Gamma-tocopherol Concentrations Research Articles

Nutritional quality of kabuli and desi chickpea in Argentina: Effects of environment

AbstractThe environment to which a crop is exposed during the growing season has a significant impact on seed composition. The objectives of this study were to (1) estimate the contribution of genotype (G), environment (E), and their interaction (G × E) to the agronomic features and seed quality of chickpea and (2) identify climatic variables that significantly affect chickpea nutritional composition. A total of 10 pre‐commercial and commercial cultivars of Cicer arietinum L. were evaluated in 15 environments in Argentina. Average plant height ranged between 44.7 and 55.2 cm, 100‐seed weight was 38 and 27 g, and grain yield was 750 and 1500 kg ha−1 for kabuli and desi chickpea, respectively. The results obtained from the variance component analysis showed statistically significant (p < 0.05) contributions of the effects of G, E, and G × E interaction on the nutritional quality of chickpea seeds. Protein, carbohydrates, and mineral content were mostly affected by E, whereas oil content was G‐dependent. Only tocopherols were affected by G × E interaction. The total phenotypic variance is mostly composed of environmental effects captured during the seed filling period. High mean daily air temperature had a negative effect on carbohydrates and increased protein and mineral content. The fatty acid profile and gamma tocopherol contents were affected by accumulated precipitation and evapotranspiration. Air humidity was negatively correlated with protein content and iodine value. Results from this research are useful for breeders to broaden the genetic background of chickpea genotypes and for farmers to identify climatic conditions that impact grain quality.

β-Carotene Supplementation Increases Antioxidant Capacity of Plasma in Older Women , ,

The antioxidant effect of dietary beta-carotene supplementation on the peroxidation potential of plasma was investigated in a randomized double-blind, placebo-controlled study. Twelve healthy women (62-80 y) supplemented their usual daily diet with 90 mg of beta-carotene (n = 6) or placebo (n = 6) capsules for 3 wk. Plasma concentrations of beta-carotene, alpha- and gamma-tocopherol, ascorbate, urate, bilirubin and in vitro production of phosphatidylcholine hydroperoxides (PC-OOH) and utilization of plasma antioxidants in the presence of 50 mmol/L 2,2'-azobis (2-aminopropane) hydrochloride (AAPH), a free radical generator, at 37 degrees C were measured before and after dietary treatment. Plasma beta-carotene increased from 0.76 +/- 0.16 to 6.45 +/- 1.16 micromol/L (P < 0.05) in supplemented but not placebo-treated subjects. The plasma concentrations of other antioxidants did not change significantly in either group. beta-Carotene supplementation did not affect basal levels of plasma PC-OOH as measured by HPLC post-column chemiluminescence but did affect AAPH-induced production of PC-OOH. Before supplementation, the induction period of plasma PC-OOH production was 2.4 +/- 0.4 h, with levels reaching 5.39 +/- 1.50 micromol/L after 6 h of incubation. After supplementation, the induction period increased significantly to 4.2 +/- 0.4 h (P < 0.01), with a lower PC-OOH production of 2.16 +/- 0.90 micromol/L after 6 h (P < 0.05). In this system, plasma ascorbate concentrations were depleted first, followed by loss of bilirubin and alpha-tocopherol and then by the sequential loss of gamma-tocopherol, urate and beta-carotene. These results indicate that beta-carotene supplementation increases the plasma antioxidant capacity of older women.

Prevalence of vitamin E inadequacy, dietary intake and sources of alpha-tocopherol, and predictors of alpha- and gamma-tocopherol status in adolescent girls in Central Mozambique.

