Thermal degradation kinetics of bioactive compounds from black rice flour (Oryza sativa L.) extracts     

《Journal of Cereal Science》2016

The effect of thermal processing on the degradation of the phytochemicals in black rice flour by means of fluorescence spectroscopy and degradation kinetics was investigated. In order to investigate the influence of food matrices, a comparative analysis between integral rice flour and different fractions was performed. The preliminary compositional results suggested a higher content in phytochemicals in fraction four of the seven fractions of black rice flour, which was sifting through a sieve with a diameter of 180 μm. The compositional complexity was highlighted by fluorescence spectroscopy. The heat-treatment caused structural changes that led to red- or blue-shifts in maximum emission. The first-order kinetic model was used to describe the mechanism of degradation. The activation energies were 10.07 ± 1.04 kJ/mol for total polyphenolic, 7.26 ± 0.58 kJ/mol for total monomeric anthocyanins and 6.71 ± 1.12 kJ/mol for antioxidant activity in case of integral flour extract. For fraction four extract obtained by, the E_a values were: 3.51 ± 0.53 kJ/mol, 11.49 ± 1.47 kJ/mol, 15.80 ± 1.50 kJ/mol and 19.91 ± 3.27 kJ/mol, respectively. The calculated values of the activation energy revealed higher temperature dependence of total polyphenols in integral flour and of antioxidant activity in fraction four, respectively.  相似文献   

Optimising the DPPH Assay for Cell-Free Marine Microorganism Supernatants     

Yehui Gang  Tae-Yang Eom  Svini Dileepa Marasinghe  Youngdeuk Lee  Eunyoung Jo  Chulhong Oh 《Marine drugs》2021,19(5)

Antioxidants prevent ageing and are usually quantified and screened using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. However, this assay cannot be used for salt-containing samples, such as the cell-free supernatants of marine microorganisms that are aggregated under these conditions. Herein, the DPPH solvent (methanol or ethanol) and its water content were optimized to enable the analysis of salt-containing samples, aggregation was observed for alcohol contents of >70%. The water content of methanol influenced the activities of standard antioxidants but did not significantly affect that of the samples. Based on solution stability considerations, 70% aqueous methanol was chosen as the optimal DPPH solvent. The developed method was successfully applied to the cell-free supernatants of marine bacteria (Pseudoalteromonas rubra and Pseudoalteromonas xiamenensis), revealing their high antioxidant activities. Furthermore, it was concluded that this method would be useful for the screening of marine microorganism–derived antioxidants, which also has numerous potential applications, such as salt-fermented foods.  相似文献   

仙草蜜抗氧化活性的研究     

陈鑫  陈虹  颜国钦  朱显荣  郑宝东 《农产品加工．学刊》2008,(5):43-46

利用Fenton反应,研究了仙草蜜清除羟自由基的作用;采用邻苯三酚自氧化法,研究仙草蜜清除超氧阴离子自由基的作用。结果表明,仙草蜜具有清除羟自由基和超氧阴离子自由基的作用,且在实验的范围内,其清除能力随浓度的增大而增强。  相似文献   

Antioxidant and Antifungal Activity of <Emphasis Type="Italic">Verbena officinalis</Emphasis> L. Leaves   总被引：1，自引：1，他引：0  

Casanova E  García-Mina JM  Calvo MI 《Plant foods for human nutrition (Dordrecht, Netherlands)》2008,63(3):93-97

The scavenging activity against DPPH (1,1-diphenil-2-picrylhydrazyl) radical and the antifungal effect against chloroform, ethyl acetate and 50% methanolic extracts of Verbena officinalis leaves were investigated. The activity of different fractions of 50% methanolic extract and some isolated compounds were also investigated. The results suggest that 50% methanolic extract and caffeoyl derivatives could potentially be considered as excellent and readily available sources of natural antifungal and antioxidant compounds.  相似文献   

