The Experts below are selected from a list of 46473 Experts worldwide ranked by ideXlab platform
L Van Campenhout - One of the best experts on this subject based on the ideXlab platform.
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suitability of Microwave Drying for mealworms tenebrio molitor as alternative to freeze Drying impact on nutritional quality and colour
Food Chemistry, 2018Co-Authors: Silvia Lenaerts, M Van Der Borght, A Callens, L Van CampenhoutAbstract:Abstract Freeze Drying represents the current practice to stabilize mealworms, even though it is an energy demanding technique. Therefore, it was examined in the present study whether Microwave Drying could be a proper alternative. To this end, the impact of both Drying techniques on the proximate composition, vitamin B12 content, fatty acid profile, oxidation status and colour parameters of mealworms was investigated. Furthermore, the influence of the application of vacuum during Microwave Drying was studied. The different Drying technologies resulted in small differences in the proximate composition, while the vitamin B12 content was only reduced by Microwave Drying. The fat fraction of freeze dried mealworms showed a higher oxidation status than the fat of Microwave dried mealworms. Application of a vacuum during the Microwave Drying process did not appear to offer advantages. This research shows that for mealworms Microwave Drying can be a proper alternative to freeze Drying.
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effect of blanching followed by refrigerated storage or industrial Microwave Drying on the microbial load of yellow mealworm larvae tenebrio molitor
Food Control, 2017Co-Authors: D Vandeweyer, A Callens, Silvia Lenaerts, L Van CampenhoutAbstract:Yellow mealworm larvae (Tenebrio molitor) are being introduced into Western food products. The effect of blanching, followed by either chilled storage or industrial Microwave Drying, on microbial counts of the larvae was investigated. Whatever time applied (10, 20 or 40 s), considerable log reductions were obtained after blanching (total viable count, Enterobacteriaceae, lactic acid bacteria, yeasts and molds and psychrotrophs), except for aerobic endospores. No major growth was observed during subsequent chilled storage for 6 days. Total viable counts were below 3.5 ± 0.3 log cfu/g for all samples. When blanching for 40 s was followed by industrial Microwave Drying, Drying for 8, 10 or 13 min did not yield larvae with a water activity below 0.60, which is necessary to eliminate all microbial growth. Drying times of 16 or 20 min yielded average water activities of 0.16 and 0.23, respectively. The number of vegetative cells was reduced to a large extent by blanching plus Drying, but the number of bacterial endospores only slightly. Total viable counts were maximally 3.4 ± 0.8 log cfu/g for all samples. Bacterial endospores were the most resistant to the processing technologies investigated.
Juming Tang - One of the best experts on this subject based on the ideXlab platform.
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Microwave Drying of Food and Agricultural Materials: Basics and Heat and Mass Transfer Modeling
Food Engineering Reviews, 2012Co-Authors: Hao Feng, Yun Yin, Juming TangAbstract:Microwave Drying is based on a unique volumetric heating mode facilitated by electromagnetic radiation at 915 or 2,450 MHz. The responses of a lossy food product to dielectric heating result in rapid energy coupling into the moisture and lead to fast heating and Drying. A significant reduction in Drying time in Microwave Drying is often accompanied by an improvement in product quality, making it a promising food dehydration technology. The need for improvement in engineering design and process optimization for Microwave Drying has stimulated the development of computer simulation techniques to predict temperature and moisture history and distribution in the product to be dried. In this article, we present the basics of dielectric heating and Drying, examine the heat and mass transfer models developed for the simulation of Microwave Drying processes, and discuss dielectric properties of selected food products as influenced by moisture, temperature, and porosity. In addition, we analyze nonuniform heating caused by the geometry and composition of the product, as well as by the nonuniform distribution of electromagnetic field in a Microwave cavity, followed by a discussion on how to improve the Microwave heating uniformity. We focus the discussion on heat and mass transfer models developed over the years to simulate Microwave Drying, including simplified ones, those based on diffusion theory, and coupled heat and mass transfer analysis with the Philip and de Vries theory, Luikov scheme, Whitaker method, and two-region model. In the end, the determination of the heat source term in the energy equation, numerical schemes used to solve the partial differential equations, and the model validation are also discussed.
