| Summary: | 碩士 === 國立中興大學 === 生命科學院碩士在職專班 === 92 === For convenience and stability throughout shelf life, the addition of probiotic powder into foods served as functional food became an interesting trend. Probiotic should tolerate gastric acid and bile salts when transit through stomach and small intestine, then adhere to intestinal mucosal and proliferate to promote the health of host. Therefore, evaluated the characteristics of commercial probiotic powder including acid tolerance, bile tolerance, thermal tolerance, acid production and antimicrobial activity were executed in this study, further evaluated the viability of probiotics contained in functional foods affected by storage temperatures.
Three commercial probiotics powder based on Lactobacillus acidophilus, Streptococcus faecalis and Bacillus coagulans were evaluated. The heat treatment on L. acidophilus and S. faecalis (45 - 50 ℃) and on B. coagulans (60 - 70 ℃) promoted the thermal viability. L. acidophilus was the highest acid producer (52 — 121 mM) among the three probiotics and acid production was proportional to the inoculum size. The antimicrobial activity of the supernatant from L. acidophilus on Gram negative bacteria Escherichia coli and Salmonella choleraesuis but not Stapylococcus aureus and Candida albicans was observed and was the most effective among three probiotics tested. All three probiotics are weakly bile salt tolerance at 0.01 %. The major factor influenced the viability and acid production of probiotics contained in functional food during storage was the storage temperature. The viability of the probiotics stored at 5 ℃ for 3 months was higher than 67 % and was superio
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