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1.
Menkov ND 《Die Nahrung》2000,44(6):443-446
The equilibrium moisture contents in broad bean seeds were determined using the gravimetric static method at 5, 20, 40 and 60 degrees C over a range of water activities from 0.110 to 0.877. The sorption capacity of seeds decreased with the increase in temperature at constant water activity. Five models, modified Chung-Pfost, modified Halsey, modified Oswin, modified Henderson, and GAB (Guggenheim-Anderson-de Boer) equations, were applied to analyse the experimental data. The modified Oswin and GAB models were found to be the most suitable for describing the sorption isotherms. 相似文献
2.
Moisture adsorption isotherms of guar grain and guar gum splits were determined at 10, 20, 30 and 40 °C and 23-96% relative humidities using gravimetric method. The sorption data were fitted to six well-known sorption isotherm models (modified Chung-Pfost, modified Halsey, modified Henderson, modified Oswin, Chen-Clayton, and GAB models) using non-linear least square method. The GAB model was found the most satisfactory for representation of the equilibrium moisture content data for guar grain and guar gum splits. The equilibrium moisture content of guar gum splits was found to be significantly higher (p < 0.05) than that of guar grain. The isosteric heat of sorption was determined from the equilibrium moisture adsorption data using Clausius-Clapeyron type equation. Exponential relationship described well the dependence of isosteric heat of sorption on the equilibrium moisture content. The enthalpy-entropy compensation theory applied to sorption isotherms indicated enthalpy controlled sorption process. 相似文献
3.
Modelling moisture sorption isotherms for maize flour 总被引:1,自引:0,他引:1
O.J. Oyelade T.Y. Tunde-Akintunde J.C. Igbeka M.O. Oke O.Y. Raji 《Journal of Stored Products Research》2008,44(2):179-185
The sorption isotherm of food material is pertinent in the processing and storage of food products. Adsorption and desorption isotherms for maize flour were investigated using the static gravimetric method over the range of temperature (27–40 °C) and water activity (aw) (0.10–0.80) commonly experienced in the tropical environment. The experimental data were compared with five widely recommended models in the literature for food sorption isotherms (GAB, modified GAB (MGAB), modified Oswin (MOE), modified Henderson (MHDE), and modified Chung–Pfost (MCE)). The GAB, MGAB, and MOE models were found to be acceptable in predicting the moisture sorption isotherms for maize flour. Overall, the MGAB appears to be most suitable for fitting the adsorption and desorption moisture isotherms data for the maize flour. 相似文献
4.
SHIBY VARGHESE K. SINIJA V RAMACHANDRANNAIR HARI NIWAS MISHRA 《International Journal of Dairy Technology》2009,62(1):85-92
The moisture sorption behaviour of curd (Indian yogurt) powder was studied at 20, 30, 40 and 50°C for water activity ranging from 0.07 to 0.85. GAB, BET, Henderson, Halsey, Chung & Pfost, Smith, Oswin and Peleg models were applied to analyse the data. Estimated parameters and fitting ability for sorption models were evaluated. The GAB model showed the best fit to the sorption data of curd powder at 20, 30 and 40°C, and the Peleg model fitted well at 50°C. 相似文献
5.
Hamid Reza Gazor Hossein Chaji 《International Journal of Food Science & Technology》2010,45(8):1703-1709
The equilibrium moisture contents of saffron (Crocus sativus L.) stigmas were determined experimentally using the standard gravimetric method at temperatures 30, 45 and 60 °C and water activity ranging from 11% to 83%. The sorption isotherm curves of saffron were sigmoidal in shape and decreased with increased temperature at constant relative humidity. Five selected isotherm models GAB, modified Henderson, modified Chung‐Pfost, modified Halsaey and modified Oswin were tested to fit the experimental isotherm data. Modified Oswin and modified Henderson models were found acceptable for predicting desorption moisture isotherms and fitting to the experimental data, respectively. The isosteric heats of desorption, determined from equilibrium data using the Clausius‐Clapeyron equation, were found to be a function of moisture content. The net isosteric heat of desorption of saffron varied between 1.38 and 5.38 kJ mol?1 at moisture content varying between 2% and 20% (d.b). 相似文献
6.
