Guggenheim, Anderson And De Boer Research Articles

Nutritional, functional properties and estimated shelf-life of defatted <i>Rhynchophorus phoenicis</i> (Fabricius, 1801) larvae flours

Rhynchophorus phoenicis (Fabricius, 1801) is an insect of the coleopteran family widely consumed in Africa and particularly in Cameroon. Their dehydrated larvae are rich in lipids and proteins that can help in combating malnutrition. The present work aimed at producing low-lipid content larvae flours of R. phoenicis and to determine their nutritional and functional properties as well as their estimated shelf-life. The flour was obtained by the cooking-pressing process. The shelf-life of the flour was estimated using adsorption isotherms. The results showed that the flours obtained had low lipids (8 g/100 g of flour) and high protein content (69 g/100 g of flour). Their water and oil absorption capacities, swelling power, foaming properties and foam stability make them good ingredients for food formulations. As regards of storage capacity, the adsorption isotherms obtained can be modelled by the Guggenheim-Anderson-and-de-Boer (GAB) and Brunauer-Emmett-and-Teller (BET) equations. The shelf-life was estimated at 300 days when flour is packed in polyethylene bag and stored at 20°C in enclosure with a relative humidity of 90%. In short, the cooking pressing process makes it possible to obtain flours of high nutritional and technological values. The resulting flours can be used as ingredients to fortify food with poor proteins content.

Moisture Sorption Characteristics of Weaning Food

Stickiness and caking are the significant problems for food powders due to moisture migration from the storage environment. This study was conducted to determine the moisture sorption isotherm of weaning food (Nutrilac and Superceral) and to fit the sorption data in different sorption isotherm models. Static gravimetric method was used to determine the equilibrium moisture content (EMC) at 22-89% RH at 30°C. The EMC data obtained were plotted to the models Brunauer Emmet Teller (BET), Guggenheim Anderson and De Boer (GAB). Results indicated that sorption isotherms were of type II isotherm according to Brunauer et al., (1940) classification. BET model was fitted to the sorption data with coefficient of regression 0.985 and 0.986 for Nutrilac and Supercereal respectively. The GAB model was fitted with coefficient of regression 0.983 and 0.979 for Nutrilac and Supercereal respectively. Monolayer moisture content determined from the BET and GAB model at 30°C were 1.63 and 2.24 g/100g dry matter for Nutrilac and 1.51 and 2.26 g/100g dry matter for Supercereal respectively.

Sorption isotherms of coffee in different stages for producing Turkish coffee

The aim of this research was to determine the adsorption behavior of coffee as green and roasted beans and ground. For this aim, the static gravimetric method was used and samples were kept in the different water activity levels between 0.01 and 0.91 at 25°C for 7 days. The data were evaluated using the BET (Brunauer-Emmett-Teller), GAB (Guggenheim, Anderson and deBoer), Halsey, and Peleg sorption equations. The constants m0 and C of BET and GAB equations were determined to be between 2.13 and 6.61 g water/100 g of dry matter and 30.05–429.60, respectively. The isotherms of all coffee samples were defined as Type II because the C constant of the GAB equation was higher than 2. Additionally; the BET, GAB, and Peleg equations were determined to fit better than the Halsey for adsorption properties of coffee because E% values were lower than 10% and the coefficient of regression values approached the 1.00. Practical applications The obtained results with that research could be useful for understanding the physicochemical relationship between water and dry matter of coffee. Because this relationship is quite important in foods that have easily changing characteristics and quality like coffee, and determination of their sorption characteristics ensures maintaining the physical, chemical, biochemical, and microbiological quality stability of food during processing, packaging, and storage.

Moisture sorption characteristics of food powders containing freeze dried avocado, maltodextrin and inulin

Moisture adsorption isotherms of the freeze-dried powders containing avocado, maltodextrin and inulin with different ratio, were determined using gravimetric static method of saturated salt solutions at 25 °C and the range of the water activity from 0.11 to 0.86. The data obtained were evaluated using sorption models: BET (Brunauer-Emmett-Teller), GAB (Guggenheim, Anderson and deBoer), Peleg, Lewicki, Oswin and Henderson. The goodness of the fit evaluated on the basis of criteria such as coefficient of the determination and root mean square values. Sorption isotherm of the pure avocado powder was III type while curves plotted for others powders showed sigmoid shape. It was found that the Peleg model was the most adequate for representation of the sorption data of all analyzed blends. In order to characterize the research material, chemical composition of the edible part of the avocado fruit was determined. Main component of the dry matter was fat.

