Antioxidant activity of proteins and peptides

Proteins can inhibit lipid oxidation by biologically designed mechanisms (e.g. antioxidant enzymes and iron-binding proteins) or by nonspecific mechanisms. Both of these types of antioxidative proteins contribute to the endogenous antioxidant capacity of foods. Proteins also have excellent potential as antioxidant additives in foods because they can inhibit lipid oxidation through multiple pathways including inactivation of reactive oxygen species, scavenging free radicals, chelation of prooxidative transition metals, reduction of hydroperoxides, and alteration of the physical properties of food systems. A protein's overall antioxidant activity can be increased by disruption of its tertiary structure to increase the solvent accessibility of amino acid residues that can scavenge free radicals and chelate prooxidative metals. The production of peptides through hydrolytic reactions seems to be the most promising technique to form proteinaceous antioxidants since peptides have substantially higher antioxidant activity than intact proteins. While proteins and peptides have excellent potential as food antioxidants, issues such as allergenicity and bitter off-flavors as well as their ability to alter food texture and color need to be addressed.     

添加紫甘蓝粉、花椰菜粉、麦胚粉对曲奇中丙烯酰胺生成的影响

目的 探究添加紫甘蓝粉、花椰菜粉、麦胚粉对曲奇中丙烯酰胺生成的影响,为优化焙烤食品配方、控制丙烯酰胺生成提供基础。方法 参考AACC方法,分别以一定比例的植物粉替代等量面粉制作曲奇,以未添加植物粉曲奇为对照,采用HPLC-MS/MS法测定曲奇中丙烯酰胺的含量。结果 三种植物粉对丙烯酰胺生成的影响不同。在添加量为1%~10%时,添加紫甘蓝粉、花椰菜粉的曲奇中丙烯酰胺含量随添加量增加而增大。添加量为10%时,丙烯酰胺含量分别为对照的26.25、68.52倍,而添加麦胚粉曲奇则影响不显著。结论 添加紫甘蓝粉、花椰菜粉和麦胚粉对曲奇中丙烯酰胺的生成有不同影响。     

Inhibitory Effects of Red Wine on Lipid Oxidation in Fish Oil Emulsion and Angiogenesis in Zebrafish Embryo

The capabilities of red wine against lipid oxidation and angiogenesis were evaluated by using a fish oil emulsion system and an in vivo zebrafish embryos model, respectively. The red wine contained 12 different antioxidant phenolics which levels were led by anthocyanins (140.46 mg/L), catechin (55.08 mg/L), and gallic acid (46.76 mg/L). The diversity of the phenolics in red wine was greater than the tea, coffee, or white wine selected as a peer control in this study. The total phenolics concentration of red wine was 305.53 mg/L, although the levels of tea, coffee, and white wine were 85.59, 76.85, and 26.57 mg/L, respectively. The activity of red wine in scavenging DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) free radicals was approximately 4 times higher than the tea and 8 times than the coffee or white wine. The red wine showed the highest capability in preventing long chain PUFA oxidation in the fish oil emulsion. Because of the outstanding antioxidant activity of red wine, the red wine dried extract was used to monitor its inhibitory effect against angiogenesis by using transgenic zebrafish embryos (Tg[fli1:egfp]^y1) with fluorescent blood vessels. After incubated in 100 μg/mL of the extract solution for 26 h pf, each of the embryos had a lower number of intersegmental vessel than the control embryo. The inhibition rate of red wine extract against growing of angiogenic blood vessel reached 100%.     

Antioxidant potential of rice bran extracts and its effects on stabilisation of cookies under ambient storage

Methanolic extracts of rice bran (MRB) were found to be the richest in phenolics than all the other extraction media, i.e. water, 80% methanol, 70% ethanol, diethyl ether. Thermal stability of MRB was determined by evaluating antioxidant activity of heated extracts in linoleic acid system. Cookies were prepared in sunflower oil premixed with MRB at different concentrations, i.e. 500, 1000 and 2000 ppm, and with butylated hydroxytoluene and α‐tocopherol at 200 ppm. Oxidative stability of cookies was measured by storing under ambient conditions for an year with periodical analysis after every 2 months. Fatty acid composition was determined by gas–liquid chromatography. A regular decrease in unsaturated fatty acids (USFA) and increase in saturated fatty acids was observed with the increase in storage period; all the stabilised samples showed appreciably less decrease in USFA than that of control sample. Induction period ranged from 14.73 to 31.22 h while control exhibited 7.5 h. Peroxide value, iodine value and free fatty acids were chosen as the parameters for quality evaluation of cookies. Results suggest rice bran to be a potential source of antioxidants for stabilisation of cookies.     

