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Pro-Oxidant Effects of β-Carotene During Thermal Oxidation of Edible Oils
Abstract
β-Carotene is one of the most important fat soluble pigments with well-known antioxidant and pro-vitamin A activity. It is used in industries as a food colorant and a source of vitamin A. The thermal induced degradation during processing of wide varieties of carotenoid-rich foods leads to color and properties losses. The thermal stability of edible oils is thus of great importance to food manufacturers. Corn oil, rapeseed, and sunflower oils were fortified with 50–300 μg/g of β-carotene and oxidized using a Rancimat apparatus (air flow rate 20 L/h) at 110 °C for 14 h. β-Carotene degradation was measured using high performance thin layer chromatography and confirmed by HPLC–DAD–MS. Triacylglycerols and polar compounds (PC) were determined using LC–ESI–MS. Results showed that most of the β-carotene was degraded during the first 5 h of the thermal oxidation. It was found that the addition of β-carotene produces significant effects (P < 0.05) on the peroxide index, free fatty acid values and radical scavenging activity of the three oils. Triacylglycerols containing high amounts of oleic acid show higher stability toward thermal oxidation and β-carotene treatment. Among the oils, rapeseed oil was the most stable oil in terms of the formation of polar compounds (PC), followed by corn oil, while sunflower oil was more prone to oxidation and thus higher amounts of PC were formed.
... Regarding margarine, this still remains a challenging task as various additives, contained in the product, influence the oxidative stability [8], such as emulsifiers, antioxidants, metal ions, NaCl, citric acid or carotenoids [9][10][11][12]. ...
... The prooxidative behavior of β-carotene can be referred to the instability of carotenoids. Zeb et al. [12] showed that by adding β-carotene to corn, rapeseed and sunflower oils, most of it oxidized in the first five hours of heating at 110 °C in a rancimat apparatus. Moreover, the addition of β-carotene yielded in significant effects on the peroxide index, free fatty acid values and radical scavenging activity [12], as thermally oxidized β-carotene products can increase the peroxide value of oil, thereby showing a prooxidant behavior of β-carotene or its oxidized species [34]. ...
... Zeb et al. [12] showed that by adding β-carotene to corn, rapeseed and sunflower oils, most of it oxidized in the first five hours of heating at 110 °C in a rancimat apparatus. Moreover, the addition of β-carotene yielded in significant effects on the peroxide index, free fatty acid values and radical scavenging activity [12], as thermally oxidized β-carotene products can increase the peroxide value of oil, thereby showing a prooxidant behavior of β-carotene or its oxidized species [34]. As the here described margarine was heated at 80 °C for 1 h to accelerate lipid oxidation, it can be assumed that the carotenoids oxidized, which led to an increase of the PV. Figure 4b shows that the OITs of the margarine samples consisting of the individual minor components (M16-M18) did not differ from M14, which can be explained by the thermal degradation of prooxidants, such as β-carotene, in the rancimat apparatus [70]. ...
This study reports the impact of margarine-representative ingredients on its oxidative stability and green tea extract as a promising antioxidant in margarine. Oil-in-water emulsions received much attention regarding factors that influence their oxidative stability, however, water-in-oil emulsions have only been scarcely investigated. Margarine, a widely consumed water-in-oil emulsion, consists of 80–90% fat and is thermally treated when used for baking. As different types of margarine contain varying additives, their impact on the oxidative stability of margarine during processing is of pressing importance. Thus, the influence of different ingredients, such as emulsifiers, antioxidants, citric acid, β-carotene and NaCl on the oxidative stability of margarine, heated at 80 °C for 1 h to accelerate lipid oxidation, was analyzed by the peroxide value and oxidation induction time. We found that monoglycerides influenced lipid oxidation depending on their fatty acyl chain. α-Tocopheryl acetate promoted lipid oxidation, while rosemary and green tea extract led to the opposite. Whereas green tea extract alone showed the most prominent antioxidant effect, combinations of green tea extract with citric acid, β-carotene or NaCl increased lipid oxidation in margarine. Complementary, NMR data suggested that polyphenols in green tea extracts might decrease lipid mobility at the surface of the water droplets, which might lead to chelating of transition metals at the interface and decreasing lipid oxidation.
... Thus, in order to overcome the stability problem of rapeseed oil rich in polyunsaturated fatty acids, antioxidants are used as additives to retard the oxidation reactions. The effect of addition of natural and synthetic antioxidants such as phenolic acids, α-tocopherol, vegetable powders, plant and fruit extracts, essential oil, lecithin, β-carotene, galloyl phytosterols, BHA, BHT, TBHQ at different concentrations (100-500 μM, 0.005-10%) on oxidative stability of rapeseed oils was analyzed by the Rancimat method (Aladedunye, Kersting, & Matthäus, 2014;Fu et al., 2014;Judde, Villeneuve, Rossignol-Castera, & Le Guillou, 2003;Sayyad & Farahmandfar, 2017;Tabee, Azadmard-Damirchi, Jägerstad, & Dutta, 2008;Tundis et al., 2017;Turan, 2014;Taha et al., 2014;Zeb & Murkovic, 2013). Rapeseed oils with various amounts of antioxidants revealed approximately 1.03-4.50 ...
... Moreover, radical scavenging activity of rapeseed, corn and virgin olive oils insignificantly reduced after supplementation of various amounts of β-carotene (0.05-0.3 mg/g) and lecithin (2.5-10.0 mg/ g), whereas the pronounced progress of DPPH reduction (from 20% to 2%) for sunflower oil enriched with the same concentrations of β-carotene was reported by Koprivnjak et al. (2008) as well as Zeb and Murkovic (2013). ...
... These authors also observed that higher concentrations of the added antioxidants significantly improved the oil stability by an increase of IP values up to 10-350%. On the contrary, there were no significant effects of an increasing concentrations of β-carotene (0.05-0.3 mg/g), ferulic acid and syringaldehyde (0.1-0.5 mM), Teucrium polium essential oil (0.2-1.2 ppm) and bay extract (0.25-2.0 mg/g) on the IP values of rapeseed oils (Sayyad & Farahmandfar, 2017;Tundis et al., 2017;Turan, 2014;Zeb & Murkovic, 2013). However, the addition of α-tocopherol at concentrations between 0.5 and 2.0 mg/g to high-oleic and low erucic acid rapeseed oils caused a decrease of the IP values by about 20% and 16%, respectively (Tabee et al., 2008). ...
Octyl esters of sinapic, ferulic and caffeic acids added to refined rapeseed oil in the concentration range between 0.005 and 0.9% were studied as a potential antioxidants soluble in fats. The effect of octyl esters addition on oxidative stability of rapeseed oil was evaluated by the Rancimat method, and a positive linear correlations (r = 0.8993–0.9546) between the induction times (IP) and phenolipids concentrations were found. Moreover, radical-scavenging capacity of oils with lipophilized phenolic acids was evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The fortified rapeseed oils revealed higher antioxidant capacity (DPPH = 361–15191 μmol Trolox (TE)/100 g) and an increase in oxidative stability (IP = 4.0–12.5 h) in comparison with the refined rapeseed oil (DPPH = 334 μmol TE/100 g and IP = 3.9 h). Protection factors (1.03–3.21) for the enriched rapeseed oils indicate an antioxidant activity of the synthesized phenolipids. Moreover, a new antioxidant - octyl sinapate inhibits the growth of yeast, Gram-positive bacteria and Gram-negative bacteria, whereas this ester has not anti-mould properties.
... The authors found out that β-carotene lowered soybean oil oxidation at all concentrations, especially at 20 mg/kg. However, during the auto-oxidation of the soybean oil stored in darkness, the products of the carotene thermal dissociation acted as pro-oxidants, while lycopene showed antioxidant activity after thermal degradation in the systems similar to soybean oil (Zeb & Murkovic, 2013). ...
... They realized that the rise in the conjugated diene and triene values was proportional to oxygen absorption. In the sunflower oil, as the β-carotene was elevated, the diene and triene values were raised and the oil stability was lowered; as a result, a pro-oxidant effect was produced(Zeb & Murkovic, 2013). ...
The purpose of this work was ultrasound‐assisted extraction of red quinoa carotenoid, and antioxidant effect of the purified carotenoid on soybean oil stability was compared with that of commercial carotenoid. Red quinoa carotenoid was extracted using 50 mL ethanol as the solvent in an ultrasonic bath at 45±1°C and 20 kHz for 3 min. After the carotenoid purification, its effect on the oxidative stability of soybean oil was compared with that of commercial β‐carotene during 8 days of storage at 60°C. Peroxide value (PV), conjugated diene value (CV), thiobarbituric acid (TBA) value, and color parameters were measured. 100 mg/kg of the commercial and natural carotenoids was the best concentration to decrease the TBA value during the 8 days of storage, compared with the other concentrations (200 and 300 mg/kg). On the last day, the samples containing 100 mg/kg of the commercial and natural carotenoids had the lowest CV, and TBA value, and lowest PV was in samples containing 200 mg/kg. In addition, the lowest PV (7.8 meq/kg) was obtained on the 8th day, owing to the performance of β‐carotene at 200 mg/kg, while the samples free of the carotenoids had the highest PV, CV, and TBA value. The samples containing the commercial antioxidant had higher b* values than those with the natural antioxidant, because the commercial β‐carotene was yellower than the natural carotenoid. the samples containing the commercial carotenoid had lower a* values than those containing the natural one. Carotenoid extracted from red quinoa could influence the oxidative stability of soybean oil.
... It is rich in oleic acid and linoleic acid (Zeb, 2019). The amount of linoleic acid (53.9 mg/kg) is a higher component of triacylglycerols than oleic acid having an amount of 23.9 mg/kg (Zeb, 2011;Zeb & Murkovic, 2013). Sunflower oil is also rich in several types of natural antioxidants, which include phenolic compounds. ...
... The composition of edible oils is categorized into two components, i. e., major components, and minor components. The former components of edible oils are lipids constituting free fatty acids, monoacylglycerols, diacylglycerols, triacylglycerols, phospholipids, sterols, fat-soluble vitamins, oxidized lipids, and squalene (Zeb & Murkovic, 2013). The major component is largely comprised of triacylglycerols (95-98%). ...
Edible oils are used as a frying medium and in the preparation of several food products. They are mainly constituting triacylglycerols as major components, while other compounds are classified as minor constituents, which include polyphenols. This class of compounds plays an important role in the thermal stability and quality attributes of the finished industrial food products. In addition to other antioxidants, the desired thermal stability of edible is achieved by either fortification or mixing of edible oils. This comprehensive review was therefore aimed to review the different classes of polyphenolic compounds present in commonly consumed edible oils. The edible oils reviewed include soybean, olive, rapeseed, canola, sunflower, flaxseed, sesame, cottonseed, palm, and hazelnut oils. The identified classes of polyphenolic compounds such as simple phenols, hydroxybenzoic acids, phenylethanoids, hydroxycinnamic acid, esters of hydroxycinnamic acids, coumarins & chromans, stilbenes, flavonoids, anthocyanins, and lignans were discussed. It was observed that a single edible from different origins showed the varied composition of the different classes of phenolic compounds. Among the oils, soybean, sunflower, olive, and brassica oils received higher attention in terms of polyphenol composition. Some classes of phenolic compounds were either not reported or absent in one edible oil, while present in others. Among the different classes of phenolics, hydroxybenzoic acids, hydroxycinnamic acid and flavonoids were the most widely present compounds. Phenolic compounds in edible oils possess several health benefits such as antioxidant, antibacterial, anti-viral, anti-inflammatory, anti-tumour, antioxidants, cardioprotective, neuroprotective, anti-diabetic properties and anti-obesity.
