scholarly journals Hygroscopic Behavior and Thermodynamic Properties of Ziziphus joazeiro Mart. Kernel Flour

2020 ◽  
Vol 8 (3) ◽  
pp. 50
Author(s):  
Hanndson Araujo Silva ◽  
Josivanda Palmeira Gomes ◽  
Alexandre José de Melo Queiroz
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Isosteric Heat ◽  
Type Ii ◽  
Differential Entropy ◽  
Differential Enthalpy ◽  
Gab Model ◽  
Hygroscopic Behavior ◽  
Best Fit

The hygroscopic and thermal behavior of kernel flour from Ziziphus joazeiro fruits were investigated. Adsorption isotherms were obtained at temperatures of 293, 303 and 313 K and adjusted to GAB, Oswin and Peleg models. The best fit of the experimental data was obtained with the GAB model with R² values> 0.994 and mean percentage deviation P <10%. The isotherms obtained were sigmoidal type II. Isosteric heat and other thermodynamic properties were calculated as a function of moisture content. Adsorption isosteric heat decreased exponentially with increasing moisture content and differential entropy increased with moisture content, while differential enthalpy decreased. The theory of compensation confirmed that these properties are dependent on moisture content. The isotherms presented a spontaneous and enthalpy process.

scholarly journals Determination of the hygroscopic equilibrium and isosteric heat of aji chili pepper

2017 ◽  
Vol 21 (12) ◽  
pp. 865-871 ◽  
Author(s):  
Ednilton T. Andrade ◽  
Vitor G. Figueira ◽  
Luciana P. Teixeira ◽  
José H. da S. Taveira ◽  
Flávio M. Borém
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Isosteric Heat ◽  
Chili Pepper ◽  
Sorption Behavior ◽  
Activity Levels ◽  
Air Humidity ◽  
Relative Air Humidity ◽  
Best Fit

ABSTRACT This study focuses on the determination of the hygroscopic equilibrium and isosteric heat of the aji chili pepper (Capsicum baccatum) under different controlled temperature and relative air humidity conditions. In addition, the objective was to adjust the model among the existing literature models that best represent the isothermal sorption behavior, as well as propose a new model to represent this phenomenon. Having obtained the mathematical models and experimental data, the best model and parameters that represent the hygroscopicity and the isosteric heat satisfactorily was determined. The temperatures used were 30, 55, and 70 °C, with water activity levels from 0.11 to 0.84. The model that best fit the data had a R2 value of 0.97. The integral isosteric heat of sorption for ‘Dedo-de-Moça’ chili pepper within a moisture content from 0.07 to 0.55 (dry basis) ranged from 3641.66 to 2614.38 kJ kg-1.

scholarly journals Moisture Adsorption and Thermodynamic Properties of California Grown Almonds (Varieties: Nonpareil and Monterey)

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Li Zuo Taitano ◽  
R.P. Singh
Keyword(s):  
Diffusion Coefficient ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Water Activity ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Moisture Adsorption ◽  
Constant Weight ◽  
Differential Enthalpy ◽  
Monolayer Moisture

Moisture adsorption characteristics of California grown almonds (Nonpareil: pasteurized and unpasteurized almonds; Monterey: pasteurized, unpasteurized and blanched almonds) were obtained using the gravimetric method over a range of water activities from 0.11 to 0.98 at 7-50ºC. The weights of almonds were measured until samples reached a constant weight. The relationship between equilibrium moisture content and water activity was established using the Guggenheim-Anderson-de Boer model. The diffusion coefficient of water in almond kernels was calculated based on Ficks second law. The monolayer moisture value of almonds ranged from 0.020 to 0.035 kg H2O kg-1 solids. The diffusion coefficient increased with temperature at a constant water activity, and decreased with water activity at a constant temperature. The thermodynamic properties (net isosteric heat, differential enthalpy and entropy) were also determined. The net isosteric heat of adsorption decreased with the increasing moisture content, and the plot of differential enthalpy versus entropy satisfied the enthalpy-entropy compensation theory. The adsorption process of almond samples was enthalpy driven over the range of studied moisture contents.

scholarly journals Germination Impact in the Nutrition and Technological Properties of Jackfruit Seeds