The desorption and adsorption equilibrium moisture isotherms of sorghum malt at the temperatures of 40 and 50 °C, over the water activity range of 0.1-0.9, were determined using the static gravimetric method. A non-linear regression programme was used to fit five moisture sorption isotherm models [Modified Henderson, Modified Chung-Pfost, Modified Guggenheim-Anderson-de Boer (GAB), Modified Halsey and Modified Oswin] to the experimental data. The models were compared using the standard error of estimate, mean relative percentage deviation, fraction explained variation and residual plots.The Modified Chung-Pfost model was found to be the best for predicting the desorption equilibrium moisture content, while the adsorption equilibrium moisture content was best predicted by the Modified Oswin model. The desorption and adsorption water activities were found to be best fitted by the Modified Oswin model.The moisture sorption isotherms were sigmoidal in shape and showed a marked effect of temperature. The span of the moisture sorption hysteresis loop formed, decreased with increase in temperature, while the size increased with increase in temperature. 相似文献
7.
The sorption isotherms of Oolong tea were determined at temperatures ranging from 5 to 50 °C. Estimated parameters and fitting
ability for nine equilibrium relative humidity (ERH) models were evaluated. The modified Oswin equations were found to be
an adequate model of three parameters to describe the sorption data. The Andrieu model was the only adequate model of four
parameters. In comparing the results of this study with previously published data, it was found that the sorption properties
were affected by species and manufacture techniques. The Guggenheim–Anderson–de Boer (GAB) model was not an adequate model
as indicated by checking residual plots. The monolayer moisture content calculated from the Brunauer–Emmett–Teller (BET) model
was lesser than that calculated from the GAB model. The errors of moisture content determined by measuring the ERH and temperature
of samples was within 0.35%. 相似文献
8.
Experiments were conducted to determine the equilibrium moisture content of pumpkin (cv Cucurbita Pepo L.) at different temperatures (278.1 K, 298.1 K and 318.1 K) and relative humidities (8–91%). Fresh and partially osmotically dehydrated (using sucrose solutions) samples of pumpkin parenchyma were employed. The desorption isotherm of pumpkin seeds at 298.1 K was determined as well and was found to be similar to other sorption isotherms of other seeds with similar fat and protein compositions. No significant dependence of the equilibrium experimental data on the temperature or osmotic pre-treatment was found. Several common mathematical models were used to fit the experimental data. For the parenchyma tissue, statistical analysis proved that those of Halsey, Oswin, Chirife and GAB were the best, while for the seeds, the Henderson, GAB and Peleg models are preferable. 相似文献
9.
Antonio Vega-Gálvez Jessica López Margarita Miranda Karina Di Scala Francisco Yagnam & Elsa Uribe 《International Journal of Food Science & Technology》2009,44(10):2033-2041
The sorption isotherms of blueberry variety O'Neil were determined at 20, 40 and 60 °C, for a range of water activity of 0.10–0.95. The isotherms showed that the equilibrium moisture content increased when temperature decreased at constant water activity. The BET, GAB, Halsey, Henderson, Caurie, Smith, Oswin and Iglesias-Chirife equations were tested for modelling the sorption isotherms. The results showed that GAB, BET and Halsey models gave the best fit quality for the experimental desorption data, and BET, Oswin and Henderson for adsorption data as suggested by the statistical tests employed. The net sorption heat was calculated using the Clausius–Clapeyron equation giving 38.62 kJ mol−1 (desorption) and 30.88 kJ mol−1 (adsorption) at a moisture content of 0.01 g water (g d.m.−1 ). Tsami equation was applied to estimate the net isosteric heat of sorption as function of equilibrium moisture content with satisfactory results. 相似文献
10.
Zhengyong Yan Maria J. Sousa-Gallagher & Fernanda A. R. Oliveira 《International Journal of Food Science & Technology》2008,43(8):1430-1436
Sorption isotherms of intermediate moisture content (IMC) products are essential to predict shelf-life of packaged moisture-sensitive product by modelling moisture uptake during storage and distribution. The effect of temperature and initial moisture content (MC) of IMC banana on the relationship between MC and water activity were investigated. Raw bananas were dried in a tunnel dryer at 2% relative humidity (RH), 70 °C, and a 3.2 ± 0.2 m s–1 air velocity. Drying procedure was carried out a number of times until various IMC levels were obtained (5%, 14%, 22% and 33% db for banana). Sorption isotherms of bananas were determined at 10, 20, 30 and 40 °C. The initial MC of IMC banana had no significant effect on the relationship between MC and water activity according to statistical analysis. All the sorption curves were found to be Type II. BET, GAB, modified GAB, Oswin, Halsey and modified Freundlich models were fitted to the data and it was found that the best results were obtained with a modified Freundlich equation. A secondary modified Freundlich model was built accounting for the effect of a w and temperature on the sample MC. 相似文献
11.
