Infrared Drying of Food Materials: Recent Advances

Infrared (IR) radiations are an important source of energy used in the food industry for a wide range of applications such as drying, roasting, pasteurization, blanching, peeling, and removal of antinutrients from legumes. IR drying can be combined with other drying methods such as hot air, vacuum, microwave, and freeze drying to augment the speed of the process and also to get better results. The review puts forward a critical discussion on the principle, applications, and comparative performance of IR energy for drying a range of food materials including grains, fruits, vegetables, and sea food in the recent past. The effects of process variables on energy consumption, drying time, rate of drying, and quality of the dried product are explained in detail. Model calculations for penetration depth of IR in food materials and for heat and mass transfer are also explained. Thin layer drying models to govern kinetics of drying under different configuration of infrared drying systems are also reviewed. The insights presented by this review would help in better understanding and proper selection of process variables for design of advanced IR drying systems.