... There were no significant changes during 15-25 min frying. Previous studies showed that PV increases with the increase of thermal treatment time in sunflower [24] and other edible oils. During thermal oxidation, triacylglycerols are degraded to consequent FFA. ...
... The decrease in RSA was highly significant in sunflower oil (80%) than watercress leaves (50%) during 15 of frying. These results are in agreement with the previous finding that frying decreased the RSA values of sunflower and other oils [24]. The plant extract had been found to increase the stability of the sunflower oil [28], which suggests that plant extracts or the extracted compounds leached during frying of sunflower oil have the ability to increase the stability of oil against thermal stress. ...
Watercress leaves were fried in sunflower oil and analysed for lipid oxidation and phenolic compounds by high-performance
liquid chromatography with diode array detection (HPLC–DAD). Results revealed that total phenolic contents and
radical scavenging activity decreased significantly at the initial stages and were stable in frying oil, indicating stability
of frying oil. A significant increase occurred in chlorophylls of watercress leaves and frying oil. HPLC chromatograms
showed a total of 12 phenolic compounds containing caftaric acid (17.3–31.8 μg/g), sinapic acid derivative (11.2–14.4 μg/g),
4-O-caffeoylquinic acid (9.98–12.8 μg/g), 4-O-feruloyl quinic acid (8.47–13.4 μg/g), caffeoyl feruloyl quinic acid (7.31–
11.7 μg/g) and 5-O-caffeoylquinic acid (3.73–6.51 μg/g) as major compounds. A significant increase in the caffeic acid,
caffeoyl hexose, chlorogenic acid, caftaric acid, coumaric acid derivatives and 3, 4-di-O-caffeoylquinic acid was observed,
while a decrease occurred in Sinapic acid derivative, 5-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 4-O-feruloyl quinic
acid and caffeoyl feruloyl quinic acid. Frying of watercress leaves increase the bioavailability of medicinally important
phenolic compounds and also help to stabilise the frying oil.
... Lipid oxidation is one of the most critical factors affecting the shelf life and the quality attributes of oil (da Silva and Jorge, 2014). Lipid oxidation causes undesirable changes in taste, odor, texture, flavor, and appearance of foods, and also destroys fat-soluble vitamins (Gallego et al., 2013;Zeb and Murkovic, 2013). Furthermore, the oxidative degradation of lipids can damage biological membranes, enzymes and proteins, which may pose a direct threat to human health (Malheiro et al., 2013). ...
... The measurement of antioxidant capacity of oils is a widely used method for the determination of the stability of vegetable oils (Zeb and Murkovic, 2013). The change in antioxidant capacity of oils measured by both DPPH and ABTS assays during storage is shown in Fig. 1A and B and analyzed using ANOVA (data for day 6, 12, 18 is not shown as no large difference between them). ...
The protecting ability of rosemary extract as a plant-based antioxidant and an alternative to synthetic antioxidants against the oxidation of vegetable oils was investigated in the present study. The effect of rosemary extract on improving the oxidative stability of oils was evaluated using the Rancimat and Schaal oven tests. Oils with or without incorporation of rosemary extract or synthetic antioxidants were analyzed using the Rancimat method at 120. °C to determine their induction periods (IP). The changes in antioxidant capacity, total phenolic content, peroxide value, fatty acid composition, and tocopherol content were measured under the Schaal oven test during storage at 62. °C. The IP of oils incorporated with rosemary extract was significantly (p<. 0.05) higher than blank oils and oils with synthetic antioxidants. The incorporation of rosemary extract into oils effectively prevented the oils by increasing the antioxidant capacity and total phenolic content, decreasing the peroxide value, and delaying the degradation of tocopherols and polyunsaturated fatty acids of oils. Results of this study suggested the potential use of rosemary extract as an effective alternative to synthetic antioxidants.
... An important parameter of fats is their oxidative stability [18]. As seen from Table 3, the most resistant to temperature were raw materials (walnut oil, mutton tallow) and the initial blend. ...
... Reduction of fats' oxidative stability could be caused by interesterification of antioxidants from walnut oil or their deactivation during the interesterification process. According to other authors, the presence of partial acylglycerols in the final products could also have detrimental effects on oxidative stability [18]. ...
In this work, modified fats were produced by enzymatic interesterification of mutton tallow with walnut oil. As a result of forcing the fat hydrolysis process by addition of water to the enzymatic preparation (11.5, 13.0, 14.5, 16.0 wt %), additional levels of polar fractions (MAGs, DAGs, and FFAs) were observed. The aim of this work was to evaluate the stability of emulsions of modified fats containing natural emulsifiers resulting from enzymatic interesterification of mutton tallow with walnut oil. The physical-chemical parameters of obtained fats were determined in this study. Using several methods, the stability of the formed emulsions was also evaluated. The results showed that the fats resulting from interesterification in the presence of Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, Novozymes Bagsvaerd, Denmark) with 13.0, 14.5, and 16.0 wt % of water in the enzymatic preparation could form stable emulsion systems. On the other hand, the emulsion of the interesterification system where the amount of water in the enzymatic preparation was 11.5 % showed very low stability. The number of natural emulsifiers (MAGs and DAGs) that arose after interesterification was insufficient to stabilize the emulsion system. The work has shown the possibility of using interesterified fats as the fat phase. Emulsions formed on the basis of interesterified fats without any additional emulsifiers such as sunflower lecithin had properties comparable to emulsions containing mixed non-interesterified fat containing additional emulsifier. The natural emulsifiers formed as part of enzymatic interesterification allow formation of stable emulsion systems.
... Recently, there are several research groups studying b-carotene oxidation in lipid/organic systems (Benevides, Veloso, Pereira, & de Andrade, 2011;Bosser, Paplorey, & Belin, 1995;Rodriguez & Rodriguez-Amaya, 2007;Wache, Bosser-DeRatuld, Lhuguenot, & Belin, 2003;Zeb, 2012;Zeb & Murkovic, 2013a, 2013b) concerning b-carotene antioxidant activity, off-flavor compounds formation and synthesis. However, there is a lack in the literature in works concerning the b-carotene pathways during refining practices and its importance in the quality of fully refined oils. ...
... It is clear, that allylic hydrogen abstraction does not occurs in bleaching conditions due to its moderate temperature and pressures, being always lower than 50 mbar. Moreover, b-carotene behaves differently in different oils and under different conditions, i.e. temperature and lipid system composition (Zeb & Murkovic, 2013b). Burton and Ingold (1984) suggested that b-carotene reacts with peroxyl groups by addition, rather than by hydrogen abstraction. ...
Although studies indicate chemical changes during bleaching such as carotene and unsaturated fatty acids oxidation, which are probably responsible for the color fixation of palm oil, this process is not very clear. The objective of this study was to investigate the effect of type and amount of bleaching earth (BE) on the final quality of refined palm oils, especially on the oxidative state and color. Two types of bleaching earth were tested, one natural (NBE) and one acid-activated (ABE) (0.5–3.0% w/w). Crude palm oils were bleached at 105 °C, during 30 min at 50 mmHg pressure. Afterwards, a deodorization step was performed at 260 °C, 3 mbar, 1.5% steam during 60 min. These refining procedures were evaluated after each step by measuring β-carotene, color, peroxide (PV) and p-anisidine (pAV) values. It was observed that both BE can decompose peroxides. However, a maximum pAV followed by a decrease was observed for ABE while the pAV remains approximately constant at a maximum for NBE, suggesting only ABE catalytically decomposes secondary oxidation products. The color after deodorization was inversely proportional to pAV when bleaching was performed with ABE, even though the oil has a lighter color after deodorization.
... This phenomenon strongly confirmed that the carotenoids (β-carotene, lutein and zeaxanthin) used in this study, had a significant protective effect against fish oil oxidation under heat stress. Zeb and Murkovic (2013) reported similar findings when they studied the oxidative thermal stability of plant oils (i.e., corn, rapeseed, and sunflower oils) with the addition of β-carotene. ...
This work aimed to study the co‐encapsulation of ω‐3 Long‐Chain Polyunsaturated Fatty Acids (LC‐PUFAs) with β‐carotene, lutein and zeaxanthin and the cellular uptake of carotenoids. Monodisperse microcapsules with good properties, including particle surface morphology, water activity, microencapsulation efficiency, and glass transition temperature, were successfully prepared using a microfluidic‐jet spray drier with OSA‐modified starch as a wall matrix. The presence of carotenoids enhanced the oxidative stability of ω‐3 LC‐PUFAs. Caco‐2 cell uptakes of the carotenoids from the spray‐dried microcapsules were studied and compared to those encapsulated in the methylcellulose (MC) or xanthan gum (XG) delivery systems. The microcapsules encapsulated by OSA‐modified starch showed higher cellular uptakes of carotenoids (i.e., β‐carotene, 0.31 μg/mg protein; lutein, 0.52 μg/mg protein; zeaxanthin, 0.54 μg/mg protein) than those in the MC or XG delivery systems. The Caco‐2 cell uptake depended on carotenoid type, where hydrocarbon carotenoids (i.e., β‐carotene) had lower uptake than oxygenated carotenoids (i.e., lutein or zeaxanthin).
... Fluorescent byproducts may arise during the oxidation of beta-carotene in mango juices as mention previously [30] that most of the β-carotene was oxidized during thermal treatment of edible oil with the generation of polar compounds. Similarly oxidation process in unsaturated fatty acid double bonds is accelerated by heating [31], resulting in the formation of hydro-peroxides which then decompose into aldehydes and ketones. ...
The current study looks into the characterization and differentiation of mango juices that are sold commercially using fluorescence spectroscopy. The emission spectra displayed well-defined and prominent peaks that suggested the existence of many fluorophores, such as water content, β-carotene, tartrazine food color, and chlorophyll components. For this study, water and yellow food coloring solution, the two most popular adulterants were added to pure and authenticated mango pulp that had been diluted to an 8% concentration. The fluorophore profile of the samples was ascertained by using multivariate analysis (principal component analysis) in conjunction with fluorescence spectroscopy. The findings showed that the existence of water content is directly correlated with the spectral bands at 444 and 467 nm, and for food color at 580 nm thus the best indicators to detect adulteration of high water contents and food color. Chlorophyll and β-carotene intensities varied among juices, acting as a discriminant marker to distinguish between those with unripened pulp (high chlorophyll intensity) and those with more water and other pigments (lower chlorophyll and β-carotene intensities). With fluorescence emission spectroscopy, qualitative assessment of mango juice can be quickly determined by spectral features, providing details on composition and quality.
