Antioxidant properties of desferrioxamine E, a new hydroxamate antioxidant

Antioxidant properties of desferrioxamine E, a cyclic trihydroxamate produced by microorganisms, were tested and compared to those of desferrioxamine B and butylated hydroxyanisole (BHA). Desferrioxamine E exhibited significant antioxidant effects in linoleic acid emulsions as well as in emulsions of linoleic acid and β-carotene. In concentrations of 100 ppm, the effect of both desferrioxamines in linoleic acid emulsion was equal to that of BHA. The antioxidant activity of the desferrioxamines in emulsions of β-carotene and linoleic acid was significantly higher than that of BHA. In addition, the initial rate of β-carotene destruction was significantly lower when desferrioxamines were added to the emulsion.     

Antioxidant properties of phenolic compounds in macadamia nuts

Phenolic compounds in macadamia nuts and shells were identified, and their antioxidant activities were evaluated in refined macadamia nut oil. Thin-layer chromatography of oil extracted from macadamia nut kernels and shells indicated the possible presence of catechol, phrogallol, and 3,4,5-trihydroxy phenolic compounds. Four phenolic compounds were tentatively identified as 2,6-dihydroxybenzoic acid, 2′-hydroxy-4′-methoxyacetophenone, 3′,5′-dimethoxy-4′-hydroxyacetophenone, and 3,5-dimethoxy-4-hydroxycinnamic acid. Adding 0.01% of 2′-hydroxy-4′-methoxyacetophenone, 3′,5′-dimethoxy-4′-hydroxyacetophenone, or 3,5-dimethoxy-4-hydroxycinnamic acid to the oil significantly increased the Rancimat induction time against the control (P<0.0001). At this concentration, 3′,5′-dimethoxy-4′-hydroxyacetophenone was the most effective compound added. Although induction times of oils with 0.01%, 2,6-dihydroxybenzoic acid were not significantly different from the control, at 0.1% there was a significant difference from the control (P<0.0001). The activity was the same as that of 2′-hydroxy-4′-methoxyacetophenone at 0.1%.     

Antioxidant properties of myricetin and quercetin in oil and emulsions

The effect of quercetin and myricetin on the stability of sunflower oil and oil-in-water emulsions was studied by storage experiments monitored by measurement of peroxide values, conjugated dienes, and headspace volatile analysis. Myricetin showed strong antioxidant activity in oils stored at 60 or 30°C and in oil-in-water emulsions stored at 30°C, whether tocopherols or citric acid were present or not; however, quercetin showed similar antioxidant activity in stripped sunflower oil but no activity in oils that contained tocopherols and citric acid. This showed that myricetin is effective owing to strong radical scavenging and metal-chelating properties, whereas quercetin has weaker radical scavenging activity, although it is also active by metal-chelation. The effects of copper and iron salts on the antioxidant activity of myricetin and quercetin were studied in sunflower oil and oil-in-water emulsions. Quercetin and myricetin enhanced the prooxidant effect of cupric chloride in oil-in-water emulsions (pH 7.4), but this effect was not observed with cupric stearate. The addition of myricetin to emulsions that contained ferric chloride at pH 5.4 also produced a strong prooxidant effect, and small prooxidant effects of flavonols were also detected in the presence of cupric chloride under these conditions. However, myricetin and quercetin reduced the prooxidant effect of ferric palmitate in oils. Myricetin also showed a strong antioxidant effect in oil that contained cupric stearate, although quercetin had no significant effect on the oxidative stability of this system. It therefore appears that flavonols may exert a prooxidant effect in the presence of metal salts, but the nature of the metal salt is important in determining whether a prooxidant effect occurs.     

Antioxidant properties of individual phospholipids in a salmon oil model system

The antioxidant properties of phospholipids (PL) in a refined salmon oil model system were measured by determining changes in the 2-thiobarbituric acid number and decreases in the ratio of docosahexaenoic acid (DHA)/palmitic acid (22:6/16:0) of a fish oil system incubated at 180°C for up to 3 h. The more phosphatidylcholine (PC) added to the oil system, the higher the oxidative stability obtained. The order of effectiveness of commercial phospholipids in inhibiting oxidation and the loss of polyunsaturated fatty acids was as follows: sphingomyelin (SPH)=lysophosphatidylcholine (LPC)=phosphatidylcholine (PC)=phosphatidylethanolamine (PE)>phosphatidylserine (PS)>phosphatidylinositol (PI)>phosphatidylglycerol (PG)>control salmon oil. Nitrogen containing PL, including PE, PC, LPC and SPH, were equally effective in exerting greater antioxidant properties than PS, PG and PI. The inverse relationship observed between the oxidation index (C22:6/C16:0) and color intensity for treatments following 2 h of heating suggests that Maillard-type reaction products may have contributed to the oxidative stability of PL-supplemented fish oils.     

