【作者】 吴海涛；

【导师】 朱蓓薇；

【作者基本信息】 大连轻工业学院 ， 食品科学， 2005， 硕士

【摘要】 牡蛎含有多种生理活性物质，是非常有潜力的天然抗氧化剂资源。本文以低温条件下制备三种牡蛎水提液：原液、内液及外液，并从原液中分离出三种抗氧化有效组分：多肽氨基酸、超氧化物歧化酶及金属硫蛋白。采用还原体系、二苯代苦味酰自由基（DPPH）体系、Feton体系、邻苯三酚自氧化体系及脂蛋白PUFA过氧化体系研究样品的抗氧化活性，并对牡蛎水提液抗氧化活性进行综合评价。结果表明，牡蛎水提液具有较强的清除自由基能力，并具有一定抗脂质过氧化作用。在还原体系中，牡蛎原液、内液及外液还原性相当；原液的还原性低于维生素C溶液；有效组分还原性大小为原液＞多肽氨基酸＞金属硫蛋白＞超氧化物歧化酶。在二苯代苦味酰自由基（DPPH）体系中，牡蛎原液、内液及外液清除自由基能力相当，且原液的清除能力强于维生素E；有效组分清除能力大小为：原液＞多肽氨基酸＞金属硫蛋白及超氧化物歧化酶，其中金属硫蛋白及超氧化物歧化酶无清除能力。在Feton体系中，牡蛎原液、内液及外液清除羟基自由基能力大小为：内液＞原液＞外液；原液的清除能力略低于硫脲；有效组分清除能力大小为：原液＞多肽氨基酸＞金属硫蛋白＞超氧化物歧化酶，其中超氧化物歧化酶无清除能力。在邻苯三酚自氧化体系中，牡蛎水提液清除超氧阴离子自由基能力大小为：外液＞原液＞内液，且原液的清除能力低于标准超氧化物歧化酶；有效组分清除能力大小为：原液＞超氧化物歧化酶＞多肽氨基酸＞金属硫蛋白。在脂蛋白PUFA过氧化体系中，牡蛎水提液抗氧化能力大小为：原液＞外液＞内液，其中内液具有助氧化作用；有效组分清除能力大小为：超氧化物歧化酶＞金属硫蛋白＞多肽氨基酸＞原液。由结果可知，牡蛎水提液清除自由基大小为O₂^-·＞·OH＞DPPH·；清除超氧阴离子自由基的能力与还原性密切相关。牡蛎水提液抗脂质过氧化能力不及自由基清除能力。牡蛎是很好的自由基清除剂和抗氧化剂，牡蛎水提液的抗氧化作用是多种组分协同作用的结果，抗氧化剂的抗氧化活性与评估的试验体系紧密相关。更多还原

【Abstract】 Oyster （Ostrea talienwhanensis Crosse） is a prosperous resource of natural antioxidantcontaining many active substances. Water extracts of full oyster （FO）, visceral mass （VM） andmantle cavity （MC） were prepared at low-temperature and the compositions in FO, peptideand amino acid （PAA）, superoxide dismutase （SOD） and metallothionein （MT） wereseparated. The antioxidant activities of these samples were studied in reducing power assay,DPPH assay, Feton assay, pyrogallol autoxidation assay and liposome oxidation assay. Theantioxidant activities of the extracts were synthetically evaluated.The results indicated that in reducing power assay, FO, VM and MC had similar power,which of FO was weaker than that of ascorbic acid. The power of compositions in FOincreased with the same diluted fold in following the order: FO＞PAA＞MT＞SOD. InDPPH assay, FO, VM and MC had similar scavenging capacity, which of FO was greater thanthat ofα-tocophenol. The scavenging capacity of compositions in FO increased with the samediluted fold in following the order: FO＞PAA＞MT and SOD, among them MT and SOD hadno scavenging effect on DPPH radical. In Feton assay, the scavenging capacity of oysterwater extracts increased in following the order: VM>FO>MC, and the capacity of FO wasweaker than that of thiourea. The scavenging capacity of compositions in FO increased withthe same diluted fold in following the order: FO＞PAA＞MT＞SOD, among them SOD hadno scavenging effect on hydroxyl radical. In pyrogallol autoxidation assay, the scavengingcapacity of oyster water extracts increased in following the order: MC＞FO＞VM, and thecapacity of FO was greatly weaker than that of standard Cu/Zn-SOD. The scavengingcapacity of compositions in FO increased with the same diluted fold in following the order:FO＞SOD＞PAA＞MT. In liposome oxidation assay, the antioxidant activity of oyster waterextracts increased in following the order: FO＞MC＞VM, and VM exhibited slightprooxidant effects. The antioxidant activity of compositions in FO increased with the samediluted fold in following the order: SOD＞MT＞PAA＞FO.The scavenging capacity of oyster water extracts on the different free radicals increased inthe following order O₂^-·＞·OH＞DPPH·. The remarkable scavenging activities on O₂^-·may be concerned with the reducing power. Oyster water extracts had weaker antioxidant activitiesin egg lecithin oxidation system than radical system. Oyster water extracts were goodantioxidants, and their antioxidant activities were attributed to the interaction ofmulticomponent. Furthermore, it was reconfirmed that the antioxidant activities wereconnected with the experiment system of evaluation.更多还原