Biological value of zaanen goats' pasteurized milk proteins
Abstract
Goat's milk is positioned as biologically complete, suitable for the creation of functional products and baby food products. This is explained by the qualitative and quantitative composition of its main nutrients: proteins, lipids, carbohydrates, biologically active substances, micro- and macro-elements. The biological value of food raw materials is assessed by its ability to satisfy protein needs. Strict thermal treatment regimens are used for goat milk. This is caused by the quantitative ratio of casein and albumin fractions in goat milk and its specific organoleptic properties. Pasteurization of milk causes partial destruction of proteins, enzymes, hormones and evaporation of gaseous. This contributes to the improvement of sensory properties of dairy goat raw materials. The effect of high temperatures on goat milk proteins and its biological value has been little studied. The effect of pasteurization regimes on proteins was studied and indicators of the biological value of the samples were determined: without heat treatment; heat treatment 63 ± 2 °С, duration 30 minutes; heat treatment 87 ± 2 °С duration 5-6 minutes. The amino acid composition of the test samples was determined by acid hydrolysis on an LC2000 amino acid analyzer (Biotronik, Germany). Indicators of the biological value of proteins of pasteurized goat milk were calculated – coefficient of difference of amino acid composition, biological value, coefficient of utilitarian amino acid composition, coefficient of rationality of amino acid composition, coefficient of comparative redundancy. The general analysis of the obtained data revealed a positive effect of heat treatment on the indicators of the biological value of goat milk. The amino acid score of the limiting amino acid increased by 14.82–14.92 %; biological value – 11.4–13.02 %; the PDCAAS indicator – by 14.18–14.29 %; changes in the values of formalized indicators had the same tendency. The biological value of proteins for the application of thermal regimes is at the same level. It has been proven that pasteurization has a positive effect on the biological value of goat milk proteins. This makes the product safe and useful for all segments of the population and can be recommended for feeding children from 0 to 6 months. Prospects for further research are the development of milk drinks of a combined composition of raw materials with an improved recipe in order to enrich the product with limiting amino acids.
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