... Therefore, incorporating other types of oils such as hemp seed (Cannabis sativa L.) oil that contain these PUFAs into the formulation, which primarily consists of β-carotene from a natural source, should also facilitate chylomicron formation and enhance the absorption of β-carotene. Additionally, hemp seed oil contains natural antioxidants such as tocopherols which can help protect β-carotene against oxidative decomposition [6,7]. ...
... Moreover, Hussain et al. (2018) also observed the same trend of results regarding lycopene. Plants contain an un-oxidized carotenoid form known as beta-carotene with antioxidative properties (Zeb and Murkovic 2013). Moreover, Sajjad et al. (2020) reported an increment in betacarotene levels in salt stress occurs as a result of providing inhibition of beta-carotene to zeaxanthis and providing tolerance to the plant. ...
Salt stress causes plants to undergo metabolic and physiological disturbances, affecting growth, development, quality, and yield. With the increasing demand for food in the world and this environmental problem, the cultivation of salt-tolerant varieties or lines of crops is needed to compensate for the demands of food for mankind. This study was designed for salt tolerance problems; the four lines of Linum usitatissimum in terms of the plant’s agronomic attributes, yield, different metabolites (secondary and primary), antioxidant enzymatic activities, endogenous hormones, lipid peroxidation and ion analysis. This research was completely randomized-design (CRD) and four lines of flax (Alsi ARI-50, Alsi ARI-22, Alsi ARI-20 and Alsi ARI-1) were raised using water (control) and 150 mM NaCl in irrigation water. Salinity had a negative impact on different growth parameters, photosynthetic pigments-level (Chlorophyll a, Chlorophyll b, total chlorophyll and chlorophyll a/b ratio), Indole-3-acetic acid (IAA), and different essential ions. On the other hand, at the same salt concentrations, carotenoid content, sugar level, total protein, lipids, phenolic content, proline amount, flavonoid, tannin, β carotene, antioxidant level, lipid peroxidation, catalase activity, guaiacol peroxidase activity, ascorbic acid, salicylic acid, sodium and chloride ions significantly increased. Based on the present study, it was concluded that Alsi ARI-50 and Alsi ARI-22 showed higher salt tolerance compared to the other lines based on measured parameters. So, these lines are recommended to be used in the salinity area and also in the breeding programme.
... The evaluation of the total antioxidant activity (TAA) of oils is commonly employed to determine the stability of oils [27,45]. Results are presented in Figure 5 A-C. ...
The protective effect of olive mill pomace (OMP) loaded ethylcellulose microparticles as an alternative to synthetic antioxidants against the oxidation of olive oils was assessed. OMP extract was obtained by an optimized two-step solid-liquid extraction; encapsulation was performed by double emulsion solvent evaporation technique considering a theoretical loading content in phenolic compounds of 5% (w/w). The changes in the peroxide values, the p-anisidine values, the total oxidation values, the free fatty acids content, the total antioxidant activity, and the total phenolic content were synchronized under storage at 62 °C. The results of oxidative stability were compared with plain oils, oils enriched with synthetic antioxidants, and oils fortified with OMP extract. The encapsulation efficiency of phenolic compounds was 96.0 ± 0.3%. The fortification of olive oils with microparticles retarded the appearance of peroxides, reduced the content of secondary oxidation products, and slowed down hydrolysis processes. The microparticles were efficiently designed to sustain the release of antioxidants to control the oxidative status of oil samples, retarding the free fatty acids formation rather than synthetic antioxidants. The results of this study bring new perspectives regarding the potential use of encapsulated extracts rich in antioxidants as an alternative to synthetic antioxidants to improve oil oxidative stability.
... The most significant and widelyinvestigated carotenoid is β-carotene, which is a red-orange colored compound showing the highest vitamin A activity. It reacts with peroxyl radicals to protect the oil from free radical auto-oxidation, thus inhibiting the propagation and promoting termination of the oxidation chain reaction [69]. There was 21.2-24.7 and 5.0-5.5 mg/kg oil of β-carotene determined in crude and refined sunflower oil, respectively, while 63.6 and 10.2 mg/kg oil of β-carotene determined in crude and refined rapeseed oil, respectively [70]. ...
The demand for plant source of polyunsaturated fatty acid (PUFA) is increasing due to the health concern over animal oils, but oxidation in PUFA-rich oils occurs rapidly during frying process. Under frying conditions, numerous reactions take place with the formation of degradative products which reduce nutritional quality and shelf-life of frying oil and fried foods. Using natural antioxidants instead of synthetic ones has been the tendency for retarding oil deterioration during frying. The chemical degradation of natural antioxidants during frying operation, seems to be the major pathway for antioxidant loss. This suggest to require a continuous modification to enhance their performances. In fact, much study was carried out on the activities of natural antioxidative agents at ambient or accelerated storage temperatures. The information on the fate of natural antioxidants at frying conditions is limited. Nevertheless, the need to develop a safe, potent, and stable natural antioxidative agent for frying operation still remains an appealing task. This review highlights the recent information on the performance of exogenous natural antioxidants in frying stability of polyunsaturated oils. The present investigations indicate that the stability is not just a function of individual components but may be a cumulative effect of various endogenous and exogenous antioxidants. Most of common antioxidants such as β-carotene, tocochromanols etc. may retard oxidative degradation during storage at lower temperature, they are less effective under frying conditions. Tocopherol, β-carotene and phenolic acids may form synergistic mixture. Under frying conditions, γ-oryzanol and phenolic compounds offer good protection of oils against oxidative deterioration.
... The improvement in tensile strength upon the aging process observed for the QUloaded sample might be explained with the previously evidenced ability of quercetin to cross-link ENR-containing blends [60]. On the other hand, the negative effect of β-CT on the ENR/PLA blend's properties during the aging process might be explained with two factors: the above-mentioned ability to take part in the crosslinking process (and, thus, over-crosslinking of the polymer blend) and possible prooxidative behavior related to the not properly adjusted amount of β-CT in the polymeric mixture [61][62][63]. ...
The aim of this study is to present the possible influence of natural substances on the aging properties of epoxidized natural rubber (ENR) and poly(lactic acid) (PLA) eco-friendly elastic blends. Therefore, the ENR/PLA blends were filled with natural pro-health substances of potentially antioxidative behavior, namely, δ-tocopherol (vitamin E), curcumin, β-carotene and quercetin. In this way, the material biodeterioration potential was maintained and the material’s lifespan was prolonged while subjected to increased temperatures or high-energy UVA irradiation (340 nm). The investigation of the samples’ properties indicated that curcumin and quercetin are the most promising natural additives that may contribute to the delay of ENR/PLA degradation under the above-mentioned conditions. The efficiency of the proposed new natural anti-aging additives was proven with static mechanical analysis, color change investigation, as well as mass loss during a certain aging. The aging coefficient, which compares the mechanical properties before and after the aging process, indicated that the ENR/PLA performance after 200 h of accelerated aging might decrease only by approximately 30% with the blend loaded with quercetin. This finding paves new opportunities for bio-based and green anti-aging systems employed in polymer technology.
... Lipid oxidation is one of the most common drawbacks for the oil industry as it affects the shelf life and quality of oils and fats [1]. Oxidative lipid degradation affects negatively the organoleptic attributes of oils by causing unfavorable changes in odor, taste, and appearance, and also decreasing its nutritional value [2,3]. For several years, synthetic antioxidants have been extensively used by food industries in order to retard lipid oxidation and preserve the quality standards of oils. ...
Arabinoxylans (AX) are polysaccharides with antioxidant activity and emulsifying properties, which make them an attractive alternative for its potential application as a natural antioxidant in oils. Therefore, this work aimed to investigate the effect of ultrasonic treatment of AX on their antioxidant capacity and its ability to improve the oxidative stability of soybean oil. For this purpose, AX were exposed to ultrasonic treatment at 25% (100 W, AX-1) and 50% (200 W, AX-2) power and an operating frequency of 20 KHz during 15 min, and their macromolecular properties (weight average molecular weight (Mw), polydispersity index and intrinsic viscosity) were evaluated. The antioxidant capacity of AX was determined by the DPPH assay and Rancimat test. Results showed that ultrasonic treatment did not affect the molecular identity of the polysaccharide but modified its Mw distribution. AX-1 showed the highest antioxidant activity (75% inhibition) at 533 µg/mL by the DPPH method compared to AX and AX-2. AX at 0.25% (w/v) and AX-1 at 0.01% (w/v) exerted the highest protective effects on oxidative stability of soybean oil with induction periods of 7.69 and 5.54 h, respectively. The results indicate that AX could be a good alternative for the potential application as a natural antioxidant in oils.
... However, the chemical interesterification, which is the redistribution of the fatty acids on the glycerol molecule, has high cost when compared to the partial hydrogenation (Mba, Dumont, & Ngadi, 2015), involving high consumption of water and energy (Patterson, 2010), once deodorization and further clarification of the interesterified lipid base is required (Holm & Cowan, 2008). In addition, the interesterified lipid base exhibits reduced oxidative stability when compared to the original raw materials (Kowalska, Zbikowska, & Tarnowska, 2015;Zeb & Murkovic, 2013), and minor compounds, such as mono-and diacylglycerols, which delay the crystallization events necessary to structure the lipid base to form a semi-solid system (Masuchi et al., 2014). From the nutritional point of view, the main issues are related to the increase in saturated fatty acids concentration, whose reduction in diet is globally indicated to reduce the risk of cardiovascular disease, once they are associated with the increase in plasma cholesterol (Wassell, Bonwick, Smith, Almiron-Roig, & Young, 2010) and the possible negative nutritional effects due to the formation of isomers in the sn-2 position of triacylglycerols during interesterification (Domingues, Ming, Ribeiro, & Gonçalves, 2015;Karupaiah & Sundram, 2007). ...
Food production and consumption patterns have changed dramatically in recent decades. The universe of oils and fats, in particular, has been changed due to the negative impacts of trans fatty acids produced industrially through the partial hydrogenation of vegetable oils. Regulations prohibiting its use have led the industry to produce semisolid lipid systems using chemical methods for modification of oils and fats, with limitations from a technological point of view and a lack of knowledge about the metabolization of the modified fats in the body. Milk fat is obtained from the complex biosynthesis in the mammary gland and can be a technological alternative for the modulation of the crystallization processes of semi‐solids lipid systems, once it is naturally plastic at the usual processing, storage, and consumption temperatures. The natural plasticity of milk fat is due to its heterogeneous chemical composition, which contains more than 400 different fatty acids that structure approximately 64 million triacylglycerols, with a preferred polymorphic habit in β', besides other physical properties. Therefore, milk fat differs from any lipid raw material found in nature. This review will address the relationship between the chemical behavior and physical properties of semisolid lipids, demonstrating the potential of milk fat as an alternative to the commonly used modification processes.
