ŻYWNOŚĆ. Nauka. Technologia. Jakość, 2005, 2 (43) Supl., 289 – 297

DOROTA ZIELIŃSKA

SELECTING SUITABLE BACTERIAL STRAINS OF LACTOBACILLUS AND IDENTIFYING SOYA DRINK FERMENTATION CONDITIONS

S u m m a r y

The objective of this study was: to develop a special soya drink fermentation technique in order to obtain a soya drink with special probiotic properties, to identify and select fermentation conditions, and to determine the number of live bacteria during a 16 day period of storing the fermented soya drink at a temperature of 10^oC. Furthermore, sensory qualities of the product were evaluated.

The soya drink was inoculated using ten different, potentially probiotic bacterial strains, their initial number being 7,5x10⁷ cfu/ml; next, the drink was fermented at a temperature of 32^oC during 9 hours or at 37^oC during 6 hours. It was stated that the better fermentation conditions were created when the fermentation time was 6 hours, and the fermentation temperature was 37^oC. It was proved that there were no statistically significant differences regarding the palatability of the product. The number of bacteria in the soya drink inoculated using Lactobacillus casei KN291, fermented during 6 hrs at a temperature of 37^oC, and stored at a temperature of 10^oC, increased from the initial number of 8,87 log cfu/ml just after the fermentation process accomplished to 9,29 log cfu/ml on the 12^th day, and remained at the same level until the 16^th day. During this period, the sensory quality of the soya drink worsened, the intensity of sour and bitter taste increased, and consistency of the dink unfavourably changed.

Key words: probiotics, soya drink, fermented food