An adequate alpha-tocopherol status is important for females at reproductive age. We studied the dietary intake and sources of alpha-tocopherol and alpha- and gamma-tocopherol status indicators in 14-19-year-old girls in Central Mozambique. We also explored factors associated with alpha- and gamma-tocopherol status. The participants (n 508) were from the cross-sectional ZANE Study that was conducted in 2010. We recruited two separate samples, one in January-February and the other in May-June. We collected venous blood samples and conducted 24 h dietary recall interviews. At the time of blood sampling, 11% of participants were pregnant and 10% were lactating. In the total sample, both seasons combined, the median intake of alpha-tocopherol was 6⋅7 mg/d, the mean plasma alpha- and gamma-tocopherol concentrations were 13⋅5 and 0⋅75 μmol/l, respectively, and the prevalence of vitamin E inadequacy (alpha-tocopherol <12 μmol/l) was 36⋅7% (95% CI: 31⋅9-42⋅0%). Season and lactation status were significant predictors of alpha-tocopherol status regardless of which the three indicators (plasma concentration, alpha-tocopherol:total cholesterol ratio, gamma-tocopherol:alpha-tocopherol ratio) were used. Being a lactating mother was negatively associated and having a blood sample taken in January-February, when the main sources of alpha-tocopherol were mango and dark green leafy vegetables, was positively associated with alpha-tocopherol status. In conclusion, vitamin E inadequacy was common in Central Mozambique, and the status may fluctuate due to seasonal changes in the diet. We suggest that lactating mothers are specifically at risk of poor alpha-tocopherol status in resource-poor settings.

Influence of in-ovo vitamin E and ascorbic acid injections on chick development, hatching performance and antioxidant content in different tissues of newly-hatched quail chicks

ABSTRACT 1. This study determined the influence of in ovo (IO) vitamin E and ascorbic acid injections on hatching performance, chick development and antioxidant content of different tissues in day-old quail chicks. The experiment compared a control group (C: non-injection group) and injection groups, which had the yolk sac injected with 3.75 mg α- tocopherol (T1), or had the amniotic sac injected with 0.9% saline solution (T2), 2.5 mg ascorbic acid containing 0.9% saline solution (T3) and 2.5 mg ascorbic acid solution (T4), respectively. 2. Mean relative asymmetry (RA) of bilateral lengths increased in the T2, T3 and T4 groups, whereas it decreased in the T1 group compared to C. The highest total carotene content in the residual yolk sac (RYS) was seen for the T1 group, which was significantly higher compared to T2, T3 and T4 groups. The highest total carotene concentration in the liver was in the T1 group. 3. The concentrations of delta-tocopherol, gamma-tocopherol and total vitamin E in RYS tissue were significantly higher in the T1 group than T2, T3 and T4 groups. Alpha-tocopherol and total vitamin E levels in the liver were significantly higher in the T2 and T4 groups than C. 4. In ovo injections of vitamin E and ascorbic acid to different embryonic sacs caused antioxidant-specific effects on developmental stability of bilateral traits, RYS absorption, concentrations of total carotene and derivatives of vitamin E in newly hatched quail chicks.

Chemical characterization of Echium plantagineum seed oil obtained by three methods of extraction.

Echium seed oil has been considered an important alternative source of omega 3 fatty acids (n-3 FA) for human consumption. Considering the oxidative instability of n-3 FA richer oils, the objective of this study was to determine the chemical and sensory parameters of the oil obtained from Echium plantagineum seeds obtained by three extraction methods (hydraulic press: HYD; continuous screw press: PRESS; and solvent technique: SOLV). Stearidonic acid (C18:4, n3), the most important n-3 FA present in the oil, changed from 12.5% to 12.7%. Regarding the minor compounds, PRESS sample showed the highest concentration of gamma-tocopherol (782.24mg/kg oil), while SOLV samples presented the highest amount of β-sitosterol (73.46mg/100g) with no difference of campesterol concentration (159.56mg/100g) among the samples. Higher values of total phenolics (19.65mg GAE/kg oil) and β-carotene (34.83mg/kg oil) were also found in the SOLV samples, suggesting the influence of hexane in the extraction of these bioactive compounds. High resolution mass spectrometry identified caffeic acid and its derivatives as the main phenolic compounds present in the echium oil. PRESS sample showed the best oxidative stability as measured by PV (0.61mmol/kg oil) and malondialdehyde (173.13µmol), probably due to faster time of processing compared to HYD and SOLV samples. Our data showed that the extraction method changed the chemical composition of the minor compounds in the echium oil, but these alterations did not reduce its nutritional quality or sensory acceptability. PRACTICAL APPLICATION: Echium oil represents a great potential source of omega 3 fatty acids, but there is not enough information about its oxidative stability and chemical composition, especially toward minor compounds. Our study characterizes echium oil composition obtained from three extraction methods, contributing to amplify the technical information about this important alternative oil for human consumption.

