Canola extract as an alternative natural antioxidant for canola oil

The antioxidative activity of ethanolic extracts of canola meal at 100, 200, 500 and 1000 ppm on refined-bleached (RB) canola oil was examined and compared with commonly used synthetic antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), BHA/BHT/monoglyceride citrate (MGC) andtert-butyl-hydroquinone (TBHQ). Stability of RB oil was monitored under Schaal oven test conditions at 65°C over a 17-d period. Progression of oxidation was monitored by weight gain, peroxide, conjugated diene, 2-thiobarbituric acid and total oxidation values. Canola extracts at 500 and 1000 ppm were more active than BHA, BHT and BHA/BHT/MGC and less effective than TBHQ at a level of 200 ppm.     

Inhibited Oxidation of Lipids I: Complex Estimation and Comparison of the Antioxidative Properties of Some Natural and Synthetic Antioxidants

The activity A of antioxidants, representing a ratio between the stabilization factor F and the decrease in oxidation rate after the introduction of an inhibitor DOR (A = F/DOR) is proposed for a complex estimation of the effect of antioxidants. The specific changes in F, DOR and A are discussed in association with the participation of the inhibitor molecule and the radical formed from it in the different reactions of initiation and propagation of the chains. Several types of antioxidants (α-tocopherol, ferulic acid, BHT and BHA) in concentrations ranging from 0.02 – 0.20 wt% are investigated during the oxidation of lard at 100°C. It is established that at concentrations of 0.02–0.05 wt% the antioxidative activity increases in the sequence ferulic acid < BHT < BHA <α-tocopherol. At high concentrations (above 0.10 wt%) the activity increase follows the sequence α-tocopherol < BHT < BHA < ferulic acid. Enhancement of the antioxidant concentration above 0.02 wt% is expedient only in the case of ferulic acid. The molecules of α-tocopherol, BHA and BHT participate not only in chain termination but also in first order rate side reactions with respect to the inhibitor, which explains the decrease in their efficiency with rising concentration. The molecule of ferulic acid does not participate in side reactions. The aroxyl radical formed from BHT does not participate in chain propagation, whereas the radicals of BHA and ferulic acid take part in such reactions. The aroxyl radical of α-tocopherol joins in more than one side reactions.     

Effect of evening primrose extracts on oxidative stability of sunflower and rapeseed oils

Antioxidative activities of evening primrose seed meal extracts in sunflower and rapeseed oils were compared with that of commercially used antioxidants, namely butylated hydroxytoluene (BHT), ascorbylpalmitate as well as Grindox‐118. The study was carried out under Schaal oven conditions at 60 °C and the weight gain was followed up by p‐anisidine value measurement following the oxidation. An Oxidograph apparatus monitored the oxidation of oils at 110 °C. Among the examined extracts, the ethyl acetate extract (0.2%), containing only 87 mg/g of total phenolics, exhibited a stronger antioxidant activity than BHT (0.01%) and effectively stabilised both oils. A strong antioxidative effect was also noted for the ethanol‐ethyl acetate extract (168 mg/g of total phenolics). The study showed that addition of ethyl acetate and ethanol‐ethyl acetate extracts could extend the sunflower and rapeseed oils shelf‐life by protecting oils from further decomposition that naturally occurs during thermal treatments.     

Antioxidant activity of blackcurrant seeds extract and rosemary extracts in soybean oil

The objective of this research was to investigate the antioxidative properties of extract from blackcurrant seeds (BCSs) and commercially available rosemary extracts (Stabiloton OS, oil‐soluble and WS, water soluble) in soybean oil (SO). The antioxidant activity of plant extracts was compared with those of α‐tocopherol and butylated hydroxytoluene (BHT). The results of present research reveal differentiation of action of investigated extracts toward primary (peroxide value (PV), conjugated dienes (CDs)) and secondary (measured as anisidine value (AV), hexanal) oxidation products in SO. WS and OS rosemary extracts show high efficiency in delaying primary and secondary oxidative changes. BCSs extract markedly retards oxidation, nevertheless its activity falls down with formation and succeeding deterioration of primary products. Although the use of BCSs, residues of fruit processing, as a source of antioxidants would be reasonable because of economic and environmental reasons, it may be limited by low activity toward secondary oxidation products in certain lipid substrates. Taking primary oxidative changes into consideration, all extracts studied perform better than used standard antioxidants – BHT and α‐tocopherol.     

