1998 Fiscal Year Final Research Report Summary
Study of peptides generated during milk fermentation of Lactobacilli and protease related to the peptide formation
| Project/Area Number |
08660334
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Zootechnical science/Grassland science
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| Research Institution | Kyushu Tokai University |
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Principal Investigator |
IGOSHI Keiji Kyushu Tokai University Faculty of Agriculture Professor, 農学部, 教授 (80148973)
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| Project Period (FY) |
1996 – 1998
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| Keywords | yogurt / peptide / Lactobacillus delbruekii subsp bulgaricus / protease / fermented milk |
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| Research Abstract |
The peptides generated during the skim milk fermentation of Lactobacillus delbrueckii subsp. bulgaricus(Lb. bulgaricus) and the protease which was related to the peptide formation were studied. 1, The peptides in the yogurt were examined by using the high performance liquid chromatography(HPLC). The primary structure of 22 peptides which were found in the yogurt was determined after the purification by HPLC.Most of determined peptides were from beta casein and some peptides were from kappa -casein. 2, The peptides generated during the skim milk fermentation of Lb bulgaricus were examined with the HPLC.The primary structure of the main peaks, which were found during fermentation, were cleared by automatic peptide sequencer. Most of them were from beta-casein and were located in two region of beta-casein, beta -casein(47-91) and beta-casein(193-207). 3, Protease were highly purified from the skim milk culture medium of Lb.bulgaricus. The protease was purified about 275 fold with a yield of 6.5 % using various chromatogray. The enzyme was most activity at pH 6.0, and had a temperature optimum at 35ﾟC.The enzyme was strongly inhibited by DlFP, and also inhibited by EDTA.The enzyme could degradedbeta-casein, but had no effect on as1- and k-casein. The many peptides originated from the beta- and alpha s2-casein were found as a result of action of casein by the enzyme.
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