Quality properties and adsorption behavior of freeze-dried beef meat from the Biceps femoris and Semimembranosus muscles

The aim of this research was to determine the quality properties and adsorption behavior of freeze-dried beef meat from the Biceps femoris and Semimembranosus muscles. Most quality properties of both muscles were similar apart from total fat content. Freeze-dried meat pieces were kept in ten different equilibrium levels of relative humidity (2.0–97.3%) at 5, 15, 25 and 30°C. The experimental data were evaluated using BET (Brunauer-Emmett-Teller) and GAB (Guggenheim, Anderson and deBoer) models. The equilibrium moisture contents of freeze-dried Biceps femoris were lower than those of Semimembranosus at all water activities and temperature. The constants m0 and C of BET and GAB equations were determined to be between 6.27 and 8.07g/100g dry matter and 9.32–13.73, respectively. Constant k was about 0.90 at all temperatures, and the GAB equation exhibited a better fit to the experimental data of both muscles as a result of all %E values being approximately equal to 10%.

Acceleration of mass transfer rates in osmotic dehydration of elephant foot yam (Amorphophallus paeoniifolius) applying pulsed-microwave-vacuum

Abstract The elephant foot yam slices were processed with combined pulsed-microwave-vacuum osmotic drying. Osmotic dehydration at ambient (28 °C and 45% RH) was carried out using different levels of sucrose concentration (30, 40, 50 and 60% w/w), salt concentration (5, 7.5, 10 and 12.5% w/w) and dehydration time (10, 20, 30, 50, 70, 90 and 120 min). During the osmotic dehydration, pulsed microwave vacuum (15 kPa pressure, 1 W/g power density and 1.853 pulsating ratio) was maintained for 2 min over the sample and solution to enhance the mass transfer. For this purpose, the osmotic dehydration experiments were conducted in the microwave-vacuum cavity. Azuara model predicted the moisture loss and solid gain by elephant foot yam slices during osmosis. It was observed that both the moisture loss and the solid gain increased with increasing concentration of the osmotic solution. The optimum conditions found in the process were 40% w/w sucrose concentration, 6% w/w salt concentration and 70 min osmotic dehydration time, resulting in to 42.80% moisture loss (initial weight) and 14.65% solid gain (initial weight). Further, samples were dried using microwave vacuum dryer up to moisture content of 5–6% d.b. by varying microwave power density (2, 4, 6 and 8 W/g) and pulsating ratio (1.312, 1.625, 1.983 and 2.250). Page model was fitted to the data to study the microwave vacuum drying kinetics. The microwave vacuum drying at 1.625 pulsating ratio with microwave power density 4 W/g yielded a product with the highest overall acceptability score. Guggenheim, Anderson and deBoer (GAB) model was used in the study of the sorption behavior of dehydrated elephant foot yam and shelf life prediction. Industrial relevance The production of elephant foot yam in India and South East Asia is comparatively higher than other vegetables. Although, it is nutritious product and good source of energy, food industries are not interested to process elephant foot yam using a time consuming traditional osmotic dehydration process followed by hot air drying. Therefore, present research work was undertaken from industry suggestion to develop accelerated osmotic dehydration process for elephant foot yam using novel pulsed-microwave-vacuum combination followed by finish drying by microwave-vacuum. This research has been carried out to decrease industrial processing time, energy consumption and improving quality of the product. Industry will start adopting this new hybrid process of drying elephant foot yam on large scale.

Adsorption behaviour of bulgur

The aim of this research was to determine the adsorption behaviour of bulgur. Three different particle sizes (2<coarse<3.5, 1.6<medium<3.0, 0.5<fine<2.0mm) of bulgur, purchased from market, were kept in nine different equilibrium levels of relative humidity (8.2–97.3%) at 20, 30 and 40°C. The data obtained were evaluated using BET (Brunauer–Emmett–Teller) and GAB (Guggenheim, Anderson and deBoer) sorption equations. The equilibrium moisture content of bulgur increased both with decreasing temperature and bulgur size. The constants m0 and C of BET and GAB equations were determined to be between 2.54 and 5.03g water per 100g of dry matter and 4.96–16.57, respectively. Constant k was between 0.85 and 0.93, and GAB equation was determined to fit very well for bulgur adsorption, because of %E values lower than 10%. Bulgur must be stored below 70% relative humidity and with less than 10g water per 100g of dry mater.