Identification,in vitro and in vivo Antioxidant Activity,and Gastrointestinal Stability of Lignans from Silver Fir (Abies alba) Wood Extract

Lignans are generally known for their beneficial impact on human health. In this study, we found that the water extract of silver fir (Abies alba) wood contains lignans, which constitute approximately 10% of the extract and include isolariciresinol, hydroxymatairesinol, secoisolariciresinol, lariciresinol, pinoresinol, and matairesinol. The antioxidant activity of the extract was measured by several in vitro assays and an assay in a eukaryotic cell model (yeast). The extract had greater in vitro antioxidative activity than ascorbic acid, resveratrol, or butylated hydroxytoluene (BHT) and similar antioxidative activity to epigallocatechin gallate. The intracellular antioxidant effect in the yeast gave indirect evidence that the components of the silver fir wood extract (SFWE) effectively pass through eukaryotic cell membranes and have higher in vivo antioxidative activity than ascorbic acid, resveratrol, tocopheryl succinate, or BHT and similar to epigallocatechin gallate. The in vitro gastrointestinal digestion of the lignans in the extract is not significant; therefore, it is reasonable to expect antioxidative effects from orally applied SFWE.     

Antioxidative components,xanthone derivatives,inSwertia japonica Makino

Substances with antioxidative properties were obtained from an ether extract ofSwertia japonica Makino. Six active components of the extract were isolated and identified as methylbellidifolin, methylswertianin, swertianin, bellidifolin, norswertianin and desmethylbellidifolin. These six xanthone derivatives were shown to possess different antioxidant activities by chemiluminescent assay. The antioxidative activities of bellidifolin, norswertianin and desmethylbellidifolin were higher than those of butylated hydroxytoluene (BHT) and α-tocopherol. On autoxidation of methyl linoleate, bellidifolin had activity similar to that of BHT. On the basis of the data present on antioxidative properties and data reported on the mutagenicities of the xanthones, both activities were shown to give a good correlation.     

The influence of carotenoids and tocopherols on the stability of safflower seed oil during heat-catalyzed oxidation

The stability and antioxidant effects of carotenoids and tocopherols in safflower seed oil were evaluated under thermal (75°C) and oxidative conditions and the oxidative stability index (OSI) determined. The antioxidant capability of butylated hydroxytoluene (BHT) was also compared with that of β-carotene in a model system. Lycopene and β-carotene (1 to 2000 ppm) were heated (75°C) and exposed to air (2.5 psi) in an oxidative stability instrument. β-Carotene had no antioxidant effect at concentrations below 500 ppm, because it did not alter the induction time. Lycopene increased the induction time only slightly at low concentrations. However, at concentrations greater than 500 ppm, both β-carotene and lycopene acted as prooxidants, significantly decreasing the induction period. At the highest concentration, 2000 ppm, lycopene was more prooxidative than β-carotene. α- and γ-Tocopherol (concentration, 1000 ppm) delayed the induction time by 16 and 26 h, respectively. There was no cooperative interaction between α-tocopherol and β-carotene in delaying the onset of oxidation. Furthermore, BHT was significantly more antioxidative than β-carotene. Thus, under thermal and oxidative conditions, β-carotene could not delay the onset of oxidation. The tocopherols and BHT were effective in suppressing the onset of oxidation, as determined by the oxidative stability measurement.     

Antioxidant Activity of Piceatannol in Canola Oil

Piceatannol has shown to be a strong antioxidant in vivo, however, its ability to suppress lipid oxidation in foods has not been examined. The present study is to examine the antioxidant effect of piceatannol on heated canola oil compared with that of butylated hydroxytoluene (BHT). The oxidation of canola oil is conducted at 60, 90, 120, and 150 °C by monitoring the depletion of oxygen, the decrease in unsaturated fatty acids, and the changes of primary and secondary oxidation products. Results demonstrated that piceatannol can suppress lipid oxidation of canola oil in a dose-dependent manner with its effect being more effective than BHT. Practical Applications: Lipid oxidation is a major factor in the deterioration of food quality. Synthetic antioxidants, such as BHT and butylated hydroxyanisole, are used to inhibit oxidation in foods, but their safety has been always concerned. Piceatannol has exhibited a strong antioxidant activity to attenuate lipid oxidation and it should be further explored for use as a natural antioxidant in foods.     

