| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 102 === Cordyceps militaris has various physiological activities including antimicrobial, anti-inflammatory, anti-cancer, hypochlosterol, and immune-enhancing activities. The active components in C. militaris include cordycepin, cordycepic acid, polysaccharids and nucleoside. Higher amounts of cordycepin and adenosine are obtained by solid state cultivation of C. militaris, compared with submerged cultivation of this species. γ-aminobutyric acid (GABA) has various physiological activities including hypotension activity, hypoglycemic activity, anti-depression and protecting liver and kidney from alcoholic damage. Fungi and lactic acid bacteria (LAB) are known for producing GABA; however, the activity varies with strains. The aim of this study was to establish a two-stage incubation of C. militaris and lactic acid bacteria (LAB). Koji by incubation of C. militaris in rice will be prepared. After adding water to C. militaris koji, LAB will be inoculated and incubated. 3 strains of C. militaris (C. militaris BCRC 32219、BCRC 33739 and BCRC 33740) were screened by optimal condition for solid state, C. militaris BCRC 32219 showed the highest GABA-producing ability among the screened strains. Optimum culture conditions for GABA production were determined: the ratio of embryo rice to wheat germ=2:1 containing 1% beef extract, 0.01% Vit B1, the incubation temperature at 25oC for 7 days. Under these conditions, C. militaris BCRC 32219 produced GABA at an amount of 32.02 ± 2.02 mg/g. Five high-GABA producing strains of LAB (FPA 3709, FPP 3713, FKR 3737, FKR 3739 and FKR 3741) from fish intestines were used as tested LAB to ferment the koji of C. militaris (CM koji). Three GABA-rich LAB strains, FKR 3737, FKR 3739 and FKR 3741 were screened out after incubation in the suspension of CM koji (12%, w/v) at 37oC for 48 hours, with GABA contents being 5.09 ± 0.18, 5.18 ± 0.26 and 4.76 ± 0.05 mg/mL. Furthermore, adding Zizyphus jujube and Dimocarpus lingan could improve aroma of final product, but the GABA production would decline.
Keywords: Cordyceps militaris; fish intestine; γ-aminobutyric acid (GABA)
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