Sorption of vapours and liquids in PDMS: novel data and analysis with the GAB model of multilayer adsorption

Novel data on the sorption of vapours and liquids in cross-linked poly(dimethylsiloxane) (PDMS) elastomer at 25–40°C are reported together with the accurate and original way of parameterising the sorption isotherms by using the GAB (Guggenheim, Anderson and De Boer) model of multilayer adsorption. The GAB model has been found to provide acomparable or better representation of sorption isotherms than the Flory–Huggins model with a concentration-dependent interaction parameter and better than the ENSIC (Engaged Species Induced Clustering) model. This comparison holds true for poor solvents of PDMS (water, methanol), mild solvents (acetone, methyl acetate, dimethyl carbonate) and good solvents (tert-butyl methyl ether, tert-amyl methyl ether, cyclopentyl methyl ether). The GAB model provided anoticeably good assessment of the sorption of liquids and highly saturated vapours, which makes the model applicable within the entire activity range.

Selection of Fitting Models of the Moisture Content for Paper Honeycomb Sandwich Panel

The influence of temperature and relative humidity on the moisture content of paper honeycomb sandwich panels was studied. The moisture content of paper honeycomb sandwich panels was fitted by three mathematical models. The fitting results were evaluated by experimental data, and the best fitting model and its parameters were determined. The results indicate that in three models, the GAB (Guggenheim, Anderson and De Boer) model is the best suited to predict the moisture content of paper honeycomb sandwich panels in different temperature and humidity conditions.

Kinetic Study of Convective Drying of Blueberry Variety O’neil (Vaccinium corymbosum L.)

The aim of this research was to study and to model the drying kinetics of the blueberry (Vaccinium corymbosum L.) at three temperatures (60, 70 and 80 oC) with an airflow of 2.0 ± 0.2 m s -1. Modeling of the desorption isotherm was carried out with the GAB (Guggenheim, Anderson and de Boer) equation, showing a good fit to experimental moisture data, giving as a result a monolayer moisture level of 0.084 g water g-1 dm. Newton, Henderson-Pabis, Page, Modified Page and Logarithmic mathematical models were applied in the study and in the modeling of the drying kinetics of this fruit. Kinetic parameters k of each model showed dependence on temperature, and were evaluated by an Arrhenius-type equation, with an activation energy of between 36.2 and 54.5 kJ mol-1. Logarithmic and Modified Page models gave the best fits for each drying curve, based on the statistical test determination coefficient, sum square error, root mean sum errors and Chi-square. In consequence, both models are excellent tools for estimating the drying time of this product.

Desorption isotherms and isosteric heat of desorption of previously frozen raw pork meat

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.

Moisture sorption isotherms of grape pestil and foamed grape pestil.

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.

DRYING OF CLAY. I MATERIAL CHARACTERISTICS

ABSTRACT In this study, one got involved in the thermodynamic characterization of two types of clay to be dried. It concerns the determination of the chemical composition through X-ray diffraction, index of plasticity, volumic mass and especially the determination of the sorption isotherms of water vapor on these products at three different temperatures 30, 50 and 70°C. The isosteric enthalpy of adsorption is calculated by the Clapeyron equation it varies from 0 to 2 kJ/mol for Tunisian clay G, and from 0 to 3 kJ/mol for French clay R. Four models provided by the literature i.e., Chung-Pfost, Henderson, Halsey and Guggenheim-Anderson and de Boer (GAB) have been tested and evaluated (correlation factor, standard deviation) to determine the best possible fitting, allowing for the interpolation of experimental results. From the comparison of the results, one noticed that both the Henderson and the GAB models perfectly described the experimental measures for the two types of clay with factors of correlation situated around one and standard deviations tending towards zero. This set of characterizations will allow us at a later stage to understand the drying process of these two types of clay.

Moisture Adsorption Behaviour of Pasta Products

The moisture sorption isotherms of conventional (from 100% durum wheat semolina) and diet (high protein) spaghetti were constructed at 22, 30, 37 and 45°C, using a computerized inverse gas chromatographic method (CIGC). Conventional spaghetti exhibited a higher sorption capacity than diet spaghetti. This is attributed to the higher carbohydrate content of conventional spaghetti as compared to diet spaghetti. Good agreement was observed between moisture sorption isotherms obtained from the CIGC method and the gravimetric static method. BET (Brunauer, Emmett and Teller), GAB (Guggenheim, Anderson and De Boer) and 'Local' isotherm models were tested to fit the experimental sorption data. Goodness of fit, standard deviation and the applicable range of water activity (a w) indicated that GAB and 'Local' isotherm models could explain the data well over a wide a w range up to 0.80.