Antioxidant Activity of Sesamin in Canola Oil

The present study presents the antioxidant activity of sesamin in canola oil compared with that of butylated hydroxytoluene (BHT) by monitoring the oxygen consumption and the decrease in linoleic acid and α-linolenic acid. The oxidation of canola oil was conducted at 35, 60, 90, 120 and 180 °C with addition of 50–400 ppm sesamin. Results from the oxygen consumption test showed that sesamin dose-dependently inhibited the oxidation of canola oil at concentrations of 50–200 ppm at temperatures of 60–180 °C, however, sesamin lost its antioxidant activity at a low temperature of 35 °C. The fatty acid analysis also demonstrated that sesamin at 50, 100 and 200 ppm dose-dependently prevented the oxidation of linoleic acid and α-linolenic acid in canola oil. Both the oxygen consumption and the fatty acid analysis demonstrated sesamin was less effective than BHT as an antioxidant at temperatures of 60–180 °C. It was therefore concluded that sesamin could prevent the lipid oxidation of frying fats and oil, however, its antioxidant activity was not as potent as that of BHT.     

Testing the Antioxidant Effect of Essential Oils and BHT on Corn Oil at Frying Temperatures: a Response Surface Methodology

Food habits worldwide have increased the demand for oxidative-resistant oils that can be used for deep-frying. Oxidative stability in oils can be improved by changing the fatty acid composition of the oil or by adding natural antioxidants to the oil. In this study, the effect of essential oils of seven plants; cinnamon, rosemary, sage, turmeric, clove, thyme and oregano enriched with carvacrol on the oxidative stability of corn oil at frying temperatures were studied. Experiments were conducted by using a PetroOxy device, a rapid small scale oxidation stability test. A central composite design was used to evaluate the effects of concentration of essential oil (X1: 1,500–5,000 ppm) and temperature (X2: 150–180 °C), on the induction time of corn oil. In order to compare the results with the synthetic antioxidant, butylated hydroxy toluene (BHT), another design was made with a concentration range (60–350 ppm) containing the legal upper limit of BHT, 200 ppm. Induction periods obtained from the accelerated oxidation test revealed that increasing temperature decreased the induction time of all the samples. However, the essential oils except for oregano oil had no significant antioxidative effect on corn oil, probably due to a lower content of their active components. The antioxidative effect of oregano oil was also found to be higher compared to BHT. At very high temperatures (e.g., 180 °C), the concentration of antioxidants had no effect on the induction periods.     

Antioxidant Activity of Oat Malt Extracts in Accelerated Corn Oil Oxidation

Oat cultivar AC Vermont was malted to concentrate antioxidants, milled to fractionate only the endosperm portion and extracted with methanol to isolate the crude antioxidants. The oat malt antioxidant fraction was assessed as a natural antioxidant based upon enhancing the stability of corn oil against oxidation and compared to the synthetic antioxidant butylated hydroxytoluene (BHT). The induction time (time required for the formation of 10 meq hydroperoxide per kilogram corn oil thermally oxidized) was used to measure antioxidant activity of oat antioxidant or BHT. The protection factor achieved by crude oat malt antioxidant extract concentrate at 0.26% (2,600 μg/g) was comparable to BHT (75 μg/g). The antioxidant activity of the oat and barley malt extract concentrates was not significantly different. However, the extract concentrate of oat malt had 44% less color compared to that of barley malt at equal concentrations showing its potential as a natural food antioxidant.     

Evaluation of natural and synthetic compounds according to their antioxidant activity using a multivariate approach

The antioxidant activity of natural and synthetic compounds was evaluated using five in vitro methods: ferric reducing/antioxidant power (FRAP), 2,2‐diphenyl‐1‐picrylhydradzyl (DPPH), oxygen radical absorption capacity (ORAC), oxidation of an aqueous dispersion of linoleic acid accelerated by azo‐initiators (LAOX), and oxidation of a meat homogenate submitted to a thermal treatment (TBARS). All results were expressed as Trolox equivalents. The application of multivariate statistical techniques suggested that the phenolic compounds (caffeic acid, carnosic acid, genistein and resveratrol), beyond their high antioxidant activity measured by the DPPH, FRAP and TBARS methods, showed the highest ability to react with the radicals in the ORAC methodology, compared to the other compounds evaluated in this study (ascorbic acid, erythorbate, tocopherol, BHT, Trolox, tryptophan, citric acid, EDTA, glutathione, lecithin, methionine and tyrosine). This property was significantly correlated with the number of phenolic rings and catecholic structure present in the molecule. Based on a multivariate analysis, it is possible to select compounds from different clusters and explore their antioxidant activity interactions in food products.     

