Effect Of Ultra High Pressure Treatment On The Quality Of Fresh Camel Milk

In this paper,the factors of treatment pressure,dwell time and sample temperature were taken as the variables,microbial,physicochemical properties and sensory characteristics were used as the detection indexes.Single factor and orthogonal experiments were carried out to investigate the effect of ultra high pressure treatment on the quality of fresh camel milk and the optimal process parameters of ultra high pressure sterilization fresh camel milk were optimized.The main findings are as follows:(1)Ultra high pressure treatment with different pressures has significant bactericidal effect on fresh camel milk,and its bactericidal effect is improved with the increase of treatment pressure.Among them,600 MPa ultra high pressure treatment has the best bactericidal effect,and the total number of colonies is<10 CFU/mL.After ultra high pressure treatment,the acidity of fresh camel milk decreased,pH value and apparent viscosity increased,but the conductivity did not change significantly.Ultra high pressure treatment can improve the sensory characteristics of fresh camel milk,reduce2*value and sour taste,increase umami and volatile aromatic substances,and have no significant effect on salty taste.(2)With the prolongation of ultra high pressure treatment time,the bactericidal effect on fresh camel milk is more significant.When the time exceeds 20 minutes,the mortality rate of microorganisms does not change significantly.Ultra high pressure treatment at different times can reduce the acidity and conductivity of fresh camel milk while increasing its pH and apparent viscosity.In terms of organoleptic properties,ultra high pressure treatment reduced the L*value and sour taste of fresh camel milk,increased umami and volatile aromatic substances,and had no significant effect on salty taste.(3)The lethal effect of sample temperature on the total number of colonies in fresh camel milk did not show a good linear correlation.When the sample temperature was 40“C,the lethal rate was the lowest,and the result of ultra high pressure sterilization treatment was the worst.In terms of physical and chemical properties,the acidity and electrical conductivity of fresh camel milk decreased,and the pH value and apparent viscosity increased.The ultra high pressure treatment of different sample temperatures reduces the L-*value of fresh camel milk,increases the volatile aromatic substances,and has a certain influence on the taste.(4)According to the orthogonal test,the optimal conditions for the treatment of fresh camel milk by ultra-high pressure are treatment pressure 600 MPa,dwell time 20 min,sample temperature 55 C,and the order of action factors on the sterilization effect of total colony is:treatment pressure>sample temperature>dwell time.(5)Pasteurization and ultra high pressure treatment can reduce the total number of colonies in fresh camel milk,but the bactericidal effect of ultra high pressure treatment is more significant,the total number of colonies is<10 CFU/mL,the optimized ultra high pressure treatment conditions can be effective,and extend the shelf life of fresh camel milk.