Fig seed oil‐loaded nanostructured lipid carriers: Evaluation of the protective effects against oxidation

The aim of this study was to develop a carrier system that protects fig seed oil (FSO) from oxidation by encapsulating into nanostructured lipid carriers (NLCs). NLCs were prepared by high shear mixing technique and the effects of solid lipids and surfactants on the formulation parameters were investigated. The formulations were characterized in terms of particle size, polydispersity index, and zeta potential, and fatty acid and tocopherol amounts were determined by GC and HPLC, respectively. NLC loaded with FSO was obtained at a particle size of 241 nm with low polydispersity (0.259) and a negative electrical charge (−13.6 mV). The antioxidant capacity has been evaluated by accelerated oxidation storage tests, radical and hydrogen peroxide scavenging activity tests. The stability of the final formulation with high concentration of gamma tocopherol and unsaturated linoleic acid content of FSO was increased by loading into NLCs. Novelty impact statement NLC formulations loaded with FSO were prepared for the first time at a dimension of 241 nm with low polydispersity. FSO was protected against lipid oxidation by encapsulation into NLC as revealed by lipid peroxidation, hydrogen peroxide, and radical scavenging activity tests. FSO-loaded NLC formulations were shown to be valuable carriers for encapsulation of bioactive food materials for stability.

Feeding Broiler Chickens with Grape Seed and Skin Meals to Enhance α- and γ-Tocopherol Content and Meat Oxidative Stability.

Grape seeds (GS) and grape skins (GK) are natural sources of polyphenols with featured antioxidant capacity. An experiment was conducted to investigate the effect of these polyphenol sources in diets formulated to contain the same total extractable grape polyphenol content on growth performance, protein and extractable polyphenol digestibility, plasma and meat α- and γ-tocopherol and thigh meat oxidation in broiler chickens. Five experimental diets were formulated: control, control + vitamin E (200 mg/kg), 30 g/kg GS diet, 110 g/kg GK diet, GS + GK diet (a mixture of 24.4 g/kg GS and 13.1 g/kg GK designed to simulate a reconstituted grape pomace). Feeding chickens with 110 g/kg GK reduced (p < 0.001) daily weight gain, worsened (p < 0.001) feed conversion ratio, increased (p < 0.001) non-extractable polyphenol content in the ileum and in the excreta and decreased (p < 0.05) ileal protein digestibility. Regardless of the grape polyphenol source used, the inclusion of grape byproducts in the diets led to an increase of total extractable polyphenol contents in the ileum (p < 0.01) and the excreta (p < 0.001), which resulted (p < 0.001) in a decrease of extractable polyphenol digestibilities. Alpha- and gamma-tocopherol concentrations increased (p < 0.001) in plasma and in seven-day stored meat in birds fed the diet combining GS and GK with respect to the control group. As it happened with the vitamin E supplementation, feeding the combination of GS and GK also reduced (p < 0.001) the concentration of the lipid peroxidation marker (malondialdehyde) in the stored meat of chickens.

Fast detection of adulteration of aromatic peanut oils based on alpha-tocopherol and gamma-tocopherol contents and ratio

A fast method based on normal-phase high-performance liquid chromatography with UV detection was applied to determine the tocopherols in aromatic peanut oil (APO) and four refined vegetable oils (soybean, sunflower, maize, and rapeseed oils). Our results showed that the tested oils varied greatly on the content of tocopherol isomers, especially on α- and γ-tocopherol concentrations. Consequently, (α+γ)-tocopherol (297.9–393.2 mg kg−1) and α-/γ-tocopherol (1.05–2.13) were successfully applied as discriminating parameters for detecting the adulteration of APO with above four refined vegetable oils. Furthermore, APO was mixed with the four oils (at the levels of 5, 10, 15, 20 and 25 g/100 g, w/w) to determine whether the tocopherol analysis is a better approach than fatty acid profiling for detecting APO adulteration. Our results showed that for tocopherols, our detection limits were 5 g/100 g for soybean oil and 10 g/100 g for other three oils in APO, showing a higher sensitivity than fatty acids profile based method for detecting APO adulteration. Thus, our newly developed method is an alternative and innovative tool for fast and cost-effective detection of the adulteration of APO with soybean, sunflower, maize, and rapeseed oils.

