碩士 / 國立中興大學 / 食品暨應用生物科技學系所 / 99 / Lactobacillus reuteri is a species of microbes which is naturally present in the animal stomach and intestine microflora could benefit the human health. L. reuteri produces reuterin that can inhibit the growth of a broad range of pathogenic microbes. However, a major problem is low viability of lactic acid bacteria when arriving at the lower digestive tract due to the gastric acid and bile salts existed in the gastrointestinal system. In order to increase the viability of lactic acid bacteria at the harsh environments, microencapsulation could be used to improve probiotic survival against severe environmental factors. In this study, Ca-alginate was applied to L. reuteri for microencapsulation and trehalose 2％ (w/v) was used as a cryoprotectant for protecting the cell during -60°C frozen storage so as to study their protection effect on the enhancement of cell survival during frozen storage and their adhesion in the intestine. We also focused on the resistance of lactic acid bacteria against adverse environmental factors (pH 2, 3, 4 and 0.1%, 0.2%, 0.4% bile salt) and their antibacterial ability on Salmonella enteritidis. Results showed that microencapsulation techniques and trehalose not only protect L. reuteri from freezing injury but also maintain their activity for the production of acid. Microencapsulation could enhance bile salts tolerance of L. reuteri but unable to improve on acid tolerance. Besides, both microencapsulation techniques and trehalose enable to increase the inhibition of L. reuteri against Salmonella enteritidis and adherence to Caco-2 cells after frozen storage. In the well diffusion assay, the supernatant of L. reuteri could inhibit the growth of Salmonella enteritidis. As the frozen storage time increased, the antibacterial activity of L. reuteri supernatants significantly decreased (p <0.05). In addition, L. reuteri did not show any invasion effect and is safe for human health.
| Identifer | oai:union.ndltd.org:TW/099NCHU5253022 |
| Date | January 2011 |
| Creators | Su-Fen Teh, 鄭淑芬 |
| Contributors | V. An-Erl King, 金安兒 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 110 |
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