摘要
Production of polysaccharides by lactic acid bacteria is vital and its technology is very important, too in dairy study. The selection ofexpolysaccharides producing encapsulated Lactobacillus bulgaricus in alginate gel and the factors affecting the production of polysaccharides such as time, temperature, pH and the growth with Streptococcus thermophilus were studied, pH 5.5 and temperature 35℃/18hr were found to be optimal for exopolysaccharides production by encapsulated L. bulgaricus and free culture yielding 600 mg/L and 380 mg/L respectively. Co-culturing L. bulgaricus with S. thermophilus increased exopolysaccharides production at 35 ℃/18hr to 660 mg/L by encapsulated cells and 400 mg/L by free culture. Results of this study were applied in the manufacture of Labneh cheese vitally containing probiotic species ofL. acidophilus, L. gasseri, L. johnsonii and protection of these bacteria by polysaeeharide produced encapsulated L. bulgaricus. The use of exopolysaccharides producing encapsulated L. bulgaricus and probiotic bacteria can provide acceptable quality to functional Labneh. This product can be used as therapeutic and diabetic milk product with highly acceptable qualities. It is noted that all of the results are the means of triplicate experiments.
