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Campos Motta TM, Hoff RB, Barreto F, Andrade RBS, Lorenzini DM, Meneghini LZ, Pizzolato TM. Detection and confirmation of milk adulteration with cheese whey using proteomic-like sample preparation and liquid chromatography-electrospray-tandem mass spectrometry analysis. Talanta 2013; 120:498-505. [PMID: 24468402 DOI: 10.1016/j.talanta.2013.11.093] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 11/29/2013] [Accepted: 11/30/2013] [Indexed: 02/02/2023]
Abstract
Caseinomacropeptide (CMP) is a peptide released by chymosin in cheese production, remaining in whey. Thus, CMP can be used as a biomarker to fluid milk adulteration through whey addition. Commonly, CMP is analyzed by reversed phase (RP-HPLC) or size-exclusion chromatography (SEC). However, some psychrotropic microorganisms - specially Pseudomonas fluorescens - when present in storaged milk, can produce, by enzymatic pathway, a CMP-like peptide generally called pseudo-CMP. These two peptides differ from each other only by one amino acid. RP-HPLC and SEC methods are unable to distinguish these two peptides, which demand development of a confirmatory method with high selectivity. Considering the several degrees of glycosilation and phosphorylation sites in CMP, allied with possible genetic variation (CMP A and CMP B), analytical methods able to differentiate these peptides are extremely complex. In the present work, we developed a proteomic-like technique for separation and characterization of these peptides, using liquid chromatography coupled to mass spectrometry with electrospray ionization able to differentiate and subsequently quantify CMP and pseudo-CMP in milk samples in order to identify adulteration or contamination of these products. The method shows satisfactory precision (<11%) with a detection limit of 1.0 µg mL(-1) and quantification limit of 5.0 µg mL(-1). Specificity, matrix effects and applicability to real samples analysis were also performed and discussed.
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Affiliation(s)
- T M Campos Motta
- Instituto de Química, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil; Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil.
| | - R B Hoff
- Instituto de Química, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil; Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil
| | - F Barreto
- Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil; Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil
| | - R B S Andrade
- Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil
| | - D M Lorenzini
- Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil
| | - L Z Meneghini
- Laboratorio Nacional Agropecuário - LANAGRO/RS, Ministerio da Agricultura, Pecuária e Abastecimento, Brazil
| | - T M Pizzolato
- Instituto de Química, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil
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