The sorption isotherms of dudh churpi, a shelf-stable traditional milk product in India, determined at 15, 25, 35 and 45 degrees C, were typical type II sigmoidal according to the BDDT (Brunauer-Deming-Deming-Teller) classification. Nine equations, namely Bradley, Henderson, Iglesias and Chirife, Khun, Mizrahi, GAB (Guggenheim-Anderson-de Boer), modified Mizrahi, Oswin and Caurie were fitted to the sorption data. Caurie's equation was found to be suited best to predict equilibrium moisture content of dudh churpi. Monolayer value, density of sorbed water, number of monolayers and area of adsorbent decreased with the increase in temperature. 相似文献
12.
S. A. Hossain P. K. Pal P. K. Sarkar G. R. Patil 《Molecular nutrition & food research》2002,46(3):136-140
The sorption isotherms of dudh churpi, a shelf‐stable traditional milk product in India, determined at 15, 25, 35 and 45°C, were typical type II sigmoidal according to the BDDT (Brunauer‐Deming‐Deming‐Teller) classification. Nine equations, namely Bradley, Henderson, Iglesias and Chirife, Khun, Mizrahi, GAB (Guggenheim‐Anderson‐de Boer( modified Mizrahi, Oswin and Caurie were fitted to the sorption data. Caurie's equation was found to be suited best to predict equilibrium moisture content of dudh churpi. Monolayer value, density of sorbed water, number of monolayers and area of adsorbent decreased with the increase in temperature. 相似文献
13.
The equilibrium moisture contents (MC) of leaves and stems of lemon balm (Melissa officinalis L.) were determined separately at temperatures of 25, 35 and 45 °C over a stepwise increase of relative humidity (RH) ranging from 3 to 90% by an automatic, gravimetric analyzer (DVS system). Equilibrium was achieved within 6 h for most of the target values of relative humidity. The equilibrium moisture content of leaves was significantly higher than that of stems (p < 0.05). Differences in moisture sorption capacity between the leaves and stems can be attributed to chemical composition and structure of the tissues. Five three-parameter moisture sorption models (modifications of Chung–Pfost, GAB, Halsey, Henderson and Oswin) were tested for their effectiveness to fit the experimental sorption data. The modified Oswin equation was found to be the best model to describe the adsorption isotherms of both leaves and stems of lemon balm. The recommended MC values of leaves and stems for microbial safe storage at 25 °C were 0.124 and 0.113 kg water per kg dry solids, respectively. The net isosteric heat of sorption was computed from the predicted sorption data by applying the integrated form of the Clausius–Clapeyron equation. 相似文献
14.
为给在干燥、贮藏及运输过程中保证大豆的品质提供理论依据,实验测定了大豆在室温(25 ℃)条件下的水分解吸-吸附等温线。采用非线性回归分析,应用常见的5 种模型Oswin、Halsey、Hendenson、GAB、Chung-Pfost对大豆在室温条件下测得的水分进行解吸-吸附等温线拟合分析,以确定最佳拟合模型及其参数。结果表明:大豆的解吸等温线属于第Ⅱ种类型;吸附等温线属于第Ⅲ种类型;在整个水分活度范围内,大豆的解吸-吸附等温线均存在着滞后现象;最佳的解吸-吸附等温线拟合方程都是Oswin模型,它们的决定系数均高于0.993;Oswin模型拟合大豆解吸等温线的参数A和B分别为0.075和0.500,吸附等温线的参数A和B分别为0.075和0.498。 相似文献
15.
The equilibrium moisture contents of almond were determined using the gravimetric‐static method at 15, 30, 55 and 75C for powder and 15, 55 and 75C for nut state of almond for water activity (aw) ranging from 0.11 to 0.87. At a given aw, the results show that the moisture content decreases with increasing temperature. The experimental sorption curves are then described by the BET, GAB, Henderson, Oswin, Smith and Halsey models. A nonlinear regression‐analysis method was used to evaluate the constants of equations. The GAB model was found to be the most suitable for describing the sorption curves; the monolayer‐content values for the sorption at different temperatures are calculated. Also, the isosteric heats of adsorption of water were determined as a function of moisture content from the equilibrium data at different temperatures using the Clasius‐Clapeyron equation. 相似文献
16.
