29G-22 |
Screening of cholesterol assimilation lactic acid bacteria with bile salt and acid tolerance in Taiwan |
Y. J. LIU and C. C. Liao. Bioresources Collection & Research Center, Food Industry Research & Development Institute, PO Box 246, HSINCHU, 30052, Taiwan Lactic acid bacteria are frequently associated with health-promoting effects in human or animal intestinal tract. The purpose of this study was to screen cholesterol assimilation strains with bile salt and acid tolerance. Lactobacillus sp. strains were obtained from 43 feces samples of healthy toddlers or preschool children in Taiwan. Bile salt tolerance of the isolates was measured by growth in MRS broth with 0.3% oxgall (MRSO broth). Acid tolerance was verified by the total plate counts after incubating the isolates in pH 2.0 or pH 7.0 solutions at 37 oC for 2 hr. O-Phthaladehyde method was used to test cholesterol assimilation of the isolates grown in MRSO broth supplemented with horse serum or phosphatidylcholine-cholesterol micelles. Six isolates, B6T7, B21T1, B21T6, C21T1, X21B7, and B38T38, with desired properties were obtained. The properties of the isolates were compared to reference strain Lactobacillus acidophilus BCRC 17064 which has been shown to control serum cholesterol in pig in 1985 by Gilliland et al. Less than two logs reduction in cell number of the isolates was observed after grown in MRSO broth for 24 hr. Acid treatment of the isolates resulted in reduction of cell number by four logs. The degree of cholesterol assimilation the six isolates ranged from 91.2 to 97.2 % for horse serum and 26.4 to 44.6 % for phosphatidylcholine-cholesterol micelles, while these of the reference strain for horse serum and phosphatidylcholine-cholesterol micelles were 88.4 % and 29.1%, respectively. The results showed that all the isolates were tolerant to bile salt and acid and able to assimilate cholesterol.
Session 29G, Food Microbiology: General
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