Effect of Refractance-Window RW Drying Method on Quality Criteria

The phase II design improvements targeting the commercialization of RW drying will be facilitated by prototyping and testing auxiliary and alternative product application, product conditioning, and product removal equipment. In October, fresh walnuts harvested with the green hull (Juglans regia L.) were procured Refractance Window Dryer from the Tral area of Jammu and Kashmir . The outer green hull and shell were removed before drying. The initial moisture content was determined in triplicates by the simple hot air oven method at 105 ± 2 °C. A laboratory-scale Refractance Window drying equipment was developed for drying purposes.
However, knowledge about its use and adoption remains lacking both in academic curricula and industry in the developing world. Energy efficient and with low water use, Refractance Window® drying preserves air quality in and around the drying facility because little product essence is lost. In addition, the process does not generate exhaust dust, a significant pollution problem.

In drying, aw is an important parameter as it helps in determining the quality of the product. It also plays a significant role in walnut lipid oxidation as controlled water activity decreases oxidative rancidity in walnuts. The maximum water activity was found in the sundried sample at 0.69 ± 0.015 and minimum water activity i.e. 0.32 ± 0.017 was found in RW dried sample treated at 90 °C.
Also, the thicker film results in relatively lower conductive heat transfer, which requires a longer drying time. Therefore, the unit price of thinner films is higher than that of thicker films. In other words, the use of thinner film increases the operating cost. Considering each parameter, the optimum thickness is specified as 0.25 mm.
Also, the correlation is 1 or − 1 for a perfectly positively or negatively correlated image. Correlation measures the joint probability of occurrence of pixel pairs of GLCM36. The textural feature inverse difference moment measures the texture uniformity or orderliness of an image but normalized for distance.

The cooling part is to reduce the product’s temperature below the glass transition temperature and to prevent product stickiness. Sun drying and hot air drying cause significant loss of color that make the product less appealing to consumers and can result in losses  of nutrient content and rehydration ability. •Effects of refractance window drying on process and quality properties were shown. Andrés A., Fito P., Heredia A., Rosa E.M. Combined drying technologies for development of high-quality shelf-stable mango products. Azizi D., Jafari S.M., Mirzaei H., Dehnad D. The inflluence of refractance window drying on qualitative properties of kiwifruit slices. Materials widely used in construction include new specialty plastics and stainless steel for better cleanability and longer life.
Dehydration is one of the most effective means to preserve foods in a stable and safe condition for an extended shelf life. Loss of heat sensitive nutrients and other health promoting compounds in dried foods are major concerns in the design and operation of food drying equipment. Scientific information is lacking on the operation of the Refractance Window drying process. Lipoxygenase activity is shown in Table 1 for sun-dried and RW-dried samples at different temperatures. The lipoxygenase activity was observed to increase with an increase in temperature.

Later that day, I went to an ocean beach to swim and began to think of a way to preserve these foods. After exploring several different ideas, I concluded that the most cost effective way to preserve food was to dry it. “Work done to date has demonstrated that RW dried strawberry retains more Vitamin C than freeze-drying and similar levels of Vitamin A,”​ she said. Refractance Window Drying or Drying Technology is considered as the novel fourth-generation drying technique that has been gaining much attention nowadays, owing to its numerous benefits. At MegaFood, it’s the same dilemna.
The water activity of RW and HA dried UGBF was 0.28 ± 0.05 and 0.39 ± 0.07, respectively. The RW drying showed a higher whiteness index of 90.26 ± 0.30, whereas HA drying showed 87.04 ± 0.45. The SEM analysis showed the presence of oblong and sphere-shaped starch granules with a smooth surface in the case of RW dried UGBF. The crystallinity of RW and HA dried UGBF were found to be 9.61% and 8.73%, respectively by using x-ray diffractograms. The gelatinization temperature and enthalpy of UGBF obtained by RW and HA  drying were found to be 80.92 °C and 2.05 Jg−1K−1; 75.74 °C and 2.64 Jg−1K−1, respectively.
The presence of different functional groups in UGBF was observed from FTIR analysis. The TPC, DPPH, and TFC for RW dried flour were found to be 0.85 ± 0.04 mg GAE/ g, 19.04 ± 1.03%, and 7.68 ± 0.05 µg quercetin/ g. The compressibility index and compressibility ratio of RW and HA dried UGBF are 26.49% and 1.36; 36.18% and 1.41, respectively which proves that RW dried flour has a fair flowability and intermediate cohesiveness.