Antioxidants In Vegetable Oils Research Articles

Effects of Endogenous Antioxidants in Camellia Oil on the Formation of 2-Monochloropropane-1, 3-diol Esters and 3-Monochloropropane-1,2-diol Esters during Thermal Processing.

2-Monochloropropane-1, 3-diol (2-MCPD) esters and 3-monochloropropane-1,2-diol (3-MCPD) esters, a class of substances potentially harmful to human health, are usually formed during the refining of vegetable oils under high temperature. The effects of endogenous antioxidants in vegetable oils on the formation of 2- and 3-MCPD esters is still unknown. In this study, the effects of endogenous antioxidants (α-tocopherol, stigmasterol and squalene) on the formation of 2- and 3-MCPD esters in model thermal processing of camellia oil were investigated. The possible formation mechanism of 2- and 3-MCPD esters was also studied through the monitoring of acyloxonium ions, the intermediate ions of 2- and 3-MCPD esters formation, and free radicals by employing infrared spectra and electron paramagnetic resonance (EPR), respectively. The results indicated that the addition of α-tocopherol had either promoting or inhibiting effects on the formation of 2- and 3-MCPD esters, depending on the amount added. Stigmasterol inhibited the formation of 3-MCPD ester and 2-MCPD ester at low concentrations, while promoting their formation at high concentrations. Squalene exhibited a promotional effect on the formation of 3-MCPD ester and 2-MCPD ester, with an increased promotion effect as the amount of squalene added increased. The EPR results suggested that CCl3•, Lipid alkoxyl, N3• and SO3• formed during the processing of camellia oil, which may further mediate the formation of chlorpropanol esters. This study also inferred that squalene promotes the participation of the free radical in chlorpropanol ester formation.

Effects of α-Tocopherol, β-Carotene and Epigallocatechin Gallate on the Oxidative Stability of Sunflower Oil.

Using sunflower oil as the oil matrix, the antioxidant effects and types of interactions of three natural components, α-tocopherol, β-carotene and epigallocatechin gallate (EGCG), were investigated and the kinetic model of oxidation reaction was established. The results showed that the ability of the three antioxidants to scavenge DPPH radicals was ranked as EGCG > β-carotene > α-tocopherol in the concentration range of 0~100 mg/kg. 15 samples were obtained by combining two of three natural components. When the concentration ratios of β-carotene and EGCG were 1:20 and 1:7.5, α-tocopherol and EGCG were 1:13.3, 1:6, and 1:2, and α-tocopherol and β-carotene were 1:0.2 and 1:0.05, the type of interaction was synergistic, while the rest of the samples showed antagonistic effects. The sample with a 1:13.3 concentration of α-tocopherol and EGCG showed the longest induction period, the lowest oxidation rate constant, the highest activation energy, the best oxidative stability, and the longest shelf life at different temperatures. This compounded natural antioxidant was the most favorable for the stability of sunflower oil. This provides some theoretical basis for the development and application of compounded natural antioxidants in vegetable oils.

Bicarbonates and carbonates as antioxidants in vegetable oils at frying temperatures

Antioxidant activity of bicarbonates and carbonates including NaHCO3 , Na2 CO3 , KHCO3 , and K2 CO3 was evaluated in soybean oil (SBO) at 180°C. KHCO3 and K2 CO3 had stronger activity than NaHCO3 and Na2 CO3 . KHCO3 (5.5mEq/L, 0.060wt.%) and K2 CO3 (5.5mEq/L, 0.041wt.%) were more effective than 0.02wt.% tert-butylhydroquinone (TBHQ) in preventing oxidation of SBO. While the antioxidant activity of KHCO3 and K2 CO3 increased with increasing their concentrations up to 5.5mEq/L, it decreased at 11mEq/L. KHCO3 and K2 CO3 were also effective in preventing oxidation of other vegetable oils including avocado, canola, corn, high oleic soybean, and olive oils. Correlation tests conducted with the results from the six oils showed that KHCO3 and K2 CO3 had weak to moderate positive correlations with γ- and δ-tocopherols. In a separate study in stripped SBO, it was found that KHCO3 had a synergistic effect with α-tocopherol, but not with γ- and δ-tocopherols. KHCO3 had additive or synergistic effect with rosemary extract, epigallocatechin gallate, ascorbic acid, and ascorbyl palmitate. Antioxidant activity of KHCO3 was confirmed in frying of potato cubes in SBO and canola oil. Although more studies should be conducted for better understanding of the mechanisms and factors affecting the antioxidant activity of bicarbonates and carbonates, this study demonstrated that they could serve as antioxidants or co-antioxidants of other antioxidants in frying. PRACTICAL APPLICATION: Inorganic salts including NaHCO3 , KHCO3 , Na2 CO3 , and K2 CO3 hadstrong antioxidant activity in vegetable oils at frying temperatures when they wereadded as powder. Antioxidant activity of 0.06 wt.% KHCO3 was higherthan that of 0.02 wt.% TBHQ in soybean oil and canola oil during frying potato. KHCO3 had additive orsynergistic effect with rosemary extract, epigallocatechin gallate, ascorbicacid, and ascorbyl palmitate indicating that these inorganic salts can be usedas co-antioxidants to enhance the antioxidant activity of existing antioxidantswhile they can be used alone as well.

