Passive fillers for water activity measurement

The paper is dedicated to passive fillers, which are the necessary substances for a method of water activity determination in liquid samples by mirror dew-point temperature measurement. A number of such fillers for water activity analyzer Roremeter RM-10 are tested. The comparative analyses of their features and standard cellit-powder’s characteristics is provided. The following fillers are recommended as the most effective replacers of cellit: carefully dried absorbent carbon, cleaved lignin, kaolin, silicagel, pounded red and fire brick, and ceramic plate pieces

Changing of milk freezing temperature after introduction of new requirements to its acidity

The article deals with some consequences of changing requirements to the level of cow milk acidity under different thermal treatment. The factors, which affect the normalized acidity values of raw milk, are under consideration. The interconnection of cryoscopic temperature and titratable acidity of the product is shown. The general dynamics of freezing temperature changes of heat-treated milk has been traced by the example of three finishedproducts from well-known Belarusian producers for a few last years. It is shown the decrease of freezing point for milk products after introduction of more stringent requirements to acidity of the raw material

Analysis of milk some physical-chemical properties after introduction of new requirements to its acidity

Some consequences of recent change of the demands to cow fluid milk acidity are discussed. The average results of freezing point, titratable and active acidities, conductivity, water activity, density, moisture, nonfat milk solids of milk were analyzed. The samples of market pasteurized milk, ultra-high-pasteurized milk, sterilized milk and baked milk were investigated. The factors that affect the normalized titratable and active acidities value were described. The relationship between the study of physical and chemical properties is shown. The dynamics of their changes in drinking milk in recent years is traced. Losses of the freezing point, pH and titratable acid ity of dairy products following the introduction of new requirements to its acidity were demonstrated. The amount of ions and nonfat milk solids in pasteurized milk were increased. The water activity and nonfat milk solids in ultra-high-pasteurized milk were not changed. The stabilization of moisture in sterilized milk and increase the conductivity of baked milk is shown. The technological modes produces of drinking milk led to increase the pH value range

Application of cryoscopy for detection of milk adulteration by ammonia

The results of researches of freezing temperature and titratable acidity of milkforcibly adulterated by ammonia are given in the article. Samples of the sterilized milk are used for researches. To reconstruct the origin of the phenomena the conditions of high acidity milk production are considered in details. The process of natural souring of sterilized milk is analyzed. Buffer properties of milk are described. Much attention is paid to the description and discussion of occurring processesat introduction of additives of water solution of ammonia

Sorption isotherms of milk mixture

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

Comparative analysis of optimal algorithms treatment of stationary Poisson fluxes

Two Poisson signals detectors that use the results of number of events' accounts accounting or time intervals between the neighboring events measurements are described. It is displayed the both detectors could provide the close detection characteristic