虱目魚含氮抽出物抗氧化活性之探討

Antioxidative Activity of Nitrogen Extractive Components from Milkfish

為篩選開發水產物作為天然抗氧化劑，本研究針對虱目魚含氮抽出物之各組織部位的游離肢基酸組成與含量及抗氧化強度差異做一比較。各組織之游離胺基酸總量在63至8μmol/g之間，其中普通肉的主要游離胺基酸為組膿酸，約佔縝量的78%；而血合肉及內臟的主要游離胺基酸為牛磺酸，分別估縝量的47%和29%。五種抗氧化性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、還原力、螯合銅、鐵離子等被用來評估虱目魚各部位含氮抽出物之抗氧化性。結果顯示普通肉含氮抽出物具有較強的抑制亞麻油酸自氧化能力及螯合銅、鐵離子能力；而血合肉及內臟則具有較強之捕捉超氧陰離子能力與還原力。經統計分析得知，普通肉的抗氧化性強弱與組胺酸含量有關；而血合肉與內臟之抗氧化性強弱則與牛磺酸含量有關。

The antioxidation of the extractive components from seafood was evaluated for natural antioxidant. The objective of this study was to investigate the differences in antioxidative activities of milkfish tissues nitrogen extractive components. The levels and compositions of free amino acids (FAA) of milkfish tissues were determined and their association with related antioxidant activities were also studied. The total amount of FAA in tissues varied from 63 to 8 μmol/g. Histidine was the dominant FAA and accounted for 78% of the total FAA in white muscle. In dark muscle and viscera, taurine was the dominant FAA and accounted for 47% and 29%, respectively. Five methods including the inhibition of linoleic acid autoxidation, scavenging effects on DPPH (α, α-diphenyl-β-picrylhydrazyl) free radical and superoxide anion, reducing power, and chelating abilities of Cu(superscript 2+) and Fe(superscript 2+) were used to evaluate the antioxidative activities of trichloroacetic acid (TCA) extractives from milkfish tissues. The results indicated that white muscle extractives had stronger inhibition of linoleic acid autoxidation and chelating abilities of Cu(superscript 2+) and Fe(superscript 2+) The dark muscle and viscera extractives had stronger scavenging effects on superoxide anion and reducing power. The amount of histidine and taurine in white muscle, dark muscle and viscera extractives might be an important factor influencing their antioxidative activities.