INFLUENCE OF BERRY EXTRACTS ON THE TECHNOLOGICAL AND FUNCTIONAL PROPERTIES OF PROBIOTIC YOGURT BASED ON LACTIC ACID BACTERIA

Abstract

This document describes the effect of berry extracts on the fermentation process, sensory parameters and the number of viable bacterial cells of lactic acid bacteria in probiotic yogurt.

The document presents the results on the effect of berry extracts of Rubus caesius L. (blackberry) and Rubus idaeus L. (common raspberry) on the growth and reproduction of probiotic lactic acid bacteria Lactobacillus acidophilus 0015k-1 and Lactobacillus delbrueckii subsp. bulgaricus 018k-3 and commercial bacterial sourdough thermophilic streptococcus viscous (BZ-TV) (StST). In addition, the document presents the results on the fermentation kinetics and sensory characteristics of the final probiotic yogurt.

As a result, it was found that the addition of berry water extracts reduces the acidity of milk at the beginning of fermentation, then the acidity is almost equal to that of the control sample. Fermentation of milk in the control sample (without berry extracts) was observed after 4.5 hours. Samples with raspberry and blackberry extracts fermented with a difference of 15 and 30 minutes, respectively.

It was found that the addition of berry extracts during the fermentation of the probiotic product does not reduce its sensory qualities. In other words, no deviations in acidity, taste and consistency of the product were observed.

When determining the number of viable lactic acid bacteria cells in the final product on the 1st, 7th and 14th day, it was shown that the addition of berry extracts to the starter culture before fermentation had a positive effect on the viability of lactic acid bacteria. As a result, abundant growth of probiotic lactic acid bacteria was determined on the 3rd day of storage, in the number of cells not less than 1 * 10¹⁰ CFU. Determination of CFU titers was carried out in the laboratory "Nurtitest" at the Kazakh Academy of Nutrition.