Thermal Treatment Effects on Milk Proteins

Thermal processing of milk—ranging from low-temperature pasteurisation to ultra-high-temperature sterilisation—induces a cascade of structural and functional modifications in milk proteins. Heat exposure disrupts the native conformations of globular whey proteins and alters the colloidal stability of casein micelles. Denaturation exposes hydrophobic regions, promoting aggregation and the formation of intermolecular disulphide bonds. These changes diminish enzymatic activity, reduce bacteriostatic and immunological functions, and modify digestibility. Conversely, controlled heat treatments can enhance certain techno-functional properties, such as emulsification and foaming, by partially unfolding proteins. The intensity and duration of heating govern the extent of Maillard reactions, whereby lactose reacts with lysine residues, further altering protein solubility and nutritional quality. Advances in mass-spectrometry-based proteomics have enabled detailed profiling of heat-induced modifications, revealing shifts in protein abundance and post-translational changes. A comprehensive understanding of these effects underpins the optimisation of dairy processing protocols, balancing microbial safety and extended shelf life with the preservation of nutritional and bioactive attributes. Such insights are crucial for the development of tailored treatments that meet regulatory standards while addressing consumer demand for minimally processed, functionally rich dairy products.

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Thermal Treatment Effects on Milk Proteins publication trend

The graph below shows the total number of articles in thermal treatment effects on milk proteins across all publications each year (not limited to Nature Index journals).

Technical terms

Denaturation: The irreversible unfolding of protein secondary and tertiary structures due to heat, leading to loss of native function.

Casein micelles: Colloidal aggregates of casein proteins and calcium phosphate that form the primary structure of milk’s protein phase.

Whey proteins: Soluble globular proteins in milk, including β-lactoglobulin and α-lactalbumin, that are sensitive to thermal unfolding.

Ultra-high-temperature sterilisation (UHT): A process typically at ≥135 °C for a few seconds, ensuring commercial sterility but causing significant protein modifications.

Maillard reaction: A non-enzymatic browning reaction between reducing sugars and amino groups in proteins, accelerated by heat.

Proteomics: The large-scale study of proteins, their structures and functions, often using mass spectrometry to detect heat-induced changes.

References

1. Label-free quantitative proteomic analysis of functional changes of goat milk whey proteins subject to heat treatments of ultra-high-temperature and the common low-temperature. Food Chemistry X (2024).
2. Effect of vat pasteurization, ultra-high temperature sterilization, retort sterilization and homogenization on soluble proteins in donor human milk detected via proteomics. LWT (2023).
3. Effect of heat treatment on bacteriostatic activity and protein profile of bovine whey proteins. Food Research International (2019).