Prediction Modeling for Moisture Sorption Isotherms of Rice Starch/Carboxymethyl Cellulose from Durian Rind Blend Films

2013 ◽  
Vol 431 ◽  
pp. 32-36 ◽  
Author(s):  
Rungsiri Suriyatem ◽  
Pornchai Rachtanapun
Keyword(s):  
Sorption Isotherm ◽  
Carboxymethyl Cellulose ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Rice Starch ◽  
Percentage Error ◽  
Blend Films ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Durian Rind

Rice starch/carboxymethyl cellulose from durian rind (RS/CMCd) blend films were prepared by solution casting. The effect of different ratios between rice starch and CMCd (100:0, 88:12, 67:33, 50:50, 33:67, 12:88 and 0:100) on moisture sorption isotherm of blend films was investigated. The sorption isotherm of RS/CMCd blend films was determined at various relative humidity (RH) at 25°C. The isotherm curves revealed that the highest equilibrium moisture content (EMC) was obtained from CMCd film, at aw=85. Knowledge of sorption isotherms is important to predict the moisture sorption properties of the filmsviamoisture sorption empirical models. The Lewicki, Peleg, Guggenheim-Anderson-deBoer (GAB), BrunauerEmmettTeller (BET), and Oswin models were tested to fit the experimental data. The root mean squares percentage error (%RMS) of Lewicki, Peleg, GAB, BET and Oswin was in the range of 5.3-83.1, 2.2-20.0, 6.9-20.2, 3.4-26.4 and 4.7-41.2, respectively. The Peleg model was found to be the best fitted model for RS/CMCd blend films.

scholarly journals Determination of Moisture Sorption Isotherm of Crosslinked Millet Flour and Oxirane Using GAB and BET

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
M. S. Alamri ◽  
A. A. Mohamed ◽  
S. Hussain ◽  
M. A. Ibraheem ◽  
Akram A. Abdo Qasem
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Water Binding ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures

Epoxy resin was prepared by crosslinking epoxidized oil and millet flour. The reaction was carried out at three different temperatures (25, 40, and 55°C) and zinc chloride levels (1, 2, and 3%). Moisture sorption isotherms were determined at 0.1 to 0.9 water activity (aw) using a gravimetric sorption analyzer (Q 2000). The sigmoidal shape (type II) of the resin isotherms exhibited lower equilibrium moisture content (EMC) at higher temperature. The experimental data were modeled using GAB (Guggenheim–Anderson–de Boer) and BET (Brunauer–Emmett–Teller). The EMC of the resin was significantly lower than that of the flour, which could be attributed to the decrease in the number of water-binding sites due to the creation of dense areas during crosslinking. The low root-mean-square error (RMSE) indicates that GAB and BET were suitable for predicting the water sorption isotherm for millet flour resin. The heat of sorption of the resin was large at low moisture content and increased at higher relative humidity. It is recommended that millet flour resin be used at relative humidity below 60%.

Moisture Sorption Isotherms and Isosteric Heats of Sorption of High-Pressure Treated Paulownia Wood under Different Storage Conditions

2019 ◽  
Vol 62 (1) ◽  
pp. 105-114
Author(s):  
Xiuping Jiang ◽  
Xiuping Jiang ◽  
Huanhuan Li ◽  
Hosahalli S. Ramaswamy ◽  
Songming Zhu ◽  
...  
Keyword(s):  
High Pressure ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Storage Conditions ◽  
Sorption Behavior ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Paulownia Wood

Abstract. Understanding of moisture sorption isotherms (MSI) is critical for predicting the stability of wood during handling, transport, and storage. The aim of this study was to evaluate the adsorption and desorption isotherm characteristics of high-pressure (HP) treated paulownia wood and to identify the best-fitting model to describe its sorption behavior. The equilibrium moisture contents (EMCs) of HP-treated paulownia wood were obtained using a static gravimetric method under different storage conditions: three temperatures (20°C, 30°C, and 40°C) and five water activity (aw) levels (0.32 to 0.95). Results showed that HP parameters did not significantly affect the MSI trend of treated groups. Eight modified models (modified Chung-Pfost, modified Henderson, modified Oswin, modified Halsey, Chen-Clayton, Guggenheim-Anderson-de Boer (GAB), simply modified GAB, and Peleg) were fitted to the experimental data. The Chen-Clayton model (temperature-dependent) produced randomized residuals and the best prediction performance for both adsorption and desorption among all models. Net isosteric heat of adsorption and desorption decreased from 7.55 to 4.84 kJ mol-1 and from 18.1 to 12.2 kJ mol-1, respectively, with an increase in EMC from 7.5% to 10%. The isosteric temperature (Tß) was 352 K for adsorption and 335 K for desorption, between which all the adsorption and desorption reactions proceeded at the same rate. All thermodynamic functions were adequately characterized by a power law model. Keywords: Equilibrium moisture content, High-pressure treatment, Modeling, Moisture sorption isotherm, Paulownia wood, Temperature, Thermodynamic analysis.

