| 摘要: | 本研究目的欲探討乳酸菌在經模擬胃腸道條件之酸及膽鹽作用後其益生功效之改變，以Lactobacillus acidophilus BCRC 10695, Bifidobacterium bifidum BCRC 14615, L. paracasei BCRC 14023作為益生菌株，Clostridium perfringens BCRC 13019作為拮抗能力試驗之病原菌株，試驗項目包括乳酸菌之酸及膽鹽耐受性、酸及膽鹽作用前後其吸附能力、拮抗病原菌能力、β-半乳糖苷酶活性(β-galactosidase activity)及其安全性試驗等。酸與膽鹽耐受性是分別及連續以pH 2, 3, 4之酸液及0.1, 0.2, 0.3%膽鹽溶液進行試驗。模擬腸道吸附試驗則以乳酸菌對模擬腸道細胞Caco-2 cell之吸附能力為試驗模式，病原菌拮抗能力則以乳酸菌對產氣莢膜梭菌在模擬腸道細胞之吸附抑制與取代試驗來進行。結果顯示L. acidophilus具最佳酸耐受性(p<0.05)、L. paracasei具最佳膽鹽耐受性(p<0.05)，在不同pH值酸液及不同濃度膽鹽連續作用後，各試驗乳酸菌株於pH 4酸液及0.1% 膽鹽作用後具較高存活菌數及存活率。在模擬腸道吸附性試驗方面，L. acidophilus具最佳吸附能力(p<0.05)，而在酸(pH 4)及膽鹽(0.1%)連續作用後之吸附能力則是L. paracasei (80.6%)>L. acidophilus (9.71%)>B. bifidum (5.20%)。拮抗能力的試驗結果則顯示，乳酸菌經pH 4酸液及0.1% 膽鹽作用後，各試驗菌株仍保有拮抗C. perfringens之能力。β-半乳糖苷酶活性試驗中發現在經相同pH值之酸液作用後，接著隨膽鹽作用濃度增加，其β-半乳糖苷酶的活性也隨之增加，顯示菌體細胞膜因受上述條件作用後之傷害程度也增加。此外，安全性分析試驗也顯示本研究所使用試驗菌株具有安全性。本研究發現低pH值酸液及高濃度膽鹽致使乳酸菌株無法存活，而喪失其吸附能力，但於pH 4酸液及0.1% 膽鹽連續作用後存活之菌株，仍具有吸附力並能有效拮抗病原菌吸附。
This study investigated the changes in probiotic properties of lactic acid bacteria (LAB) after being treated with simulate gastrointestinal condition of acid and bile salts. Lactobacillus acidophilus BCRC 10695, Bifidobacterium bifidum BCRC 14615, L. paracasei BCRC 14023 were used as probiotics, and Clostridium perfringens BCRC 13019 was studied in the antagonistic activity for the selected LAB. Tested items included acid and bile tolerance, adherence, antagonistic activity, β-galactosidase activity, and safety aspect of the LAB after acid and bile treatment. For the acid and bile tolerance tests, the LAB were treated with pH 2, 3, 4 acid solution and 0.1, 0.2, 0.3% oxgall bile solution, respectively or continually. The adhesion assay determined the adherence rate of LAB adhered to the simulate intestinal Caco-2 cell as the tested model. Both adherence inhibition and displacement test were used for the study of LAB antagonistic activity against C. perfringens. Results showed that L. acidophilus exhibited the best acid tolerance (p<0.05), and L. paracasei had better bile resistance than the other two tested probiotics (p<0.05). All tested LAB had better viable count and survival rate after being treated with pH 4 acid solution and then 0.1% bile soluion. Adhesive ability of LAB after exposure to acid (pH 4) and bile (0.1%), shown in adherence rate in descending order, were L. paracasei (80.6%)>L. acidophilus (9.71%)>B. bifidum (5.20%). LAB pretreated with pH 4 acid solution and 0.1% bile solution retained the ability of diminishing the adhesion of C. perfringens (p<0.05). After exposure to the same pH acid solution, the injury of LAB cell membrane raised with the increased bile salt content, leading to higher β-galactosidase values. The result of invasion test for safety aspect revealed that LAB possessed a safety property. Some of the tested LAB after the treatments of acid solution with low pH value plus bile solution of high concentration would lead to death. The tested LAB surviving the treatment of pH 4 acid and 0.1% bile solution still remained the characteristics of adhesiveness and antagonistic activity toward the pathogen. |
