The objective of this study was to investigate the differences in antioxidative activities of swordfish tissues. The levels and compositions of free amino acids (FAA) of swordfish tissues were determined and their association with antioxidant activities was also studied. The total amount of FAA in tissues varied from 67 to 14 μmol/g. Anserine was the dominant FAA and accounted for 73% of the total FAA in white muscle. Five methods including the inhibition of linoleic acid autoxidation, scavenging effects on DPPH (a,a-diphenyl-b-picrylhydrazyl) free radical and superoxide, and chelating abilities of Cu2+ and Fe2+ were used to evaluate the antioxidative activities of trichloroacetic acid (TCA) extractives from swordfish tissues. The white muscle extractives of swordfish had stronger activities than other tissues. The composition of free amino acids and dipeptides showed that the white muscle with the higher activity contained much more histidine, carnosine and anserine. The amount of histidine-related compounds in fish extractives might be an important factor influencing their antioxidative activities. 本研究為探討旗魚各組織部位游離胺基酸組成與含量及其抗氧化性強度之差異。旗魚各部位的游離胺基酸總量在67至14 μmol/g之間，其中普通肉之甲肌肽為主要成分，約佔總量之73%。五種檢測方法包括抑制亞麻油酸自氧化、捕捉DPPH自由基、捕捉超氧陰離子、還原能力、螯合銅、鐵離子等被使用來評估旗魚各組織部位含氮萃取物之抗氧化性。結果顯示普通肉含氮抽出物具有較強的抗氧化能力，經比對其游離胺基酸與雙胜肽組成與含量，發現普通肉含有較多量的組胺酸、肌肽及甲肌肽。統計分析顯示魚類萃取物含組胺酸相關化合物者與抗氧化能力的強弱有關。
