Moisture sorption isotherms and modeling for pre-cooked flours of pigeon pea (Cajanus cajans L millsp) and lima bean (Canavalia ensiformis)

The effect of 24-epibrassinolide and clotrimazole on the adaptation of Cajanus cajan (L.) Millsp. to salinity

“…The seeds, rich in protein, can be consumed in natura, or as a supplement in flour used for preparing pasta (Corzo and Fuentes 2004).…”

Moisture Sorption Isotherms and Net Isosteric Heats of Sorption of Green Soybean

“…Water activity (a w ) is defined as the ratio of the equilibrium water vapor pressure of a foodstuff to the saturated vapor pressure at same temperature (Corzo & Fuentes, 2004), it is of much concern to foodstuffs quality and stability than the total amount of moisture content (Athanasia et al 2008). According to Lahsasni et al (2002), water activity value in the range of 0.1 to 0.3, water is in a state of monolayer; from 0.3 to 0.7, water is in a state of multilayer; if above a water activity of 0.7, water is in a relative free state, which is named as condensed water.…”

“…The models and values of isosteric heat have practical significance as follows: giving information on interaction forces between the water vapor molecules and the adsorbent surface (binding energy) (Corzo & Fuentes, 2004); estimating the total energy requirements for equipment and process design, especially in drying processes as the heat of sorption rise well in excess of the heat of vaporization as food is dehydrated to low moisture content (Samapundo et al, 2007). Thus thermodynamic properties give basic information of water properties and energy requirements in sorption process (Arslan & Toğrul, 2005;Toğrul & Arslan, 2006), and special drying technologies could be optimized to reach the goal of saving energy.…”

“…Direct calorimetric measurement has a higher difficulty, because it needs high precision instrument to measure small additional heat change, this method is not used commonly; BET equation is only applied to the low water activity area, the isosteric heat calculated by this method is much lower than Clausius-Clapeyron equation, so this method are not considered in this work. The common method getting isosteric heat is to apply Clausius-Clapeyron equation (Corzo & Fuentes, 2004) shown in Eq. (1):…”

“…(1) that a group of net isosteric heat calculated needs two groups isotherms data under two temperatures, this method is a timeconsuming work. Water activity is a function of temperature and equilibrium moisture content (Basunia & Abe, 2001), researchers found that the optimal isotherm model can describe the relationship of water activity and equilibrium moisture content accurately at different temperatures for crushed chillies (Arslan & Toğrul, 2005), groundnut powder (Alakali & Satimehin, 2007), rice (Toğrul & Arslan, 2006), angustifolia seed (Thys et al, 2010), pigeon pea (Corzo & Fuentes, 2004), tomato pulp (Goula et al, 2008), soybean (Aviara et al, 2004), corn (Samapundo et al, 2007), amaranth seeds (Abalone et al, 2006). As long as getting the optimal water activity model, through Clausius-Clapeyron thermodynamic model, net isosteric heat can be deduced by the water activity isotherm model (Chen, 2006), this method can simplify isosteric heat calculation process effectively.…”