... This process, which is the major cause of quality losses in the food industry, could take place during preparation, processing, and storage of food products. Lipid autoxidation and inadequate storage contribute significantly to the deterioration and reduction of the shelf-life of vegetable oil, causing changes to appearance, taste, as well as odour, colour, texture, and loss of vitamins (Yang et al., 2016;Milanez and Pontes, 2014;Gallego et al., 2013;Zeb and Murkovic, 2013). Several studies reported that, besides these changes degrade the functional and nutritional compounds of food, they also generate potential toxic compounds through the action of free radicals and reactive oxygen species that are harmful to human health and are implicated in degenerative diseases such as cancer, cardiovascular diseases and early ageing (Difonzo et al., 2018;Womeni et al., 2016). ...
The effects of adding palmitic acid (PA) and linoleic acid (LA) on the performance of tert-Butylhydroquinone (TBHQ), in inhibiting the autoxidation of palm olein was studied. These fatty acids were employed to test their effectiveness on antioxidant performance, experimentally and theoretically. In experimental studies, palm olein added with fatty acids at four different concentrations in the presence or in the absence of TBHQ were heated in the oven at 60°C for 15 days and collected after 0, 1, 3, 6, 10 and 15 days for peroxide values analysis. In the theoretical study, a quantum mechanical at the theoretical level of DFT B3LYP/ 6-31G (d,p) was used in optimising the molecular structures of single species and complexes, and then tested for physical parameters (dipole moment, stabilisation energy, and bond indexes). It was found in the presence of TBHQ, synergistic behaviour was found between fatty acid and antioxidants. The addition of PA, which is the same as the main component of palm olein, significantly decreased oxidation and peroxide formation, thus gave less effect to the degradation of triacylglycerides. Based on the theoretical calculations, the interaction energy is shown as the major contributor to the performance of the antioxidant.
... Polar or oxidized compounds in the liver lipids were determined using the HPLC-DAD method reported previously (19). Twenty microliters of the extracted lipids sample were dissolved in acetone-isopropanol and filtered with Agilent 0.45-micron PTFE filter (Agilent Technologies, Germany) into 2 mL HPLC vial. ...
Dietary oxidized olive oil, alone or in combination with different doses of α-tocopherol, were given to Swiss albino rats for 30 days; in order to determine its role in oxidative stress and fatty liver, induced by the oxidized olive oils. Serum biochemical parameters and hematological indices of blood were analyzed. The liver was analyzed for histopathological changes, lipid peroxidation, and polar triacylglycerols composition. Results revealed that there was a significant decline in the serum total cholesterol, triglycerides, LDL, glucose and ALT; while a significant increase occurred in the serum HDL levels through the supplementation of α-tocopherol in male and female rats. Hematological parameters were almost in the normal reference range in the groups that were fed α-tocopherol, alone or in combination with oxidized oil, while being significantly altered by the oxidized olive oil. There were acute hepatitis and necrosis in the liver with no fatty changes after feeding with oxidized olive oil, along with varying doses of α-tocopherol. Higher amounts of polar compounds were present in female rats (15.2–93.1 μg/g) compared to male rats (12.2–82.3%) that correspond to the supplementation of α-tocopherol in combination with oxidized oil. Lipid oxidation in liver was minimized by tocopherol, while an increase occurred in the accumulation of oxidized lipids in the liver. These findings revealed that tocopherol is beneficial against the oxidized oil induced biochemical and hematological changes and lipid peroxidation but causes fatty accumulation in the liver. Therefore, the role of tocopherol in patients with fatty liver disease may be considered, as tocopherol may increase the chance of survival.
... There was no significant (p > 0.05) difference between the PV-values of 30 and 45 min of frying. The results are in agreement with the previous findings (Zeb and Murkovic, 2013;Ramadan, 2015). The non-significant changes during 30 and 45 min may be due to the increased availability of carotenoids and phenolic compounds in the system. ...
Spinach is one of the highly consumed vegetable, with significant nutritional, and beneficial properties. This study revealed for the first time, the effects of high temperature frying on the carotenoids, chlorophylls, and tocopherol contents of spinach leaves. Spinach leaves were thermally processed in the sunflower oil for 15, 30, 45, and 60 min at 250°C. Reversed phase HPLC-DAD results revealed a total of eight carotenoids, four chlorophylls and α-tocopherol in the spinach leaves. Lutein, neoxanthin, violaxanthin, and β-carotene-5,6-epoxide were the major carotenoids, while chlorophyll a and b' were present in higher amounts. Frying of spinach leaves increased significantly the amount of α-tocopherol, β-carotene-5,6-epoxide, luteoxanthin, lutein, and its Z-isomers and chlorophyll b' isomer. There was significant decrease in the amounts of neoxanthin, violaxanthin, chlorophyll b, b' and chlorophyll a with increase of frying time. The increase of frying time increased the total phenolic contents in spinach leaves and fried sunflower oil samples. Chemical characteristics such as peroxide values, free fatty acids, conjugated dienes, conjugated trienes, and radical scavenging activity were significantly affected by frying, while spinach leaves increased the stability of the frying oil. This study can be used to improve the quality of fried vegetable leaves or their products at high temperature frying in food industries for increasing consumer acceptability.
Cooking emissions account for a major fraction of urban volatile organic compounds and organic aerosol. Aldehyde species, in particular, are important exposure hazards in indoor residential and occupational environments, and precursors to particulate matter and ozone formation in outdoor air. Formation pathways of aldehydes from oils that lead to their emissions are not well understood. In this work, we investigate the underlying mechanisms involved in the formation of aldehydes from heated cooking oil emissions, through studying how antioxidants and oil composition modulate oxidation chemistry. Our results demonstrate that gaseous emissions are driven by radical-mediated autoxidation reactions in cooking oil, and the composition of cooking oils strongly influences the reaction mechanisms. Antioxidants have a dual effect on aldehyde emissions depending on the rates of radical propagation reactions. We propose a mechanistic framework that can be used to understand and predict cooking emissions under different cooking conditions. Our results highlight the need to understand the rates and mechanisms of autoxidation and other reactions in cooking oils in order to accurately predict the gas- and particle-phase emissions from food cooking in urban atmospheres.
This chapter comprehensively reviewed the different classes of polyphenolic compounds present in commonly consumed edible oils. The edible oils reviewed include soybean, olive, rapeseed, canola, sunflower, flaxseed, sesame, and cottonseed oils. The identified classes of polyphenolic compounds such as simple phenols, hydroxybenzoic acids, phenylethanoids, hydroxycinnamic acid, esters of hydroxycinnamic acids, coumarins and chromans, stilbenes, flavonoids, anthocyanins, and lignans were discussed. It was observed that a single edible from different origins showed the varied composition of the different classes of phenolic compounds. Among the oils, soybean, sunflower, olive, and brassica oils received higher attention in terms of polyphenol composition. Some classes of phenolic compounds were either not reported or absent in one edible oil, while present in others. Among the different classes of phenolics, hydroxybenzoic acids, hydroxycinnamic acid and flavonoids were the most widely present compounds.
One of the main trends in the development of lipid micro and nanoparticles is the use of edible oils and fats to replace synthetic matrices, which are not viable for application by the food industry. Milk fat is the most complex fat found in nature. Its vast composition in triacylglycerols allows to classify it as a plastic fat at room temperature and with a wide melting range (−40 to 40°C). Due to these characteristics, different types of modification have been explored with the objective of obtaining a versatile fat (e.g.: zero trans, medium melting point, adequate solid fat content at the usual application temperatures and stable crystals), capable of structuring complex systems and that meets the needs of application in different areas of the food industry. The main strategies found in the literature to modify the physicochemical properties of milk fat and broaden its application are biological, physical and chemical modifications. This review aimed at investigating modification strategies and demonstrating the potential of application of milk fat on a macro, micro and nanoscale.
The current work is focused on the evaluation of oxidative stability, thermal behavior, antioxidant activity, phenolic content and physicochemical properties of nectarine kernel oil. The antioxidant activity of the oil was remarkably high, i.e., IC50 = 95.1 μg/ml. Thermogravimetric experiments indicated thermal stability of the oil at temperatures up to 261ºC, where only 2% mass loss was observed, and the oil decomposition occurred in three main stages. Total phenolic content was found to be 334.5 mg GAE/100 g oil. The extracted oil was highly stable for up to 20.92 h, as per calculations by the Rancimat method. Gas chromatography analysis demonstrated that the extracted oil consisted mainly of unsaturated fatty acids that formed some 92% wt.% of the total content. Among others, the fatty acids were mainly composed of oleic (74.55%) and linoleic acids (16.85%). The extracted oil was characterized. The results highlighted the potentials of the nectarine kernel oil for enriching various pharmaceutical products and human nutrition.
Plasma, the fourth stage of matter, is a partially or wholly ionized state of gas. Degree of lipid oxidation and effects of antioxidants were evaluated in bulk oils at plasma treatment. Significant changes in the conjugated dienoic acid were induced after 10 min of plasma treatment, which corresponded to treatment for 2.5 h at 100 °C and 48 h at 60 °C. Tocopherol stability in the stripped corn oil was significantly higher than that in medium-chain triacylglycerol after the plasma treatment. The antioxidant capacities of 10 μM of α-tocopherol and sesamol were higher than that of β-carotene, and synergistic effects among α-tocopherol, sesamol, and β-carotene were not observed. Added α-tocopherol and sesamol decreased CDA formation by 33 and 30% compared to control samples after plasma treatment. Moisture content in oils decreased significantly about 20% moisture after 6 min plasma treatment. Lipid oxidation could be an important issue in plasma-treated lipid-rich products.
Frying produces complex changes in the chemistry of both the food and the frying medium. This chapter looks only at analytical methods related to composition studies, mostly chromatographic studies. During frying, triacylglycerols (TAGs) are oxidized to form hydroperoxides, epoxide, and other oxidized species. These species are responsible for several properties of oils and fried foods. Therefore, analysis of oxidized TAGs is considered a prime target in food frying. Fatty acids (FAs) produced by the hydrolysis of TAGs form several minor oxidation products. Foods of animal origin are largely formed of cholesterol, which is oxidized to form cholesterol oxidation products (COPs). The characterization of acrylamide (AA) formed in fried foods has been reported mainly in starch‐based foods, such as potato chips, due to the extensive market for these products. Tocopherols and tocotrienols are important antioxidants that are found both in frying medium and in foods.
Oxidative deterioration is one of the most important factors limiting shelf-life of fatty food products, where the use of active packaging produced with natural antioxidants is a strategy to minimize these reactions. Poly(acid lactic) (PLA) films were produced with carotenoids extracts rich in beta-carotene, lycopene, and bixin. The kinetics of carotenoids’ release to a fat simulant was evaluated and successfully explained by a new mathematical release model which considered the degradation of the migrants after their release. In the presence of light, films with lycopene and beta-carotene protected sunflower oil mainly by their light barrier properties, and secondly by their barrier to oxygen and antioxidant gradual releasing. The films produced with bixin presented the best performance as antioxidant active packaging to sunflower oil, where differences found in films barrier properties and in the transfer coefficients among the carotenoids were influenced by their molecular structures.
