共查询到16条相似文献,搜索用时 93 毫秒
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建立脱皮花生涉税归类鉴定的快速检测方法——过氧化氢酶和过氧化物酶活性测定法。以pH 7.7的磷酸盐缓冲液提取花生中的过氧化氢酶,加入过氧化氢溶液后30℃水浴15 min,以0.1 mol/L高锰酸钾标准滴定溶液滴定剩余过氧化氢,通过高锰酸钾耗液量计算过氧化氢酶活动度;以pH 7.0的磷酸盐缓冲液提取花生中的过氧化物酶,25℃孵育30 min,加入愈创木酚和过氧化氢,在436 nm波长下,测定初始时和2 min后的吸光度值,计算两者之差ΔA,计算过氧化物酶活力。分别对鲜花生、出口生花生、干燥脱皮花生以及150℃烘烤30 min出口生花生和干燥脱皮花生进行过氧化氢酶和过氧化物酶活性测定。对数据做方差分析,结果有显著性差异。鲜花生中2种酶活性最高,经干燥后活性降低,150℃烘烤30 min后,2种酶失去活性。 相似文献
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过氧化物酶(peroxidase, POD)是一类大量存在于自然界及生物体内的氧化还原酶。其家族成员众多,但都可以催化以过氧化氢(H2O2)作为底物的氧化反应。现有研究表明可以通过利用过氧化物酶的氧化特性,来提高功能食品的质量属性和营养特性。而辣根过氧化物酶作为过氧化物酶家族的一员,近些年来被大量研究。尤其是在食品研究开发中,有很多都是通过使用辣根过氧化物酶去催化蛋白质或淀粉等食品分子来改善食品本身的性质或获得更合适的食品胶体,因此值得更深层次的挖掘其应用价值及市场。本文在介绍过氧化物酶的结构、催化机理及影响其催化的关键因素基础上,分析了过氧化物酶催化对食品分子结构和性质的影响,综述了近年来过氧化物酶在食品分子及其胶体体系修饰中的一些应用。 相似文献
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过氧化氢酶的功能及研究 总被引:43,自引:0,他引:43
过氧化氢酶是一类广泛存在于动物、植物和微生物体内的氧化酶,其功能是催化细胞内过氧化氢分解,防止氧化。在论述过氧化氢酶类型划分、结构特点及生理功能的基础上,对其分离纯化、活性测定、性质研究做了综述。 相似文献
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基于聚硫菫的一次性过氧化氢生物传感器的研究 总被引:1,自引:0,他引:1
用循环伏安法将硫堇电聚合在丝网印刷碳电极上,再用壳聚糖-二氧化硅溶胶凝胶将辣根过氧化物酶固定于聚硫堇电极表面,利用聚硫堇作为电子传递介体,用壳聚糖-二氧化硅溶胶凝胶固定辣根过氧化物酶并保持酶的生物活性,制成了新型过氧化氢生物传感器。实验发现,该传感器响应快、灵敏度高、稳定性好,对H2O2表现出良好的响应特性;检测线性范围为7.5×10-6~3.12×10-3mol/L,检出限为1.22×10-6mol/L,并具有抗葡萄糖、抗坏血酸等干扰的特点,有望用于食品中过氧化氢残留的检测。 相似文献
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检测牛奶中过氧化氢的电化学酶传感器的研制 总被引:3,自引:0,他引:3
构建一种基于聚硫堇的丝网印刷电化学酶传感器,用于牛奶中过氧化氢的检测。将硫堇电聚合在丝网印刷碳电极上,用壳聚糖二氧化硅溶胶凝胶包埋辣根过氧化酶并固定于聚硫堇电极表面,制成新型过氧化氢生物传感器。结果显示:在牛奶标液中加入不同浓度的过氧化氢后,该酶传感器的响应电流与过氧化氢浓度在3×10-5~1.5×10-3mol/L范围内呈良好的线性关系(R=0.9964),最低检出限为1.675×10-5mol/L。该传感器应用于牛奶中过氧化氢的检测与国标碘量法基本一致,其加样回收率范围为85.6%~89.4%。该酶传感器灵敏快速(15min)、制作方便、样品处理简单,有望用于牛奶中过氧化氢的快速检测。 相似文献
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Margaret A. Dix Charles J. Fairley David J. Millin Derwent Swaine 《Journal of the science of food and agriculture》1981,32(9):920-932
The natural peroxidase and catalase of tea leaf were shown to be active under the conditions employed for the fermentation of minced tea leaf in aqueous suspension. Fermentations carried out under nitrogen with ethyl hydrogen peroxide, which is not decomposed by catalase, yielded predominantly thearubigins, a high proportion of which were polymeric in nature. Fermentations using an excess of hydrogen peroxide gave similar results. Fermentations under conditions of controlled dissolved oxygen using both air and hydrogen peroxide resulted in a pigment distribution intermediate between those observed using air alone and using ethyl hydroperoxide under nitrogen. Adjustment of the amount of hydrogen peroxide used to around 120 μmol g?1 leaf resulted in a pigment distribution closely similar to that of a good quality black tea. A mixture of theaflavins was stable in the presence of air and tea polyphenoloxidase but decomposed rapidly to yield polymeric materials under the action of hydrogen peroxide and peroxidase derived from tea or horseradish. Kinetic measurements suggest that tea flavanols are generally poorer substrates