The variation of oxidative stability and sensory attributes of sunflower oil induced by essential oil from Magnolia liliflora Desr. during high‐temperature storage

SummaryEssential oils are considered one of the most prominent natural antioxidants in vegetable oils. Herein, sunflower oil was flavoured by the essential oil extracted from the flowers of Magnolia liliflora Desr. (MLEO), and its oxidative stability and sensory properties during the high‐temperature storage at 65 °C were explored. After the storage for 30 days, MLEO at 1600 mg kg−1 could significantly suppress the increase for acidity value, peroxide value, ρ‐anisidine value and total oxidation values (P < 0.05 or P < 0.01). In the meantime, the elevation for thiobarbituric acid reactive substances, conjugated dienes and trienes was significantly suppressed as well (P < 0.05 or P < 0.01). Additionally, MLEO at 1600 mg kg−1 was able to restrict the transformation for the fatty acid composition of sunflower oil, and the sensory attributes of sunflower oil could be obviously improved. Consequently, MLEO could be employed as one potential natural antioxidant for sunflower oil.

Antioxidant Effects of Hemp (Cannabis sativa L.) Inflorescence Extract in Stripped Linseed Oil.

The ability of hemp (Cannabis sativa L.) inflorescence extract to counteract lipid oxidation was studied in stripped linseed oil. The ethanolic extract was characterized in terms of terpenes (6.00 mg/mL), cannabidiol (4.99% w/w), phenolic compounds (1.80 mg gallic acid equivalents (GAE)/mL), antiradical, and metal ion-chelating activities (50% effective concentration (EC50) of 2.47 mg/mL and 0.39 mg/mL, respectively). The stripped linseed oil, used as control (CO), was mixed with hemp extract (HO) or α-tocopherol (EO) at a ratio of 0.6% (w/w) and stored for 7 days in darkness at 40 °C. Hemp extract reduced the oxidation and lipolysis processes. At the end of the storage, HO showed a significantly higher level of α-linolenic acid (ALA; 26.64 g/100 g), lower peroxide value (PV) (21.19 meq O2/kg oil), and lower hexanal content (7.67 mmol/kg oil) than those found in the control. In contrast, EO showed a marked lipolysis (the free fatty acids increased by 42.57%) and a noticeable oxidation, since the ALA content decreased by 2.10% and a PV of 50 meq O2/kg oil was observed. This study demonstrates that hemp inflorescences can be used as a source of natural antioxidants in vegetable oils and lipid products to retard their oxidation, especially those characterized by a high degree of unsaturation.

Effect of leaf and fruit extracts of <em>Schinus molle</em> on oxidative stability of some vegetables oils under accelerated oxidation

