The Preparation Of Alginate Oligosaccharides And Itsapplication In The Production Of Beer

Oligosaccharides is oligomer of alginate, a kind of functional oligosaccharides. In recent years, the application of alginate oligosaccharides have already attracted more attention, but the effects of alginate oligosaccharides on the growth of contaminating bacteria in beer rarely reported. The methods of preparation of alginate oligosaccharides with H2O2 were optimized for bacteriostasis of beer bacteria. The degradation time, temperature, concentration of H2O2 and concentration substrate of preparation of alginate oligosaccharides was optimized. The alginate oligosaccharides prepared by different conditions were added to MRS medium and the bacteriostasis of Lactobacillus brevis 49 was tested for confirming high antibacterial activity of oligosaccharides. The results showed that alginate oligosaccharides have optimal antibacterial effect under the condition 50 min, 70℃, 5%(v/v) H2O2 and 1.25%(w/v) alginate. The different alginate oligosaccharides which were of preparation by the method of aicd and H2O2 were compared on the antibacterial effect.We were found that the method of H2O2 was better than that of aicd. The results showed that the antibacterial effect had been found when alginate oligosaccharides were added to the medium which were used to culture mixed beer bacteria strains, Escherichia coli, Bacillus subtilis, Saccharomyces, Penicillium and Aspergillus. The antibacterial effect had been strengthened when the concentration of alginate oligosaccharides increased, and finally the alginate oligosaccharides could complete inhibition beer bacteria. A new way was provided for the study of alginate oligosaccharides on the effect of inhibition beer bacteria.The effect of different concentrations of alginate oligosaccharides on the germination ability of barley was studied. Alginate oligosaccharides had effect on sprouting and growth of the barley. Germination rate decreased with the increase of concentration of alginate oligosaccharides. The influence of different steeping technology on the barly germination was compared. Alginate oligosaccharides(0.5%) were added in the first steeping. One was 0.5 % added of alginate oligosaccharides in the first time. The other was 0.5 % added of alginate oligosaccharides in the first two time steeping. The result showed that the germination of barly was increased when the alginate oligosaccharides was added at the first time.