scholarly journals Drying kinetics and determination of water sorption isotherms of corn

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
J Roy ◽  
MA Alim ◽  
MN Islam
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Water Sorption ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Drying Kinetics ◽  
Drying Time ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Monolayer Moisture

The study was carried out for the purpose of determining the drying kinetics as well as moisture sorption isotherm of hybrid-81 corn. Corn at about 31% moisture content (wb) was dried in a forced convective hot air cabinet dryer at different drying conditions, such as variable air dry bulb temperature (40°C, 50°C and 60°C) and loading density (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2) as well as in shining sun at different layers (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2). The water sorption isotherm of the dried corn was developed using vacuum desiccators, which contained saturated salt solutions in the range of 11-93% RHs. The mono-layer moisture content calculated by the Brunauer–Emmett–Teller (BET) model (6.76 g/100 g solid) was lesser than that calculated by the Guggenheim–Anderson–De Boer (GAB) model (10.53 g/100 g solid). The energy constants were 10.45 and 4.64 as per BET and GAB equation, respectively. Both models gave suitable fits for corn. The activation energy (Ea) for diffusion of water was found to be 11.09 kcal/gm-mole for corn. Furthermore, it was noticed that, with the increase of corn layer, the drying rate decreased in case of both sun and mechanical drying. However, higher loading density resulted in efficient drying, at least up to 10.7 kg/m2. It was shown that the drying time to obtain stability was the lowest for moisture content (12.08 %) corresponding to aw of 0.65 in case of BET or GAB monolayer moisture content. This finding could be helpful in predicting the storage life of corn.J. Bangladesh Agril. Univ. 15(2): 309-317, December 2017

Water-Binding and Oxygen Permeability in Poly(vinyl alcohol) Films

2002 ◽  
Vol 55 (8) ◽  
pp. 507 ◽  
Author(s):  
L. Lien ◽  
C. M. Fellows ◽  
L. Copeland ◽  
B. S. Hawkett ◽  
R. G. Gilbert
Keyword(s):  
Vinyl Alcohol ◽  
Oxygen Permeability ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Poly Vinyl Alcohol ◽  
Contributing Factors ◽  
Water Binding ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Copolymer Poly

The measurement and interpretation of isotherms for sorption of water onto, and oxygen permeability of, polymer substrates are important for designing polymers in applications such as agricultural seed coatings. In a preliminary study of water sorption in the commonly used copolymer poly(vinyl alcohol–co-vinyl acetate), moisture sorption isotherms were measured for a series of substrates of different comonomer composition at 25°C. The data were fitted to the D'Arcy–Watt model, which gave physically reasonable values for parameters related to the strength of monolayer adsorption to high affinity sites on the substrate and the number of sites for secondary water adsorption per unit mass. The oxygen permeability of poly(vinyl alcohol) films was found to be a function only of the water content of the films, with no other obvious contributing factors. Marked differences were seen in the populations of 'bound' and 'unbound' water characterized by 1H nuclear magnetic resonance (NMR) spectroscopy and moisture sorption isotherm fitting. There was no correlation of oxygen permeability with 'bound' or 'unbound' water measured by any means, a fact suggesting that there is a continuum of water environments within the materials.

scholarly journals Comparison of moisture sorption isotherm models in freeze-dried pineapple pulp

1969 ◽  
Vol 77 (3-4) ◽  
pp. 113-128
Author(s):  
Humberto Vega-Mercado ◽  
Gustavo V. Barbosa-Cánovas
Keyword(s):  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isotherm Models ◽  
Crystalline Cellulose ◽  
Moisture Sorption Isotherm ◽  
Freeze Dried ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
Pineapple Pulp