紫草抗氧化成分的提取及其活性研究

分别用石油醚、三氯甲烷和乙醇依次提取紫草成分 ,用OSI仪测定了三种提取物对猪油氧化稳定性的影响 ,发现石油醚提取成分 (LE - pet)和三氯甲烷提取成分 (LE -chl)有明显的抗氧化活性 ,添加到猪油中后 ,w =0 0 2 %时 ,猪油的氧化稳定性比空白样品提高了约 1倍。对LE -pet和LE -chl进行薄层层析分离鉴定 ,得到三种化合物 :β ,β 二甲基丙烯酰紫草醌 (Ⅰ)、乙酰紫草醌 (Ⅱ)和紫草醌 (Ⅲ)。对它们的抗氧化活性进行测试 ,化合物Ⅱ和Ⅲ表现出明显的抗氧化活性 ,当w(Ⅱ)=0 .0 6 %、w(Ⅲ) =0 0 6 %时 ,猪油的氧化稳定性分别提高了 6 0 4和 3 94倍。化合物Ⅰ、Ⅱ、Ⅲ与VE均有较强的协同作用 ,化合物Ⅰ、Ⅱ、Ⅲ的质量分数为 0 .0 2 %与VE 的质量分数为 0 0 2 %共同使用时 ,其抗氧化协同系数 (SE)分别为 81 4(Ⅰ)、5 2 7(Ⅱ)和 132 6 (Ⅲ )     

抗氧剂在聚合物中的应用

阐述了抗氧剂的分类、品种及其在聚合物中的应用情况,介绍了抗氧剂的发展现状并指出了其发展趋势。     

Antioxidant capacity of flaxseed lignans in two model systems

The flaxseed lignans secoisolariciresinol (SECO) and its diglucoside secoisolariciresinol diglucoside (SDG) are reported to have a number of health benefits associated with their consumption that have in part been attributed to their antioxidant properties. In this study the relative antioxidant capacity of the flaxseed lignans vs. BHT was determined in two model systems. First, an antioxidants stoichiometric value was determined for SECO and SDG in a liposomal system as a mimic of lipid peroxidation. Stoichiometric values for SECO (1.5) and SDG (1.2) vs. BHT (2.0) were measured from the lag time for the formation of conjugated dienes; all values were significantly different (P<0.01). Second, the ability of flaxseed lignans to prevent oxidative degradation of canola oil was determined. Samples were stored at room temperature and analyzed at 30-d intervals over 120 d using a Rancimat^™ analyzer. The lignans prevented degradation of canola oil, as measured by induction time, in a concentration-dependent manner. Although SECO demonstrated a trend for better protection than either SDG or polymer containing SDG, they were not significantly different (P>0.01). There was also no significant difference between SECO or SDG and BHT, suggesting flaxseed lignans may be good alternatives to minimize rancidity in oil-based food products.     

复配型受阻酚类抗氧剂对聚甲醛的稳定作用

将受阻酚类抗氧剂Irganox245和Irganox1010进行复配并加入聚甲醛中,通过将物料在设定温度下多次挤出,测定挤出物料的黄色指数、拉伸强度、冲击强度、熔体质量流动速率、热失重率等方法对单剂和复配抗氧剂在聚甲醛中的稳定作用进行了研究。结果表明：将抗氧剂Irganox245和Irganox1010复配后,提高了聚甲醛的分解温度,较好地保持了聚甲醛的各项性能,没有发生劣化现象,作用效果介于两种抗氧剂单独作用效果之间;在聚甲醛的热氧稳定性能方面起到一定的协同作用。     

