| Summary: | 碩士 === 嘉南藥理大學 === 保健營養系 === 105 === B0014, B0059, B0096 and, B0137 have been investigated and have the function of lowering blood pressure. Therefore, these four strains of lactic acid bacteria were further studied. The proportion of soybean milk powder in the medium were 4.5% (containing 4.5%yeast extract) and 8%, the results showed that 4.5% milk powder (containing 4.5%yeast extract) medium was the best medium for producing GABA with B0096. Then, the effects of different fermentation times on GABA were tested, the results showed that incubation at 37°C for 48hr was the best fermentation time for producing GABA. 4.5% soybean milk powder containing 4.5%yeast extract as base medium, different carbon sources (glucose, brown sugar, sucrose) were added and inoculated with B0096, cultivate at 37°C for 48 hours, from the test, addition 3% glucose into the medium for the production of GABA is better than other sugars. 4.5% skim milk powder was added to substitute for 4.5% soy milk powder, we found that 4.5% soy milk powder is still the best medium for producing GABA. Different nitrogen sources (soy peptone, peptone, yeast extract) were added into 4.5% soy milk powder containing 3%glucose. The yeast extract was shown to be more suitable for the production of GABA than the others. 3%, 6% and 4.5% of the yeast extract were tested, it was found that 4.5% yeast extract is the preferred medium for producing GABA. The final medium composition formula were 4.5% soy milk powder, 3% glucose, 4.5% yeast extract (4.5% SMP+4.5% YE+3% G). Using this medium formula, B0014, B0059, B0096, B0137 were inoculated, and incubated at 37°C for 48 hours, the results showed that the content of GABA produced by B0096 was higher than other strains. Followed using 1% protease to hydrolyze the 4.5% soy milk powder, 3% Glucose, 4.5% yeast extract medium for 1 hour, and then inoculated B0096. lt was found that GABA content was higher after hydrolysis treatment. GABA lyophilization experiments were carried out under the same condition and ground into powder, the GABA content was analyzed by HPLC. When no excipient was added, GABA content was 12.8 ± 1.9 g/100g and the yield was 16.13% ,whereas, the addition of excipient ,GABA content was 5.20 ± 1.14 g/100g and the yield was 52.60%。
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