Moisture sorption isotherms of freeze-dried pineapple pulp were determined at 5, 25, 30, 35 and 55°C. Water activity were controlled by using preselected saturated salt solutions in evacuated glass desskators according to Wolf et al. (20), where micro crystalline cellulose is the reference material for the determination of sorption isotherms. The data were correlated in terms of some empirical models involving two single parameters: models of Henderson, Oswin, Chung-Pfost, Halsey, Iglesias-Chirife, and Smith. Also, the data was correlated by the Guggenheim-Anderson-deBoer (G.A.B.) model involving three adjustable parameters. It was found that the models proposed by Henderson and Iglesias-Chirife were the most useful ones in predicting water activities at different levels and at different temperatures.

scholarly journals Experimental Determination of Moisture Sorption Isotherm of Fecal Sludge

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 303 ◽  
Author(s):  
Catherine Bourgault ◽  
Paul Lessard ◽  
Claire Remington ◽  
Caetano C. Dorea
Keyword(s):  
Relative Humidity ◽  
Water Distribution ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Critical Data ◽  
Moisture Sorption Isotherm ◽  
Fecal Sludge ◽  
Moisture Sorption Isotherms ◽  
Gab Model

Dewatering and drying of fecal sludge (FS) is a key treatment objective in fecal sludge management as it reduces volume (thereby reducing emptying frequency and associated transportation costs), inactivates pathogens, and is beneficial and/or necessary to resource recovery activities such as composting and combustion as fuel. However, studies on dewatering performances of FS are limited. The physical water distribution of such matrices is not fully understood, limiting the progress in the development and optimization of FS dewatering technologies. The objective of this study is to present a gravimetric method intended to assess the dewatering characteristics and associated modelling of FS through moisture sorption isotherms. Samples were placed in airtight jars containing different saturated salt (NaOH, CaCl2, NaCl, KCl, K2SO4) solutions to reproduce a range of relative humidity values (6 to 97%). Results confirmed the achievement of characteristic sigma-shaped moisture sorption isotherms with increasing moisture adsorption at higher values of relative humidity. Furthermore, experimental data best fit the three-parameter Guggenheim–Anderson–de Boer (GAB) model. This method can be replicated to contribute critical data about the characterization of fecal sludge, a seriously under-researched matrix.

scholarly journals The Effect of Freeze-Drying on the Properties of Polish Vegetable Soups

2021 ◽  
Vol 11 (2) ◽  
pp. 654
Author(s):  
Ewa Jakubczyk ◽  
Aleksandra Jaskulska
Keyword(s):  
Water Content ◽  
Sorption Isotherm ◽  
Freeze Drying ◽  
Color Change ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Moisture Sorption Isotherm ◽  
Freeze Dried ◽  
Polyphenolic Content ◽  
Total Polyphenolic Content

The aim of this study was to investigate selected physical and biochemical properties of four vegetable freeze-dried soups. The water content, water activity, pH, color parameters, antioxidant activity (EC50), total polyphenolic content of fresh tomato, pumpkin, beetroot, and cucumber, and freeze-dried soups were measured. Sensory analysis was applied to compare sensory attributes of fresh and rehydrated soups. The sorption isotherms of freeze-dried soups were obtained with the application of the static and dynamic vapor sorption (DVS) method. The application of the freeze-drying method enabled the obtaining of dry soups with a low water content of 2–3%. The drying caused a significant change of color of all soups. The redness of soups decreased after drying for the beetroot soups from +39.64 to +21.91. The lower chroma value of 25.98 and the highest total color change ΔE*ab = 36.74 were noted for freeze-dried beetroot soup. The antioxidation activity and total polyphenolic content were reduced after drying, especially for the cucumber and tomato soups. The Peleg model was selected to describe the sorption isotherms of dried soups. The sorption isotherm of freeze-dried cucumber and beetroot soups had a sigmoidal shape of type II. The shape of the moisture sorption isotherm for freeze-dried tomato and pumpkin soups corresponded more with type III isotherms. The DVS method can be used to characterize the moisture sorption isotherms of freeze-dried products.

scholarly journals Sorption isotherms for oat flakes (Avena sativa L.)

