Investigations On The Manufacture Procedure Of Low-Lactose Milk And Methods Of Determining The Lactose Hydrolytic Percentage

Hydrolysing lactose of milk with the lactose can slove the problem of lactose intolerance. At the same time, hydrolysed milk has more advantages than common milk, like tasted well and nutrition improved. So, hydrolysing lactose of milk has great significance. The low-lactose milk has larger market.Aimming at the problem of lactose intolerance, this text studied how to produce the low-lactose milk which lactose hydrolytic percentage beyond 60%. through the single factor experiment of different hydrolysing temperature 38℃ ,20℃, 6℃, different quantity of lactase 0.5g/kg,0.8g/kg,1.0g/kg,1.5g/kg, and different function of the time.defmed the production craft parameter of the low-lactose milk. And determined the hdrolytic percentage of the same low-lactose milk sample production. In which four methods were used, iodimetry method, freezing point decent method, HPLC and enzymic method. Though analysed the different methods, pointing out its characteristics. At the same time, the production craft parameter was defined using the method of mid-experiment.The experiment result made clear that when the hydrolysing temperature is 38℃, the quantity of the lactase is 0.8g/kg,and function time is 3 hours can produce milk with 60% lactose hydrolytic percentage, and the acidity and microorganism of the milk are up to standard.The hydrolysing temperature of 20℃ can not be used, because the microorganism was polluted severely. The hydrolysing Temperature is 6℃, the quantity of the lactase is 1.0 g/kg and function time is 20 hours can also produce milk with the hydrolytic percentage beyond 60%,and the level of the acidity and microorganism are satisfied.To the same sample production, using the iodimtry method, freezing point decent method, HPLC and enzymic method, the difined hydrolytic percentage is 63.2%,62%,61%,61.8% separatedly. The test result suggest that every unit take one's owns according to its actual by the order below HPLC, enzymic method, iodimetry method and freezing point decent method, and do not adopt the last method as far as possible. Enzymic method is first suggested to interprise.The defined production craft parameter for hydrolysing temperature, quantity of the lactase and function time of the low-lactose milk for mid-experiment was 38℃,0.8g/kg, 3 separatedly and 6℃,1.0g/kg,22 separatedly. The problem which should to be notice and the solve methods relatively were bring forward in this text.