The most highly recommended oils for the diet are those which are rich in unsaturated fatty acids. However, the presence of these components in the oils is related to oxidation, which can be determined by the induction period. Further safety and the prolongation of the storage period for such oils can be achieved by the addition of efficient antioxidants, which today are preferably from natural sources. In order to contribute to the related research, the main objective of this study was to evaluate the efficacy of Schinus molle extracts compared to synthetic antioxidants (BHT) in delaying the oxidation of some vegetable oils. The results of the present study showed that the fruit and leaf extracts of Schinus molle presented activities and potential for being used as antioxidants in vegetable oils based on the tested methods (DPPH and ABTS). The extracts were also characterized as containing phenolic compounds by the Folin Ciocalteau method and by high performance liquid chromatography (HPLC). The action of the extracts as natural antioxidants was proven in the vegetal oils of chia (Salvia hispanica) and peanut (Arachis hypogaea) by the Rancimat method. It was observed that the oils increased their resistance to oxidation when incorporated with the extracts of Schinus molle, and the extract from the leaves increased the induction period of peanut oil by more than three hours (from 19.5 to 22.9 hours) with an extract concentration of 2.5%. The fruit extract was more efficient in delaying the oxidation of chia oil, prolonging its induction period by more than one hour with a concentration of 2.5% (from 3.1 to 4.3 hours). According to the results, the extracts of Schinus molle have favorable properties for possible use as an additive which inhibits the oxidation process of the tested vegetables oils.

Analysis of nine antioxidants in vegetable oils by high performance liquid chromatography

A method was developed for the determination of nine antioxidants in vegetable oils by high performance liquid chromatography (HPLC). The samples were extracted with methanol, and the fat in the samples was degreased by freezing. Separation of the targeted compounds was performed on an XBridge C18 column in gradient elution mode using methanol-0.1% (v/v) formic acid aqueous solution as the mobile phase. The analytes were detected using a diode-array detector by the external standard method. The stability and storage conditions for the nine antioxidants were systematically investigated. Ascorbyl palmitate (AP) was introduced into the preparation and pre-treatment of the targets. The concentration of AP was optimized to improve the stability and recovery of the targets. The effects of different extraction solvents and purification methods on the extraction efficiencies were discussed. The results showed that the nine antioxidants could be separated well under the optimized conditions. Good linear relationships in the linear range were obtained, and the correlation coefficients (R2) were greater than 0.999. The average recoveries of the nine antioxidants ranged from 85.3% to 104.1%, with RSDs of the method ≤5.0%. The limits of quantitation (LOQs) for the nine synthetic antioxidants were in the range of 0.6-3.0 mg/kg. The method is simple, rapid, sensitive, and it shows good recovery and reproducibility.

Low-density solvent-based dispersive liquid–liquid microextraction coupled with hydrophobic magnetic nanoparticles for determination of synthetic phenolic antioxidants in vegetable oils by high-performance liquid chromatography

ABSTRACTA novel and rapid low-density solvent-based dispersive liquid–liquid microextraction technique combined with magnetic solid-phase extraction (MSPE) was developed for preconcentration and separation of synthetic phenolic antioxidants (SPAs) in vegetable oils prior to high-performance liquid chromatography. 1-Heptanol was used as extractant and decanoic acid@Fe3O4 nanoparticles (DA@Fe3O4 NPs) as carrier to retrieve and separate the 1-heptanol. In that manner, the upper extractant containing the SPAs is the target of the MSPE step rather than the SPAs directly. Thanks to the interaction between carboxyl group present on the surface of the magnetic nanoparticles and the alcohol functional group of the extractant, the DA@Fe3O4 NPs facilitates the recollection of the 1-heptanol after extraction. The main parameters affecting the extraction recoveries of four SPAs were investigated, and the proposed method provided a good linearity in the range of 50–2000 ng mL−1, low limits of detection (1.2–5.8 ng mL−1), and good repeatability of the extractions (relative standard deviations ≤6.7%, n = 5), and recoveries were ranged from 90.2% to 99.5%.

Effect of Fat-Soluble Anti-oxidants in Vegetable Oils on Acrylamide Concentrations During Deep-Fat Frying of French Fries.

BackgroundThis study attempted to evaluate the effect of fat-soluble anti-oxidants in vegetable oils on acrylamide during the deep-fat frying of French fries.MethodsThree vegetable oils with different fat-soluble anti-oxidant contents were selected and par-fried potato strips were fried in these oils. Acrylamide in the French fries at different frying times (at 180 °C) and over 10 consecutive frying sessions were measured. The anti-oxidant contents and quality degradation of oils were monitored before and after the 5th and 10th consecutive frying sessions.ResultsThe effect of the fat-soluble anti-oxidants in red palm oil on the acrylamide was more apparent when a prolonged frying time was used for consecutive frying sessions than when different frying conditions were used. Using red palm oil, acrylamide concentration in French fries significantly dropped to the lowest level, at 524 ng g−1, after the 10th frying session. The β-carotene content after the 10th frying session was the highest in red palm oil.ConclusionThe use of red palm oil for deep-fat frying French fries can be a mitigation strategy to reduce acrylamide formation, but further studies are necessary to investigate the influence of different types of fat-soluble anti-oxidants on the inhibition of acrylamide formation.

