In this study, apple slices were dried using infrared (IR) and hot air techniques and comprehensively analyzed in terms of drying and product characteristics. The influence of IR power level (450–650 W) and hot air temperature (60–75°C) on mass transfer, color kinetics, product texture, microstructure, and rehydration characteristics was studied. The results indicated that drying time, color change, and energy requirement were lower in IR drying than in hot air drying. Moisture diffusivity was observed to increase with IR power (3.367 × 10−9–5.579 × 10−9 m2/s) and hot air temperature (1.288 × 10−9–2.387 × 10−9 m2/s). The activation energies of apple slices in IR and hot air drying were 11.94 and 21.90 kJ/mol, respectively. IR‐dried apple slices were more crispy, with a porous structure and higher rehydration ability. Experimental data were fitted to nine different thin‐layer drying and four‐color kinetic models using nonlinear regression analysis. The results of regression analysis indicated that the Midilli–Kucuk model is the best model to describe the drying behavior in both techniques. The color characteristics (L, a, and b) can be best explained by the modified color model and total color change by fraction conversion model for both IR and hot air drying of apple slices. This study revealed that IR drying of apple slices results in a better quality product in less time and energy as compared to hot air drying. Practical applications Drying is a vital food processing and preservation technique based on the principle of reducing the water content of the product. Although several drying techniques are available, there have been continuous efforts to improve drying methods in terms of energy efficiency and product quality attributes. The present work has been carried out considering the dearth of information on the influence of infrared power/intensity on the drying behavior and product quality of apple slices. Mass and color kinetics have been studied for a better understanding of the process, along with texture, microstructure, and rehydration properties. Our results showed that the process is superior, in terms of energy and product quality, as compared to other published work. It is concluded that infrared drying can be effectively used in the dehydration of apple slices on an industrial scale and can be promoted as a healthy alternative to fried snacks.

The present study investigated the effects of infrared and forced convective air at different infrared power levels (300, 400, and 500 W) and hot air temperatures (50, 57, and 65°C) on thin layer drying of rose petals. Infrared drying requires 50%–52% less time as compared with forced convective drying. The initial and final moisture content of rose petals were 84% (w.b.) and 4.5% (w.b.) respectively. The Midilli–Kucuk model gives a superior fit for both the drying methods followed by Avhad and Marchetti, and the Page model. The zero‐order, followed by the first‐order color kinetics model gives the best fitting for L*, a*, and b* values. Moisture diffusivity was increased by infrared power (1.7308 × 10−8 to 4.1495 × 10−8 m2/s) and hot air temperature (9.3715 × 10−9 to 1.1709 × 10−8 m2/s). The activation energy obtained for rose petals in hot air dryers and infrared dryers was 51.09 kJ/mol and 6.50 kW/kg, respectively. Samples dried at 500 W infrared drying for 18 min demonstrated higher retention of color, ascorbic acid (61.03 ± 2.6 mg/100 g), and anthocyanin content (295.75 ± 65.70 mg/100 g) in the rose petals. Practical Applications Several drying techniques are available, though continuous efforts have been made to improve drying methods in terms of energy efficiency and product quality attributes. The present work has been carried out considering the dearth of information on the influence of infrared power/intensity on drying behavior and product quality of rose petals. Mass and color kinetics has been studied for a better understanding of the process along with rehydration, ascorbic acid and anthocyanin content. Our results showed that the infrared drying has significant industrial importance as it provides an efficient way to dry flowers, preserving their quality and extending their shelf life.

Ginger (Zingiber officinale Rosc.) is a commercial crop grown for its aromatic rhizomes which is used both as a spice and medicine. Being a root crop and owing to its physical structure, ginger rhizomes contain heavy soil load which makes washing as an important and prime post-harvest operation. Manual washing of ginger is a laborious and time consuming process. An experiment was conducted at the ICAR-Indian Agricultural Research Institute, New Delhi during 2020 with an objective to develop a continuous rotary drum type battery operated ginger washer and to evaluate its performance.The machine consists of the frame, feeding and discharge chutes, rotary drum with internal flights, pressure pump and nozzle assembly, battery and a drive unit. The developed washer was evaluated at different feed rate and residence time to appraise the washing efficiency, microbial washing efficiency, bruise index and colour of washed ginger. Increase in feed rate significantly reduced the washing and microbial efficiencies but increased mechanical damage. Washing and microbial efficiencies increased with increase in residence time.Significant difference in the colour was found between washed and unwashed ginger.The best set of conditions under which the washer could be operated was 150 kg/h and 25 sec, at which the machine was found to have mechanical washing efficiency of 92.48%, microbial washing efficiency of 93.18% and 4.54% bruise index. Besides eliminating drudgery of washing operation, the developed washer was found to save time, water and operating cost as compared to manual washing.