Effects Of Combined Instantaneous High-pressure And Medium Temperature On Microorganisms And Physical-chemical Properties Of Milk

With the advantages of the traditional thermal processing and ultra-high pressure processing technology,instantaneous high-pressure is a new food processing technology. The processing method of combined medium temperature and high-pressure was studied in the milk in order that high pressure industrialization can realized the aim.The effects of microorganisms and physicochemical characteristics by high-pressure of pressure,material temperature,processing time in the milk were investigated under 20-100 MPa,25-55℃and processing time 2-10 min.The relationship between the estimation index and the influence factors was also discussed.Results showed that combined medium temperature high-pressure could evidently promote bactericidal effect.With the material temperature of 55℃and the processing time of 4 min,the best bactericidal effect was achieved at 20 MPa.There was an interaction influence between temperature and pressure,time and pressure,temperature and time on bactericidal effect.Among them,the pressure made a significant influence on bactericidal effect.Instantaneous high-pressure had an influence on the acidity,lightness,turbidity, hydration of milk,but didn't affect the freezing point of milk.The pressure had a significant influence on the acidity,lightness of milk.When changed at the range of 20～100 MPa,the increased pressure made acidity and lightness of milk reduce.The feed temperature also had a significant influence on the acidity and lightness of milk.When changed at the range of 25～55℃,the temperature made the acidity reduce and lightness increase.By the instantaneous high-pressure treatment,the pressure and temperature pressure and time,temperature and time had an interaction influence on acidity,lightness, turbidity,hydration of milk.Generally considered the effects of combined instantaneous high-pressure and medium temperature on microorganisms and physicochemical characteristics of milk,the best condition of instantaneous high-pressure treatment was as follows:the work pressure of 20 MPa,the feed temperature of 25℃,the treatment time of 2 min.