Effect of methionine enrichment on the biological activities of food proteins.

A special enzymatic technique, the enzymatic peptide modification (EPM) reactions have been worked out in our laboratory, by which proteins can be modified with respect to their biological activities. Enzymatic modification methods provide several advantages in producing proteins of desired nutritional properties. Proteolytic modification, particularly when combined with methionine enrichment, significantly altered the biological activities and leads to increased nutritional value.

[The effect of keeping condition and genotype on the electrophoretic properties of pork proteins]. / Einfluss der Haltungsbedingungen und des Genotyps auf das Elektrophoreseverhalten von Schweinefleischproteinen.

Besides differentiation of animal species the electrophoretic methods are efficient also in determinations of the factors effecting the protein patterns. The goal of this study is to compare the effect of the genotype and the keeping conditions on the electrophoretic behaviour of the pork meat proteins. Isoelectric focusing was found to be more efficient than SDS-PAGE concerning studies of the effect of these factors. An optimal separation has been achieved with an ampholyte-mixture at pH ranges 2-11, 5-7 and 7-9. Peroxidase activity of the separated myoglobines of the meat samples was stained for detecting the differences in protein zones according to the keeping conditions. The myoglobin zones stained with o-dianisidin were evaluated by densitometry. The protein zones of the organic meat samples showed higher intensity than those of the control-samples.

Differences in the electrophoretic patterns of soluble pork proteins as a consequence of pig rearing conditions.

In recent years the importance of 'organic meat' has increased. Rigorous rearing conditions has raised the emphasis on meat quality problems. Pigs (genotype: Hungarian Large White 75% and Mangalica, pigs with curly bristles, 25%) were kept in a natural farming system, and did not receive growth promoters, hormones or antibiotics. The meat of these pigs is called 'organic meat', or 'bio meat'. Longissimus dorsi muscles of pigs kept under natural circumstances and under traditional conditions were compared using SDS polyacrylamide gel electrophoresis and isoelectric focusing. Electrophoretic separation, protein and esterase enzyme staining showed definite differences between the proteolysates of organic and control meat samples.