1,2,6-三磷酸-3,4,5-三己酸肌醇酯的制备及其抗油脂氧化活性研究

植酸水解得到1,2,6-三磷酸肌醇,然后与三乙胺反应生成相应的铵盐,在脂酶NovozyTne 435催化下,该铵盐与己酸反应生成1,2,6-三磷酸-3,4,5-三己酸肌醇酯.以过氧化值(POV)和茴香胺值(AV)为指标研究不同剂量的1,2,6-三磷酸-3,4,5-三己酸肌醇酯对策籽油的抗氧化性能.结果表明,1,2,6-三磷酸-3,4,5-三己酸肌醇酯对菜籽油具有明显的抗氧化作用且存在剂量效应关系,在添加量为0.06%时,其抗氧化能力和0.02%BHT相当.     

Antioxidants and stabilizers LXIX. Effect of products of the oxidation transformation of 4,4′-thio-bis(2-methyl-6-tert-butylphenol) on the oxidation of tetralin

The effect of products of the oxidation transformation of an antioxidant for polyolefins, 4,4′-thio-bis(2-methyl-6-tert-butylphenol), on the oxidation of tetralin initiated with 2,2′-azobis(isobutyronitrile) at 60°C, and with tetralylhydroperoxide at 120°C was investigated. Nearly all investigated sulphur-containing compounds possessed antioxidative activity. Their formation under conditions which inhibit the oxidation of polyolefins and the comparison of their effectivity observed for various modes of the initiation of oxidation show that there exist two mechanisms by which antioxidants containing sulphidic sulphur in their molecule may be operative and indicate which transformation products of the originally present antioxidant take part in the autoxidation. The antioxidative activity of compounds of the thiobisphenol type is lost only after complete transformation into products of a quinoid type and into sulphon.     

New oxidation pathway of 3,5-di-tert-butyl-4-hydroxytoluene: An ionspray tandem mass spectrometric and gas chromatographic/mass spectrometric study

The autoxidation of 3,5-di-tert-butyl-4-hydroxytoluene (BHT, 1) in bar soap was investigated with ionspray tandem mass spectrometric and on-line gas chromatographic/mass spectrometric methods. The oxidation products of BHT were extracted from the bar soap surface, concentrated, and fractionated with open-column chromatography to remove the impurities. New oxidation products of BHT (BHT phenol-type dimer 7 and others) were identified with the two mass spectrometric methods. The results suggested that oxidation of BHT in bar soap occurred in a way different from that in the previous studies. In the new pathway, oxidation of BHT first generates an excited state of phenol-type dimer 4, and then this species decomposes, due to its high energy, to form dimer 7. The mechanism of oxidation is discussed.     

紫甘薯花青素的功能特性研究

采用抗坏血酸和BHT作为对照,测定了紫甘薯花青素的还原能力、对食用油脂的抗氧化能力及对.OH自由基和O2-.自由基的清除能力。结果表明,当浓度大到0.5mg/mL时,其还原能力接近抗坏血酸;在豆油基质中紫甘薯花青素的抗氧化活性高于BHT;在试验质量浓度范围内,紫甘薯花青素对.OH自由基的清除率为81.2%,活性略低于抗坏血酸;对O2-.自由基的清除率可达91.3%,活性强于BHT。     

Phenol antioxidant efficiency in various lipid substrates containing hydroxy compounds

The oxidation stability of triacylglycerols of sunflower oil (TGSO) at 80 �C in the presence of 0.1 mM 2, 6‐di‐tert‐butyl‐4‐methylphenol (BHT) was found to decrease in the presence of 40 mM lipid hydroxy compounds (R'OH), 1‐tetradecanol (1‐TD), 1‐octadecanol (1‐OD), and 1‐monopalmitoylglycerol (1‐MP). Taking into account the significant effect of these compounds on the chain initiation via an acceleration of the hydroperoxide decomposition, the relative protection activity of BHT was found to increase in the presence of R'OH in the sequence: (TGSO) < (TGSO+1‐TD) < (TGSO+1‐OD) < (TGSO+1‐MP). This result was explained with the so‐called “micellar effect”: the relatively higher concentration of polar species such as hydroperoxide, peroxyl radicals and BHT within and nearby the micro aggregates formed in the presence of R'OH, leads to an increase of the rate of chain termination compared to that in the bulk lipid. When free radicals are generated in the bulk oil via the decomposition of a special nonpolar initiator, azo‐bis‐isobutyronitrile, 1‐OD and 1‐MP do not affect the BHT antioxidant efficiency. The effect of the lipid medium (linoleate or oleate type) on the antioxi‐dant activity of α‐tocopherol (TOH), 1.3 mM, in the presence of 1‐OD has been assessed on an example of oxidation of sunflower oil (SO) and lard (L) at 100 �C. Inspite of their different oxidizability 1‐OD caused the same relative decrease in the TOH efficiency during SO and L oxidation.     

