Design, development, and drying kinetics of infrared‐assisted hot air dryer for turmeric slices

Abstract

An infrared-assisted hot air dryer was designed and developed for turmeric slices. The dryer has been developed using an infrared heating source, heating coils, and blower.The total power required for the infrared drying and hot air drying was 2.25 kW and 36.35 kWh, respectively, with a blower capacity of 6.06 m 3 /min. An infrared drying (IRD), hot air drying (HAD), and infrared-assisted hot air drying (IRHAD) were used to dry turmeric slices (5 mm thickness) at different drying temperatures 50 C, 60 C, and 70 C with constant air velocity 2 m/s and bed thickness 25 mm. The maximum drying efficiency of 25.22% and the minimum specific energy consumption of 1.24 kWh/kg were observed in the IRHAD method at 70 C and considered as the best drying method for drying turmeric slices. The drying rates values were double in IRHAD than IRD and HAD. Seven drying models, namely, Newton, Page, Modified page, Diffusion approximation, Two-term exponential, Henderson-Pabis, and Logarithmic, were used to validate the experimental data obtained during drying. Based on the maximum R 2 value and lowest error values, the Page model was found to be the best fit for characterizing the drying kinetics of turmeric slices. At 60 C drying temperature, the logarithmic model and twoterm exponential model were found best fit for HAD and IRHAD, respectively. Practical ApplicationsRecently, turmeric gaining a lot of economic importance due to its antiviral properties and health benefits. Turmeric has many applications in the food industry, including natural coloring agents, flavor enhancers, and preservatives. Washing, boiling, drying, polishing, and size reduction are the unit operations involved during the processing of turmeric. The commercial value of turmeric can be decided based on the percentage of volatile compounds present. Many studies observed that the reduction in volatile compounds due to improper drying. The farmers following the sun drying techniques, which consume more time, non-homogenous drying, and lesser drying rate. Hence, an efficient alternate drying technique should be identified to overcome the problems faced by the farmers and turmeric processing industries. In this context, the present study was undertaken to design an infrared-assisted dryer for efficient, quick, and uniform heating of turmeric slices.

Design, development, and evaluation of rotary drum dryer for turmeric rhizomes (Curcuma longa L.)

“…The curcumin, oleoresin, starch, and color ( L , a , b value) of 4.92%, 16.5%, 58.09%, and 59.87 ( L ), 28.43 ( a ), 74.21 ( b ) was found higher at 9 rpm, 50°C air temperature, and 3 m/s air velocity. Similar results were reported for infrared assisted hot air drying of turmeric slices (Jeevarathinam et al, 2021a, 2021b), blanching of turmeric (Farzana et al, 2018), and solar and convection oven drying of turmeric (Raza et al, 2018). The statistical analysis showed a significant difference ( p ≤ 0.01) between the speed of drum, air temperature and velocity for all quality parameter (Table 3).…”

“…The contour plots were compared between 60° and 70°C of 9 rpm (Figure 6c) and 6 rpm (Figure 7c) at 3 m/s. The contour plots showed that the higher moisture removal ratio was found at 70°C because of rapid moisture evaporation (Falade, Olurin, Ike, & Aworh, 2007; Jeevarathinam et al, 2021b). At 9 rpm and 3 m/s, 70°C (Figure 6b,c) showed higher drying rate and moisture removal compared to 60°C and for both temperatures the predicted and observed values were on par (Figure 6a,c).…”

“…The drying rate of rhizomes was high at the initial stage of drying, and it decreased gradually with the increase in drying time. The higher drying rate at the initial stages of drying might be due to the removal of free moisture, and the decrease in the drying rate in the later stages was due to the moisture tightly bound to the cell walls or other chemical components of the turmeric rhizomes (Jeevarathinam et al, 2021a(Jeevarathinam et al, , 2021b. Higher air velocity (3 m/s) and rotational speed (9 rpm) increase the amount of moisture removed compared with drying at a lower velocity (2 m/s) and rotational speed (6 rpm; Figure 4a,b).…”

“…Indian sub‐continent was the origin of the plant and at present, India ranks first in the production and consumption of turmeric. Turmeric is also cultivated in some of the Asian, African, and Central American countries (Jeevarathinam et al, 2021b). Ground turmeric rhizome (the turmeric spice that is bright yellow in color) plays an essential role in Indian culture as an important constituent in most food products.…”

Application of Artificial Neural Networks, Support Vector, Adaptive Neuro-Fuzzy Inference Systems for the Moisture Ratio of Parboiled Hulls

“…In addition, the drying time of the products was decreased at higher inlet temperatures, so the longest and shortest process times were related to drying at 40 and 60 • C, respectively. Increasing the temperature of the product surface led to an increase in mobility of water molecules and as a result easier migration of these molecules from the internal parts to the product surface [54]. Increasing the temperature on the one hand increased the moisture absorption capacity of the air due to increasing the temperature difference between the air and the product and on the other hand caused faster heating of the product and better evaporation of water from it and ultimately reduced drying time [55].…”