Micellization in vegetable oils: A structural characterisation

The solubilisation of polar and polyphenol antioxidant in vegetable oils was studied. It was shown that the use of a polyglyceryl-3-diisostearate (PG3DS), a bio-sourced emulsifier well known in cosmetics, increases the yield of solubilisation thanks to some aggregation properties analysed using x-ray scattering technique. We show indeed that PG3DS forms reverse aggregates with a critical concentration that depends on the oil polarity. PG3DS reverse aggregates are elongated with a polar core and cannot be really swollen by addition of water. This supramolecular organisation allows however an efficient solubilisation of polar antioxidants in vegetable oils.

Determination of Synthetic Phenolic Antioxidants in Vegetable Oil and Oil-Enriched Foods by High-Performance Liquid Chromatography with Electrochemical Detection

ABSTRACTThree synthetic phenolic antioxidants, tertiary butyl hydroquinone, butylated hydroxytoluene, and butylated hydroxyanisole, were determined in vegetable oil and oil-enriched food by high-performance liquid chromatography (HPLC) with electrochemical detection. The separation was achieved using a reverse-phase column and gradient elution with methanol and 1% acetic acid. The limits of detection and quantification of the analytes were 2–120 lower, higher than those obtained by diode-array detection. The recoveries were 103.3% for tertiary butyl hydroquinone, 97.3% for butylated hydroxyanisole, and 95.2% for butylated hydroxytoluene. The results showed that HPLC with electrochemical detection is suitable for the quantification of low concentrations of phenolic antioxidants in vegetable oil and oil-enriched food with high sensitivity and accuracy.

Hierarchical triple-shelled porous hollow zinc oxide spheres wrapped in graphene oxide as efficient sensor material for simultaneous electrochemical determination of synthetic antioxidants in vegetable oil

Hierarchical triple-shelled porous hollow zinc oxide spheres (ZnO TPHS) were conveniently synthesized via a hard template method. And the ZnO TPHS were then wrapped into graphene oxide (GO) nanosheets though electrostatic attraction after being amino-functionalized. The composition of ZnO TPHS@GO hybrid was determined using energy dispersive X-ray spectroscopic analysis, X-ray diffraction and Raman spectra. The morphology of ZnO TPHS@GO hybrid was comprised of ZnO nanoparticles and ultrathin GO nanosheets that were characterized with scanning electron microscopy and transmission electron microscopy. The porous hollow structure and intimate contact between ZnO TPHS and GO interfaces provided a large surface area and high electron transfer activity for synthetic antioxidants in an acidic electrolyte. Based on this, a novel electrochemical sensor for the simultaneous determination of tert-butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) has been constructed using ZnO TPHS@GO as sensing material. Under optimal conditions, the developed sensor exhibited excellent electrochemical responses in the co-detection of TBHQ and BHA, with limits of detection of 0.137 and 0.0488μM (S/N=3), respectively. Besides, the selectivity, reproducibility and application in edible vegetable oil samples were also investigated. This study proposed a novel method of fabrication of metal oxide-decorated GO-based materials for the fabrication of sensitive electrochemical sensors that met the needs of food safety control.

Evaluation of antioxidant activity of loquat fruit (Eriobotrya japonica lindl.) skin and the feasibility of their application to improve the oxidative stability of soybean oil.