ZET: Çalışma, 15 gün boyunca 60°C'de hızlandırılmış depolama testi altında standart antioksidanlar ve glukoz yağ asidi esterleri eklenmesinin ayçiçeği, mısır ve zeytinyağının termal stabilitelerini nasıl etkilediğiyle ilgili sonuçları sunmaktadır. Çalışmada glikoz oleat ve glikoz laurat sentezlenerek karakterize edildi. Zeytin, ayçiçek ve mısır yağının yağ asidi bileşenleri GC kullanılarak belirlendi ve bütün numunelerde peroksit değeri, serbest yağ asidi oranı ve fenol içeriği saptandı. Yüksek oleik asit içeriği yenilebilir yağlarda termal bozunmayı artırdı. Glikoz oleat ve glikoz laurat bitkisel bazlı yenebilir yağlar için bir termal oksidasyon önleyici olarak etkili olurken, glikoz oleat her türlü yağ için glikoz laurattan daha iyi antioksidan özellik gösterdi. Anahtar Kelimeler: Bozunma, yenilebilir yağlar, glikoz esterleri, oksidasyon.
ABSTRACT: The study presents the results on the thermal stability of the sunflower, corn and olive oil with addition of standard antioxidants and glucose fatty acid esters under accelerated storage test at 60°C for 15 days. During the work, glucose oleate and glucose laurate were synthesized and characterized. Fatty acid compositions of olive, sunflower and corn oil were determined by using GC and in all samples peroxide value, free fatty acid value and phenolic content are specified. High oleic acid content increased the thermal degradation in edible oils. Glucose oleate and glucose laurate acted as a thermal oxidation suppressor for the vegetable based edible oils and glucose oleate showed better antioxidant properties than glucose laurate for all types of oils.
Accès restreint aux membres de l'Université de Lorraine jusqu'au 2015-10-01
Research development of palm oil products such as red palm oil (RPO) need to be prioritized. The high content of -carotene and tocopherol in RPO has been shown to give functional effect on health. However, RPO processing without bleaching is not only able to maintain -carotene and tocopherol content, but also chlorophyll content which is sensitizer in photo-oxidation reaction. The existence of chlorophyll, tocopherol, and carotene affect the photo-oxidative stability of RPO.
This research aims to (1) study the changes of minor compounds (chlorophyll, tocopherol, carotene) and oxidative stability (peroxide, p-anisidine, total oxidation values) of RPO due to influence of exposure to light, (2) determine kinetics parameters of the minor compounds changes and oxidative stability of RPO during photo-oxidation, and (3) study the effect of tocopherol, tocotrienol, -carotene, and chloropyll on the photo-oxidative stability of RPO. The study was designed into 2 stages using RPO and system models, which covered (1) study of the minor compounds changes and photo-oxidative stability of RPO due to the influence of light intensities and (2) study of the effect of tocopherols, tocotrienols, -carotene, and chloropyll on the photo-oxidative stability of RPO. Photo-oxidation is performed by exposing the samples to light on intensities of 5000, 10000, and 15000 lux in the incubator box equipped with fluoresence light at controlled temperature (31±2 °C). Two different controls used in this research are namely dark and normal light control on intensity of 476.25-496.25 lux in laboratory room.
Red palm oil is produced from crude palm oil (CPO) having chlorophyll (4.36 mg/kg), tocopherol (1127.49 mg/kg), and carotene (559.39 mg/kg) contents, with ratio of saturated and unsaturated fatty acid composition of 45:55. Exposure to light triggered photo-oxidation reaction in RPO. Photo-oxidation reactions were shown by decrease on chlorophyll and tocopherol contents and increase on peroxide (PV) and total oxidation (Totox) values. The chlorophyll experienced a sharp decline at early stage of light exposure followed by an increase of PV and Totox values. The tocopherol directly decreased on light intensities of 10000 and 15000 lux, while the carotene was relatively constant up to 7 days of storage both on dark control and light treatments. Exposure to light accelerated the increase of PV and Totox values that could be discribed using zero order kinetics model with k value of 0.81 (r2=0.99), 1.11 (r2=0.99), 1.47 mequiv/kg/day (r2=0.99), and 1.93 (r2=0.95), 2.63 (r2=0.96), 3.83 per day (r2=0.95) on light intensities of 5000, 10000, and 15000 lux, respectively. A significant negative correlation between the changes of PV and tocopherol content showed that at the same degradation of tocopherol content (>20%), the higher light intensities have bigger effect on the increase of PV.
Exposure to light on intensities of 5000, 10000, and 15000 lux at room temperature (31.60±0.69 °C) accelerated degradation of chlorophyll, tocopherol, and carotene in RPO. Photo-degradation of chlorophyll, tocopherol, and carotene during storage could be evaluated to determine its kinetics parameters. Chlorophyll underwent photo-degradation following first order kinetics model in two periods. The photo-degradation of chloropyll were fast photo-degradation period during the first 6 hours of storage with k value of 3.8110-2, 4.4510-2, 5.6410-2 per day, followed by slow photo-degradation period in longer storage duration with k value of 1.4110-2, 3.0110-2, 4.5910-2 per day on light intensities of 5000, 10000, and 15000 lux, respectively. The photo-degradation of tocopherol and carotene also followed first order kinetics model. The photo-degradation of tocopherol occured with the highest rate (k values of 9.1010-2, 12.0210-2, 17.3310-2 per day), while the photo-degradation of carotene with the lowest rate (k values of 0.8010-2, 1.4010-2, 1.9810-2 per day) on light intensities of 5000, 10000, and 15000 lux, respectively. Light intensity coefficient (zi) can be used as dependence indicator of k values to the changes of light intensity. The zi values of chlorophyll, tocopherol, and carotene were respectively of 20000, 33333, and 25000 lux, indicated that the degradation rate of chlorophyll was the most sensitive to the changes of light intensity.
The effects of tocopherols, tocotrienols, -carotene, and chloropyll on photo-oxidative stability of RPO were studied using model systems. The model systems were prepared from refined bleached deodorized palm (RBDP) olein and RPO. The model systems consist of TAG+Toc containing tocols compound (704.72 mg/kg), TAG+Car containing -carotene (529.47 mg/kg), and TAG+Toc+Car containing tocols compound (641.02 mg/kg) and -carotene (535.73 mg/kg). RPO which contained tocols compound (698.76 mg/kg), -carotene (518.61 mg/kg), and chlorophyll (3.44 mg/kg) was assumed as TAG+Toc+Car+Chlor model system. The tocols compound and -carotene which were separated in TAG+Toc or TAG+Car model systems showed degradation during 7 hours of exposure to light on intensities of 5000, 10000, and 15000 lux. The increase of exposure to light accelerated the degradation rate of tocols compound with the following order -T3>-T>-T3>-T3. The increase of exposure to light also accelerated degradation rate of -carotene with k values of 0.3710-2, 0.7210-2, and 2.1910-2 per h on intensities of 5000, 10000, and 15000 lux, respectively. The degradation rate of -carotene was the most sensitive compound to an increase of light intensity followed by tocotrienols and tocopherols with order -karoten>-T3>α-T3>-T3>-T. The existence of tocols compound and -carotene together in TAG+Toc+Car model system showed the highest protection and inhibitory effects on photo-oxidation. The presence of chloropyll accelerated the degradation of tocols compound and -carotene at an early stage of photo-oxidation and photo-oxidation rate of RPO on very high-light intensity.
The chemical instability of β-carotene limits its utilization as a nutraceutical ingredient in foods. In this research, the effect of continuous phase alpha-lactalbumin (α-LA) and (-)-epigallocatechin-3-gallate (EGCG) on β-carotene degradation in medium chain triacylglycerol (MCT)- and corn oil-in-water emulsions was examined. EGCG significantly inhibited β-carotene degradation in both MCT and corn oil-in-water emulsions in a dose dependent manner. α-LA was not able to protect β-carotene in MCT emulsions and the combination of EGCG and α-LA had a similar effect as EGCG alone. EGCG had no effect on lipid oxidation in corn oil-in-water emulsions but can protect β-carotene. β-Carotene was more stable in corn oil emulsions stabilized by α-LA compared to emulsions stabilized by Tween 20. These results show that EGCG is effective at protecting β-carotene in different emulsion systems without negatively impacting lipid oxidation suggesting that it could be utilized to increase the incorporation of β-carotene into food emulsions.
Triacylglycerols (TAGs) are one of the major components of the cells in higher biological systems, which can act as an energy reservoir in the living cells. The unsaturated fatty acid moiety is the key site of oxidation and formation of oxidation compounds. The TAG free radical generates several primary oxidation compounds. These include hydroperoxides, hydroxides, epidioxides, hydroperoxy epidioxides, hydroxyl epidioxides, and epoxides. The presence of these oxidized TAGs in the cell increases the chances of several detrimental processes. For this purpose, several liquid chromatography (LC) methods were reported in their analyses. This review is therefore focused on the chemistry, oxidation, extraction, and the LC methods reported in the analyses of oxidized TAGs. The studies on thin-layer chromatography were mostly focused on the total oxidized TAGs separation and employ hexane as major solvent. High-performance LC (HPLC) methods were discussed in details along with their merits and demerits. It was found that most of the HPLC methods employed isocratic elution with methanol and acetonitrile as major solvents with an ultraviolet detector. The coupling of HPLC with mass spectrometry (MS) highly increases the efficiency of analysis as well as enables reliable structural elucidation. The use of MS was found to be helpful in studying the oxidation chemistry of TAGs and needs to be extended to the complex biological systems.
The aim of this work was to develop a new fat by enzymatic interesterification of mutton tallow with rapeseed oil. It was assumed that by inducing hydrolysis of fats by addition of water to the enzymatic preparation (8, 10, 15 wt%) natural emulsifiers would be produced in the reaction environment. Fat blends obtained from the enzymatic reactions were evaluated as a fat base for emulsion systems. It was found that the fat resulting from interesterification in the presence of Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, Novozymes Bagsvaerd, Denmark) with 15 wt% of water possessed the highest content of polar fraction (MAG and DAG), and served as the most suitable blend for emulsification, producing emulsions that exhibited the highest stability.
Lipophilic components of three herbs, sage, thyme, and rosemary, were extracted into refined rapeseed oil by continuous stirring at 30°C for 24 h. The oxidative and frying stability of the flavored oil was assessed by Rancimat at 120°C and frying of French fries at 175°C, respectively. In comparison to the control with an induction period of 4.1 h in the Rancimat test, the treatment with thyme, rosemary, and sage resulted in induction periods of 5.3, 9.3, and 11.0 h, respectively, corresponding to stabilization factors of 1.1, 2.0, and 2.4, respectively. In contrast to the oxidative stability at 120°C, treated oils exhibited significantly lower frying stability, compared to the control. For instance, whereas rapeseed oils treated with plant materials exceeded the 12% regulatory limit for oligomeric triacylglycerols within 20 h of frying, the limit was only exceeded after 25 h of frying in the control. However, despite the significantly higher level of thermo‐oxidative degradation in the flavored oils, the sensory quality of the French fries prepared in these oils remained still acceptable within the frying time of 32 h whereas fries prepared in the control oil were judged unacceptable. Further, endogenous tocopherols were better protected in the treated oils.
