Allergen Targets

Soy

Food Matrix

Meat

Identification of Marker Proteins for the Adulteration of Meat Products with Soybean Proteins by Multidimensional Liquid Chromatography−Tandem Mass Spectrometry†

Leitner A., Castro-Rubio F., Marina M.Luisa, Lindner W.

Journal of Proteome Research (2006), 5, 9, 2424--2430 DOI: 10.1021/pr060145q

Abstract

Soybean proteins are frequently added to processed meat products for economic reasons and to improve their functional properties. Monitoring of the addition of soybean protein to meat products is of high interest due to the existence of regulations forbidding or limiting the amount of soybean proteins that can be added during the processing of meat products. We have used chromatographic prefractionation on the protein level by perfusion liquid chromatography to isolate peaks of interest from extracts of soybean protein isolate (SPI) and of meat products containing SPI. After enzymatic digestion using trypsin, the collected fractions were analyzed by nanoflow liquid chromatography-tandem mass spectrometry. Several variants and subunits of the major seed proteins, glycinin and β-conglycinin, were identified in SPI, along with two other proteins. In soybean-protein-containing meat samples, different glycinin A subunits could be identified from the peak discriminating between samples with and without soybean proteins added. Among those, glycinin G4 subunit A4 was consistently found in all samples. Consequently, this protein (subunit) can be used as a target for new analytical techniques in the course of identifying the addition of soybean protein to meat products. Keywords: multidimensional chromatography, tandem mass spectrometry, soybean proteins, meat products, glycinin