Effect of Zinc Salts on Dairy Raw Materials

Functional dairy products fortified with zinc lactate and zinc citrate can eliminate nutritional deficiencies in human diet. This research featured buttermilk obtained as a by-product of sweet butter. It was combined with skimmed milk powder to provide 5% protein mass fraction. Salts were added separately, from 15% recommended intake to 100% permissible daily consumption. The resulting experimental samples underwent pasteurization at (87 ± 2) °C without exposure. Both salts proved highly soluble in buttermilk. Zinc citrate tended to reduce the active acidity of the samples whereas zinc lactate caused a significant pH decrease, starting with 0.013 g per 100 g buttermilk, which corresponded to 30% recommended daily zinc intake. Both salts raised the titrated acidity, but as their acid residues had different properties, this variable was 37-42 °T in the samples with zinc lactate and 35 °T in the samples with zinc citrate. The active acidity remained almost the same as titrated acidity grew, which means that the protein component in the skimmed milk powder increased the buffer capacity of the systems. However, neither zinc lactate nor zinc citrate affected the sensory properties of the experimental products.