Practical applications: The prolongation of the shelf life of frying oils is of great economical and commercial importance. Thus, food processors are very interested in the improvement of the thermal stability of frying oils, which may provide remarkable savings. On the other side more and more flavored oils come to the market. Therefore it is important to have more information about the oxidative and thermal stability of such oils.
The oxidation kinetics of sunflower oil (SO), as well as of pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.001-0.02 %) β-carotene was studied. The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature in the dark and under daylight. The results from the oxidation of SO and TGSO at 100ºC in the presence of β-carotene were also presented. It was established that in the antioxidant-free lipid system, the β-carotene did not give any antioxidative protection. It worked as a prooxidant during the oxidation at room temperature and at sufficiently high oxygen concentration, the effect being more pronounced in the dark than under daylight. β-carotene increased the stability of tocopherol-containing SO during its oxidation at room temperature and under daylight. This effect is more strongly expressed in a kinetic regime of oxidation. The synergism of β-carotene with the tocopherols was characterized by the stabilization factor F and the activity A. In the kinetic regime of oxidation F and A varied in the interval F=2.0-6.3, and A =2.7-21.0. In the diffusion regime F=1.3-1.5, and A=1.5-2.8.
The aim of this study is to enrich edible oils with carotenoids and lycopene from tomato purée or tomato peel, an industrial tomato waste. These tomato derivatives were incorporated in refined olive oil, extra virgin olive oil and refined sunflower oil. The incorporation of peel enhanced the concentration of β-carotene and lycopene more than tomato purée. Furthermore, the incorporation of both tomato purée and peel induced better thermal stability of the refined olive oil compared to extra virgin oil and sunflower oil. A decrease on total phenols as well as some prooxidant activity account for this, when tomato purée was incorporated. In our oil preparations, rutin and naringenin, as flavonoids coming exclusively from tomato purée or peel, were detected. The enrichment of oils with tomato carotenoids and lycopene, in particular low quality oils like refined olive oils, might be an alternative approach to elaborate new functional foods.
Sea buckthorn is a valuable medicinal plant, cultivated and naturally grown in northern Pakistan. The plant produces berry with small hard seed in the centre. The seed is the source of all nutrients and phytochemcials. However, there is lack of literature regarding the biochemical and physico-chemical quality of the seed. This study consists of evaluation of the physiochemical parameters; elemental components, seed storage protein profile and anatomical structure of sea buckthorn ssp turkestanica seed. Results showed that ash content was 2.05%, moisture content 5.5%, thousand seed mass value 10.20 g; sodium 47.65 ppm, potassium 88.0 ppm, phosphorus 0.43 ppm, magnesium 758.0 ppm, calcium 912.0 ppm, zinc 96.50 ppm, iron 290.25 ppm and silver 3.10 ppm. Seed storage protein electrophoresis reveals the presence of only low molecular weight proteins. SEM analysis shows that seed was 4.3 mm long and 2.4 mm wide with 0.1 -0.2 nm thicken seed coat. The study provides a good source of information of sea buckthorn seed of Pakistani origin and its potential for cultivation in various parts of the world.
The thermal and oxidative degradation of carotenoids was studied in an oil model system to determine their relative stabilities
and the major β-carotene isomers formed during the reaction. All-trans β-carotene, 9-cis β-carotene, lycopene, and lutein were heated in safflower seed oil at 75, 85, and 95°C for 24, 12, and 5 h, respectively.
The major isomers formed during heating of β-carotene were 13-cis, 9-cis, and an unidentified cis isomer. The degradation kinetics for the carotenoids followed a first-order kinetic model. The rates of degradation were
as follows: lycopene>all-trans β-carotene≈9-cis β-carotene>lutein. The values for the thermodynamic parameters indicate that a kinetic compensation effect exists between
all of the carotenoids. These data suggest that lycopene was most susceptible to degradation and lutein had the greatest stability
in the model system of the carotenoids tested. Furthermore, there was no significant difference in the rates of degradation
for 9-cis and all-trans β-carotene under the experimental conditions.
Natural antioxidants have recently gained increased interest because of the belief that natural food ingredients are better and safer than synthetic ones. The review presents the results on stabilisation of the main edible oils with different types of natural antioxidants, Sources of natural antioxidants are spices, herbs, teas, oils, seeds, cereals, cocoa shell, grains, fruits, vegetables, enzymes, proteins. Researchers concentrate on ascorbic acid, tocopherols and carotenoids as well as on plant extracts containing various individual antioxidants such as flavonoids (quercetin, kaemferol, myricetin), catechins or phenols (carnosol, rosmanol, rosamaridiphenol) and phenolic acids (carnosic acid, rosmarinic acid). Ascorbyl palmitate is regarded as a 'natural' antioxidant because it is hydrolysed in the body to ascorbic and palmitic acids. Among the herbs of the Lamiaceae family, rosemary has been more extensively studied and its extracts are the first marketed natural antioxidants. Oregano, which belongs to the same family, has gained the interest of many research groups as a potent antioxidant in lipid systems. The review concerns the following main topics: stabilisation of oil with individual natural antioxidants, interaction of antioxidants with synergists, stabilisation of oil with extracts or dry materials from different plant sources (e.g. herbs and spices), stabilisation at frying temperatures and in emulsions.
Carotenoids are natural pigments which are synthesized by plants and are responsible for the bright colors of various fruits and vegetables. There are several dozen carotenoids in the foods that we eat, and most of these carotenoids have antioxidant activity. beta-carotene has been best studied since, in most countries it is the most common carotenoid in fruits and vegetables. However, in the U.S., lycopene from tomatoes now is consumed in approximately the same amount as beta-carotene. Antioxidants (including carotenoids) have been studied for their ability to prevent chronic disease, beta-carotene and others carotenoids have antioxidant properties in vitro and in animal models. Mixtures of carotenoids or associations with others antioxidants (e.g. vitamin E) can increase their activity against free radicals. The use of animals models for studying carotenoids is limited since most of the animals do not absorb or metabolize carotenoids similarly to humans. Epidemiologic studies have shown an inverse relationship between presence of various cancers and dietary carotenoids or blood carotenoid levels. However, three out of four intervention trials using high dose beta-carotene supplements did not show protective effects against cancer or cardiovascular disease. Rather, the high risk population (smokers and asbestos workers) in these intervention trials showed an increase in cancer and angina cases. It appears that carotenoids (including beta-carotene) can promote health when taken at dietary levels, but may have adverse effects when taken in high dose by subjects who smoke or who have been exposed to asbestos. It will be the task of ongoing and future studies to define the populations that can benefit from carotenoids and to define the proper doses, lengths of treatment, and whether mixtures, lather than single carotenoids (e.g. beta-carotene) are more advantageous.
The fatty material of olive oil was separated, yielding a fat-free concentrate of pigments, by solid-phase extraction on octadecyl (C18) columns. The study of recovery carried out with lutein and pheophytin a gave an excess error lower than 4%. A total of 17 pigments was separated from this extract and quantified by HPLC using a reversed-phase C18 column. The method consisted of an elution gradient of 2 mL/min of water-ionic reagent-methanol (1:1:8) and methanol-acetone (1:1). Detection was performed by absorption at 410 and 430 nm and quantification from the straight lines of calibration of each analytically pure standard. The application of this technique to five monovariety virgin olive oils showed that pigment content among them is very different, depending on the variety of olive.
Carotenoids are important pigments found in foods and biological samples. Among carotenoids, beta-carotene is the major carotenoid present in vegetable oils. It plays an important role in the thermal stability of the vegetable oil. We established a simple, precise, specific, sensitive, repeatable, and accurate HPTLC method for the analysis of beta-carotene in fortified vegetable oils and assessment of its degradation. Analysis was performed on silica gel HPTLC plates with petroleum ether hexane acetone 2:3:1 (v/v) as mobile phase and densitometric detection. The R(F) of beta-carotene was 0.91 and regression analysis showed response was a linear function quantification of amount of beta-carotene in the range 100-600 ng (r(2) = 0.99991). The limits of detection and quantification were 0.11 and 0.37 ng, respectively. The thermal degradation (1-5 h at 100 degrees C) of beta-carotene in fortified sunflower oil was studied. It was observed that this HPTLC method could be used for efficient analysis and monitoring of the degradation of beta-carotene in edible oils.
Carotene is one of the most important fat soluble pigment with well known antioxidant and provitamin A activities. It is used in industries as food colorant and a source of vitamin A. The thermal induced degradation during processing leads to color and properties losses. The thermal stability of the fatty acids composition of edible oils is of great importance to food manufacturers. Corn oil, rapeseed and sunflower oils were fortified with 50 to 300 μg/g of β-carotene and oxidized using Rancimat (air flow rate 20 L/h) at 110°C for 14 h. Fatty acid methyl esters (FAMEs) were measured using gas chromatography with Agilent-Technologies DB-Wax capillary column. It was found that by adding β-carotene (50 to 300 µg/g) to the corn, rapeseed and sunflower oils, no significant changes was observed in saturated fatty acids. Saturated fatty acids were relatively more protected in the presence of unsaturated fatty acids of similar carbon atoms and in the presence of β-carotene. The addition of β-carotene affected the composition of unsaturated fatty acids in the tested oils. Thus, β-carotene acts as a pro-oxidant in highly unsaturated sunflower oil. Unsaturated fatty acids are oxidized earlier and results to the formation of unpleasant flavor and consequent rancidity.
The effects of ascorbyl palmitate at 0, 300, 600, 900, or 1,200 ppm, tocopherol at 0, 200, 400, 600, or 800 ppm, and β-carotene at 0, 3, 6, 9, or 12 ppm on the oxidative stabilities of Oil 1, Oil 2, and Oil 3 containing 0, 0.55, and 0.67% of combined arachidonic acid (AA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), respectively, were studied by a central composite experimental design. The oxidative stability of oil was evaluated by determining the induction time using the Oxidative Stability Index. Ascorbyl palmitate and tocopherol had a significant effect on the stability of all three oils at α = 0.05. β-Carotene did not have any effect on the stability of oils at α = 0.05. The interaction effect of ascorbyl palmitate and tocopherol was significant for the three oils at α = 0.05. The induction time of oils decreased as the total amounts of AA, DPA and DHA increased from 0 to 0.55% or 0.55 to 0.67%. The addition of 1,200 ppm ascorbyl palmitate, 800 ppm tocopherol and 12 ppm β-carotene to Oils 1, 2, and 3 increased the induction time from 13.5 to 29.9 h, from 11.8 to 27.0 h, and from 10.5 to 20.0 h, respectively. The coefficient of determination (r
2) for the linear regression between the experimentally determined and statistically predicted induction time of the three oils was greater than 0.95. The use of an optimum combination of ascorbyl palmitate and tocopherols from the response surface analysis could improve the oxidative stabilities of oils containing AA, DPA and DHA.
