ALTERAÇÕES NA DENSIDADE E CRIOSCOPIA DO LEITE PELA ADIÇÃO DE DIFERENTES CONCENTRAÇÕES DE CITRATO E FORTIFICANTE

Abstract

Considering that milk is susceptible to fraud, this study aimed to evaluate the effect of different concentrations of sodium citrate and fortifier in density and freezing point of milk. The addition of citrate in 0.1%, the maximum regulated by Brazilian legislation, was sufficient to decrease the average freezing point for 0.021 °H and increase the density average in 0.0008 g cm - 3 . In these samples was possible to add up to 5.6% water without exceeding the Brazilian standards density and freezing point. The fortifier added to milk in con- centrations higher than 0.05% decreased the average freezing point 0.0024°H compared to the control treat- ment. The average density difference only in the group with addition of 0.44% of tonic, an increase of 0.0034 g cm - 3 compared to the control treatment. However, the dilution recommended by the manufacturer (0.007%) not changed density and freezing point average of milk. The results showed that the addition of citrate in percent- ages permitted by Brazilians law was able to change the freezing point and the density of milk. It should be pointed that in direct UHT process the evaporation of water excess from milk with 0.1% of citrate is based on - 0.530 o H, it is possible that the removal of the incorporated water in UHT process could be incomplete, and can be present in percentages higher than 5%. Thus, the manufacturer recommended concentration of fortifier did not change the density and the freezing point of milk.