Micellar liquid chromatographic determination of arbutin and hydroquinone in medicinal plant extracts and commercial cosmetic products

A simple micellar liquid chromatographic (MLC) procedure for simultaneous determination of arbutin and hydroquinone in medicinal plant extracts and commercial cosmetic products was proposed. This method was developed and validated. The chromatographic conditions were also optimized. All analyses were performed at room temperature in an isocratic mode, using a mixture of 1% (v/v) acetonitrile and 0.006 mol L^?1 Brij 35 (pH 6.0) as a mobile phase. The flow rate was set at 1.0 mL min^?1. The analytical column was a 150 × 3.9 mm Nova‐Pak C‐18 column. The effluent from the analytical column was monitored by UV detection at 280 nm. Under the optimum conditions, arbutin and hydroquinone could be determined within a concentration range of 2–50 μg mL^?1 of arbutin, and hydroquinone was obtained with the regression equations; y = 0.045x + 0.042 (r² = 0.9923) and y = 0.091x + 0.050 (r² = 0.9930) respectively. The limits of detection were found to be 0.51 μg mL^?1 and 0.37 μg mL^?1 for arbutin and hydroquinone respectively. The proposed MLC method was applied for the determination of arbutin and hydroquinone contents in medicinal plant extracts and commercial cosmetic products. This proposed MLC method is thus suitable for routine analysis of arbutin and hydroquinone in the pharmaceutical formulations, cosmetic products and raw medicinal plant extracts.     

Antioxidant activity and polyphenol content of aqueous extracts from Colombian Amazonian plants with medicinal use

The total phenol and flavonoid contents of 19 Amazonian plants and their related antioxidant activities were determined. The extracts from the plant leaf, bark, root, fruit and/or stem were prepared as infusions, as are traditionally used in popular medicine. Total phenols ranged from 0.8 to 22.2 mg gallic acid equivalents/g and flavonoids from 0.0 to 10.2 mg catechin equivalents/g, by using Folin–Ciocalteau and aluminium chloride colourimetric methods. Differences were observed in phenol and flavonoid contents at the organic level, the leaf presenting greater values than the stem. All the extracts showed different degrees of antioxidant activity with TEAC, 1.1 up to 117.4 and ORAC, 7.8 up to 359.1 μmol Trolox equivalents/g. These values correlated with total phenol content (r² = 0.90) and flavonoid content (r² = 0.70 for TEAC; r² = 0.76 for ORAC). Piper putumayoense, Piper glandulosissimum, Piper krukoffii and Senna reticulata leaves and Brownea rosademonte bark showed elevated antioxidant activities, thus representing promising plant-sources of medicine.     

Antioxidant activity of water and alcohol extracts of chamomile flowers,anise seeds and dill seeds

The antioxidant activities of water and alcohol extracts of the flowers of chamomile (Matricaria aurea Schultz) and the seeds of anise (Pimpinella anisum L) and dill (Anethum graveolens L) were investigated. The extracts showed marked antioxidant activity in both linoleic acid and liposome model systems. This indicates that the extracts could be used as antioxidants in fat‐containing foods. The water extracts of chamomile flowers and dill seeds showed higher antioxidant activity than butylated hydroxyanisole, whereas the antioxidant activities of the alcohol extracts of all three plants were lower. The water extracts showed higher antioxidant activity than the corresponding alcohol extracts. The antioxidant activity of both water and alcohol extracts decreased in the order chamomile flowers > gtill seeds > gtnise seeds. The extracts also showed good free radical‐scavenging activity, indicating that they act as hydrogen donors. Copyright © 2004 Society of Chemical Industry     

Inhibition of methyl linoleate autoxidation by phenolics and other related compounds under mild oxidative conditions

Methyl linoleate (MeLo) is a commercially available substrate widely used for studying the inhibitory properties of pure compounds and plant extracts against lipid oxidation. In this paper, 13 phenolic (benzoic and cinnamic acids, aldehydes and derivatives, and flavonoids) and other related compounds (butylated hydroxyanisole, butylated hydroxytoluene and tocopherols) as well as nine complex mixtures rich in phenolics (wines) or tocopherols (soybean oil extracts) were assayed for their inhibitory activity against MeLo autoxidation under mild conditions (40 °C, darkness and atmospheric pressure). Samples were also assayed for their free radical‐scavenging capacity against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^?). Protocatechuic aldehyde, a compound that has not been previously evaluated by either of the two methods, showed the highest antioxidant activity. Some variations in the antioxidant ranking for some compounds were found between our results and those obtained by other authors using accelerated conditions for MeLo oxidation. Antioxidant activity of wines and soybean oil extracts was related to their richness in phenolics and tocopherols respectively. Correlation between antioxidant capacity measured by the MeLo and DPPH^? methods was found for wines but not for the other samples studied. Therefore the measure of the free radical‐scavenging capacity of a compound is not always a reliable indicator of its lipid oxidation inhibitory ability. Copyright © 2004 Society of Chemical Industry     

