枣果皮中酚类物质提取工艺优化及抗氧化活性分析

为提高枣果皮中的酚类物质的提取效率,该文以马牙枣为试验材料,对枣果皮中酚类物质提取条件进行了优化,同时通过测定酚类物质清除2,2’-二苯基-1-间三硝苯基联肼(DPPH),2,2'-连氮基双(3-乙基苯并噻唑啉)-6-磺酸(ABTS)自由基和铁还原能力,分析了枣果皮提取物中酚类物质的抗氧化活性。结果显示,枣果皮中酚类物质提取的最优条件是采用70%(V/V)的甲醇、在40℃下,以1∶60的料液比浸提4h,重复浸提2次。枣果皮中酚类物质具有很强的抗氧化能力,与合成抗氧化剂2,6-二叔丁基对甲酚(BHT)相比,虽然果皮中酚类物质清除ABTS·+自由基能力略低于BHT,但其清除DPPH自由基和铁还原能力与之相当。研究结果表明枣果皮中酚类物质具有很强的抗氧化能力,在一定程度上可以取代合成抗氧化剂BHT,应用于食品加工业。     

大豆豆渣粗提物清除DPPH自由基活性及其协同效应的研究

用二苯代苦味肼基自由基(DPPH)-TLC法和酶标仪法对大豆豆渣石油醚、乙酸乙酯、丙酮、乙醇粗提物的自由基清除活性进行了定性和定量分析,考察了抗氧化剂维生素C、柠檬酸对大豆豆渣乙醇粗提物清除DPPH自由基活性的协同效应。结果表明:大豆豆渣不同极性粗提物均有一定的自由基清除活性,其中乙醇粗提物的自由基清除活性最强,在浓度为10.0 mg.mL-1,于37℃下保温15 min时,对0.4 mg.mL-1的DPPH自由基的清除率可达76.48%;维生素C和柠檬酸对大豆豆渣乙醇粗提物均能产生一定的协同效应,且维生素C的协同作用强于柠檬酸。     

Effects of genotype and environment on avenanthramides and antioxidant activity of oats grown in northwestern China

To investigate the effects of genotype and growing environment on avenanthramides and antioxidant activity of oats, the total phenolic content (TPC), avenanthramide compositions, and antioxidant activity were determined for whole oat from 39 cultivars grown in four locations in northwestern China (Inner Mongolia, Qinghai, Shanxi and Gansu). The results demonstrated that environment (E), genotype (G) and the interaction of these factors (E × G) significantly affected TPC, concentration of avenanthramide 2c (2c, ranged from 6.24 to 136.20 mg kg⁻¹), avenanthramide 2p (2p, 6.07–112.25 mg kg⁻¹), avenanthramide 2f (2f, 7.26–222.77 mg kg⁻¹) and antioxidant activity of oats. The effect of E was considerably greater than that of G or E × G. Based on G plus G × E interaction biplots (GGE biplots) analysis, the four locations in northwestern China can be divided into either two or three regions. Qinghai was determined to be distinct from the other locations. Cultivar Bayou 9 and oats grown in Gansu exhibited the highest TPCs, concentrations of 2c, 2p, 2f and antioxidant activity. The results suggest that oats containing more avenanthramides and exhibiting high levels of antioxidant activity could be obtained by selecting an appropriate genotype and growth location.     

Effects of gamma irradiation on starch granule structure and physicochemical properties of brown rice starch

In the present research effects of gamma irradiation (5–20 kGy) on the physicochemical, antioxidant and thermal properties of brown rice starch were studied. Scanning electron microscopy displayed mostly polyhedral shapes with no surface fractures. XRD displayed characteristic A type pattern and decrease in per cent crystallinity (22.53–20.41%) was observed as the dose increased from 5 to 20 kGy. DPPH % inhibition and FRAP values were increased in a dose dependent manner. Pasting properties (peak, final and setback viscosity) decreased with irradiation. Pasting temperature also significantly decreased with irradiation for all the irradiated starches. The transition temperatures, enthalpy of gelatinization, pH and apparent amylose content of starch decreased significantly with increase in irradiation dose.     

红树莓‘海尔特兹’组培苗抗氧化性的初步研究

本试验以‘海尔特兹’未生根和生根两个时期的组培苗为材料,对其各个部位的抗氧化酶活性、总酚含量及其对DPPH自由基的清除作用进行研究。结果表明:‘海尔特兹’组培苗的SOD活性在19.71~28.17U/g,未生根组培苗-茎的SOD活性最高,为28.17U/g,极显著高于其它器官;CAT活性在11.39~76.40U/g之间,生根组培苗—叶的CAT活性最大,为76.40U/g·min,极显著高于其它器官;POD活性在19.03~92.12U/g·min之间,未生根组培苗-茎的POD活性最高,为92.12U/g·min,极显著高于其它器官;POD活性与CAT活性呈负相关,未生根、生根组培苗均为茎的抗氧化酶活性叶根,未生根组培苗的抗氧化酶活性高于生根组培苗。‘海尔特兹’红树莓组培苗总酚含量在0.076~1.907mg/g FW之间,DPPH清除率在68.6%~93.4%之间,未生根组培苗-叶的总酚含量最高,为1.907mg/g FW,DPPH清除率为93.4%,叶的DPPH清除率茎根,总酚含量与DPPH清除率呈正相关,未生根的组培苗的总酚含量及DPPH清除率高于生根组培苗。     

