Detection of fraudulent addition of bovine whey in water buffalo ricotta cheese by isoelectric focusing

BACKGROUNDPrevention of food fraud in the dairy field is a difficult issue for researchers, industries and policy makers, both for commercial and health reasons. Currently, no analytical method allows detection of the addition of bovine whey to water buffalo ricotta, so this fraudulent practice cannot be prevented. The authors' aim was to develop such a method. RESULTSThe conditions for extraction and purification of denatured ricotta whey proteins, which are unfolded and coagulated by heating during the production process, were optimized. The optimal composition of the polyacrylamide gel (pH range, type and concentration of chemical separator) was first evaluated and then the best conditions to perform the separation by isoelectric focusing were established. The performance of the method (precision, selectivity, robustness, sensibility) was determined. CONCLUSIONSThe method was shown to be reliable and robust for detection of the presence of bovine whey added to water buffalo Ricotta at percentages above 5% (v/v). The results suggest that the differences observed between bovine and water buffalo electrophoretic profiles are due to bovine -lactoglobulin isoform A, which is never detected in water buffalo samples. (c) 2014 Society of Chemical Industry