Fundamentals of Infrared Heating and Its Application in Drying of Food Materials: A Review

Abstract

Drying is an energy-intensive unit operation in chemical, food and allied industries. It is always desired to have low energy consumption for drying operation without compromising the quality of products. In this review, fundamental aspects of infrared heating are described in detail with the focus on its application to the drying of food materials. The modeling techniques are explained in detail to get emphasis on the design of large-scale infrared dryers. This review also contains the investigations carried out by several researchers by experimentation and/or modeling to describe the infrared drying, infrared-convective drying, infraredmicrowave drying and infrared-freeze drying. The present work describes the author's views regarding the capability and applicability of infrared source for drying of food materials. After going through a literature survey, it can be seen that infrared source especially in the far-IR range has been widely used in convective hot air dryer than other types of dryers. PRACTICAL APPLICATIONSThe energy loss in convective air drying is found to be very large in chemical and allied food industries. Air, the drying medium, needs to be heated using air heaters, which generally have low thermal efficiency. On the contrary, as the infrared radiation is recognized as surface heater, it can be very suitable for drying of food materials whose drying is generally carried out in thin slices. Moreover, use of infrared heaters in other dryers is very beneficial to lower the drying time without significantly affecting the quality of the final products. Lowering the drying time can increase the productivity and decrease the cost of operation practically.

A novel infrared freeze drying (IRFD) technology to lower the energy consumption and keep the quality of Cordyceps militaris

“…Infrared (IR) radiation belongs to electromagnetic radiations with the wavelength range of 0.78-1,000 μm (Pawar and Pratape 2017). Water and organic materials such as carbohydrates, fats and proteins are the main ingredients of foodstuffs.…”

“…Like other electromagnetic waves, the transmission of IR energy does not require media. The energy emitted from the IR lamp directly reaches the materials and does not heat the surrounding air (Pawar and Pratape 2017). When the wavelength of the radiation source coincides with the absorption wavelength of the irradiated object, the substance absorbs a large amount of infrared energy, thereby altering and aggravating the movement of its molecules and achieving the effect of…”

Effect of contact ultrasonic power on moisture migration during far‐infrared radiation drying of kiwifruit

“…Comparing with traditional drying methods, FIR drying could achieve higher rate of heat and mass transfer. There are several significant advantages of FIR drying including short drying time, high energy efficiency, uniform heating, and high quality of dried products (Pawar & Pratape, 2017). Several studies have reported about FIR drying of agricultural products including strawberry (Adak, Heybeli, & Ertekin, 2017), rice (Khir, Pan, Salim, Hartsough, & Mohamed, 2011), longan (Nathakaranakule, Jaiboon, & Soponronnarit, 2010), red ginseng (Ning & Han, 2013), and jujube (Doymaz, Karasu, & Baslar, 2016), and the results showed that FIR heating could promote dehydration rate and improve product quality.…”

Intelligent models based nonlinear modeling for infrared drying of mahaleb puree

“…However, drying process can decrease the product quality especially nutritional value and therefore the drying method to be used has to be selected correctly and the operating conditions should be adjusted. It is thought that infrared radiation can be used as an alternative to the production of healthy snack products, such as fruit bars due to its ability to penetrate the product quickly, to save energy considerably, and to have lower nutritional loss than conventional methods (Nowak & Lewicki, ; Pawar & Pratape, ; Riadh, Ahmad, Marhaban, & Soh, ). Besides the choice of suitable drying method, the modeling of the drying process is very important in terms of optimizing the product quality and reducing operational costs.…”