Refractance Window Dryer
Vegar-Mercado, Gongora-Nieto and have grouped these drying methods into four generations noting that the latest developments in drying have produced drying technologies that fall in the fourth generation. Also opined that the fourth generation drying techniques give food products with greater retention of Refractance Window Dryer food quality and they include microwave drying, infrared drying, Refractance Window drying etc. Changes in color, glass transition, specific heat, and surface morphology of the dried fruits were also evaluated. The quality retention in the dried fruits was found to be product and drying method specific.
The “window” aspect of the transparent sheet allows infrared energy from the hot water to pass rapidly and directly into the slurry. Heat is also conducted through the belt, which helps to evaporate moisture in the product. Evaporate is carried away by mechanically boosted airflow. The transfer of infrared energy through the transparent sheet slows as the product loses moisture, creating a controlled drying process that retains nutrition, flavor, color and aroma. Ascorbic acid is an important vitamin and an essential nutrient for humans and some animal species. It is found in many fruits and vegetables but it is very sensitive to heat and oxidation (Burdurlu, Koca, & Karadeniz, 2006).
The dryer had an evaporation rate of 4.63 × 10–4kg/s and 4.25 × 10–4kg/s, the energy of evaporation of 1.05 kW and 0.96 kW and thermal energy efficiency of 25.64% and 21.73% while drying tomato and mango pulps, respectively. Dryer throughput of 0.6 kg/h of dried mango Pulp and 0.47 kg/h of dried tomato pulp was obtained. Phenols are important antioxidant compounds and have much stronger antioxidant activities than other nutrient compounds . The sun-dried sample showed 1155 ± 2.88 mgGAE/100 g. Here the increasing trend was observed with an increase in temperature in the RW dryer as shown in Table 1.
Rapid, efficient and economical industrial scale infrared assisted refractance window dryer for high quality foods, pharmaceuticals and chemicals. As the moisture decreases in the product, the window gradually closes and the transmission of thermal radiation decreases. The material is prevented from reaching the water bath (95-97° C) temperatures with the close of the window. RWD system uses circulating water molecules at 95-97°C and at atmospheric pressure to provide heat transfer to the product, and the product temperatures generally remain below 70°C. Although several commercial drying methods have been developed over time, none have previously been able to provide high quality yet economical products. This is a large-volume drum type dryer, and is suitable for drying a wide range of feed products and animal protein materials.
Only temperature had a significant impact on water activity pattern value also significantly affected aw (pS1 of Supplementary file shows the equations describing water activity pattern for each formulation. The analysis of microstructure of flakes was performed using a scanning electron microscope (Phenom Pro, Cecoltec Ltda, Bogotá, Colombia) at an acceleration voltage of 5 kV. The samples of 2 mm wide were placed on the scanning electron microscope slides with the aid of colloidal silver and a magnification of 4000x was used for the analysis. Water activity was checked by using a water activity meter . The water activity was measured at room temperature (24 ± 2 °C) in triplicates and the instrument was calibrated with the supplied calibration kit before the measurements. Moisture content was determined by the AOAC method.
There was no significant difference in browning index between freeze-died and RW-died samples (A. Topuz, Dincer, Ozdemir, Feng, & Kushad, 2011; Ayhan Topuz, Feng, & Kushad, 2009). This study emphasised the relationship between drying temperature and aw, as increasing the drying temperature led to a reduction in the flakes’ aw; this could have been related to the fact that more water would have been evaporated at higher temperatures43. However, no mention was found in the pertinent literature of variation concerning drying temperature and its effect on aw, as most studies compare RW with other drying methods at a single temperature or vary drying times or sample thickness. The development of off-flavor is one of the major problems during storage which make food unacceptable.
When RW drying of the sample was done at 90 °C and 50 °C, the maximum and minimum lipoxygenase activity were discovered in the sample, which is 0.098 ± 0.013 µkatal and 0.065 ± 0.015 µkatal, respectively. There was no significant difference value found among RW dried sample. However, compared to RW (50, 60 and 70 °C) sample, lipoxygenase activity was significantly higher in sun dried sample. The sun-dried samples showed maximum lipoxygenase activity of 0.134 ± 0.011 µkatal.
Planning for this upkeep is crucial to keep production flowing and avoid unplanned downtime. She added that the dryer is easily cleaned by simply removing and washing certain components and by washing others in place. According to Bolland-Magoon, the company received a grant in 1998 from Washington Technology Center to work with Washington State University to document qualitative aspects of RW drying. Fruits and vegetables play an important role in the diet of human beings and economic development of a country. They are cheapest and most available sources of important proteins, vitamins, minerals and essential amino acids. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
InfraRWD dryers are designed and produced by NFDS Arge in Turkey. The aim of this research was to study the use of Refractance window™ (RW™) in the dehydration of salmon , beef , and apples through the analysis of the effective diffusivity determined through the Fick's model and the anomalous model. Abonyi B.I., Feng H., Tang J., Edwards C., Chew B., Mattinson D., Fellman J. Quality retention in strawberry and carrot purees dried with Refractance WindowTM system. Babalis S.J., Belessiotis V.G. Influence of the drying conditions on the drying constants and moisture diffusivity during the thin-layer drying of figs. Ochoa-Martínez C., Quintero P., Ayala A., Ortiz J. Drying characteristics of mango slices using the Refractance WindowTM technique. Krokida M.K., Maroulis Z.B. Structural properties of dehydrated products during rehydration.