Twenty four school children of 7–9 years of age were divided into two groups of six boys and six girls each. One group was given a daily supplement of ‘Suji halwa’, a sweet snack made with semolina and red palm oil, supplying 2400 µg of ß-carotene and the second group was the control group which was given 600 µg of oral vitamin A palmitate, for 60 days. Vitamin A status before and after supplementation was assessed by the Modified Relative Dose Response Assay (MRDR). Results indicated that serum vitamin A levels increased from the basal level of 0.86±0.13 µmol/l to 1.89±0.23 µmol/l in the Red Palmoil (RPO) group and from 0.74±0.09 to 1.94±0.21 µmol/l in the control vitamin A group. Dehydroretinol/Retinol (DR/R) ratio decreased from 0.073±0.025 to 0.023±0.004 in the RPO group and from 0.090±0.023 to 0.023±0.004 in the vitamin A group, indicating liver saturation with vitamin A after feeding RPO snacks, comparable to synthetic vitamin A. This study indicates that RPO is an efficient source of ß-carotene which is found to be bioavailable in all the subjects tested, hence it can be used for supplementary feeding programmes to combat vitamin A deficiency in target population.
Carotenoids (β-carotene and astaxanthin) were added to refined olive oils and oxidised in a Rancimat at 110 °C for 1–14 h. Triacylglycerols (TAGs) were found to oxidise much faster in the presence of β-carotene and slower in the presence of astaxanthin, while β-carotene degradation was much faster than that of astaxanthin. Astaxanthin was found to protect the TAGs of olive oils for up to 10 h of thermal treatment. Both carotenoids were found to significantly increase peroxide values at higher exposure time. A total of 11 TAGs oxidised species were identified, including a new class of oxidised species (hydroxy epidioxides), reported here for the first time. The effect of carotenoids on the formation of oxidised TAGs illustrates that the pro-oxidant action of β-carotene was much stronger than that of astaxanthin. We suggest that astaxanthin could be used as an alternative to β-carotene in edible oils fortification and as a food colourant.Research highlights► Carotenoids were pro-oxidants during thermal oxidation in the refined olive oil. ► β-Carotene degradation was much faster than astaxanthin. ► First time report on thermal oxidation products of triacylglycerols in olive oil. ► New class of oxidised compounds, i.e. hydroxy epidioxides was identified. ► Hydroperoxides, epidioxides and epoxides were also identified.
The fatty material of olive oil was separated, yielding a fat-free concentrate of pigments, by solid-phase extraction on octadecyl (CIS) columns. The study of recovery carried out with lutein and pheophytin a gave an excess error lower than 4%. A total of 17 pigments was separated from this extract and quantified by HPLC using a reversed-phase CIS column. The method consisted of an elution gradient of 2 mL/min of water-ionic reagent-methanol (1:1:8) and methanol-acetone (1:l). Detection was performed by absorption at 410 and 430 nm and quantification from the straight lines of calibration of each analytically pure standard. The application of this technique to five monovariety virgin olive oils showed that pigment content among them is very different, depending on the variety of olive.
The effects of 0, 5, 10, and 20 ppm β-carotene on the oxidation of 0.033, 0.066, 0.165, 0.330, or 0.660M soybean oil in methylene chloride containing 4 ppm chlorophyll have been studied by measuring headspace oxygen depletion in gas-tight sample bottles during 24 hr of light storage. The oxygen depletion was measured by a thermal conductivity gas chromatograph. The rate of singlet oxygen formation in soybean oil by 4 ppm chlorophyll was 0.17 μmoles O2/mL head-space during first 24 hr of storage. The quenching mechanism study of g-carotene on the chlorophyll sensitized photooxidation of soybean oil showed that g-carotene minimized the oxidation of soybean oil by quenching singlet oxygen. p-carotene did not quench chlorophy11.
The main goal of the present work was to compare and correlate the results of physicochemical parameters and antiradical performance of some oil blends during deep-frying, which will be an initial indicator for applying antiradical tests for monitoring deep-frying oils. Two oil blends were prepared. The first blend was a mixture (1 : 1, wt/wt) of sunflower seed oil and palm olein (SO/PO) and the second was a mixture (1 : 1, wt/wt) of cottonseed oil and palm olein (CO/PO). The oil blends were evaluated during intermittent frying of French fries on two consecutive days for 16 h, with oil replenishing after 8 h. Changes in the fatty acid profile and some physicochemical parameters (peroxide value, color index, viscosity, total polar compounds and UV absorbance at 232 and 270 nm) were used to evaluate the alterations during frying. A quick spectrophotometric method was developed to assess deep-frying oil quality. With the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, the neutralization of the stable radical DPPH by antioxidants present in the oil during frying was measured. Radical-scavenging activity (RSA) of both oil blends was recorded during frying, wherein the results showed that the SO/PO blend had the highest RSA. It was evident from the results that a proportional correlation and positive relationship existed between the levels of fatty acids and the physicochemical characteristics of the vegetable oil blends and their RSA. The initial results obtained allow us to suggest that antiradical measurements could be used to quantify the oxidative and hydrolytic deterioration of vegetable oils upon frying.
A simple, fast and reproducible reversed-phase high performance liquid chromatography (HPLC) method coupled to electrospray ionization mass spectrometry (ESI-MS) for the analysis of triacylglycerols (TAGs) species in the commercial edible oils has been developed. The TAGs species were separated using isocratic 18% isopropanol in methanol and a Phenomenex C18 column. The ESI-MS conditions were optimized using flow injection analysis of standard TAG. Fifteen, fourteen, and sixteen TAGs were separated and identified in corn oil, rapeseed oil, and sunflower oil, respectively. The presence of intense protonated molecular (M + H+), ammonium (M + ), and sodium (M + Na+) adducts ions and their respective diacylglycerols ions in the ESI-MS spectra showed correct identification of TAGs. Some minor potassium adducts (M + K+) were also found. In addition, the identity of the fatty acid, position of each fatty acid, and the location of the double bond in the fatty acid moiety were explained. It was found that this isocratic method is useful for fast screening and identification of triacylglycerols in lipids.
RP HPLC method coupled to ESI-MS was used for the analysis and characterization of the oxidation of model triacylglycerols (TAGs) in presence of β-carotene. β-Carotene was added to the TAGs and oxidized in the Rancimat at 110°C. The samples were separated isocratically using a mixture of isopropanol with methanol and a Phenomenex C18 column. β-Carotene degradation was measured using high performance TLC. We found that β-carotene plays an important role during the thermal degradation of high oleic acid model TAGs. Half of the β-carotene was degraded before 3 h of thermal treatment. β-Carotene significantly increases the peroxide value of the TAGs after the third hour, suggesting a pro-oxidant action. However, different TAGs show different activity toward thermal treatment and β-carotene. The LLL was found to be less stable, OLL and OLO were stable till 10 and 12 h respectively, while POO, OOO, and OSO were the stable TAGs till 14 h. In TAGs, replacing linoleic acid by oleic acid, the stability of the corresponding TAG was found to increase by 2 h. A new class of oxidized TAGs was reported for the first time, together with previously reported species. The proposed mechanism of formation and identification of the newly identified species have been explained. Among the oxidized species of TAGs, mono-hydroperoxides, bis-hydroperoxides, epoxy-epidioxides, and epoxides were the major compounds identified.
Natural antioxidants have recently gained increased interest because of the belief that natural food ingredients are better and safer than synthetic ones. The review presents the results on stabilisation of the main edible oils with different types of natural antioxidants. Sources of natural antioxidants are spices, herbs, teas, oils, seeds, cereals, cocoa shell, grains, fruits, vegetables, enzymes, proteins. Researchers concentrate on ascorbic acid, tocopherols and carotenoids as well as on plant extracts containing various individual antioxidants such as flavonoids (quercetin, kaemferol, myricetin), catechins or phenols (carnosol, rosmanol, rosamaridiphenol) and phenolic acids (carnosic acid, rosmarinic acid). Ascorbyl palmitate is regarded as a 'natural' antioxidant because it is hydrolysed in the body to ascorbic and palmitic acids. Among the herbs of the Lamiaceae family, rosemary has been more extensively studied and its extracts are the first marketed natural antioxidants. Oregano, which belongs to the same family, has gained the interest of many research groups as a potent antioxidant in lipid systems. The review concerns the following main topics: stabilisation of oil with individual natural antioxidants, interaction of antioxidants with synergists, stabilisation of oil with extracts or dry materials from different plant sources (e.g. herbs and spices), stabilisation at frying temperatures and in emulsions.
Conventional canola oil (CO) and high oleic canola oil (HOCO) were stored under autoxidative and photooxidative conditions, β-carotene was added at 0 to 120 ppm. The oils were diluted in mobile phase and injected onto an HPLC column to track β-carotene changes over time. Peroxide values were followed to assess the oxidative stability of the oils. β-carotene was more stable in HOCO than in CO under autoxidative conditions, but no difference between oils was observed under photooxidative conditions. The HOCO was more stable against autoxidation, and CO was more stable against photo-oxidation. Antioxidant activity was shown by β-carotene in both oils, which contained natural tocopherols, during both autoxidative and photooxidative conditions.
The relative oxidative stability of soybean oil samples containing either thermally degraded β-carotene or lycopene was determined
by measuring peroxide value (PV) and headspace oxygen depletion (HOD) every 4 h for 24 h. Sobyean oil samples containing 50
ppm degraded β-carotene that were stored in the dark at 60°C displayed significantly (P<0.01) higher HOD values compared with controls. Lycopene degradation products (50 ppm) in soybean oil significantly (P<0.05) decreased HOD of samples when stored in the dark. PV and HOD values for samples containing 50 ppm of either β-carotene
or lycopene degradation products stored under lighted conditions did not differ significantly from controls (P<0.05). However, soybean oil samples containing 50 ppm of unheated, all-trans β-carotene or lycopene stored under light showed significantly lower PV and HOD values than controls (P<0.01). These results indicated that during autoxidation of soybean oil held in the dark, β-carotene thermal degradation products
acted as a prooxidant, while thermally degraded lycopene displayed antioxidant activity in similar soybean oil systems. In
addition, β-carotene and lycopene degradation products exposed to singlet oxygen oxidation under light did not increase or
decrease the oxidative stability of their respective soybean oil samples.