Some meat products involve drying previously frozen pork meat, which makes the knowledge of sorption characteristics very important for the design and management of meat dehydration processes. The sorption isotherms of raw pork meat from the Biceps femoris and Semimembranosus muscles were determined at four temperatures: 25, 30, 35 and 40 °C. The experimental results were modelled using the GAB (Guggenheim, Anderson and De Boer) model. The effect of temperature was also taken into account to model the experimental sorption isotherms using four models (GAB, Oswin, Halsey and Henderson). The best results were provided by the GAB model. From the experimental sorption isotherms the isosteric heats of sorption were determined. For a moisture content higher than 0.15 kg water/kg dm, the isosteric heat of meat was similar to the latent heat of vaporization for pure water. For a lower moisture content, an increase in the isosteric heat was observed when the moisture content decreased. 相似文献
17.
根据吸附原理,在环境温度25℃下,水分活度0.11~0.90范围内,采用重量法对大米淀粉的吸附/解吸等温线进行测定。用7个非线性回归方程对吸附及解吸等温线进行描述,以决定系数(R2)、残差平方和(RSS)、平均相对误差(MRD)和均方根误差(RMSE)为评价指标,确定最佳拟合模型及其参数。结果表明,根据国际理论和应用化学联合会(IUPAC)的分类,大米淀粉的吸附和解吸等温线都属于第Ⅱ种类型,在实验水分活度范围内等温线存在一个明显的滞后现象,该滞后现象属于H3型。Henderson模型、Oswin模型、GAB模型均适合描述大米淀粉的吸湿等温线,其中GAB模型为最佳模型。GAB拟合解吸等温线的参数X0、C、K分别为0.0800、36.43、0.7646,拟合吸附等温线的参数分别为0.0743、26.87、0.7842。 相似文献
18.
Moisture sorption isotherms and isosteric heat for pistachio 总被引:1,自引:0,他引:1
M. Yazdani P. Sazandehchi M. Azizi P. Ghobadi 《European Food Research and Technology》2006,223(5):577-584
The equilibrium moisture contents (EMC) of pistachio were determined using the standard static-gravimetric method at 15, 25, 35 and 40 °C for pistachio powder at 15, 35 °C for pistachio kernel and pistachio nut for water activity (a
w) ranging from 0.11 to 0.9. At a given water activity, the results show that the moisture content decreases with increasing temperature. The experimental sorption curves are then described by the BET, GAB, Henderson, Oswin, Smith and Halsey models. A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. The Smith model was found to be suitable for describing the sorption curves. The isosteric heat of adsorption of water was determined as a function of moisture content from the equilibrium data at different temperatures using the Clasius–Clapeyron equation. 相似文献
19.
Moisture adsorption isotherms of commercial tarhana powder, a popular Turkish food used in soup making, were determined at 10 °C, 20 °C and 30 °C. Gravimetric static method was applied at 0.08–0.92 water activity range. The data was fitted to Guggenheim-Anderson-deBoer(GAB), Oswin, Hendersonand Brunauer-Emmett-Teller(BET)equations. Mean relative deviation (%E) was used to compare the goodness of fit. The BET was found the best equation for the range of water activity 0.08–0.58. The GAB equation was found adequate and gave similar result with the Oswinequation at 10 °C and 20 °C, while the Oswinequation was better for characterizing the adsorption behavior of tarhana sample for the whole range of temperature and water activity studied. 相似文献
20.
Moisture sorption isotherms of grape pestil and foamed grape pestil were determined using the static gravimetric method at 10, 20 and 30 degrees C. The overall shape of the curves was typical of sugar-rich materials. The effect of temperature on moisture content in the lower aw range was not significant (P > 0.05). Four models, namely the Brunauer, Emmet and Teller (BET), the Guggenheim, Anderson and DeBoer (GAB) the Halsey and the Oswin, were evaluated to determine the best fit for the experimental data. The BET and GAB models fitted well the data of the samples in the temperature and water activity range studied. The Clausius-Clapeyron equation was used to evaluate the isosteric heats of sorption. 相似文献