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studies on different combined Microwave Drying of carrot pieces
International Journal of Food Science and Technology, 2010Co-Authors: Mi Zhang, Luelue Huang, Juming Tang, Aru S MujumdaAbstract:Summary Three different combined Microwave (MW) Drying methods were compared, namely Microwave-assisted vacuum Drying (MWVD), Microwave-assisted freeze Drying (MWFD), Microwave-enhanced spouted bed Drying (MWSD), in terms of Drying rate, Drying uniformity, product colour, rehydration ratio, retention of β-carotene and vitamin C, and energy consumption. The Drying rate of MWVD and MWSD were much faster than that of MWFD. The largest Drying rate was obtained in MWSD with 3.5 W g−1. In general, the colour of MWSD products was very uniform. Rehydration ratio of MWFD carrot pieces was almost the same as the freeze-dried (FD) products and better than MWVD and MWSD products. In addition, the highest retention of carotene and vitamin C was observed in MWFD carrot pieces. No significant differences were observed in carotene and vitamin C between MWVD and MWSD products. However, the energy consumption in MWFD was the highest.
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Microwave finish Drying of diced apples in a spouted bed
Journal of Food Science, 2006Co-Authors: Hao Feng, Juming TangAbstract:The combination of a spouted bed with Microwave heating to improve heating uniformity was evaluated. Experiments were performed on a laboratory system in which evaporated diced apples of about 24% moisture were dried to about 5% at 70°C air temperature using four levels of Microwave power density (0 to 6.1 W/g). With the combination method, temperature uniformity in diced apples was greatly improved as compared to that with a stationary bed during Microwave Drying. Products had less discoloration and higher rehydration rates as compared to conventional hot air Drying or spouted bed (SB) Drying. Drying time could be reduced by >80% compared with SB Drying without Microwave heating.
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dielectric properties of dehydrated apples as affected by moisture and temperature
Transactions of the ASABE, 2002Co-Authors: Hao Feng, Juming Tang, R P CavalieriAbstract:Dielectric properties directly influence Microwave Drying characteristics of food products. A knowledge of dielectric properties of foods as a function of moisture content and temperature is essential in the design and control of Microwave Drying systems. Dielectric constant and loss factor of Red Delicious apples (Malus domestica Borkh.) were measured over a moisture content range of 4% to 87.5% at 22 C and 60 C. At high moisture content (>70%), free water dispersion and ionic conduction accounted for the dielectric behavior. At medium moisture ( 23%), ionic conduction played a major role. At low moisture contents ( 4%), bound water accounted for the major dispersion mechanism. A decrease in moisture content resulted in a decrease in and . Based on this study, we expect a strong moisture leveling effect when Drying apples from 50% to 4% at elevated temperatures in 915 MHz or 2.45 GHz Microwave Drying systems.
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heat and mass transport in Microwave Drying of porous materials in a spouted bed
Aiche Journal, 2001Co-Authors: Hao Feng, Juming Tang, R P Cavalieri, O A PlumbAbstract:A heat- and mass-transfer model was developed to simulate Microwave and spouted-bed combined (MWSB) Drying of diced apples, a hygroscopic porous material. A total gas-pressure equation was introduced to take into account internal vapor generation during Microwave Drying. The governing equations for heat and mass transfer were simplified using a scaling technique and numerically solved with the finite difference method. The physical, thermodynamic, thermal, transport and dielectric properties used in the simulation were either from our measurements or from the literature. Model predictions agreed well with experimental results. The pressure-driven moisture migration during MWSB Drying resulted in a high Drying rate. The numerical analysis predicted a temperature-leveling effect that was confirmed by experimental results. The unique temperature leveling in MWSB Drying helps to control product temperature and improves product quality as compared to Microwave-assisted fixed-bed hot-air Drying methods.
