| Summary: | 博士 === 靜宜大學 === 食品營養學系 === 103 === The behaviours of lactic acid bacteria cultured in soy milk and green tea extract and then spray dried into microcapsules were investigated. In addition , the production and properties of biosurfactant from Alcaligenes piechaudii CC -ESB2 were also investigated. The minimum populations of five tested strains cultured in soy milk including B. adolescentis, B.infantis, L. acidophilus, L. brevis and L. fermentum were found to be higher than 6.0 log CFU/mL , which is the standard population of health benefits. Generally, lactic acid bacteria spray dried microcapsules produced with spray drying inlet temperature / outlet temperature at 120/60 ℃ had ideal performances in survival, water activity and moisture content . The size of the microcapsules (particle size) was affected by carrier, but not by bacteria (core material). The moisture sorption isotherm ,too, was affected by carrier, but not by bacteria (core material). Particle size of microcapsule should be large enough for the bacteria to live. The level of IMOS(isomaltooligosaccharide syrup) in carriers increased, the survival of lactic acid bacteria decreased. Microencapsulated lactic acid bacteria was found more resistant than free one to low pH test and was also found that lactic acid bacteria could proliferate with IMOS under bile salts condition.The permeability of cell membrane increased owing to high spray drying temperature and high level of IMOS in carrier and would cause the damage of cells. The viable B. adolescentis and L. acidophilus cultured in green tea extract were lower than cultured in MRS broth, but they survived to the high spray drying temperature better than the later. B. adolescentis spray drying process by not only its secretion and antibacterial effects are still better than some of those without spray drying antibacterial effect. The microcapsule added with the biosur-factant from Alcaligenes piechaudii CC-ESB2 would increase the flow ability than those who did not add. Eight BECMHFs (biosurfactant extracts from Chinese medicinal herb fermentation) produced using Alcaligenes piechaudii CC-ESB2 exhibited antioxidant capabilities, including ,2-diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide scavenging activity, and superoxide dismutase (SOD)-like activity at a concentration of 10 mg/ml.
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