Canned dairy: factors of increasing preservation

Abstract

Introduction. The main criterion for the state of water in food is the indicator of "water activity" (Aw), which affects their quality and shelf life. Problem. At present, it is advisable to propose such changes in the recipe and technology of canned milk, which would reduce the rate of "water activity" and increase the osmotic pressure. The aim of the work is scientific substantiation of factors of canned milk preservation. Methods. Objects of scientific research – low-fat condensed low-lactose milk with a sugar content of 13, 16 and 31 %, the low-fat condensed milk with sugar by traditional technology was used as a control; dry milk multicomponent mixture with the addition of dry whey protein concentrate, as a control there was selected milk-carbohydrate mixture without protein component. Water activity (Aw) was determined on the device AguaLab-3TE, osmotic pressure – by cryoscopic method. The number of mesophilic aerobic and facultative anaerobic microorganisms was determined according to DSTU ISO 4833: 2006. Results. Samples of low-lactose condensed milk with mass fraction of 34 and 32 % and sugar content of 31 % in terms of osmotic pressure and "water activity" were the closest to traditional condensed milk with sugar and complied with current regulations on microbiological indicators. The dry whey protein concentrate, included into the formula of the dry milk multicomponent mixture, acts as a water-binding component, reducing the "water activity" to 0.290. Conclusions. The use of enzymatic hydrolysis of lactose with the use of the enzyme preparation β-galactosidase has a positive effect on the osmotic pressure and the indicator of "water activity". In the dry milk multicomponent mixture, the proposed dry whey protein concentrate as a water-binding component helps to reduce the rate of "water activity" and the number of microorganisms. The proposed changes in the technology and recipe of the investigated canned milk will allow to extend the shelf life of products.