Improving modification of structures and functionalities of food macromolecules by novel thermal technologies

The macromolecules in the food system such as starch, protein and lipid are essential components and major sources of calories in the human diet. Thermal treatment is one of the most widely used processing methods for foods. Traditional thermal treatment methods could induce undesirable degradation of food quality attributes, especially for heat-sensitive food materials. Therefore, novel thermal technologies have been developed as alternative methods for food processing. This review focuses on the effects of novel thermal processing technologies, including microwave heating, radio frequency heating, ohmic heating and infrared heating on improving the modification of structures and functionalities of macromolecules including starch, protein and lipid in food systems. The principles and mechanisms of these novel technologies are introduced as well as challenges and future trends in developing and applying these technologies in the food industry are also discussed in the current review. For starch, novel thermal processing technologies induce the morphological and crystalline structure of starch granules and affect swelling, water holding capacity, oil holding capacity, solubility and digestibility of starch. For protein, they cause the structure changes via the creation of free radicals and alter the primary, secondary, tertiary and quaternary structures of protein, thereby affecting the functional characteristics such as solubility, digestibility, swelling, foaming, emulsification, water holding capacity, and oil holding capacity. For lipids, novel thermal processing technologies affect the functional properties of lipids such as oxidation stability. Therefore, novel thermal processing technologies are effective in the modification of the structures and functionalities of starches, proteins and lipids for expanding their potential applications.