丛生竹叶提取物的成分与清除自由基的能力

测定了23种丛生竹叶提取物得率、黄酮、多糖含量和提取物清除DPPH自由基的能力(IC50) 提取物各指标经聚类分析23种丛生竹可分为5簇,其中桂单竹、粉单竹、鼓节竹、大眼竹和凤尾竹的竹叶黄酮和多糖得率较高,IC50值较大,可成为提取竹叶黄酮的优良原料,分别经分离纯化得竹叶黄酮     

电子顺磁共振波谱仪分析干红葡萄酒DPPH清除能力及其与总酚含量的关系

【目的】分析不同酿酒葡萄品种所酿制的干红葡萄酒抗氧化性的差异及其与总酚含量之间的关系。【方法】利用电子顺磁共振波谱仪（Electron Paramagnetic Resonance, 简称EPR）和福林-肖卡法（Folin-Ciocalteu,简称FC）分别对河北沙城产区5个单品种干红葡萄酒检测DPPH清除率和总酚含量,筛选适当的EPR试验条件。【结果】干红葡萄酒具有很强的抗氧化能力,在样品稀释200倍、反应时间5 min的条件下,各样品清除DPPH自由基的能力以赤霞珠葡萄酒为最强72.31%,宝石解百纳72.23%,梅鹿辄68.31%,西拉和增芳德分别为59.03%和56.34%。梅鹿辄、宝石解百纳和赤霞珠葡萄酒的总酚含量,分别为3 044.43、3 026.92和2 886.81 mg•L-1。西拉和增芳德葡萄酒的总酚含量相对较低,分别为2 085.51 mg•L-1和1 647.64 mg•L-1。【结论】电子顺磁共振法可以简便、快速检测干红葡萄酒的抗氧化性,不同单品种干红葡萄酒DPPH清除能力表现明显不同,自由基清除率与总酚含量之间存在线性正相关,回归方程y=0.01116x+37.327665,相关系数rGAE/DPPHequiv=0.91753。     

紫红薯糖蛋白体外抗氧化活性研究

研究紫红薯糖蛋白的体外抗氧化活性。使用水提醇沉方法、Sevage法除游离蛋白,用DEAE-52纤维素层析及SephadexG-75纯化制备糖蛋白。采用超氧阴离子自由基(O-2.)、羟基自由基(·OH)、1,1-二苯基-2-苯肼自由基(DPPH.)清除率测定法及还原力测定法评价紫红薯糖蛋白体外抗氧化活性。糖蛋白在0～640μg/mL内,均具有明显的抗氧化活性,随着质量浓度的增加活性增强;其中在紫红薯糖蛋白的质量浓度为640μg/mL时,对超氧阴离子自由基(O-2.)清除作用达到69.80%;对羟基自由基(.OH)的清除作用达到73.29%。     

芍药花粉提取物的抗氧化能力研究

为了探究芍药花粉提取液的抗氧化能力和主要活性物质的含量,为开发芍药花粉在天然抗氧化剂和化妆品等相关领域的应用提供一定的理论和试验基础,利用不同体积分数的乙醇溶液制备芍药花粉提取液,测定其主要抗氧化组分黄酮、多酚的含量,通过研究不同质量浓度芍药花粉提取液对DPPH自由基、羟自由基的清除能力,分析芍药花粉提取液的抗氧化效果与其多酚、黄酮含量之间的相关性。结果表明,芍药花粉提取液对DPPH自由基、羟自由基具有一定的清除能力,清除率与提取液质量浓度之间呈现出良好的剂量依赖效应。在高质量浓度(0.8g/L)芍药花粉提取液中,70%乙醇提取液清除DPPH自由基的效果最佳,清除率可达79.88%,而30%乙醇提取液对羟自由基的清除能力最强,清除率达到93.82%。70%乙醇提取液中黄酮、多酚含量均显著高于30%乙醇、100%乙醇提取液中的含量。研究认为,70%乙醇是制备芍药花粉提取液较为理想的溶剂。芍药花粉提取液有着较强的抗氧化能力,其抗氧化性与黄酮含量呈线性正相关,而与多酚含量关系不密切。     

Kinetics of Antioxidant-Producing Maillard Reaction in the Mixture of Ribose and Sea Cucumber (Stichopus japonicus) Gut Hydrolysates

Maillard reaction products (MRPs) were produced in sea cucumber gut hydrolysates (SCGHs)-ribose system at 75°C, 85°C, and 95°C with a pH value of 7.0 or 8.0 for 12 hour. The parameters of amount of intermediate products, fluorescence intensity, browning development, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability showed a positive correlation with each other in SCGHs-ribose system. The amount of intermediate products, fluorescence intensity, and browning development followed the zero-order kinetic with activation energy from 62 to 91 kJ/mol in the Maillard reaction of SCGHs-ribose system. Moreover, 2-methyl-butanal has positive and significant correlation with DPPH radical scavenging ability of SCGHs-ribose MRPs. These results suggest that Maillard reaction improves the antioxidant activity of SCGHs, which contributes to the generation of intermediate, fluorescent, browning, and volatile products of SCGHs-ribose system.