5 - Fundamentals of food roasting process

Abstract

Roasting is a food processing technique which utilizes dry heat for cooking the food products evenly with temperature of at least 150°C from an open flame, oven, or other heat source. This improves the palatability, digestibility, and sensory qualities of foods along with desirable structural alterations of the food product. Roasting can significantly improve the flavor via Maillard reaction and caramelization on the surface of the food product. With the increasing demand for fortified roasted products along with food safety concerns, novel roasting processes have gained significant interest in overcoming the conventional techniques. Thermal processing at high temperatures for longer period of time affects both the structural and physicochemical characteristics of food. However, novel roasting techniques cause less destructive effect as compared to the conventional methods. Advanced roasting techniques consisting of superheated steam, microwave heating, revtech roaster, infrared hot-air, and forced convection continuous tumble (FCCT) roasting have emerged as promising methods for effective roasting of various food products without hampering the nutritional aspects. The present chapter critically analyzes different conventional and advanced roasting processes, its benefits and drawbacks along with its influence on structural properties, functional attributes, and sensory qualities for a variety of food products. Also, the heat and mass transfer mechanisms during the roasting process have been demonstrated. Comprehensive studies on the chemical and sensory changes of nuts and its coproducts, roasted tea, coffee beans, and oat products caused by different roasting processes are extensively discussed and summarized in this chapter. Taken together, this chapter effectively illustrates the progress and current achievements in different roasting processes, which can present new insights on effective heating of food products toward preserving the nutritional contents.