Moisture Sorption and Thermodynamic Properties of Vacuum-Dried Capsosiphon fulvescens Powder

Abstract

ABSTRACT:The moisture sorption isotherms of vacuum-dried edible green alga (Capsosiphon fulvescens) powders were determined at 25, 35, and 45 o C and water activity (aw) in the range of 0.11∼0.94. An inversion effect of temperature was found at high water activity (＞0.75). Various mathematical models were fitted to the experimental data, and Brunauer, Emmett, and Teller model was found to be the most suitable model describing the relationship between equilibrium moisture content and water activity (＜0.45). Henderson model could also provide excellent agreement between the experimental and predicted values despite of the intersection point. Net isosteric heat of adsorption decreased from 15.77 to 9.08 kJ/mol with an increase in equilibrium moisture content from 0.055 to 0.090 kg H2O/kg solids. The isokinetic temperature (T) was 434.79 K, at which all the adsorption reactions took place at the same rate. The enthalpy-entropy compensation suggested that the mechanism of the adsorption process was shown to be enthalpy-driven.

Moisture sorption properties of two varieties of dehydrated mango slices as determined by gravimetric method using Guggenheim–Anderson–de Boer model

“…According to Zuo et al. (2015), there is also a reduced number for sorption sites that actively bind water with increased temperature while water molecules movement increases resulting in reduced Mo values. The least Mo value obtained (8.00%) indicated that during dehydration, moisture content should not be allowed to go below 8% in order to prevent unnecessary energy and time consumption.…”

“…The monolayer moisture differences for dehydrated mango can be attributed to the different physical-chemical composition of the varieties used and the difference in choice of techniques of drying used. According toZuo et al (2015), there is also a reduced number for sorption sites that actively bind water with increased temperature while water molecules movement increases resulting in reduced Mo values. The least Mo value obtained (8.00%) indicated that during dehydration, moisture content should not be allowed to go below 8% in order to prevent unnecessary energy and time consumption.…”

The influence of elevated temperatures and composition on the water activity of egg powders

“…where a and b are constants. R 2 and P (%) were used to evaluate Equation (8) for goodness of fit (Zuo et al., 2015).…”

“…The CCE describes the a w of a food as a function of temperature for a given MC (Tadapaneni et al., 2017). This equation was initially developed to evaluate the impact of temperature on the a w of a pure system (Labuza & Altunakar, 2007), but has been used to model changes of a w in different dried food products or ingredients, including blueberry, pineapple, potato, and green algae, over a wide range of temperatures (Hossain et al., 2001; Lim et al., 1995; McMinn & Magee, 2003; Zuo et al., 2015). Recent studies show that by using the CCE, MSIs can be obtained for a larger range of temperatures and in less time than traditional methods (Jin et al., 2019; Tadapaneni et al., 2017).…”

Influence of Cellulose Polymorphism on Tunable Mechanical and Barrier Properties of Chitosan/Oxidized Nanocellulose Bio-Composites

“…Samples were weighed periodically until constant weight is reached. The equilibrium moisture sorption (EMS) isotherms were determined by the gravimetric method according to the following equation [22].…”