A great number of empirical and semi-empirical equations have been used to describe the dehydration kinetics of biological materials . Table 5 lists the dehydration kinetic equations used herein, where k, n, A and B are the model parameters. The best equation was selected based on a statistical analysis considering the correlation coefficient, the significance of parameters, and the distribution of residues . & Prasad, S. Drying kinetics and rehydration characteristics of microwave-vacuum and convective hot-air dried mushrooms. Zalpouri, R., Kaur, P. & Sain, M. Refractive window drying- A better approach to preserve the visual appearance of dried products.
The diffusion coefficient was higher when not considering shrinkage. These findings show that the RW™ technique is highly suitable for papaya drying; it makes it possible to dry the product reaching a Enhancing Food Processing: Refractance Window Dryer's Role in Nutrient Preservation low moisture content in shorter times, reducing the aw to values below 0.4 and preserving a similar color. This drying technology totally depends on Mylar film, which is the heart of this technology.

Microscopic structure and solubility is an important characteristic of fruit powders which were significantly affected by the drying process employed (Caparino et al. 2012; Celli et al. 2016). The present study was conducted to determine the physical and microbiological properties of yoghurt powders produced by RW drying, under different conditions, compared with freeze drying. Results showed that flowability, cohesiveness, wettability and solubility values were better in the powder samples produced by RW drying than those produced by freeze drying. However, slight browning occurred in RW-dried yoghurt samples due to the sensitivity of yoghurt to high temperatures during drying. Nevertheless, RW™ drying utilizes hot water (95–97 °C) to decrease the moisture content of the material, it is mentioned as a gentle drying treatment as the material temperature not rise beyond 80 °C (Nindo, Feng, Shen, Tang, & Kang, 2003).
The spectra were corrected for baseline in the region of 400–4000 cm−1 using Origin 2022b software . These window dryers help to keep your room organized and dries quickly. Refractance window dryers are a simple way to cool the air inside of the home, and they maintain a low amount of air inside of the room.
These compounds interact with amino groups from proteins and undergo Maillard reaction during the exposition to air at high temperatures, long drying times and the amount of water. In addition, color changes appear due the degradation of some thermosensitive compounds such as anthocyanins and carotenes, which results in a loss of functionality and color. A quick dehydration of the product to 15–20% moisture content can reduce Maillard reaction time. For this reason, the drying methods are designed to accelerate the drying time in order to achieve the desired moisture content while reducing the browning time . Microwave drying is based on the volumetric heating occurring when electromagnetic waves pass through the material causing a molecules oscillation. This oscillation generates thermal energy that is then used to remove water from the wet material.





Hot water comes from the thermostatic bath and circulates to the container. All samples were placed on the Mylar film as a thin layer of 3 mm. Samples were taken each 10 minutes for microbiological analysis and moisture content determination until the drying process was completed.
To align with the UN Sustainable Development Goals, which aim to halve food waste by 2030, food wastage reduction, especially from fruits and vegetables that have a short shelf life, can be processed into a stable value-added product. Hence, the application of various drying methods on fruits, vegetables, and their by-product were conducted as measures to decrease or avoid possible wastage. In addition, bio-drying processes were also presented to reduce the generation of food waste and environmental impact.

This physical parameter depends on the drying system and a well-suited one would produce materials with a high degree of porosity. Different drying methods have been compared in terms of porosity and FD was found to produce the higher porosity materials (80–90%). However, freeze-dried products were found to have a sensible structure during rehydration, which leads to a loss of elasticity and more viscous material.
This reduction in drying time highlights RWD’s unique and speedy heat transfer mechanism. Table 1 shows the drying times of the dragon fruit samples. 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). Several studies have shown that RW drying can preserve ascorbic acid content in the products.
The released water vapor is collected and directed to atmosphere through an exhaust fan mounted in the drying chamber. The resulting product has excellent color, vitamin, and antioxidant retention. To assess the functionality and effectiveness of the system several concentrate from fruits and herbs were dried and were compared with those obtained from freeze dryer. The resulting products is comparable in terms of physicochemical characteristics with those obtained using a laboratory freeze dryer but in much shorter time and less energy cost. As we all know the shelf of any product depends chiefly on its moisture content.

Interpretation of results was performed according to CLSI standard. Polymerase chain reaction was used for determination of mec genes. Fifty samples from 70 tested were positive for Staphylococcus spp. In 30% of the isolated staphylococci, the growth was observed on selective media with cefoxitin as well as on MRSA2 Agar.