Christine H Scaman - One of the best experts on this subject based on the ideXlab platform.
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flavor and texture of banana chips dried by combinations of hot air vacuum and Microwave processing
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Winnie W Y Mui, Timothy D Durance, Christine H ScamanAbstract:The behavior of 16 volatile compounds of banana during a combination of air-Drying (AD) and vacuum Microwave-Drying (VMD) of banana chips was characterized. Samples were AD to remove 60, 70, 80, or 90% of moisture (wet basis) and then subjected to VMD to achieve a final moisture content of 3% (dry basis). Banana slices were also dehydrated using only AD, VMD, and freeze-Drying (FD) for comparison. Samples that underwent more VMD had significantly lower levels of volatile compounds, which is attributed to the decreased formation of an impermeable solute layer on the surface of the chips. High values for water solubility and relative volatility of compounds correlated with losses during VMD; however, additional factors appear to influence the behavior of compounds during VMD processing. The optimal process of 90%AD/10%VMD yielded crisper banana chips with significantly higher volatile levels and sensory ratings than AD chips. Keywords: Vacuum Microwave; dehydration; air-Drying; banana chips; flavor volatile...
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characterization of vacuum Microwave air and freeze dried carrot slices
Food Research International, 1998Co-Authors: Tein M Lin, Timothy D Durance, Christine H ScamanAbstract:Vacuum Microwave Drying of carrot slices was compared to air Drying and freeze Drying on the basis of rehydration potential, color, density, nutritional value, and textural properties. Vacuum Microwave dried (VMD) carrot slices had higher rehydration potential, higher α-carotene and vitamin C content, lower density, and softer texture than those prepared by air Drying. Carrot slices that were air dried (AD) were darker, and had less red and yellow hues. Less color deterioration occurred when vacuum-Microwave Drying was applied. Although freeze Drying of carrot slices yielded a product with improved rehydration potential, appearance, and nutrient retention, the VMD carrot slices were rated as equal to or better than freeze dried (FD) samples by a sensory panel for color, texture, flavor and overall preference, in both the dry and rehydrated state.
Hao Feng - One of the best experts on this subject based on the ideXlab platform.
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Microwave Drying of Food and Agricultural Materials: Basics and Heat and Mass Transfer Modeling
Food Engineering Reviews, 2012Co-Authors: Hao Feng, Yun Yin, Juming TangAbstract:Microwave Drying is based on a unique volumetric heating mode facilitated by electromagnetic radiation at 915 or 2,450 MHz. The responses of a lossy food product to dielectric heating result in rapid energy coupling into the moisture and lead to fast heating and Drying. A significant reduction in Drying time in Microwave Drying is often accompanied by an improvement in product quality, making it a promising food dehydration technology. The need for improvement in engineering design and process optimization for Microwave Drying has stimulated the development of computer simulation techniques to predict temperature and moisture history and distribution in the product to be dried. In this article, we present the basics of dielectric heating and Drying, examine the heat and mass transfer models developed for the simulation of Microwave Drying processes, and discuss dielectric properties of selected food products as influenced by moisture, temperature, and porosity. In addition, we analyze nonuniform heating caused by the geometry and composition of the product, as well as by the nonuniform distribution of electromagnetic field in a Microwave cavity, followed by a discussion on how to improve the Microwave heating uniformity. We focus the discussion on heat and mass transfer models developed over the years to simulate Microwave Drying, including simplified ones, those based on diffusion theory, and coupled heat and mass transfer analysis with the Philip and de Vries theory, Luikov scheme, Whitaker method, and two-region model. In the end, the determination of the heat source term in the energy equation, numerical schemes used to solve the partial differential equations, and the model validation are also discussed.
