| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 96 === Chlorella was fermented with five mixed lactic acid bacteria for up to 40h at 42℃. A protease was added at the beginning of fermentation. The supernatant fraction was separated from the fermented Chlorella and freeze-dried. The inhibitory effect of supernatant against angiotensin I converting enzyme (ACE) and production of γ- aminobutyric acid (GABA) were investigated. Chlorella (with pulverized cell) was fermented with protease-facilitated. As the fermentation time extented to 40h, peptide content increased from 27.3 to 255.01 mg/g and inhibition of angiotensin I converting enzyme (ACE) IC50 decrease from 0.120 to 0.089 mg peptide/mL, and γ-aminobutyric acid (GABA) increased from 4.49 to 164.10 mg/100 g. After gastrointestinal digestion, the ACE IC50 was increased to 0.109 mg peptide/mL. The supernatant was separated into four fractions by size exclusion chromatography on a Sephadex G-15 column. The fourth fraction of supernatant having molecular weight ranged 320-290 Da showed the lowert IC50 being 0.006 mg peptide/mL. This fraction was further analyzed by HPLC. The peak (D6~D11) of most active peptide having inhibitory efficiency ratio (IER) larger than 1000%/mg/mL was selected. The amino acid sequences of the inhibitory peptide D6, D7, D8, D9, D10 and D11 were Phe-Tyr (IC50=18.05 μM), Asp-Trp (IC50=31.81 μM), Ala-Trp (IC50=9.19 μM),Tyr-Phe (IC50=45.76 μM), Val-Trp (IC50=2.27 μM ) and Ile-Trp (IC50=1.33 μM), respectively.
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