Abstract:

In order to promote the transformation of bound calcium into free form, cattle bone powder was fermented with Lactobacillus rhamnosus GG and Bifidobacterium infantis, respectively. A L9 (34) orthogonal test was designed to optimize the fermentation conditions of the above two probiotics, such as amount of added sugar, inoculation amount, bone powder concentration and fermentation time with calcium transformation rate as the main evaluation index. In addition, the survival rates of the two probiotics in simulated gastric juice and intestinal juice were compared respectively. Results indicated that the optimal fermentation conditions of cattle bone powder by Lactobacillus rhamnosus GG were as follows: amount of added sugar 11%, inoculation amount 3%, bone powder concentration 5 g/100 ml and fermentation time 72 h (the most significant affecting factor), and those by Bifidobacterium infantis were as follows: amount of added sugar 8%, inoculation amount 5% (the most significant affecting factor), bone powder concentration 10 g/100 ml and fermentation time 72  h. The calcium transformation rate by Lactobacillus rhamnosus GG fermentation was up to 32%, which was about 3 times as much as that by Bifidobacterium infantis fermentation. The survival rates of Lactobacillus rhamnosus GG in simulated gastric juice and intestinal juice were 10.38 and 16.35 times of those of Bifidobacterium infantis in the above two simulated juices, respectively.

Key words: probiotics, cattle bone powder, fermentation, free calcium, transformation rate