Grease resistance and mechanical properties of isolated soy protein-coated paper

Grease-resistant paper has been produced by coating paper with isolated soy protein (ISP). Tensile strength (TS) of ISP-coated paper is 28–30 MPa (between the TS of paper and of ISP film). TS of the ISP-coated paper (2.3 kg/ream) was highest (36.0 MPa) among other ISP-coated papers, but elongation (E) of the papers seemed to decrease (though not statistically significantly) as the thickness of the ISP coating increased. ISP-coated papers were highly impermeable to grease penetration for the first 2 h of the test. The percent stained area of two commercially used polyethylene-laminated papers was higher than those of ISP-coated papers. As the amount of plasticizer (a mixture of glycerol and polyethylene glycol) was increased in ISP-coated paper, the TS decreased and the E increased. When tested, the percent stained areas of the paper containing 0.6 and 1.0 g plasticizer/g protein were lower for the first 2 h than those of the papers containing 0.0 and 0.2 g plasticizer/g protein. Also, percent stained area increased with time. Grease resistance of papers coated with ISP at levels higher than 2.0 kg/ream was equal to or lower than that of polyethylene laminates used for quick-service restaurant sandwich packaging.     

抗氧剂300的复配及配方在松香酯化中的应用

综述抗氧剂300的作用机理及其与其它抗氧剂配合使用的协同作用,考察了复合抗氧剂F334与F335在松香酯化生产中的应用效果。     

硫酸锌对紫外线造成的角朊细胞氧化损伤及胞内抗氧化酶活性的影响

目的探讨硫酸锌对B段紫外线(Ultraviolet radiation B,UVB)造成的角朊细胞(Keratinocytes,KC)氧化损伤及胞内抗氧化酶活性的影响。方法取新生Wistar大鼠背部皮肤,采用中性蛋白酶和胰蛋白酶联合消化,经贴壁培养获得高纯度角朊细胞,在含10%FBS的L-DMEM+F12培养液中扩增培养。将细胞随机分为UVB组、加锌组和正常对照组,UVB组用15W的UVB进行照射,加锌组与50μmol/L硫酸锌共孵育24h后进行照射,正常对照组不照射。照射后24h收集各组细胞,进行氧化损伤指标(MDA、OH-、O2-)及胞内抗氧化酶(SOD和GSH)活性测定。结果 UVB组细胞MDA、OH-和O2-水平显著高于正常对照组(P<0.05),加锌组显著低于UVB组(P<0.05);UVB组细胞SOD和GSH水平显著低于正常对照组(P<0.05),加锌组显著高于UVB组(P<0.05)。结论硫酸锌可拮抗UVB对角朊细胞造成的氧化损伤,并提高胞内抗氧化物酶的水平。     

Optimization of Microwave-Assisted Extraction of Astaxanthin from Haematococcus Pluvialis by Response Surface Methodology and Antioxidant Activities of the Extracts

Abstract

Microwave-assisted extraction (MAE) was applied for the extraction of astaxanthin from Haematococcus pluvialis and response surface methodology (RSM) was used to optimize extraction parameters to the content of astaxanthin. Four independent variables such as microwave power (W), extraction time (sec), solvent volume (mL), and the number of extraction were optimized in this paper. The optimal conditions were determined and tri-dimensional response surfaces were plotted from the mathematical models. The F-test and p-value indicated that microwave power, extraction time, the number of extraction, and their quadratic had a highly significant effect on the response value (p <0.01), then the solvent volume and the interaction effects of microwave power and the number of extraction also displayed significant effect (p <0.05). Considering the extraction efficiency, the optimized conditions of MAE were as follows: microwave power was 141 W, extraction time 83 sec, solvent volume 9.8 mL, the number of extraction four times. About 594 ± 3.02 µg astaxanthin was extracted from Haematococcus pluvialis the dried powders (100 mg) under the optimal conditions, and it close to the predicted contents (592 µg). The antioxidant activities of the extracts obtained under optimal conditions were analyzed, and the results showed that the extracts presented strong ability of inhibiting the peroxidantion of linoleic acid, exhibited strong radical-scavenging properties against the DPPH, as well as strong reducing power.     

Nutritional Composition and Antioxidant Capacity in Edible Flowers: Characterisation of Phenolic Compounds by HPLC-DAD-ESI/MSn

Edible flowers are commonly used in human nutrition and their consumption has increased in recent years. The aim of this study was to ascertain the nutritional composition and the content and profile of phenolic compounds of three edible flowers, monks cress (Tropaeolum majus), marigold (Tagetes erecta) and paracress (Spilanthes oleracea), and to determine the relationship between the presence of phenolic compounds and the antioxidant capacity. Proximate composition, total dietary fibre (TDF) and minerals were analysed according to official methods: total phenolic compounds (TPC) were determined with Folin-Ciocalteu’s reagent, whereas antioxidant capacity was evaluated using Trolox Equivalent Antioxidant Capacity (TEAC) and Oxygen Radical Absorbance Capacity (ORAC) assays. In addition, phenolic compounds were characterised by HPLC-DAD-MSⁿ. In relation to the nutritional value, the edible flowers had a composition similar to that of other plant foods, with a high water and TDF content, low protein content and very low proportion of total fat—showing significant differences among samples. The levels of TPC compounds and the antioxidant capacity were significantly higher in T. erecta, followed by S. oleracea and T. majus. Thirty-nine different phenolic compounds were tentatively identified, with flavonols being the major compounds detected in all samples, followed by anthocyanins and hydroxycynnamic acid derivatives. In T. erecta small proportions of gallotannin and ellagic acid were also identified.     

