Development of soybeans with low P34 allergen protein concentration for reduced allergenicity of soy foods.

BACKGROUND: In soybean, at least 16 seed proteins have been identified as causing allergenic reactions in sensitive individuals. As a soybean genebank accession low in the immunodominant protein P34 (Gly m Bd 30K) has recently been found, introgression of the low-P34 trait into adapted soybean germplasm has been attempted in order to improve the safety of food products containing soybean protein. Therefore, marker-assisted selection and proteomics were applied to identify and characterize low-P34 soybeans. RESULTS: In low-P34 lines selected from a cross-population, concentrations of the P34 protein as identified with a polyclonal antibody were reduced by 50-70% as compared to P34-containing controls. Using 2D electrophoresis and immunoblotting, the reduction of P34 protein was verified in low-P34 lines. This result was confirmed by liquid chromatographic-tandem mass spectrometric analysis, which revealed either a reduction or complete absence of the authentic P34 protein as suggested from presence or absence of a unique peptide useful for discriminating between conventional and low-P34 lines. CONCLUSION: Marker-assisted selection proved useful for identifying low-P34 soybean lines for the development of hypoallergenic soy foods. The status of the P34 protein in low-P34 lines needs further characterization. In addition, the food safety relevance of low-P34 soybeans should be tested in clinical studies. © 2016 Society of Chemical Industry.

Bioaccessibility of the Bioactive Peptide Carnosine during in Vitro Digestion of Cured Beef Meat.

A bioactive compound is a food component that may have an impact on health. Its bioaccessibility, defined as the fraction released from the food matrix into the gastrointestinal tract during digestion, depends on compound stability, interactions with other food components, and supramolecular organization of food. In this study, the effect of pH on the bioaccessibility of the bioactive dipeptide carnosine was evaluated in two commercial samples of the Italian cured beef meat bresaola at two key points of digestion: before the gastric and after the duodenal phases. The digestion process was simulated using an in vitro static system, whereas capillary zone electrophoresis (CZE) and (1)H nuclear magnetic resonance (NMR) were used for quantitative analysis. The gap between the total carnosine content, measured by CZE, and its free diffusible fraction observable by NMR spectroscopy, was 11 and 19% for two independent bresaola products, where such percentages represent the fraction of carnosine not accessible for intestinal absorption because it was adsorbed to the food matrix dispersed in the digestion fluid.