Investigating the Effect of Diluting with Water on the Change of Physicochemical Properties and Color Indicators of Cow Milk

Despite the benefits of milk as one of the priorities of a healthy diet, the results of studies show that milk and dairy consumption in Iranian household food is less than 10%. There are many factors involved in this behavior that one of them is the consumer’s uncertainty about the quality of milk. The physical, chemical and color properties of milk can be used as a criterion in determining its quality as well as designing and manufacturing of many food processing machines. In the present study, cow’s milk was prepared with 100, 90, 80, 70 and 60% purity and viscosity, specific heat capacity, heat transfer coefficient, density, pH, electrical conductivity, total dissolved solids, and change in color characteristics were examined. By decreasing purity of milk from 100 to 60% of the specific heat capacity, the heat transfer coefficient, pH and electrical conductivity values increased from 0.508 to 0.602 W.m^-2.K^-1, increased from 3978 to 4083 J.kg^-1.K^-1, increased from 6.59 to 6.88 and decreased from 2100 to 1440 μS.cm^-1, respectively.

Keywords: Viscosity, specific heat capacity, heat transfer coefficient, electrical conductivity, image processing technique.