Impact of emerging non-thermal processing treatments on major food macromolecules: Starch, protein, and lipid

Background: The deleterious influences of thermal treatments on various foods' aspects, like decomposing flavors and nutritional components, plus developing non-healthy compounds (e.g., acrylamides), have provoked the need for novel non-thermal processing (NTP) approaches less detrimental to food products. Scope and approach: Hitherto, several non-thermal methods have been developed for the purpose of food processing, among which sonication, high-pressure processing, pulsed electric field, ozonation, plasma treatment as well as irradiation can be mentioned. Like thermal processes, these methods could intentionally/inadvertently induce remarkable changes in the structural characteristics and technofunctional attributes of food macromolecules i.e., proteins, lipids, and starch. Key findings and conclusions: Given the ever-increasing application of non-thermal methods in the realm of food processing, this review has deeply focused on the impact of such techniques on the functional and physicochemical characteristics of food macromolecules. The changes in protein structure upon non-thermal treatments were mostly confined to conformational alterations in their secondary, tertiary, and quaternary architecture where non-covalent interactions play the main role in stabilizing the molecular structure. Such techniques are also potent tools to manipulate starch characteristics by diminishing its viscosity, rheological and pasting attributes, enhancing its clarity, and reducing its retrogradability. Besides, there has also been an increasing trend in the simultaneous application of NTPs with other starch modification techniques to facilitate/intensify the modification reactions. Nonetheless, non-thermal processes in most cases have demonstrated inadvertent ability in intensifying lipid oxidation.