抗氧剂PEP—24G的研制

介绍了抗氧剂ＰＥＰ－２４Ｇ在国内外的应用情况、发展前景及应用特点,详尽描述了两步法合成技术的工艺流程和实验过程。通过优化实验,筛选出最佳的催化剂和反应溶剂;根据尾气吸收情况来判断反应时间;利用正交设计,确定了物料配比与用量。试验结果表明工艺稳定,产品纯度高,收率超过８０％。最后简单介绍了该抗氧剂在聚丙烯加工中的应用情况,并与其它抗氧剂进行了对比,结果表明,应用效果优于抗氧剂１６８。     

Study on the High Efficiency Antioxidant of Polyoxymethylene

This article reports on the properties and uses of antioxidant F/B, a type of high efficiency antioxidant for polyoxymethylene (POM), consisting of the hindered phenolic main antioxidant, the secondary thermostabilizer phosphite ester, and lactone compound. Our experimental studies focused on the thermostabilization effect of antioxidant F/B on POM, which was measured by isothermal weight loss analysis at 220°C, isothermal weight loss rate analysis at 222°C, balance torque analysis, nonisothermal gravity analysis (TGA), oxidation induction time (OIT) analysis, and multiple processing and long-term aging analysis as compared to the commonly used antioxidant Irganox245 of POM. The results showed that the thermal stability of POM can be improved remarkably by using antioxidant F/B. The aging mechanism of POM under heat and oxygen was studied by the measurements of polarized light microscopy (PLM), differential scanning calorimetry (DSC), and X-ray photoelectron energy spectrum (XPS), which showed very slight changes of spherulites dimension, crystallinity, and the surface atom concentration after 15 days of aging at 140°C. Furthermore, the small amount of degradation of POM only occurred in the amorphous region of POM. These experiments demonstrated that lower amounts of antioxidant F/B can reach the same level of thermal stabilization of POM as is achieved with higher amounts of Irganox245, and can replace Irganox245 for use in the production of POM, which can further improve the thermal stabilization and reduce the production cost of POM.     

Antioxidant and Antithrombotic Activities of Rapeseed Peptides

The antioxidant and antithrombotic activities of crude rapeseed peptides (CRPs) and peptide fractions (RP25 and RP55) prepared from aqueous enzymatic extraction (AEE) of rapeseed were determined. The reducing power of RP55 and CRPs was higher than that of RP25 at the same concentrations. Rapeseed peptides exhibited marked antioxidant activities. The median effective dose (ED₅₀) values of CRPs, RP25 and RP55 for α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging were 72, 499 and 41 μg/mL, respectively. The ED₅₀ values for RP25 and RP55 for hydroxyl radicals scavenging were 2.53 and 6.79 mg/mL, respectively while the ED₅₀ values of RP55 and CRPs for inhibition of lipid peroxidation in a liposome model system were 4.06 and 4.69 mg/mL, respectively. The inhibitory effect on lipid oxidation of RP55 was similar to that of ascorbic acid at a concentration of 5.0 mg/mL. A good positive correlation existed between the peptide concentration and antioxidant activity. RP55 generally showed more potent antioxidant activities except for hydroxyl radicals scavenging ability than RP25 and CRPs at the same concentrations, which was thought to relate to the significantly higher contents of hydrophobic amino acid, tannin, and the brown color substances in RP55. Rapeseed peptides possessed marked inhibitory activities on the thrombin-catalyzed coagulation of fibrinogen, however, their inhibitory effects were not comparable to that of heparin.     