Profiles of triacylglycerols (TAG) and fatty acids were compared in soybean oil thermally oxidized at 180°C for 60min or
methylene blue photosensitized for 10 h. Headspace oxygen in thermally oxidized and photosensitized soybean oil decreased
significantly (p<0.05) as oxidation time increased. Relative contents of linoleic and linolenic acids decreased and those of oleic acid
increased during oxidation. In both thermal and photosensitized oxidation, TAG with lower than 44 equivalent carbon number
including dilinoleoyllinolenoylglycerol (LLLn, 40), trilinolein (LLL, 42), oleoyllinoleoyllinolenoylglycerol (OLLn, 42), dilinoleoyloleoylglycerol
(LLO, 44), and dilinoleoylpalmitoylglycerol (PLL, 44) significantly decreased, while those with dioleoyllinoleoylglycerol
(OOL, 46) increased significantly in relative peak areas (p<0.05). Photosensitized oxidation decreased TAG containing linoleic and linolenic acids significantly faster than thermal
oxidation in soybean oil (p<0.05), which may be due to the singlet oxygen reaction. Photosensitized soybean oils can be differentiated from thermally
oxidized samples using the distributions of TAG by principal component analysis.
KeywordsTriacylglycerols–Fatty acids–Autoxidation–Methylene blue photosensitization–Soybean oil
Thermoxidative and hydrolytic alterations of a sunflower oil used in sixty repeated and discontinuous deep-fat fryings of
potatoes were evaluated by column and high-performance size-exclusion (HPSE) chromatography. Successive fryings of potatoes
in sunflower oil, without turnover of fresh oil during the performance of fryings, increased the level of total polar components
in the oil from 3.75% to 27.28% (w/w). Triglyceride polymers, triglyceride dimers, oxidized triglycerides and diglycerides
increased after sixty fryings 89.8, 21.8, 4.9 and 1.7 times, respectively. These increases were well correlated with the number
of fryings. However, there was not significant correlation between levels of free fatty acids and the number of fryings. Polar
compounds were highly (r=0.9691) and significantly (P<0.01) correlated with triglyceride polymers and also highly (r=0.9969 and r=0.9738) and significantly (P<0.01) with triglyceride dimers and oxidized triglycerides, respectively. Nevertheless polar compounds were not significantly
correlated with free fatty acids. Data suggest that an intensive thermoxidative rather than a hydrolytic process takes place
in experimental deep-fat frying of potatoes.
This is a book about functions of carotenoids. The reader may therefore be surprised to find that the first half of the book
is chemistry. This should not be a surprise, however. The target for researchers now is not simply to discover and describe
functions and actions, but to understand their mechanisms. This requires understanding of the underlying fundamental principles
and appreciation of the application of the advanced techniques now used to elucidate details of structure and of processes
that may occur on a very short timescale.
The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to predict the oxidative stability of edible oils. The principle of DPPH method is to measure the free radicals generated from oxidized oils directly. The absorbance of DPPH from oils before thermal oxidation decreased proportionally to the concentration of free radical scavenging compounds such as butylated hydroxytoluene (BHT). Oxidized oils with high polyunsaturated fatty acid (PUFA) contents showed high changes in DPPH absorbance or free radical formation rates than those with low PUFA. Oxidized oils with high BHT content were more stable and showed slower pattern change of DPPH absorbance from positive to negative slopes than those with low BHT content. Oxidative stability of oils could be predicted considering the initial values of DPPH absorbance, the free radical formation rates, and the oxidation period for pattern changes. The results from DPPH method on the oxidative stability of vegetable oils agreed with conventional methods such as p-anisidine value (p-AV), conjugated dienoic acids (CDA), or total polar matter (TPM).
The oxidation kinetics of sunflower oil (SO), as well as of pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.001-0.02 %) β-carotene was studied. The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature in the dark and under daylight. The results from the oxidation of SO and TGSO at 100°C in the presence of β-carotene were also presented. It was established that in the antioxidant-free lipid system, the β-carotene did not give any antioxidative protection. It worked as a prooxidant during the oxidation at room temperature and at sufficiently high oxygen concentration, the effect being more pronounced in the dark than under daylight. β-carotene increased the stability of tocopherol-containing SO during its oxidation at room temperature and under daylight. This effect is more strongly expressed in a kinetic regime of oxidation. The synergism of β-carotene with the tocopherols was characterized by the stabilization factor F and the activity A. In the kinetic regime of oxidation F and A varied in the interval F=2.0-6.3, and A =2.7-21.0. In the diffusion regime F=1.3-1.5, and A=1.5-2.8.
Carotenoids are natural pigments which are synthesized by plants and are responsible for the bright colors of various fruits and vegetables. There are several dozen carotenoids in the foods that we eat, and most of these carotenoids have antioxidant activity. Beta-carotene has been best studied since, in most countries it is the most common carotenoid in fruits and vegetables. However, in the U.S., lycopene from tomatoes now is consumed in approximately the same amount as beta-carotene. Antioxidants (including carotenoids) have been studied for their ability to prevent chronic disease. Beta-carotene and others carotenoids have antioxidant properties in vitro and in animal models. Mixtures of carotenoids or associations with others antioxidants (e.g. vitamin E) can increase their activity against free radicals. The use of animals models for studying carotenoids is limited since most of the animals do not absorb or metabolize carotenoids similarly to humans. Epidemiologic studies have shown an inverse relationship between presence of various cancers and dietary carotenoids or blood carotenoid levels. However, three out of four intervention trials using high dose beta-carotene supplements did not show protective effects against cancer or cardiovascular disease. Rather, the high risk population (smokers and asbestos workers) in these intervention trials showed an increase in cancer and angina cases. It appears that carotenoids (including beta-carotene) can promote health when taken at dietary levels, but may have adverse effects when taken in high dose by subjects who smoke or who have been exposed to asbestos. It will be the task of ongoing and future studies to define the populations that can benefit from carotenoids and to define the proper doses, lengths of treatment, and whether mixtures, rather than single carotenoids (e.g. beta-carotene) are more advantageous.
The role of beta-carotene as an anticancer agent has been questioned as a result of clinical trials in which the incidence of nonmelanoma skin cancer was unchanged in patients receiving a beta-carotene supplement and in beta-carotene-supplemented smokers who suffered a significant increase in lung cancer occurrence. In laboratory studies, beta-carotene-supplemented semidefined diets, in contrast to earlier studies employing commercial closed-formula diets, not only failed to provide a protective effect to ultraviolet (UV) carcinogenesis but resulted in significant exacerbation. A rationale for this distinct carcinogenic response to beta-carotene rests with the stability of the carotenoid radical cation, believed to be dependent on the presence of other antioxidants for rapid repair, and suggests that response to beta-carotene depends on the presence and interaction with other dietary factors. Here, we report that diet potentiates beta-carotene-mediated exacerbation of UV carcinogenesis. Although the dietary factor(s) responsible for this effect is unidentified, these studies underscore the potential risk of beta-carotene supplementation in free-living populations where dietary status is widely varied.
The high-temperature treatment of paprika oleoresins (Capsicum annuum L.) modified the carotenoid profile, yielding several degradation products, which were analyzed by HPLC-APCI-MS. From the initial MS data, compounds were grouped in two sets. Set 1 grouped compounds with m/z 495, and set 2 included compounds with m/z 479, in both cases for the protonated molecular mass. Two compounds of the first set were tentatively identified as 9,10,11,12,13,14,19,20-octanor-capsorubin (compound II) and 9,10,11,12,13,14,19,20-octanor-5,6-epoxide-capsanthin (compound IV), after isolation by semipreparative HPLC and analysis by EI-MS. Compounds VII, VIII, and IX from set 2 were assigned as 9,10,11,12,13,14,19,20-octanor-capsanthin and isomers, respectively. As these compounds were the major products formed in the thermal process, it was possible to apply derivatization techniques (hydrogenation and silylation) to analyze them by EI-MS, before and after chemical derivatization. Taking into account structures of the degradation products, the cyclization of polyolefins could be considered as the general reaction pathway in thermally induced reactions, yielding in the present study xylene as byproduct and the corresponding nor-carotenoids.
Measurement of lipid oxidation and evaluation of antioxidant activity In: Natural antioxidants, chemistry, health effects and applications
- F Shahidi
- U N Wanasundara
Shahidi F, Wanasundara UN (1997) Measurement of lipid oxidation and evaluation of antioxidant activity In: Natural antioxidants, chemistry, health effects and applications. AOCS Press,
Champaign
Characterization of the effects of b-carotene on the thermal oxidation of triacylglycerols using
- Zeb A Murkovic
- M Hplc
- Esi
- Ms
Zeb A, Murkovic M (2010) Characterization of the effects of b-carotene on the thermal oxidation of triacylglycerols using HPLC–ESI–MS.
A and carotenoids: chemistry, analysis, functions and effects
- A Zeb
Zeb A (2012) Thermal degradation of b-carotene in food oils. In:
Preedy VR (ed) Vitamin A and carotenoids: chemistry, analysis,
functions and effects. Royal Society of Chemistry, London,
pp 129-141
Measurement of lipid oxidation and evaluation of antioxidant activity In: Natural antioxidants , chemistry, health effects and applications Development of a method predicting the oxidative stability of edible oils using 2,2-diphenyl-1-picrylhydrazyl (DPPH)
- F Shahidi
- Un Wanasundara
- Jm Lee
- H Chung
- P Chang
- Jh Lee
Shahidi F, Wanasundara UN (1997) Measurement of lipid oxidation and evaluation of antioxidant activity In: Natural antioxidants, chemistry, health effects and applications. AOCS Press,
Champaign
26. Lee JM, Chung H, Chang P, Lee JH (2007) Development of a
method predicting the oxidative stability of edible oils using
2,2-diphenyl-1-picrylhydrazyl (DPPH). Food Chem 103:662–669
Official Methods and Recommended Practice AOCS, Champaign 16 Valorisation of low quality edible oil with tomato peel waste
- A Benakmoum
- S Abbeddou
- A Ammouche
- P Kefalas
- D Gerasopoulos
AOCS (1998) Official Methods and Recommended Practice. In:
Firestone D (ed), 5th Edn. AOCS, Champaign
16. Benakmoum A, Abbeddou S, Ammouche A, Kefalas P, Gerasopoulos D (2008) Valorisation of low quality edible oil with
tomato peel waste. Food Chem 110:684–690
Standard methods for the analysis of oils, fats and derivatives, 6th edn Correlation between physicochemical analysis and radical scavenging activity of vegetable oil blends as affected by frying of french fries
IUPAC (1979) Standard methods for the analysis of oils, fats and
derivatives, 6th edn. Pergamon Press, Oxford
18. Ramadan MF, Amer MMA, Sulieman ARM (2006) Correlation
between physicochemical analysis and radical scavenging activity of vegetable oil blends as affected by frying of french fries.
Eur J Lipid Sci Technol 108:670–678
Standard methods for the analysis of oils, fats and derivatives, 6th edn
- Iupac
IUPAC (1979) Standard methods for the analysis of oils, fats and
derivatives, 6th edn. Pergamon Press, Oxford
Official Methods and Recommended Practice
AOCS (1998) Official Methods and Recommended Practice. In:
Firestone D (ed), 5th Edn. AOCS, Champaign