高原农作物豌豆抗氧化和脂质过氧化研究   总被引：6，自引：1，他引：5  

李园媛 《农业科学与技术》2009,10(4):19-21

1材料与方法 1．1材料供试豌豆产于西宁互助,海拔3600m;供试小鼠体重18-22g,雌雄对半,由青海动物养殖场提供。  相似文献   

31种常见抗菌中药对DPPH自由基清除作用的分析   总被引：5，自引：0，他引：5  

李政  王国良  金珊  陈寅儿  徐国辉 《海洋水产研究》2005,26(1):38-40

采用乙醇提取法提取31种常见水产抗菌中草药中的抗氧化活性物质,采用DPPH自由基分析法测定各提取液抗氧化活性的强弱,并与茶多酚进行比较,以分析其对DPPH自由基的清除作用。结果表明,知母、白头翁和五味子3种中草药具有良好的清除自由基的作用。  相似文献   

Antioxidant activity of Cassia auriculata flowers     

Kumaran A  Karunakaran RJ 《Fitoterapia》2007,78(1):46-47

The ethanol and methanol extracts of Cassia auriculata flowers were screened for antioxidant activity. The antioxidant activity was determined by an improved assay based on the decolorization of the radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The ethanol and methanol extracts of C. auriculata flowers showed antioxidant activity in both assays.  相似文献   

山奈不同溶剂提取物对DPPH自由基的清除作用     

王锐  何嵋  周云  刘忠荣  刘磊 《安徽农业科学》2010,38(29):16232-16233

[目的]为山奈的综合利用和新型天然抗氧化剂的开发提供理论依据。[方法]山奈干燥粉碎后,用石油醚索氏抽提脱脂,以95%乙醇为溶剂,超声提取得山奈粗提物。粗提物依次用乙酸乙酯、正丁醇和重蒸水萃取,分别得到乙酸乙酯提取物（EAK）、正丁醇提取物（BK）和水提取物（WK）。用清除DPPH自由基法测试山奈不同溶剂提取物的抗氧化活性。[结果]对0.081mg/mlDPPH自由基清除率为50%时,山奈的乙酸乙酯提取物（EAK）、正丁醇提取物（BK）和水提取物（WK）的使用浓度分别为5.48、1.10、10.02mg/ml,3种提取物对自由基的清除能力（DPPH质量/提取物质量）分别为14.78、73.64、8.08。[结论]山奈正丁醇提取物对自由基的清除效果最好。  相似文献   

胡卢巴抗氧化成分提取方法研究     

冯涛  马文娜  阎国荣  彭立新 《天津农学院学报》2010,17(4):13-16,29

本研究探讨提取胡卢巴抗氧化成分的方法,旨在为胡卢巴的保健效用及其开发利用提供基本资料。采用乙酸乙酯、丙酮、水、乙醇、乙醚等溶剂,结合超声波处理从胡卢巴中提取抗氧化成分,对各种提取物设置不同的浓度梯度,分别测定清除超氧阴离子自由基的能力、对羟自由基的清除作用、抗膜质过氧化能力、DPPH自由基清除能力,以及测定总黄铜和总酚的含量。结果表明:5种溶剂提取的成分中,乙酸乙酯提取物的超氧阴离子自由基的清除率最高;乙醚提取物的羟自由基清除率最高;丙酮提取物的抗膜质过氧化能力最强;水提取物的DPPH自由基清除率最高;乙酸乙酯提取物的总黄酮测定结果最高;乙醚提取物的总酚浓度最高。  相似文献   

木绣球花清除自由基活性及其成分分析     

经弘羽 《安徽农学通报》2009,15(21):36-37,40

采用高效液相色谱和高分辨质谱以及二苯基苦基苯肼自由基试验法对木绣球（Viburnum macrocephalum）花提取物的成分及清除DPPH自由基活性进行了研究,结果表明：木绣球花的甲醇提取物具有一定的清除自由基活性,对DPPH自由基的半数清除浓度为7.1 mg/mL。供试木绣球花甲醇提取物主要成分为C7H12O6、C16H18O9、C23H22O12、C27H30O15、C19H26O12和C37H50O18。其中化合物C16H18O9和C19H26O12显示有弱的清除自由基活性。  相似文献