However, the drying process affects the characteristics of foods, including taste, texture, and appearance. Moreover, certain drying techniques result in the occurrence of browning, caramelization, and a loss of flavor and volatile compounds. There are many types of drying methods used in the food industry, such as solar, hot air, spray drying, microwave, osmotic dehydration, spouted bed, ultrasound, microwave, electrohydrodynamic, and freeze drying.
The “window” aspect of the transparent sheet allows infrared energy from the hot water to pass rapidly and directly into the slurry. Heat is also conducted through the belt, which helps to evaporate moisture in the product. Evaporate is carried away by mechanically boosted airflow. The transfer of infrared energy through the transparent sheet slows as the product loses moisture, creating a controlled drying process that retains nutrition, flavor, color and aroma. Ascorbic acid is an important vitamin and an essential nutrient for humans and some animal species. It is found in many fruits and vegetables but it is very sensitive to heat and oxidation (Burdurlu, Koca, & Karadeniz, 2006).
The dryer had an evaporation rate of 4.63 × 10–4kg/s and 4.25 × 10–4kg/s, the energy of evaporation of 1.05 kW and 0.96 kW and thermal energy efficiency of 25.64% and 21.73% while drying tomato and mango pulps, respectively. Dryer throughput of 0.6 kg/h of dried mango Pulp and 0.47 kg/h of dried tomato pulp was obtained. Phenols are important antioxidant compounds and have much stronger antioxidant activities than other nutrient compounds . The sun-dried sample showed 1155 ± 2.88 mgGAE/100 g. Here the increasing trend was observed with an increase in temperature in the RW dryer as shown in Table 1.
Rapid, efficient and economical industrial scale infrared assisted refractance window dryer for high quality foods, pharmaceuticals and chemicals. As the moisture decreases in the product, the window gradually closes and the transmission of thermal radiation decreases. The material is prevented from reaching the water bath (95-97° C) temperatures with the close of the window. RWD system uses circulating water molecules at 95-97°C and at atmospheric pressure to provide heat transfer to the product, and the product temperatures generally remain below 70°C. Although several commercial drying methods have been developed over time, none have previously been able to provide high quality yet economical products. This is a large-volume drum type dryer, and is suitable for drying a wide range of feed products and animal protein materials.
Only temperature had a significant impact on water activity pattern value also significantly affected aw (pS1 of Supplementary file shows the equations describing water activity pattern for each formulation. The analysis of microstructure of flakes was performed using a scanning electron microscope (Phenom Pro, Cecoltec Ltda, Bogotá, Colombia) at an acceleration voltage of 5 kV. The samples of 2 mm wide were placed on the scanning electron microscope slides with the aid of colloidal silver and a magnification of 4000x was used for the analysis. Water activity was checked by using a water activity meter . The water activity was measured at room temperature (24 ± 2 °C) in triplicates and the instrument was calibrated with the supplied calibration kit before the measurements. Moisture content was determined by the AOAC method.
There was no significant difference in browning index between freeze-died and RW-died samples (A. Topuz, Dincer, Ozdemir, Feng, & Kushad, 2011; Ayhan Topuz, Feng, & Kushad, 2009). This study emphasised the relationship between drying temperature and aw, as increasing the drying temperature led to a reduction in the flakes’ aw; this could have been related to the fact that more water would have been evaporated at higher temperatures43. However, no mention was found in the pertinent literature of variation concerning drying temperature and its effect on aw, as most studies compare RW with other drying methods at a single temperature or vary drying times or sample thickness. The development of off-flavor is one of the major problems during storage which make food unacceptable.
When RW drying of the sample was done at 90 °C and 50 °C, the maximum and minimum lipoxygenase activity were discovered in the sample, which is 0.098 ± 0.013 µkatal and 0.065 ± 0.015 µkatal, respectively. There was no significant difference value found among RW dried sample. However, compared to RW (50, 60 and 70 °C) sample, lipoxygenase activity was significantly higher in sun dried sample. The sun-dried samples showed maximum lipoxygenase activity of 0.134 ± 0.011 µkatal.
Planning for this upkeep is crucial to keep production flowing and avoid unplanned downtime. She added that the dryer is easily cleaned by simply removing and washing certain components and by washing others in place. According to Bolland-Magoon, the company received a grant in 1998 from Washington Technology Center to work with Washington State University to document qualitative aspects of RW drying. Fruits and vegetables play an important role in the diet of human beings and economic development of a country. They are cheapest and most available sources of important proteins, vitamins, minerals and essential amino acids. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
InfraRWD dryers are designed and produced by NFDS Arge in Turkey. The aim of this research was to study the use of Refractance window™ (RW™) in the dehydration of salmon , beef , and apples through the analysis of the effective diffusivity determined through the Fick's model and the anomalous model. Abonyi B.I., Feng H., Tang J., Edwards C., Chew B., Mattinson D., Fellman J. Quality retention in strawberry and carrot purees dried with Refractance WindowTM system. Babalis S.J., Belessiotis V.G. Influence of the drying conditions on the drying constants and moisture diffusivity during the thin-layer drying of figs. Ochoa-Martínez C., Quintero P., Ayala A., Ortiz J. Drying characteristics of mango slices using the Refractance WindowTM technique. Krokida M.K., Maroulis Z.B. Structural properties of dehydrated products during rehydration.
However, the drying process affects the characteristics of foods, including taste, texture, and appearance. Moreover, certain drying techniques result in the occurrence of browning, caramelization, and a loss of flavor and volatile compounds. There are many types of drying methods used in the food industry, such as solar, hot air, spray drying, microwave, osmotic dehydration, spouted bed, ultrasound, microwave, electrohydrodynamic, and freeze drying.
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