Antioxidant activity of pomegranate rind powder extract in cooked chicken patties

The radical scavenging activity, reducing power and phenolic composition of pomegranate rind powder extract (RP) were determined and antioxidant properties of RP was evaluated in cooked chicken patties compared with vitamin C (VC) during refrigerated storage. Freshly minced chicken meat were assigned to one of the following six treatments: control (meat without any antioxidant); RP 5, RP 10, RP 15 and RP 20 (5, 10, 15 and 20 mg equivalent RP phenolics 100 g^?1 meat, respectively) and VC 50 (50 mg VC 100 g^?1 meat). The RP exhibited significantly (P < 0.05) higher reducing power and 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity. Incorporation of RP into chicken patties significantly (P < 0.05) reduced the HunterLab L* values compared with control and VC patties. Total phenolic content (as tannic acid equivalent) significantly (P < 0.05) increased from 308 in control to 441 μg g^?1 in RP 20 patties. Addition of RP to chicken patties did not affect any of the sensory attributes. The values of thiobarbituric acid reactive substances were significantly (P < 0.05) reduced from 1.530 in control patties to 0.135 mg malonaldehyde kg^?1 samples in RP patties. Pomegranate rind powder extract treatment (RP 10, RP 15 and RP 20) substantially inhibited (P < 0.05) lipid oxidation in cooked chicken patties to a much greater extent than VC treatment. Therefore, pomegranate rind powder can be utilized as an excellent natural antioxidant source.     

Antioxidant activity of the extracts from Dillenia indica fruits

There has been growing interest in the beneficial health effects of consuming fruits and vegetables. Mainly, the presence of phenolic antioxidants is believed to have the protective mechanisms. In the present study the fruit of Dillenia indica was extracted with ethyl acetate, methanol and water. The total phenolic content of the extracts was determined by Folin–Ciocalteu method and antioxidant activity of the extracts was assayed through some in vitro models such as antioxidant capacity by phosphomolybdenum method, β-carotene-linoleate model system, and radical scavenging activity using ,-diphenyl-β-picrylhydrazyl (DPPH) method. The total phenolic contents of the fruit extracts as tannic acid equivalents were found to be highest in methanol extract (34.1%) followed by ethyl acetate extract (9.3%) and water extract (1.4%). Antioxidant capacity of the extracts as equivalent to ascorbic acid (μmole/g of the extract) was in the order of methanol extract > ethyl acetate extract > water extract. In comparison with butylated hydroxyanisole (BHA), at 100 ppm of concentration, the antioxidant and free radical scavenging activities of the extracts assayed through β-carotene-linoleate model system, and DPPH method were also found to be highest with methanol extract followed by ethyl acetate and water extracts. The results indicated that the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract and the fruit of D. indica is rich in phenolics may provide a good source of antioxidant.     

Phenolic Profiles and Antioxidant Properties of Apple Skin Extracts

ABSTRACT:  Lipid oxidation, especially the oxidation of polyunsaturated fatty acids, is a significant issue in the food industry impacting both food quality and health of consumers. Apple skin was investigated as a source of natural antioxidants. The phenolic compound composition and antioxidant properties of 21 selected apple genotypes were evaluated. The lipid stabilizing ability of the apple skin extracts was examined using an aqueous emulsion system of methyl linolenate. The total phenolic concentrations determined by high-performance liquid chromatography tandem mass spectrometry of methanolic extracts of skins of the apple genotypes varied from 150 to 700 mg/100 g DW. The antioxidant capacity measured by Folin–Ciocalteu (16.2 to 34.1 mg GAE/100 g DW), ferric reducing antioxidant power (1.3 to 3.3 g TE/100 g DW), oxygen radical absorbance capacity (5.2 to 14.2 g TE/100 g DW), and percent inhibition of oxidation of methyl linolenate (73.8% to 97.2%) varied among the apple genotypes. The apple skin extracts, specifically the crab apple varieties such as "Dolgo," were revealed to be effective inhibitors of oxidation of polyunsaturated fatty acid in a model system and thus can be considered as a potential source of natural food antioxidants.     