for peroxidase than for catechol oxidase. However, the level of peroxidase is high and, furthermore, in view of the respective pH optima of the two enzymes, its action would be favoured as the pH falls during fermentation. It is postulated that the nature and distribution of the pigments formed during the fermentation of tea is governed in part by the relative actions of catechol oxidase and peroxidase. These actions are, in turn, influenced by the availability of oxygen and the action of catalase. 相似文献
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Ammonium sulphate fractionation of citrus flavedo callus showed considerable peroxidase activity with hydrogen peroxide and guaiacol as substrates. The activity of the enzyme was comparable to that of Sigma horseradish peroxidase. Citrus callus may be a potential source of commercial peroxidase enzyme. 相似文献
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Horseradish peroxidase in the presence of hydrogen peroxide oxidizes kojic acid (5-hydroxy-2-hydroxymethyl)-4H-pyran-4-one) to a yellow product(s). The yellow product(s) formed has a major absorbance peak at 375 nm and is fluorescent. The relationships between, and effects of, various concentrations of horseradish peroxidase, kojic acid and hydrogen peroxide on the rate of oxidation of kojic acid to the yellow product(s) are described. The observation that the oxidation of kojic acid to the yellow product(s) occurs best in the presence of very low concentrations of hydrogen peroxide, relative to that of kojic acid, suggests that kojic acid is a poor hydrogen donor (AH2) for horseradish peroxidase. 相似文献
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研究了离体处理下活性氧对河岸葡萄叶圆片抗氧化酶活性的影响.结果表明,外源H2O2和Fe2++H2O2处理4 h可引起河岸葡萄叶圆片细胞膜透性明显增加,引起APOD,GPOD和SOD活性明显下降,但低浓度活性氧可不同程度引起叶圆片CAT活性增加;细胞膜透性与活性氧浓度呈显著正相关. 相似文献
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研制金钯合金纳米粒子修饰的特异性定量检测食品中过氧化氢残留量的过氧化氢传感器。以比表面积大、生物相容性好、具有优良电催化性能的金钯合金纳米粒子固定辣根过氧化物酶于玻碳电极,制得过氧化氢传感器电极。通过循环伏安法及交流阻抗法表征电极在组装过程中的电化学特性,利用计时电流法对传感器性能进行考察。研究表明:该传感器测定H2O2的线性范围为1×10-7~5×10-3mol/L,检测限为8.0×10-7 mol/L,对H2O2具有较好的催化还原活性和良好的检出性能。该传感器制作简单、成本低廉、可重复性强,可用于快速定量检测食品中过氧化氢残留量。 相似文献
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Shirasaka N Ohnishi H Sato K Miyamoto R Terashita T Yoshizumi H 《Journal of Bioscience and Bioengineering》2005,100(6):653-656
Linoleic acid hydroperoxide (LAOOH) was effectively degraded by horseradish peroxidase (HRP) in the presence of quercetin. Several natural phenolic antioxidants, such as quercetin, capsaicin, and alpha-tocopherol, acted as good hydrogen donors in the peroxidase reaction that occurs during lipid hydroperoxide degradation. However, glutathione, which is a non-phenolic antioxidant that acts as a hydrogen donor for glutathione peroxidase, could not suppress lipid peroxidation in the presence of HRP. Lipid hydroperoxides generated from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also degraded with HRP in the presence of quercetin, and oxidative decomposition of DHA was suppressed by this reaction. 相似文献