title: A control method to inspect the compositional authenticity of Minas Frescal cheese by gel electrophoresis.
abstract: This study introduces a qualitative method to inspect the compositional authenticity of white nonripened cheeses like Minas Frescal, a typical Brazilian cheese, especially when irregular replacement of milk by whey is suspected. A sodium dodecyl sulfate gel electrophoresis (SDS-PAGE) method, followed by image densitometry, was validated. Cheeses were freeze-dried to electrophoresis, and β-lactoglobulin (β-LG) was chosen as the adulteration marker. In gel trypsin digestion followed by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry provided its identification. Cheeses with a minimum of 14 mg·g(-1) of β-LG are considered to be adulterated. The method shows satisfactory precision with a detection limit of 7 mg·g(-1). Forty-two commercial samples from inspected establishments were then assessed and subjected to cluster analysis. Compliant and noncompliant groups were set with 24 (57%) authentic samples and 18 (43%) adulterated samples, respectively, showing that proper analytical monitoring is required to inhibit this practice.
authors.affiliation: Instituto Federal Catarinense , Campus Rio do Sul, Rio do Sul, Santa Catarina 89160-000, Brazil.
authors.forename: Renata B
authors.initials: RB
authors.lastname: Magenis
authors.forename: Elane S
authors.initials: ES
authors.lastname: Prudêncio
authors.forename: Luciano
authors.initials: L
authors.lastname: Molognoni
authors.forename: Heitor
authors.initials: H
authors.lastname: Daguer
mesh_terms: D000818:Animals; D002611:Cheese / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry*
chemical_list: D008894:Milk Proteins
keywords: SDS−PAGE; adulterations; dairy inspection; whey; white cheeses