Structural,photocatalytic, biological and catalytic properties of SnO2/TiO2 nanoparticles

TiO₂ and SnO₂/TiO₂ nanoparticles with different SnO₂ contents (0–20 wt%) were synthesized via surfactant-assisted sol-gel method using a cationic surfactant (cetyltrimethylammonium bromide, CTAB). The effects of SnO₂ content on the structural, optical, and catalytic activity of TiO₂ have been studied by X-ray diffraction (XRD), Transmission electron microscope (TEM), Scanning electron microscope (SEM), Fourier transformer infrared (FTIR) and UV–vis diffuse reflection spectroscopy (DRS). The total surface acidity of the prepared samples was measured by nonaqueous titration of n-butylamine in acetonitrile and the types of Brönsted and Lewis acid sites were distinguish using FTIR spectra of chemisorbed pyridine. XRD patterns analysis indicates that the crystallite size reduced remarkably and the transformation of anatase-to-rutile phase accelerated greatly with increasing the SnO₂ content. TEM images exhibit a spherical shape with an average particle size varying in the range 10–24 nm and high-resolution TEM images (HRTEM) show lattice fringes with interplanar spacing 0.35 nm and 0.32 nm which corresponding to anatase and rutile phases, respectively. SEM images show the amount of SnO₂ on the TiO₂ surface increases with increasing the SnO₂ content and the particles of SnO₂ were aggregated on TiO₂ surface with increasing SnO₂ content to 20% wt. The catalytic activity was tested by various applications: Photodegradation of Methylene Blue (MB) and Rhodamine B (RhB) under UV–vis irradiations and synthesis of xanthene (14-phenyl-14H-dibenzo [a,j] xanthene). Antibacterial and antioxidant activities were also studied. The antibacterial property test was carried out via agar disc diffusion method, and the results indicated that the prepared catalysts showed moderate antibacterial activity.     

抗氧剂168的合成与应用研究

介绍了抗氧剂１６８的合成方法和产品质量要求，测试产品在塑料加工过程中的熔体指数，抗氧化作用，热稳定性和加工性能，与Ｃｉｂａ－Ｇｅｉｇｙ公司产品Ｉｒｇａｆｏｓ１６８比较，结果证明；本技术制备的抗氧剂１６８与Ｉｒｇａｆｏｓ１６８产品相类同。     

Hypolipidemic and Antioxidant Effects of Dietary Curcumin and Capsaicin in Induced Hypercholesterolemic Rats

Health beneficial hypolipidemic and antioxidant influences of dietary spice principles—curcumin, capsaicin alone and in combination included in the diet for 8 weeks were evaluated in induced hypercholesterolemic rats, in order to verify if there is any additive or synergistic effect of these two bioactive compounds. Dietary curcumin (0.2%), capsaicin (0.015%) or their combination significantly countered the hypercholesterolemia brought about by high cholesterol feeding. Hepatic cholesterol was lowered by dietary spice principles only in normal rats. Liver triglyceride levels were lowered in both normal and hypercholesterolemic rats by capsaicin. Curcumin and capsaicin lowered hepatic and blood lipid peroxides in hypercholesterolemic rats, while the effect in blood was additive with their combination. Hepatic ascorbic acid was enhanced by dietary spice principles in normal rats; glutathione was enhanced by their combination only in hypercholesterolemic rats. Activities of serum glutathione reductase, glutathione transferase and catalase and hepatic glutathione reductase in normal rats and serum glutathione peroxidase in hypercholesterolemic rats were enhanced by dietary spice principles. While dietary curcumin and capsaicin normalized the changes in the levels of antioxidant molecules and activities of antioxidant enzymes to a significant extent, this effect was not generally additive when given in combination, and was higher than the individual effects only in a few instances.     

Functional properties of extruded-expelled soybean flours from value-enhanced soybeans

The functional properties (protein solubility, emulsification characteristics, foaming characteristics, water- and fatbinding capacities) of extruded-expelled (EE) soy flours originating from six varieties of value-enhanced soybeans (high-sucrose, high-cysteine, low-linolenic, low-saturated FA, high-oleic, and lipoxygenase-null) and two commodity soybeans were determined. The soy flours varied in protein disperisibility index (PDI) and residual oil (RO), with PDI values ranging from 32 to 50% and RO values ranging from 7.0 to 11.7%. Protein solubility was reduced at pH values near the isoelectric region and was higher at both low and high pH. There were no significant differences for water-holding capacity, fat-binding capacity, emulsification activity, or emulsification stability. Only the high-oleic soy flour had significantly lower emulsification capacity. In general, the PDI and RO values of EE soy flours originating from value-enhanced and commodity soybeans had the greatest influence on protein functionality. The genetic modifications largely did not affect functional properties.