FERMENTED KVASSWITH BEETROOT JUICE AS A BETALAIN SOURCE

IODZSN

Abstract

The study examined the changes in betalain contents of beetroot juice, kvass wort and finished kvass with time under various technological factors. The subject of the study comprised beetroot juice obtained from blanched (at 70 °С for 2 minutes) and non-blanched Bordeaux 237 table beet taproots, kvass wort with beetroot juice representing 5, 10 and 15 % of the dry solids weight, and the finished kvass. Fermentation was initiated with S. cerevisiae yeast (strain Mead BVG-08) and a starter containing yeast and lactic acid bacteria (L. casei, L. аcidophilus). The study showed that preliminary blanching of raw material had a positive impact on betalain preservation in the juice, reducing betalain degradation speed in half. Betacyanin fraction loss in the course of storage amounted to about 3 %, in contrast to the samples obtained from raw beetroot. Heat processing while stored had no effect on betaxanthin contents.

Identical patterns were noticed in the decline of betalains in kvass wort under yeast fermentation and combined fermentation. When a portion of juice amounting to 5 % of kvass wort dry solids weight was introduced, the betalain ratio decreased by 15.5 %, by 54 % when a 10 % portion was added, and by 50 % in case of a 15 % portion.

The fermentation procedure was shown to be less intense in the samples with juice than in the control samples. When a combined fermentation starter was used, the pH value reached the required level in 14 hours, while kvass wort under yeast fermentation reached the same level in 19 hours. Tasting allowed us to select 2 samples characterized by a distinctive color and a palatable beetroot flavor, namely those with 5 % and 10 % beetroot juice, which scored 14 and 13 points respectively.