2014 ◽  
Vol 32 (1) ◽  
pp. 52-58 ◽  
Author(s):  
José Edgar Zapata M. ◽  
Oscar Albeiro Quintero C. ◽  
Luis Danilo Porras B.
Keyword(s):  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Storage Conditions ◽  
Percentage Error ◽  
Relative Air Humidity ◽  
Moisture Sorption Isotherms ◽  
Relative Percentage Error ◽  
The Mean ◽  
Best Fit

Moisture sorption isotherms of oat flakes were determined at temperatures of 5, 25 and 37°C, using a gravimetric technique in an aw range of between 0.107 and 0.855. These curves were modeled using six equations commonly applied in food. The quality of the fit was assessed with the regression coefficient (r2) and the mean relative percentage error (MRPE). The best fit were obtained with the Caurie model with r2 of 0.996, 0.901 and 0.870, and MRPE of 7.190, 17.878 and 16.206, at 5, 25 and 37°C, respectively. The equilibrium moisture presented a dependence on temperature in the studied aw range, as did the security moisture (XS). These results suggest that the recommended storage conditions of oat flakes include: a relative air humidity of 50% between 5 and 25°C and of 38% up to 37°C.

Comparison of Moisture Sorption Isotherms and Quality Characteristics of Freeze-Dried and Boiled-Dried Abalone

2015 ◽  
Vol 11 (4) ◽  
pp. 573-578 ◽  
Author(s):  
Ji-Yeon Chun ◽  
Yeon-Ji Jo ◽  
Jun-Bo Shim ◽  
Sang-Gi Min ◽  
Geun-Pyo Hong
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Value Added ◽  
Quality Characteristics ◽  
Lower Shear ◽  
Moisture Sorption Isotherm ◽  
Freeze Dried ◽  
Moisture Sorption Isotherms ◽  
Monolayer Moisture

Abstract This study investigated the moisture sorption isotherm (MSI) profiles of freeze-dried (FD) and boiled-dried (BD) abalone at 15°C, 25°C, and 35°C, and compared the quality characteristics of the abalone after rehydration. The equilibrium moisture content (EMC) and the calculated monolayer moisture content of FD abalone were higher than those of BD abalone. After rehydration, FD abalone showed a higher yield and a lower shear force than BD abalone. Additionally, the appearance of FD abalone was similar to that of fresh abalone, reflecting a potential application of FD to produce value-added dried abalone.

scholarly journals Moisture Sorption Isotherms and Prediction Models of Carboxymethyl Chitosan Films from Different Sources with Various Plasticizers

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Juthamas Tantala ◽  
Chitsiri Rachtanapun ◽  
Wirongrong Tongdeesoontorn ◽  
Kittisak Jantanasakulwong ◽  
Pornchai Rachtanapun
Keyword(s):  
Water Solubility ◽  
Prediction Models ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
High Water ◽  
Carboxymethyl Chitosan ◽  
Percentage Error ◽  
Moisture Sorption Isotherms ◽  
Gab Model ◽  
The Stability

Carboxymethyl chitosan (CMCH) from different chitosan sources (shrimp, crab, and squid) and molecular sizes (polymer and oligomer) were synthesized via carboxymethylation reaction. The CMCH films were prepared by solution casting. All the CMCH films had high water solubility, higher than 85% of the dry matter of the films. The sorption isotherm of the CMCH films was evaluated at several values of relative humidity (0% RH, 23% RH, 34% RH, 43% RH, 65% RH, 77% RH, and 86% RH) at 25 ± 1°C. The equilibrium moisture content values of all the CMCH films were low at lower aw but increased considerably above aw = 0.65. The sigmoidal moisture sorption isotherms of this product can be classified as type II. Understanding of sorption isotherms is an important prerequisite for the prediction of moisture sorption properties of films via moisture sorption empirical models. The experimental data were analyzed and fitted by the nine sorption models. The various constants determined by linear fitting of the sorption equation with r2 values were in the range of 0.7647 to 0.999. The GAB model was found to be the best-fitted model for CMCH films (aw = 0.23–0.86, 25 ± 1°C), and the model presented the optimal root-mean-square percentage error (%RMS) values when compared with other models. In conclusion, it can be stated that the GAB model was found to be better estimated for predicting the CMCH films than other models. Therefore, the constant derived from different sorption models were applied for use in terms of information and for the determination of the stability of CMCH packaging films for specific end uses.

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