Influence of Heating on the Physico-Biochemical Attributes of Milk

Background: Milk, the fluid secreted by the female of all mammalian species, fulfills the complete nutritional and energy requirements. Milk is a single balanced diet enriched in physiologically important proteins and peptides, enzymes, enzyme inhibitors, immunoglobulins, growth factors, hormones, and antibacterial agents. Milk can be converted to different dairy items that occupy an important place in confectioneries and beverages and thus are subjected to various processing conditions. Objective: This review aims to discuss how the processing conditions affect the physicobiochemical and nutritional attributes of milk protein and influence its functionality with a major focus on heating or thermal treatment. Methods: Detailed literature surveys with keywords ‘thermal effect of milk proteins’, ‘dairy chemistry’, ‘Maillard reactions have been done in food science, food chemistry, dairy science, functional foods journals, PubMed, and Scopus for gathering information on thermal effects on milk proteins. Out of 25 shortlisted review and research articles, 20 most relevant ones were cited and enlisted as references. Results: Due to thermal treatment during dairy processing, the chemical characteristics of milk proteins are altered because of chemical changes like glycation, aggregation and denaturation. Chemical modifications influence the functionality, digestibility, and nutritional quality of milk proteins. Conclusion: Novel milk processing technologies viz. ohmic and microwave heating, pulsed electric field, high hydrostatic pressure, microfiltration and ultrasound find applications in dairy processing. Such non-thermal technologies do not involve heat to kill the microbes; thus reducing the detrimental effect of conventional heat treatments on milk quality.