우유 및 유제품의 점도변화에 관한 연구 = Studies on the Viscosity Variation of Milk and Milk Products

다국어 초록 (Multilingual Abstract)

This experiment was accomplished to investigate the viscosity variation effected by the temperature of raw milk, homogenized milk and cultured milk, to research the relation between the viscosity and the storage period of raw milk, cultured milk, to inquire the variation of the viscosity by addition of water, acid and alkali, lactose, fat and SNF to raw milk. The results obtained were as follows: 1. A viscosity of raw milk was 2.16 cp at 20℃. As the temperature rose, the viscosity decreased. Homogenized milk and cultured milk were to trend the same as raw milk, but homogenized milk was much higher viscosity than raw milk. Cultured milk had wide difference in accordance with various products. 2. As the storage period of raw milk has passed, the viscosity increased. At 4℃, the viscosity gradually enhanced from 1 to 5 days. 3. The storage period of cultured milk passing at 4℃, 10℃, 20℃, 30℃, the viscosity promptly added to on 2 days. At 4℃, it dropped on 3∼5 days and again rose little by little, At 10℃, 20℃, 30℃, a tendency like each other, but at 20℃, 30℃, trended slightly difference, which increased after dropped rapidly. 4. With addition of water to raw milk, the viscosity lessened. At 4℃ rather than 10℃, 20℃, 30℃, it showed a significant difference (P$lt;0.01) 5. According to addition of lactose, fat and SNF to raw milk, the viscosity appeared a significant increase (P$lt;0.01). Especially, it was greatly effected by SNF treatment rather than fat, lactose treatment. 6. In adding of acid and alkali to raw milk, as the storage period of raw milk treated by acid has passed, the viscosity increased slowly and boosted promptly on 4∼5 days. Contrary to acid treatment, alkali treatment heightened rapidly on 2 days and again cut down, ascended on 4∼5 days quickly.