INFLUENCE OF FREEZING CONDITIONS ON SURVIVAL STARTER CULTURES

Kako raste potreba za funkcionalnim pekarskim proizvodima, tako je od iznimne važnosti razvitak tehnologije proizvodnje i čuvanja ječmenog kiselog tijesta. U ovom radu je ispitan utjecaj čuvanja ječmenog kiselog tijesta u uvjetima hladnjaka i zamrzivača na preţivljavanje starter kultura. Zamrzavanje je provedeno primjenog visokog tlaka, imerzijom ili strujom brzog zraka u šokeru. Kao starter kultura je korištena heterofermentativna bakterija mliječne kiseline Lactobacillus reuteri. Određen je broj živih stanica laktobacila u svježem kiselom tijestu te nakon čuvanja 7, 14 i 28 dana na +4 ili -18oC. Dobiveni rezultati upućuju na to na nije došlo do značajnih promjena u broju živih laktobacila kod zamrzavanja imerzijom i šokerom, dok se zamrzavanjem visokim tlakom značajno smanjio broj živih stanica u kiselom tijestu.U hladnjaku se nije značajno promijenio broj živih stanica laktobacila te nije došlo do pojave plijesni na kiselom tijestu. As the need for functional bakery products grows, it is extremely important to develop production technology and methods of preserving barley sourdough. In this study, it is interrogated how cooling and freezing of sourdough will effect on survival of starter culture. Freezing is performed by applying a high pressure, immersion and with cold air in shocker. As a starter culture is used heterofermentative lactic acid bacterium Lactobacillus reuteri. Is determined by the number of living cells of lactobacillus in fresh sourdough and after saving 7, 14 and 28 days at +4 or -18 ° C. The results suggest that the there has been no significant change in the number of live lactobacilli in immersion freezing and shocker, while freezing with high pressure significantly reduce the number of viable cells in sourdough. In refrigerator the number of viable cells of lactobacillus did not change significantly and there was no mold on sourdough.