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Microwave finish Drying of diced apples in a spouted bed
Journal of Food Science, 2006Co-Authors: Hao Feng, Juming TangAbstract:The combination of a spouted bed with Microwave heating to improve heating uniformity was evaluated. Experiments were performed on a laboratory system in which evaporated diced apples of about 24% moisture were dried to about 5% at 70°C air temperature using four levels of Microwave power density (0 to 6.1 W/g). With the combination method, temperature uniformity in diced apples was greatly improved as compared to that with a stationary bed during Microwave Drying. Products had less discoloration and higher rehydration rates as compared to conventional hot air Drying or spouted bed (SB) Drying. Drying time could be reduced by >80% compared with SB Drying without Microwave heating.
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dielectric properties of dehydrated apples as affected by moisture and temperature
Transactions of the ASABE, 2002Co-Authors: Hao Feng, Juming Tang, R P CavalieriAbstract:Dielectric properties directly influence Microwave Drying characteristics of food products. A knowledge of dielectric properties of foods as a function of moisture content and temperature is essential in the design and control of Microwave Drying systems. Dielectric constant and loss factor of Red Delicious apples (Malus domestica Borkh.) were measured over a moisture content range of 4% to 87.5% at 22 C and 60 C. At high moisture content (>70%), free water dispersion and ionic conduction accounted for the dielectric behavior. At medium moisture ( 23%), ionic conduction played a major role. At low moisture contents ( 4%), bound water accounted for the major dispersion mechanism. A decrease in moisture content resulted in a decrease in and . Based on this study, we expect a strong moisture leveling effect when Drying apples from 50% to 4% at elevated temperatures in 915 MHz or 2.45 GHz Microwave Drying systems.
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heat and mass transport in Microwave Drying of porous materials in a spouted bed
Aiche Journal, 2001Co-Authors: Hao Feng, Juming Tang, R P Cavalieri, O A PlumbAbstract:A heat- and mass-transfer model was developed to simulate Microwave and spouted-bed combined (MWSB) Drying of diced apples, a hygroscopic porous material. A total gas-pressure equation was introduced to take into account internal vapor generation during Microwave Drying. The governing equations for heat and mass transfer were simplified using a scaling technique and numerically solved with the finite difference method. The physical, thermodynamic, thermal, transport and dielectric properties used in the simulation were either from our measurements or from the literature. Model predictions agreed well with experimental results. The pressure-driven moisture migration during MWSB Drying resulted in a high Drying rate. The numerical analysis predicted a temperature-leveling effect that was confirmed by experimental results. The unique temperature leveling in MWSB Drying helps to control product temperature and improves product quality as compared to Microwave-assisted fixed-bed hot-air Drying methods.
Wioletta Laszczak - One of the best experts on this subject based on the ideXlab platform.
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effect of Drying conditions on the quality of vacuum Microwave dried potato cubes
Journal of Food Engineering, 2007Co-Authors: Joanna Ondaruk, Marek Markowski, Wioletta LaszczakAbstract:Abstract The influence of Drying conditions on the color, starch content, sugar content, mechanical properties and microstructure of dried potatoes was studied. Statistically significant differences between the color of raw and dried materials were observed for every Drying methods. It was observed that the vacuum-Microwave Drying technique prevents color damage during Drying. Potato cubes dried in a vacuum-Microwave oven had lower starch and total sugar losses than those dried under forced convection conditions. The maximum force values obtained from compression tests indicated statistical differences between samples dried in a Microwave-vacuum drier and a convection drier. The averaged force and energy required to cause 3 and 5.5 mm deformation were the highest for blanched and hot-air dried (70 °C) potato cubes, and the lowest for vacuum-Microwave dried material (24 kPa). The application of Microwave energy led to different physical changes in product microstructure, compared to those observed during hot-air Drying. The extent of changes was depended on the method and parameters of Drying. In both cases the Drying process caused deformation and disintegration of cell walls and starch granules. Experiments show that in the case of hot-air Drying the intensity of structural changes depends on Drying temperature. A higher temperature causes greater damage to the microstructure of potato cubes. Microwave Drying at 24 kPa ensured the shortest Drying time and the best overall quality of dried potato cubes, and thus was chosen as the most appropriate technique for potato Drying.