A cheese or not a cheese? Proteomics redefines the regulatory categorization of mascarpone

The regulatory classification of dairy products has significant implications for international trade and labeling compliance. Mascarpone, a high-fat used in culinary applications, occupies a regulatory grey area. This study employed a comprehensive proteomic approach to determine whether mascarpone meets the molecular and compositional criteria for cheese. Proteins from two mascarpone samples were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS), targeting κ-casein, its rennet-derived fragment para-κ-casein, and the whey proteins-to-caseins ratio. Intact proteins were also analyzed by HPLC-MS. Our results showed that κ-casein remained intact, while para-κ-casein was undetectable in mascarpone samples. Furthermore, the high whey proteins-to-casein ratio reflected the absence of a drainage step typical of curd formation. These findings have been confirmed by analyzing proteins of four additional commercial samples of mascarpone in comparison with mozzarella and primo sale cheese, as examples of rennet-coagulated dairy products. Data provide evidence that mascarpone lacks key biochemical markers of cheesemaking, supporting its classification as a thermally stabilized acidified dairy emulsion rather than a true cheese. This study highlights the usefulness of proteomic markers for the accurate classification of dairy products. • Debate is ongoing on the classification of mascarpone in regulatory contexts • Proteomics demonstrated that mascarpone proteins lack rennet-induced coagulation signatures • Whey proteins-to-casein ratio indicated that mascarpone does not undergo a whey separation step • Mascarpone should be described as an acidified milk cream product rather than a cheese