (GFMF) and non-germinated foxtail millet (NGFMF) grains 13 were studied for its functional, moisture sorption and thermodynamic properties. Germination 14 and high pressure processing of foxtail millet grains significantly improved the functional 15 properties of the flour. Apart from this, the moisture sorption isotherms of both the flours 16 were determined at 10, 25 and 40 o C and the sorption data was fitted to Anderson-De Boer (GAB) sorption model. The monolayer moisture content for NGFMF and 18 GFMF ranged between 3.235 -2.364 g g -1 and 2.987 -2.063 g g -1 , respectively. The isosteric 19 heat of sorption ranged between -76.35 kJ mol -1 to -38.23 kJ mol -1 for NGFMF and 172.55 kJ 20 mol -1 to -34.02 kJ mol -1 for GFMF at a moisture range of 0 to 36%, whereas, the integral 21 entropy of sorption for NGFMF ranged between -0.404 to -0.120 kJ mol -1 K -1 and for GFMF 22 between -0.667 to -0.383 kJ mol -1 K -1 . Along with the validation of the compensation theory, 23 the values of spreading pressures lied in the range of 0 -0.078 J m -2 for NGFMF and 0 -24 0.124 J m -2 for GFMF, while, the glass transition temperatures ranged between 82.25 to 28.67 25 o C for NGFMF and from 51.11 to 11.83 o C for GFMF at all three temperatures.
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KeywordsFoxtail millet flour, germination, high pressure processing, functional 27 properties, moisture sorption isotherms, thermodynamic properties 28 29 30Water sorption characteristics are necessary for predicting the shelf life and determining the 31 moisture content and critical activity for acceptability of products that deteriorate, mainly due 32 to moisture gain, and also for drying, packaging and storage (Katz and Labuza 1981). A food 33 moisture sorption isotherm describes the relationship between the moisture uptake in food 34 and the relative humidity of the air with which the food is in equilibrium at a constant 35 temperature (Lagoudaki et al. 1993). Thermodynamics has been reported as an approach to 36 understand the properties of water and calculate the energy requirements of heat and mass 37 transfer in biological systems (Rizvi and Benado 1983; Fasina et al. 1997; Fasina et al. 1999). 38 Properties such as isosteric heat of sorption, net integral enthalpy and entropy and spreading 39 pressures are important for understanding the energy requirement during dehydration, the 40 food microstructure, physical phenomena on the food surfaces and sorption kinetic 41 parameters (Rizvi and Benado 1983). Also, the glass transition temperature is an important 42 physical parameter, which serves to explain the physical and chemical behaviour of food 43 systems (Bell and Labuza 2000), and it is defined as the temperature at which the material 44 changes from the glassy t...