Buffalo mozzarella chemical composition and authenticity assessment by electrophoretic profiling

Abstract

Buffalo milk mozzarella is often adulterated by the addition of cow’s milk. The aim of this study was to assess the quality of buffalo milk mozzarella by using electrophoresis (SDS-PAGE) to detect the addition of cow’s milk. Reference cheeses were produced exclusively from combinations of buffalo and cow milk, and labeled reference treatment buffalo or cow (RTB and RTC, respectively). Standardized cheeses were made by combining buffalo milk and 2.5%, 5.0%, 10%, 20%, 30%, 40% or 50% cow’s milk. A total of 9 cheese formulations were produced and either frozen immediately (time 0) or after 20 days (time 20). Eighteen commercial samples of buffalo mozzarella were sampled between 0–20 days of production. The chemical composition (moisture, ash, fat in dry matter, protein, total solids and defatted dry extract) and physicochemical characteristics (acidity) of the cheeses were evaluated. Proteins and water-soluble peptides (WSP) extracted from RTB, RTC and from the commercial samples, and were analyzed by SDS-PAGE electrophoresis under denaturing conditions. It was not possible to detect the inclusion of cow’s milk by the cheeses’ chemical and physicochemical properties. However, the separation and detection of peptide and protein fractions of the cheese was possible by electrophoresis. The results of the electrophoretic analysis suggest that 28% of the commercial samples considered here had evidence of the addition of cow’s milk. The methodology described here is important to identify occurrences of fraud in buffalo mozzarella production.