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

Abstract

Moisture sorption isotherms of green soybean seeds were determined by static gravimetric method and water activity ranging from 0.11to 0.94 at 20, 30 and 40°C. The optimal sorption model of green soybean was determined by using nonlinear regression method. Modified BET multilayer sorption theory model parameters at different temperatures were calculated, isosteric sorption heat was derived by the water activity sorption isosteric model. Results indicated that sorption isotherms were belong to type III behaviour, a notable hysteresis effect was observed, Green soybean monolayer saturated sorption capacity was greater in desorption process than that of adsorption. The monolayer saturated sorption capacity decreased with increasing temperature, while the number of multilayer had a reverse trend with the monolayer saturated sorption capacity, the optimal sorption isotherm model for green soybean is Halsey model, The thermodynamic parameters including net isosteric heat of adsorption and desorption calculated at 40°C were 105.2-1865.4 kJ/kg and 111.62-1939.0 kJ/kg with equilibrium moisture content between 5% and 32% (d.b.), respectively. The net isosteric heat of sorption decreased with increasing equilibrium moisture content.

Hygroscopic Balance in Pumpkin Seeds

“…In general, the use of sorption isotherms generates information regarding proper storage and decisions making about preventive measures to maintain product quality. Water activity at relative humidity above 70% indicates possible physicochemical changes from processing and relates to mechanisms that may deteriorate the seed (Yang et al, 2012;Veronezi and Jorge, 2012;Severino et al, 2019;Saath et al, 2019). Also, it was verified that the ambient temperature influenced the equilibrium humidity values, which decreased with the increase of the temperature to certain water activity.…”

Production of Oscillatoria sp. BTA‐170 biomass in photobioreactor: Analysis of composition, drying behavior, sorption isotherm, and powder flow characteristics

“…This tendency could be attributed to the presence of hydrophilic proteins and lipids in tray dried algal powder. The multilayer sorption zone, which includes the low and intermediate aw regions, have seen a linear rise in EMC, whereas the capillary condensation region, which includes the high a w region, had a rapid rise in EMC (Goula, Karapantsios, Achilias, & Adamopoulos, 2008; Yang, Zhu, & Zhu, 2012). The decrease in EMC was observed when the temperature was increased at a constant a w .…”

“…We previously reported that BTA 170 biomass had 32.25% carbohydrate, 37.44% protein, and 22.31% fat (Tiwari et al, 2019), which is validated by FTIR data. had a rapid rise in EMC (Goula, Karapantsios, Achilias, & Adamopoulos, 2008;Yang, Zhu, & Zhu, 2012). The decrease in EMC was observed when the temperature was increased at a constant a w .…”