2020 ◽  
Vol 8 (1) ◽  
pp. 79
Author(s):  
Daniela Dantas de Farias Leite ◽  
Alexandre José de Melo Queiroz ◽  
Rossana Maria Feitosa de Figueirêdo ◽  
Ana Regina Nascimento Campos ◽  
Dyego Da Costa Santos ◽  
...  
Keyword(s):  
Moisture Content ◽  
Reducing Sugars ◽  
Absorption Capacity ◽  
Oil Absorption ◽  
Type Ii ◽  
Emulsifying Properties ◽  
Technological Properties ◽  
Air Drying ◽  
Gab Model ◽  
Best Fit

The objective of this study was the production of flour from germinated jackfruit seeds. The seeds were germinated and dried at temperatures of 55, 65 and 75 °C under air drying speed of 1.0 and 1.3 m s-1. Afterward, the seeds were grounded in order to obtain the flour and characterized for chemical, physical and technological properties. It was observed that the germination increased the moisture content, proteins, and fibers; decreased the content of lipids, reducing sugars, tannins and phenolic compounds of the seeds. After dried, the flour moisture content decreased and the proteins and reducing sugars were concentrated. The flours showed good results for solubility, water, oil absorption capacity, and emulsifying properties. The moisture adsorption isotherms of the flours were classified as Type II and the GAB model was the best fit to the experimental data.

Modeling Desorption Isotherms and Thermodynamic Properties of Fresh Tea Leaves (Camellia sinensis var. assamica)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
W. Sarath Botheju ◽  
K. Sanath P. Amaratunge ◽  
I. Sarath B. Abeysinghe
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Pure Water ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Differential Entropy ◽  
Tea Leaves ◽  
Heat Of Sorption ◽  
Compensation Theory ◽  
Tea Leaf

Abstract Desorption isotherm of fresh tea leaves was studied using static gravimetric method of saturated salt solutions at temperatures of 15, 20, 25 and 30ºC and water activities of 0.07 to 0.97. Data were fitted to five mathematical equations. Using the best-fit mathematical model, thermodynamic properties of fresh tea leaves including net isosteric heat of sorption, differential entropy were estimated. The applicability of enthalpy – entropy compensation theory for fresh tea leaves was also evaluated. Results showed that the modified Oswin model was best fitted with the experimental data. Thermodynamics properties like net isosteric heat of sorption and differential entropy were found to decrease exponentially with the increase in moisture content. Net isosteric heat of sorption and differential entropy increased exponentially with decreasing moisture content of fresh tea leaves. Isosteric heat of sorption of fresh tea leaves was very close to heat of vaporization of pure water when the moisture content of tea leaves exceeded 40% (d.b.). The enthalpy-entropy compensation theory could be successfully applied for the moisture desorption behavior of fresh tea leaf samples and it was enthalpy driven spontaneous process.

scholarly journals Moisture Adsorption and Thermodynamic Properties of California Grown Almonds (Varieties: Nonpareil and Monterey)

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Li Zuo Taitano ◽  
R.P. Singh
Keyword(s):  
Diffusion Coefficient ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Water Activity ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Moisture Adsorption ◽  
Constant Weight ◽  
Differential Enthalpy ◽  
Monolayer Moisture

Moisture adsorption characteristics of California grown almonds (Nonpareil: pasteurized and unpasteurized almonds; Monterey: pasteurized, unpasteurized and blanched almonds) were obtained using the gravimetric method over a range of water activities from 0.11 to 0.98 at 7-50ºC. The weights of almonds were measured until samples reached a constant weight. The relationship between equilibrium moisture content and water activity was established using the Guggenheim-Anderson-de Boer model. The diffusion coefficient of water in almond kernels was calculated based on Ficks second law. The monolayer moisture value of almonds ranged from 0.020 to 0.035 kg H2O kg-1 solids. The diffusion coefficient increased with temperature at a constant water activity, and decreased with water activity at a constant temperature. The thermodynamic properties (net isosteric heat, differential enthalpy and entropy) were also determined. The net isosteric heat of adsorption decreased with the increasing moisture content, and the plot of differential enthalpy versus entropy satisfied the enthalpy-entropy compensation theory. The adsorption process of almond samples was enthalpy driven over the range of studied moisture contents.

scholarly journals THERMODYNAMIC PROPERTIES OF WATER DESORPTION OF SOYBEAN BRAN

2015 ◽  
Vol 33 (2) ◽  
Author(s):  
Isabel Cristina Machado Corrêa ◽  
Caciano P. Zapata Noreña
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Integral Enthalpy ◽  
Isokinetic Temperature ◽  
Water Desorption ◽  
Spreading Pressure ◽  
Differential Enthalpy ◽  
Enthalpy And Entropy

