Utjecaj praška Spiruline platensis na mikrofloru jogurta i acidofilnog mlijeka

The main purpose of this research was to monitor the influence of the powdered Cyanobacterium Spirulina platensis addition to plain yoghurt and the yoghurt containing Lactobacillus acidophilus on survival of the microbiota during the refrigerated storage. The cell viability of yoghurt starter cultures (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) and Lactobacillus acidophilus under refrigeration conditions in yoghurts prepared with (0.5 or 1.0 (w/w) %) and without the addition of Spirulina powder was investigated. The yoghurts were prepared under hygienic laboratory conditions and their pH and acidity were controlled during the process. The samples of yoghurts were stored at 4 °C and investigated on days 1, 5, 10, 15, 20, 25 and 30. Viable counts of the lactic acid bacteria were above 6 cfu g-1of all “spirulina powder” added samples whereas control yoghurt samples contained lower lactic acid bacteria count at the end of the storage period. Addition of 1 % Spirulina platensis powder into the yoghurts did not cause significant differences on the viable lactic acid bacteria (p≤0.05). The results showed the positive effect of S. platensis powder on the survival of the lactic acid bacteria during storage of yoghurt (P≤0.05). The sensory analysis was also performed for the yoghurt samples. Sensory scores of 0.5 % spirulina powder added yoghurt samples were better than 1 % spirulina powder added ones. It was determined that spirulina powder added yoghurt is a good medium of lactic acid bacteria during the 30 days of refrigerated storage.Glavni cilj ovog istraživanja bio je ispitivanje utjecaja dodatka praškastog Cyanobacterium Spirulina platensis u jogurt te jogurt obogaćen s Lactobacillus acidophilus na preživljavanje mikroorganizama tijekom čuvanja u hladnjaku. Ispitivano je preživljavanje starter kulture jogurta (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus) te Lactobacillus acidophilus u uzorcima pripremljenim uz dodatak 0,5 % ili 1 % (w/w) te bez dodatka spiruline, nakon čuvanja u hladnjaku. Uzorci su pripremljeni u higijenskim laboratorijskim uvjetima te je tijekom postupka kontrolirana njihova pH vrijednost i kiselost. Uzorci jogurta čuvani su na 4 °C te su ispitivanja izvršena nakon 1, 5, 10, 15, 20, 25 i 30 dana čuvanja u hladnjaku. Broj živih stanica bakterija mliječne kiseline bio je iznad 6 cfu/g za sve uzorke s dodanim praškom Spiruline platensis, dok su kontrolni uzorci jogurta sadržavali manje bakterija mliječne kiseline na kraju vremena skladištenja. Dodatak 1 % Spiruline platensis u uzorke jogurta nije dao značajne razlike u broju živih bakterija mliječne kiseline (p≤0,05). Rezultati pokazuju pozitivan učinak dodatka praška Spiruline platensis na preživljavanje bakterija mliječne kiseline tijekom razdoblja skladištenja jogurta. Provedena je i senzorska analiza pripremljenih uzoraka. Senzorske ocjene uzoraka pripremljenih uz dodatak 0,5 % Spiruline platensis bile su bolje od uzoraka uz dodatak od 1 %. Zaključeno je da su uzorci kojima je dodan prašak dobar medij za bakterije mliječne kiseline tijekom 30 dana hladnog skladištenja