| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 105 === The moisture content of short-finned eel (Anguilla bicolor pacifica), giant mottled eel (A. marmorata) and Japanese eel (A. japonica) is between 60.56-63.72%, crude protein 17.61-18.32%, crude fat 17.02-20.06%, and ash 1.03-1.58%. There is no significant difference in proximate composition of three species of eels. The eel meats were extracted with hot water, phosphate buffer saline (PBS) and trichloroacetic acid (TCA), and then get 1000 mg/mL (meat/water) of hot water, TCA and PBS extracts by vacuum concentration. The concentrates were diluted to 50, 100, 200, 300, 400, 500 mg/mL of each extract. The major free amino acids of eels were taurine, glycine, lysine and proline, and the predominant dipeptide was carnosine which was rich in eel meats. The contents of β-alanie and histidine in hot water and PBS extracts were higher than those of TCA extract, but carosine was lower. For the antioxidant capacity, DPPH scavenging rates of 500 mg/mL hot water extracts of short-finned eel, giant mottled eel and Japanese eel were 45.73, 42.24 and 41.46%, reapectively. The rates of hot water extracts were stronger than other extracts, but no significant difference was found in three eels. Chelating activity on Cu2+ of 500 mg/mL TCA extracts were 74.08, 87.51 and 83.24%, respectively, which were stronger than other extracts. Giant mottled eel showed higher activity than other eels. Reducing power was also higher in 500 mg/mL of hot water extracts, which were equal to 17.20, 19.79 and 24.54 ppm of Vitamin C. The power of Japanese eel was significantly higher than giant mottled eel and short-finned eel. Hot water extract showed stronger antioxidant activity than other extracts, and was selected for subsequent cell experiments. The murine RAW 264.7 macrophage cell (RAW 264.7) was induced by lipopolysaccharide (LPS, 1 μg/mL). The cell viability of RAW 264.7 cell treated with hot water extracts (50-500 mg/mL) were higher than 80%. The cell viability was also higher than 80% in the absence of LPS, indicating that RAW 264.7 cells did not cause harm by eel extracts. Three hot water extracts with the concentration of 50-200 mg/mL had a good anti-inflammatory effect by using RAW 264.7 cells induced by LPS. The inhibition rate of nitric oxide (NO) was between 13.0-25.9%, in which short-finned eel and Japanese eel were significantly higher than giant mottled eel. Few NO was released in the absence of LPS indicating that hot water extract would not promote cell inflammation. The results showed that short-finned eel, giant mottled eel and Japanese eel extracts had high content of carnosine and possessed antioxidant ability. The hot water extracts would not cause harm to cells and inhibit the inflammation using RAW 264.7 cells induced by LPS.
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