The differential and integral thermodynamic properties (enthalpy, entropy, Gibbs free energy, temperature isokinetic and spreading pressure) of soybean bran were determined. Experimental data obtained from the literature were adjusted appropriately by GAB equation (R2>0.95), whose parameters were used to estimate the thermodynamic properties of desorption of soybean bran. The differential enthalpy and entropy increased with decreasing equilibrium moisture content and the isokinetic temperature confirmed the linear chemical compensation between the enthalpy and entropy and the process was enthalpy driven. The spreading pressure increased with increasing water activity. The integral enthalpy decreased with increasing equilibrium moisture content, whereas the integral entropy increased, but negative values, reaching up to -0.02 kJ/mol.K.

scholarly journals Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process

2016 ◽  
Vol 20 (6) ◽  
pp. 576-580 ◽  
Author(s):  
Cristian F. Costa ◽  
Paulo C. Corrêa ◽  
Jaime D. B. Vanegas ◽  
Fernanda M. Baptestini ◽  
Renata C. Campos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Drying Process ◽  
Drying Temperature ◽  
Air Temperatures ◽  
Nutritional Qualities ◽  
Forced Air ◽  
Air Circulation ◽  
Best Fit

ABSTRACT Jabuticaba is a fruit native of Brazil and, besides containing many nutritional qualities, it also has a good field for use in products such as flour for cakes and biscuits, juice, liqueur, jelly and others. This study aimed to model the drying kinetics and determine the thermodynamic properties of jabuticaba peel at different drying air temperatures. Ripe fruits of jabuticaba (Myrciaria jaboticaba) were collected and pulped manually. Drying was carried out in a forced-air circulation oven with a flow of 5.6 m s-1 at temperatures of 40, 50, 60 and 70 °C. Six mathematical models commonly used to represent the drying process of agricultural products were fitted to the experimental data. The Arrhenius model was used to represent the drying constant as a function of temperature. The Midilli model showed the best fit to the experimental data of drying. The drying constant increased with the increment in drying temperature and promoted an activation energy of 37.29 kJ mol-1. Enthalpy and Gibbs free energy decreased with the increase in drying temperature, while entropy decreased and was negative.

scholarly journals Thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds

2018 ◽  
Author(s):  
Amel Zammouri ◽  
M. Ben Zid ◽  
N. Kechaou ◽  
N. Boudhrioua Mihoubi
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Water Sorption ◽  
Pharmaceutical Preparations ◽  
Sorption Isotherms ◽  
Integral Enthalpy ◽  
Isotherm Models ◽  
Water Sorption Isotherms

This investigation examines and compares the water sorption isotherms and the thermodynamic properties of two pharmaceutical preparations (Hypril and Azix) intended to be manufactured with the same process plant and equipment. The moisture equilibrium isotherms were determined at 50, 60 and 70 °C using a gravimetric technique. Five isotherm models were explored for their fitting to the experimental data. Azix showed sigmoid type II isotherms while Hypril showed type III isotherms according to the BET classification. All investigated models fitted well the water sorption isotherms of Hypril. By contrast, only GAB and Adam and Shove equations gave appropriate fit to the experimental data of Azix. For both formulations, the isosteric heat and the differential entropy decreased sharply with the increase of equilibrium moisture content to minimum values and thereafter remain constant. In the case of Azix, the integral enthalpy decreased with equilibrium moisture content while the integral entropy increased until reaching a constant value. Contrariwise, Hypril showed decreasing of the integral enthalpy and entropy with the equilibrium moisture content. Keywords: sorption isotherm, enthalpy, entropy, spreading pressure, pharmaceutical formulations  

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

2007 ◽  
Vol 13 (3) ◽  
pp. 231-238 ◽  
Author(s):  
P.C. Corrêa ◽  
A.L.D. Goneli ◽  
C. Jaren ◽  
D.M. Ribeiro ◽  
O. Resende
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Moisture Content ◽  
Mathematical Models ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Statistical Parameters ◽  
Peanut Hulls ◽  
Pass Through

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.

scholarly journals MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE

2017 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Mutiara Nur Alfiah ◽  
Sri Hartini ◽  
Margareta Novian Cahyanti
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Red Yeast Rice ◽  
Cassava Flour ◽  
Red Yeast ◽  
Moisture Sorption Isotherm ◽  
Gab Model ◽  
Monolayer Moisture

<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>

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