The influence of different heat treatments on the content and distribution of nitrogen matter from milk to sera obtained by aced coagulation of milk with glucono-δ-lactone (GDL)
PKB IMLEK, Padinska Skela, Belgrade (1)
Department of Food Techology and Biochemistry, Faculty of Agriculture, Belgrad-Zemun (2,3,4)
Skim milk with 9.15% DM was heat treated at 85°C/10 min, 90°C/10 min and 95°C/10 min, respectively. Untreated milk was used as control. Milk samples were coagulated by glucono-δ-lactone (GDL) at the temperature of 45°C until pH 4.60 was reached. Untreated milk had the longest time of acidification. Nitrogen matter content in sera obtained from untreated milk was 79.40 mg%. Sera samples obtained from milk heat treated at 85°C/10 min, 90°C/10 min and 95°C/10 min had 47.80 mg%, 45.00 mg% and 43.50 mg% of nitrogen matter, respectively. Distribution of nitrogen matter from untreated milk to milk sera was 12.70%, while distribution of nitrogen matter from milk heat treated at 85°C/10 min, 90°C/10 min and 95°C/10 min to sera samples, were 6.95%, 6.57% and 6.22%, respectively.
