MICROSTRUCTURAL AND MICROBIOLOGICAL INDICES OF THE FROZEN SOUR MILK AERATED DESSERTS AT STORAGE

ZCPGKC

Abstract

The demand for fermented milk products is due to the presence of such components of milk as fat, proteins, carbohydrates, minerals as well as lactic acid microorganisms and fermentation products. The fermented milk desserts consumed frozen and defrosted being produced according to the ice cream technology are the innovative fermented milk products with a long shelf life. The research of dispersion of the air bubbles and the ice crystals and survival of lactic acid microorganisms in the fermented milk desserts during their storage at a temperature of - 20°С with the content of a fermented component of 30 %, 50 % and 85 % were the aim of this study.

It was found that regardless of the amount of fermented base the mean size of the air bubbles and the ice crystals did not exceed the value of 50 µm being the indicator of the sensory imperceptibility of ice crystals and the creamy consistency of the product, mainly because of sizes of the air bubbles. The most stable dispersion of the air phase and slightly decreased dispersion of the ice crystals during 180 days of storage were found in desserts at using 85 % of fermented base.

The absence of pathogenic microflora and the presence of lactic acid microorganisms of at least 106 CFU/g were established in the research of microbiological indicators of desserts throughout the storage period.

Thus, the results obtained demonstrate a high dispersion of the ice crystals and the air phase and high survival of lactic acid microorganisms in the fermented milk desserts during 180 days of sto­ring. The increase of the amount of fermented base in the composition of fermented aerated milk desserts over 30 % has a positive effect on the stability of the air phase.