Influence of high altitude and of forage from alpine origin on protein composition and renneting properties of cow's milk

摘要

A two factorial design was applied to separate the effects of high altitude and alpine forage quality on milk protein and cheese-making properties. Milk was analysed for protein composition, plasmin and plasminogen content, and rennet coagulation properties. High altitude caused slightly decreased milk protein contents, a decreased plasminogen content and significantly impaired rennet clotting time. Hay of alpine origin, when compared to hay of lowland origin, led to significant lower milk yield andtotal protein concentration. Whey protein and K-casein proportions of total protein were significantly reduced, casein/total protein ratio was elevated and rennet coagulation properties were partly impaired by the alpine hay, whereas plasmin and plasminogen-derived activity were not clearly affected.