Antioxidative cosmetic additives for the protection of human skin surface lipids against environmental stress

Studies were carried out in vitro to investigate the effect of a simulated polluted atmosphere containing ozone, sulfur dioxide, and nitrogen dioxide on human skin surface lipids and to evaluate the potency of antioxidative cosmetic additives for the protection against detrimental oxidation processes caused by air polluting substances. The experiments showed that the air pollutants caused significantly increased oxidation effects on human skin surface lipids compared to non polluted atmosphere as indicated by the increase of the peroxide values. The addition of selected derivatives of ascorbic acid, tocopherol, or retinol as specific cosmetic additives with particular antioxidative activity both as pure substances and as ingredients of cosmetic skin care formulations resulted in a considerable protection against oxidative effects of the air pollutants on human skin surface lipids, in which the antioxidative complex tocopherol/hydrogenated tallow glyceride citrate is most effective. Even by additional irradiation with artificial erythemogenic sunlight during the exposure to the air polluting substances of a skin care formulation composed of tocopherol/hydrogenated tallow glycerides as antioxidative component and zinc oxide as UV-filter substance, the significant lipid-protective efficacy of the antioxidative cosmetic additive was only slightly diminished.     

Antioxidative activity measurement in lipid peroxidation systems with malonaldehyde and 4-hydroxy nonenal

Antioxidative activities of vitamin E, ethylenediamine tetraacetic acid (EDTA), ferulic acid, and butylated hydroxy toluene (BHT) were monitored with lipid peroxidation systems. Formation of malonaldehyde (MA) and 4-hydroxy nonenal (4-HN) from ethyl linoleate or rat liver microsome oxidized by FeCl₂/H₂O₂ or ADP/FeSO₄ was measured by gas chromatography. Over 90% of MA and 4-HN formation was inhibited by 100 mmol/L of vitamin E. A synthetic antioxidant, BHT, showed the strongest antioxidative activity, followed by that of vitamin E, whereas EDTA accelerated formation of MA and 4-HN in the ethyl linoleate/FeCl₂/H₂O₂ system. Vitamin E did not suppress lipid peroxidation significantly when microsome was oxidized by ADP/FeSO₄. EDTA inhibited oxidation of microsome by ADP/FeSO₄ considerably; in contrast, it did not in the case of oxidation by FeCl₂/H₂O₂.     

Kinetics of lipid oxidation in the presence of cinnamic acid derivatives

The effects of seven (prenyl‐ and methoxy‐) derivatives of cinnamic acid (0.1 mM) on the kinetics of lipid (sunflower oil triacylglycerols, TGSO) bulk phase oxidation at 80 °C have been compared. Synthesis of prenyl cinnamic acid derivatives: 3‐prenyl‐4‐hydroxy‐cinnamic acid (PHC), 3,5‐diprenyl‐4‐hydroxy‐cinnamic acid (DPHC), 2,2‐di‐methyl‐6‐carboxy‐ethenyl‐2H‐benzopyran (DMCB), 2,2‐dimethyl‐6‐carboxy‐ethenyl‐8‐prenyl‐2H‐benzopyran (DCEPB) present in Brazilian propolis has been performed. The monoprenyl derivative (PHC) has been found to exert a higher antioxidant activity as compared to the diprenyl derivative (DPHC). However, cinnamic acid derivatives DMCB and DCEPB have caused no change in the kinetics of TGSO oxidation. The results obtained have been compared with those on related compounds containing a cinnamic acid moiety as a structural feature, such as 4‐hydroxy‐cinnamic (p‐coumaric), 3‐methoxy‐4‐hydroxy‐cinnamic (ferulic) and 3,5‐dimethoxy‐4‐hydroxy‐cinnamic (sinapic) acids, as well as with data on butylated hydroxytoluene (BHT) and α‐tocopherol (αToc). PHC has shown a stronger antioxidant efficiency than BHT, p‐coumaric and ferulic acid, but a weaker antioxidant efficiency than α‐Toc and sinapic acid. The observed antioxidant effect of DPHC was stronger than that of p‐coumaric and ferulic acids and weaker than that of α‐Toc, BHT and sinapic acid.