The influence of k-casein genotype on the coagulation properties of milk collected from the local Latvian cow breeds
¹ Latvia University of Agriculture, Faculty of Agriculture, Institute of Agrobiotechnology, Street Liela 2, LV-3001 Jelgava, Latvia
² Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, Street Rigas 22, LV-3004 Jelgava, Latvia
Cheese production is becoming increasingly more diversified all over the world. The information on milk coagulation properties among Latvian dairy cow breeds and its suitability for cheese production still remains unclear. At the same time, milk with good renneting properties collected from the native Latvian cows can be used for the production of Protected Denomination of Origin (PDO) cheeses. The purpose of this research was to analyse the influence of the milk protein genotypes present in Latvian native cattle breeds on the milk coagulation properties. The data was collected in 2016 from 56 Latvian brown, 26 Latvian blue and 13 Holstein black and white cows i. Highest frequency of AA κ-casein genotype was found in Latvian brown breed (0.593), while AB genotype was more often present in the Latvian blue breed (0.636). It has been found that the presence of κ-casein genotype resulted in no significant difference in milk composition and milk coagulation properties among studied cattle breeds. We have observed a tendency that the most desirable milk coagulation properties were present in BB genotype. A significant effect of breed on milk composition has been found (p < 0.05). Milk yield of Holstein Black and White was 32.0 ± 2.99 kg, while in Latvian blue it was only 17.6 ± 1.32 kg. Higher milk yield was obtained in Latvian blue breed in comparison to that of the brown breed – 19.10 ± 0.76 kg. Better milk coagulation properties were observed in Latvian brown breed – shorter milk renneting time (16.86 ± 1.15 min), highest curd yield (24.0 ± 0.79%) and curd firmness (3.21 ± 0.17 N).