The effects of ultrasound-assisted, supercritical CO2 and solvent extraction techniques on antioxidant activity of loqua (Eriobotrya japonica Lindl.) skin extract in oxidation stability of soybean oil was evaluated. The antioxidant efficacy of extracts was determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH(•)) radical scavenging capacity, β-carotene/linoleic acid, and Rancimat test system. Results showed that solvent extract of loquat fruit skin at 400ppm had the highest antioxidant activity compared to ultrasound-assisted and supercritical CO2 extracts. Further, solvent extraction was the most effective method for extraction of phenolic compounds. Protective effects of extracts in stabilization of soybean oil during both frying and storage conditions were tested and compared to tert-butyl hydroquinone (TBHQ) by measuring their peroxide value, free fatty acids, conjugated dienes and trienes value. During frying process solvent extract of skin at 400ppm (SOEA) exhibited stronger antioxidant activity in oil compared to other oil samples, but this antioxidant potential was lower than TBHQ in storage conditions. Present study showed that loquat fruit skin is a good source of natural antioxidant compounds, and has the potential to be used as a substitute for synthetic antioxidants in vegetable oils.

Determination of tocopherols as lipid antioxidants in vegetable oils and animal fats

The content of vitamin E (tocopherols) in natural vegetable oils and fats has been determined by microcalorimetry. This technique belongs to kinetic methods for determining vitamin E, which are based on the capacity of tocopherol to inhibit liquid-phase radical oxidation reactions. It has been shown on a model reaction of initiated oxidation of cumene that fatty oils inhibit the radical reaction with an induction period proportional to the content of tocopherols in oil. From experimental curves, the content of tocopherols in oils obtained by different technological methods has been estimated. It has been shown that the amount of tocopherols is an indicator of the oil quality; therefore, the method proposed can be used to control the way of oil manufacture, oil quality, and the presence of synthetic antioxidants.

Antioxidant activities and interactions of α‐ and γ‐tocopherols within canola and soybean emulsions

During the 1940s, basic theories addressing the chemistry of lipid oxidation were developed, namely the free radical theory of hydroperoxide formation and decomposition and its inhibition by antioxidants. Tocopherols, especially the α‐ and γ‐homologs, are the primary antioxidants in vegetable oils. α‐Tocopherol having a fully substituted phenolic ring has a stronger power than γ‐tocopherol in scavenging free radicals in solutions but this is not consistently the case in foods, including vegetable oils and their emulsions. Paradoxical results on the superiority of these two closely related antioxidants over each other are often found. The article by Moser et al. in this issue of the European Journal of Lipid Science and Technology presents a comprehensive study comparing the antioxidant activities of α‐ and γ‐tocopherols and their interactions in 10% canola and soybean oil‐in‐water emulsions incubated at 50°C. The oxidation of stripped oils, supplemented with known concentrations of α‐ and/or γ‐tocopherols, was followed by measuring the evolution of hydroperoxides and their decomposition product hexanal. The results were affected by the oil matrix. In canola oil emulsions, γ‐tocopherol was a stronger antioxidant than α‐tocopherol (at 200 or 600 µg/g oil) and their interaction was additive even at 600 + 600 µg/g oil level. In soybean oil emulsions, α‐tocopherol was the stronger antioxidant at concentrations up to 250 µg/g oil while γ‐tocopherol was the stronger antioxidant at the higher concentrations and the interaction between the two tocopherols was synergistic at the low concentrations (200 + 200 µg/g oil) but was either additive or antagonistic at higher concentrations. In both oils, α‐tocopherol lost antioxidant effectiveness at around 400 µg/g oil.

Avaliação da estabilidade foto-oxidativa dos óleos de canola e de milho em presença de antioxidantes sintéticos

A estabilidade dos óleos vegetais à oxidação depende do equilíbrio entre a composição e a presença de pró-oxidantes e antioxidantes. O objetivo deste estudo consistiu em avaliar o efeito da presença de antioxidantes sintéticos durante o processo de foto-oxidação dos óleos de canola e milho. As amostras dos óleos de canola e milho em presença e em ausência dos antioxidantes butil-hidroxitolueno (BHA), propil galato (PG) e terc butil-hidroquinona (TBHQ), foram submetidas ao estresse foto-oxidativo. A reação de foto-oxidação seguiu uma cinética de primeira ordem. A constante de velocidade no período de 20 dias de foto-oxidação evidenciou que o antioxidante PG apresentou maior efeito protetor para o óleo de canola e o TBHQ para o óleo de milho. A partir dos dados de UV e RMN de ¹H, no período de 60 dias, constatou-se que os três antioxidantes apresentaram um efeito protetor a foto-oxidação. Os dados de UV evidenciaram aumento de absorção da banda em 232 nm devido à foto-oxidação e formação de dienos conjugados. A redução da intensidade de absorção desta banda na foto-oxidação com o tempo de exposição revelou que a proteção, tanto para o óleo de canola como para o de milho, foi mais efetiva com o antioxidante PG. Os índices de oxidação Roa e fração residual de hidrogênios (H) dialílicos, alílicos e vinílicos também evidenciaram que o antioxidante PG apresentou o melhor desempenho na proteção dos dois tipos de óleo.

