Skim milk samples were taken before and after the milk was subjected 2 pasteurization conditions (73 and 85°C for 17 s). Less severe pasteurizing resulted in only minimal denaturation of the 2 major whey proteins α-lactalbumin and β-lactoglobulin. At the high heat condition, percent denaturation of these proteins were in the range of 12 and 26% respectively. Milks were then ultrafiltred and spray dried to manufacture milk protein concentrates (MPC). A average concentration of protein and lactose in the dried products was 82 and 2% respectively. Rennet coagulation studies, using a Formagraph®, were conducted on reconstituted non-fat dry milk solutions supplemented with MPC at protein concentrations ranging from 4.65 to 6.25% protein by weight. Rennet clotting times were not significantly influenced by heat treatment suggesting that extent of whey protein denaturation was not sufficient to alter rennet clotting times. There was a significant effect of retentate pH on rennet clotting time Samples with added MPC produced from pH 6 retentate had significantly higher levels of ionic calcium.
|Original language||English (US)|
|Number of pages||4|
|State||Published - Dec 1 1999|