Lipid Oxidation in Cooked Turkey as Affected by Added Antioxidant Enzymes

Catalase (CAT) and glutathione peroxidase (GSH-Px) were added to turkey which had been cooked (80°C) to provide minimal activity of both enzymes, to determine their effects in development of lipid oxidation. CAT (100–500 U/g muscle) decreased the formation of thiobarbituric acid reactive substances (TBARS) 4–28% during 2 days of storage. GSH-Px (4.0 U/g muscle) decreased TBARS 8–11%. CAT (170 U/g muscle) and GSH-Px (1.3 U/g muscle) in combination decreased TBARS formation 7–14%. Reduced glutathione concentrations in the turkey were unaffected by cooking. These data suggest that heat inactivation of CAT and GSH-Px was not the only factor involved in heat-induced lipid oxidation reactions in turkey thigh muscle.     

Selective removal of tannins from medicinal plant extracts using a collagen fiber adsorbent

A novel adsorbent, used for the selective removal of tannins from medicinal plant extracts, was prepared from bovine skin collagen fiber. Some typical active constituents of medicinal plants were selected as probe molecules to investigate the adsorption selectivity of the collagen fiber adsorbent to tannins. In batch adsorption experiments, the extent of adsorption of condensed tannins, including larch tannin, black wattle tannin and bayberry tannin, was 100%. The extent of adsorption of tannic acid and the hydrolyzable tannins was also 100%. In contrast, for the most active constituents of medicinal plants, their amounts adsorbed by collagen fiber adsorbent were limited. For procyanidin, the common active constituents in medicinal plant extracts, its extent of adsorption was also low, although it has a similar basic structure to condensed tannins. In comparison with traditionally used polyamide adsorbent, the collagen fiber adsorbent exhibited an obvious advantage in adsorption selectivity over tannins. Therefore, this study provides a novel and effective method for selective removal of tannins from medicinal plant extracts. Copyright © 2005 Society of Chemical Industry     

Antioxidant Activity and Total Phenolics in Different Genotypes of Potato (Solanum tuberosum, L.)

Antioxidant activity of potato compared with that of broccoli, onion, carrot and bell peppers was higher than all except broccoli. Patatin appeared to be the major water-soluble compound that showed antioxidant activity. The activity varied among potato cultivars, but was not related to flesh color or total phenolics. Antioxidant activity was evenly distributed within tuber parts and/or sections, except for skin tissue which had the greatest antioxidant activity and total phenolic content. Total phenolics varied among cultivars, with some containing twofold higher concentrations than other cultivars. Phenolic content differences were genotype dependent and not related to flesh color.     

长裂苦苣菜甲醇提取物各极性成分的抗氧化活性研究

目的:为探明长裂苦苣菜不同溶剂提取物活性功能成分及体外抗氧化性。方法:利用石油醚、乙酸乙酯、正丁醇、水为溶剂依次萃取长裂苦苣菜全草甲醇提取物,测定不同溶剂萃取物的总酚、总黄酮及单体酚含量,采用DPPH法、ABTS法及总还原力法评价其抗氧化活性,分析其酚类物质含量与抗氧化活性间的相关性。结果:HPLC分析检测到长裂苦苣菜中至少含有9种单体酚成分,其含量在不同溶剂萃取物中存在显著差异。乙酸乙酯萃取物的总酚、总黄酮含量最高,分别达到170.74 mg GA Eq./g和6.01 mg RU Eq./g,且其抗氧化活性最强。不同溶剂萃取物的抗氧化能力与萃取物的黄酮含量之间极显著相关(p<0.01)。结论:长裂苦苣菜中含丰富的酚类、黄酮类抗氧化活性成分,乙酸乙酯可作为长裂苦苣菜抗氧化活性物质富集溶剂,富集长裂苦苣菜中的咖啡酸、芦丁、荭草素、木犀草素等抗氧化活性功能成分。      

Influence of Antioxidant Addition and Processing Treatment on the Formation of Lipid Oxidation Compounds in Spray-dried Bovine Plasma Protein

The effects of antioxidant (tert‐butylhydroquinone, propyl gallate, butylated hydroxytoluene, and rosemary) addition, processing treatments, and storage time on the formation of lipid oxidation compounds in spray‐dried bovine plasma protein (BPP) were determined. Lipid oxidation is initiated by spray‐drying; formation of lipid oxidation compounds was highest in BPP processed using a gas‐fired spray‐drier. The most effective antioxidant in inhibiting the formation of hexanal and other lipid oxidation compounds was tert‐butylhydroquinone. Increased spray‐drier residence time and extended storage contributed to increases in lipid oxidation products. Use of effective antioxidants and selection of processing parameters to minimize lipid oxidation reactions can improve the flavor quality of spray‐dried BPP.