Unraveling the Genetic Basis of Seed Tocopherol Content and Composition in Rapeseed (Brassica napus L.)

BackgroundTocopherols are important antioxidants in vegetable oils; when present as vitamin E, tocopherols are an essential nutrient for humans and livestock. Rapeseed (Brassica napus L, AACC, 2 n = 38) is one of the most important oil crops and a major source of tocopherols. Although the tocopherol biosynthetic pathway has been well elucidated in the model photosynthetic organisms Arabidopsis thaliana and Synechocystis sp. PCC6803, knowledge about the genetic basis of tocopherol biosynthesis in seeds of rapeseed is scant. This project was carried out to dissect the genetic basis of seed tocopherol content and composition in rapeseed through quantitative trait loci (QTL) detection, genome-wide association analysis, and homologous gene mapping.Methodology/Principal FindingsWe used a segregating Tapidor × Ningyou7 doubled haploid (TNDH) population, its reconstructed F2 (RC-F2) population, and a panel of 142 rapeseed accessions (association panel). Genetic effects mainly contributed to phenotypic variations in tocopherol content and composition; environmental effects were also identified. Thirty-three unique QTL were detected for tocopherol content and composition in TNDH and RC-F2 populations. Of these, seven QTL co-localized with candidate sequences associated with tocopherol biosynthesis through in silico and linkage mapping. Several near-isogenic lines carrying introgressions from the parent with higher tocopherol content showed highly increased tocopherol content compared with the recurrent parent. Genome-wide association analysis was performed with 142 B. napus accessions. Sixty-one loci were significantly associated with tocopherol content and composition, 11 of which were localized within the confidence intervals of tocopherol QTL.Conclusions/SignificanceThis joint QTL, candidate gene, and association mapping study sheds light on the genetic basis of seed tocopherol biosynthesis in rapeseed. The sequences presented here may be used for marker-assisted selection of oilseed rape lines with superior tocopherol content and composition.

Rapid micropreparation procedure for the gas chromatographic–mass spectrometric determination of BHT, BHA and TBHQ in edible oils

A rapid, accurate and organic solvent saving procedure has been developed for the GC/MS determination of three phenolic antioxidants butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and butyl hydroquinone (TBHQ) in vegetable oils. The method involves two-step microextraction and a centrifugal procedure in a 2 mL autosampler vial, consuming only 50 mg sample and total 1 mL acetonitrile. Recoveries of the phenolic antioxidants when spiked to soya bean oil, peanut oil and cereal cooking oil at 50, 200 and 250 mg/kg, respectively were in the ranges 95.6–104.3% for BHT, 99.7–107.5% for BHA and 93.6–103.8% for TBHQ with the relative standard deviation (RSD) were less than 3% for their independent measurements. The developed method was repeatable and could be applied to determine trace amounts of phenolic antioxidants in vegetable oils.

The kinetic characteristics of natural antioxidants in vegetable oils

The total content and activity of natural antioxidants of the phenol type in coconut, palm, corn, and rice oils were measured by the chemiluminescent method. The existence of antioxidants of two types in palm and rice oils was shown. The synergistic action of citric acid in the presence of tocopherol was observed for the example of coconut oil.

The use of antioxidants in vegetable oils – A review

The shelf life of vegetable oils in food uses and their applicability in industrial situations is greatly dependent on their oxidative stabilities. Methods of improving oxidative stability values currently available include genetic modifications, compositional changes via chemical means, as well as the inhibition of oxidation by means of substances known as antioxidants. This paper reviews the properties of vegetable oils which predispose them to auto oxidation reactions, explores the nature and mechanisms of the operation of antioxidants in brief, and finally summarizes current research efforts geared towards identifying and evaluating the effectiveness and commercial promise of less toxic new antioxidants derived as natural extracts from various plant species.