Study on the fermentation condition of Goat yogurt for selenium-enriched

The impact of the different fermentation conditions was studied on selenium-enriched of the fermentated goat yogurtionthrough single factor screening and orthogonal experimental. The temperature, culture time of selenium-enriched, incubation temperature and the proportion of inoculation was determined by using selenium content in the bacteria as the index. The four important factors including selenium concentration, inoculum size, culture pH and the added amount of oligofruc to selenium were optimized through orthogonal test. The results showed that the single-factor test to selenium was riched after 24 hours of bacteria cultivation, incubated for 60h at 41℃ with ratio of Bifidobacterium longum, Lactobacillus acidophilus 2 ∶1 mixed culture through single-factor test. The orthogonal test was done according to the selenium content as the index. The best fermentation conditions were as follow:mixed inoculum of 3%, selenium concentration of 8μg/g, pH6.5, and1.00% fructo-oligosaccharides by selenium content in yogurt as the main index. The selenium content of goat yogurtion was 33.46μg/kg.