The study of pasteurization temperature’s action and of the casein addition on the formation of yoghurt rennet

Abstract

The acid dairy products are acquired through the fermentation of the milk lactose, with the help of the milky starter cultures. Through lactose fermentation they obtain the milky acid, which increases milk acidity, determining his coagulation. The application of pasteurization regime is made with the purpose of destroying all the forms of micro-organisms probable to be present, respectively of the noxious bacterium’s, as well as of the ordinary milk’s micro-flora, creating this way favorable conditions for the development of the selected milky bacterium’s with what it is inseminated the milk. For getting a superior quality yoghurt with a compact consistency on a colloidal thicker structure which puts on the brake the separation of the whey, it is also recommended the addition of caseinates and coprecipitates in order to grow the dry substance content, respectively to enhance the jelly properties and the sliminess of products. The investigations regarding the study of the pasteurization temperature’s action on the formation of whey and on the physics-chemical parameters were realized using yoghurt samples with addition of casein in a proportion of 1%, 2%, 3%, 4%, 5%. The technological bearing of the samples was analyzed through classical methods of analysis. From the analysis of the resulted data we conclude that the 80 Celsius degrees temperature is optimum for pasteurization process, and the sample with addition of 1% has physics-chemical characteristics approximately similar to the ones of the yoghurt obtained according to the recipe.