Sorption isotherms of milk mixture

Abstract

The article contains a brief description of water activity determination. The impact of water activity on the humidity of the food and it affecting microbial cells are described. Definition and classification of sorption isotherms with a brief description of each type are considered. Sorption isotherms of food materials are generally in sigmoid shape. There are given for each type of sorption isotherms the examples of products that lead the type. Sorption isotherms for products with high humidity are shown. The technology of sample preparation and the experiment conduction are described in detail. It is analyzer Roremeter RM-10 was used in the work. The analyses of inert fillers like cellit powder, which are used when liquid samples, is given. The freezing point of the milk product was measured for liquid (not thick) solutions. Humidity measurement of native samples were carried out by express method with hygrometer Radwag. The initial values of water activity, the freezing temperature, and humidity of the native samples of powdered milk and sterilized milk are given. The sorption isotherms of dairy product of various fat content, when it is produced with sterilized milk or distilled water, are shown. The conclusions about contribution in type of sorption isotherm of sample and it components internals are given.