The range of protein hydrolysis and biogenic amines content in selected acid- and rennet-curd cheeses.

The aim of this experiment was to assess the range of proteolysis and biogenic amine content in the selected rennet- and acid-curd cheeses available on the Polish market, randomly chosen for the analyses: three ripened hard with eyes cheeses, three ripened hard smooth cheeses, three ripened soft moulded cheeses, three fresh unripened acid-curd cheeses, three ripened acid-curd cheeses with slimming bacteria-fried, and three ripened acid-curd cheeses with smear bacteria. The results allowed calculating the subsequent indexes and depth of proteolysis. It was found that the acid-curd short ripened cheese (harzer) was characterized by the greatest range of proteolysis and the biogenic amine content in comparison to other rennet- and acid-curd cheeses.

The changes of proteins fractions shares in milk and fermented milk drinks.

Background: The aim of this research was to observe the changes which take place in the electrophoretic picture of milk proteins after pasteurisation and inoculation with different starter cultures (both traditional and probiotic). After incubation, the yoghurt, kefir, acidified milk, fermented Bifidobacterium bifidum drink and Lactobacillus acidophillus drink were chilled for 14 days to observe the changes which occurred.

Methods: The research materials were raw and pasteurised milk, as well as fermented milk- based drinks.

Influence of milk protein cross-linking by transglutaminase on the rennet coagulation time and the gel properties.

Background: Transglutaminase (TGase) modifies milk proteins by cross-linking of caseins, with increased cheese yield being the main technological benefit. In the present work the influence of TGase addition in different concentrations (0, 1, 2 and 3 U g(-1) protein in the system) and under different incubation conditions (0 h, 40 °C/2 h, 25 °C/4 h and 5 °C/16 h) on the rennet coagulation time (RCT) and the comprehensive rennet gel properties were investigated.

Results: Modification of milk proteins by TGase in a concentration-dependent manner caused longer RCT and lower gel firmness.