Apparent viscosity and syneresis of fermented milks made from cow's and goat's milk containing intestinal bacteria
1997
Mikuljanac, A.M. | Macej, O.D. | Obradovic, D.B. | Jovanovic, S.T. (Poljoprivredni fakultet, Beograd (Yugoslavia). Institut za prehrambenu tehnologiju i biohemiju)
Milk was inoculated with starter culture ABY-1 (Chr.Hansen) that contains intestinal bacteria and yoghurt culture bacteria. Four cow's milk products and two goat's milk products were produced. The influence of fat content (0.05 and 2) and incubation temperature (40 and 43 deg C) on rheological properties of cow's milk was investigated. Skim milk products are more various and more susceptible to syneresis if compared to partially skimed milk products. These results could be explained by the fact that acid casein gel made from skim milk is more porous, consisting of thicker and stronger protein chains. Acid casein gel made from skim milk is more susceptible to structural damage during mechanical treatment, therefore of shorter time mechanical treatment and cooling is proposed. On the other hand, milk fat promotes finer gel structure with more branched protein matrix and smaller pores. Milk fat act as a "buffer" during mechanical treatment, also. From full fat goat's milk two products were made: with and without Na-caseinat (0.5), at the same incubation temperature (43 deg C). Na-caseinat improves rheological properties by increasing viscosity and decreasing syneresis. Product made from goat's milk with the addition of Na-caseinat shows markedly lower viscosity in comparison to cow's milk products.
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