Sorption Isotherms and Isosteric Heat of Peanut Pods, Kernels and Hulls

Abstract

This study was carried out to evaluate the sorption isotherms of peanut pods, kernels and hulls for several temperature and humidity conditions and to fit different mathematical models to the experimental data, selecting the one best fitting the phenomenon. The dynamic method was applied to obtain the hygroscopic equilibrium moisture content. The environmental conditions were provided by means of an atmospheric conditioning unit, in which removable perforated trays were placed to allow air to pass through peanut mass, each one containing 50 g of the product. The mathematical models frequently used for the representation of hygroscopicity of agricultural products were fit to the experimental data. Based on those results, it was concluded that peanut pods, kernels and hulls presented differentiated hygroscopicity. The equilibrium moisture content for peanut pods, kernels and hulls increased with an increase in the relative humidity at any particular temperature and decreased with increase in temperature at constant relative humidity. At a constant water activity, peanut hulls samples had higher equilibrium moisture content than the pods and kernels samples. Based on statistical parameters, the modified Henderson and Chung-Pfost models were found to adequately describe the sorption characteristics of peanut pods, kernels and hulls. Isosteric heat of desorption were evaluated by applying the Clausius—Clapeyron equation to experimental isotherms and decreased with increasing moisture content. The peanut hulls had higher isosteric heat of sorption than that peanut pods and kernels.

Study of the enthalpy-entropy mechanism from water sorption of orange seeds (C. sinensis cv. Brazilian) for the use of agro-industrial residues as a possible source of vegetable oil production

“…The experimental equilibrium moisture content of orange seeds ranged from 0.005 to 0.057, showing a similar tendency to that of other oleaginous seeds such as sesame (KAYA; KAHYAOGLU, 2006), peanut pods (CORRÊA et al, 2007) and amaranth grains (PAGANO;MASCHERONI, 2005). These values indicate that the intact seeds do not readily adsorb moisture, a property that contributes to a longer shelf life.…”

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

“…The sorption isotherm curves obtained agreed well with those of high-protein or high-sugar content materials since CF contains significant amounts of essential proteins, polysaccharides, and glycoproteins (1). On the contrary, food materials with low sugar content (hulls, dried tomato pulp, and tea) or high starch content (rice and corn starch) do not display an intersection point with an increase in water activity or temperature (24,(28)(29)(30)(31)(32).…”

Longevity of Arachis pintoi cv. BRS Mandobi seeds stored under different conditions

“…Similarly to A. hypogaea (Chen, 2000;Corrêa et al, 2007) Number of storage days Pod water content (%) and seed) differed from one another in terms of EMC when maintained under identical RH and temperature conditions (Figure 2). The EMC of the pericarp was higher (4.7%, on an average) than that of the seed; this may be explained by differences between the hygroscopicity degrees determined by their different morphologies and chemical compositions.…”

“…Therefore, it is necessary to determine other absorption/ desorption isotherms of pods, pericarp and seed from this species (and their correlations), as it was done for A. hypogaea (Chen, 2000;Corrêa et al, 2007). It is also necessary to know the physiological behavior of A. pintoi seeds stored under different environmental conditions since procedures of seed storage often applied to A. hypogaea (Azeredo et al, 2005) may not constitute appropriate alternatives for A. pintoi cv.…”

“…This topic was widely studied within Arachis hypogaea (Chen, 2000;Corrêa et al, 2007; among others), but no information was found as for A. pintoi, which differs from A. hypogaea, for example, in size, shape and number of seeds per pod. Another difference between these species is the fact that while true A. hypogaea seeds are removed from the pericarp for planting purposes, A. pintoi seeds are not.…”