Whey protein isolate-gelatin nanoparticles enable the water-dispersibility and potentialize the antioxidant activity of quinoa oil (Chenopodium quinoa).

The quinoa oil presents benefits to health, but its low water dispersibility in the aqueous matrix and instability of bioactive compounds is challenging for food application. This study performed the physicochemical and chemical characterization of quinoa oil and evaluated its water dispersibility and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity after nanoencapsulation in porcine gelatin and combination with whey protein isolate by emulsification O/W technique. Thus, three formulations were obtained: 1) OG–containing quinoa oil and porcine gelatin in aqueous phase 2; 2) OWG1—containing quinoa oil, whey protein isolate, and porcine gelatin in aqueous phase 2; and 3) OWG2—containing quinoa oil and whey protein isolate in aqueous phase 1, and porcine gelatin in aqueous phase 2. The oil characterization showed that quinoa oil presented the predominance of linoleic acid (53.4%), and concentration of alpha and gamma-tocopherol, respectively, of 8.56 and 6.28 mg.100g-1. All formulations presented a smooth surface without depression or cracking, an average diameter between 165.77 and 529.70 nm. Fourier transform infrared spectroscopy indicated chemical interaction between the encapsulating agents and the oil in all formulations, being more intensified in OWG1 and OWG2. Based on this, these formulations showed higher dispersibility in aqueous solution [68% (3.48) and 71% (2.97)]. This resulted in higher antioxidant activity for OWG1 and OWG2, showing the amounts that reduces antioxidant activity by 50% equal to 5.30 (0.19) mg/mL and 5.54 (0.27) mg/mL, respectively, compared to quinoa oil [13.36 (0.28) mg/mL] (p < 0.05). Thus, quinoa oil nanoencapsulation proved to be an efficient alternative to enable water-dispersibility and enhance antioxidant activity, increasing its potential for application in the food industry.

A Global Study by 1H NMR Spectroscopy and SPME-GC/MS of the in Vitro Digestion of Virgin Flaxseed Oil Enriched or not with Mono-, Di- or Tri-Phenolic Derivatives. Antioxidant Efficiency of These Compounds.

The effect of enriching virgin flaxseed oil with dodecyl gallate, hydroxytyrosol acetate or gamma-tocopherol on its in vitro digestion is studied by means of proton nuclear magnetic resonance and solid phase microextraction followed by gas chromatography/mass spectrometry. The extent and pattern of the lipolysis reached in each sample is analyzed, as is the bioaccessibility of the main oil components. None of the phenolic compounds provokes inhibition of the lipase activity and all of them reduce the lipid oxidation degree caused by the in vitro digestion and the bioaccessibility of oxidation compounds. The antioxidant efficiency of the three tested phenols is in line with the number of phenolic groups in its molecule, and is dose-dependent. The concentration of some minor oil components such as terpenes, sesquiterpenes, cycloartenol and 24-methylenecycloartenol is not modified by in vitro digestion. Contrarily, gamma-tocopherol shows very low in vitro bioaccessibility, probably due to its antioxidant behavior, although this increases with enrichment of the phenolic compounds. Oxidation is produced during in vitro digestion even in the presence of a high concentration of gamma-tocopherol, which remains bioaccessible after digestion in the enriched samples of this compound.

Apoptosis Induction with Enhancement of BAX/BCL2 Gene Expression Ratio via Combination Therapy in HT29 Colon Cancer Cells

Background and Aim: Combination therapy is one of the new strategies that minimize resistance to chemotherapy and reduces drug toxicity. Here, we investigated the effect of combination therapy with 5-Fluorouracil and Gamma Tocopherol on cell survival and BAX/BCL2 gene expression ratio in HT29 colon cancer cells. Methods: The proliferation of cancer cells was determined via colony formation assay. BAX/BCL2 ratio was evaluated after incubation with concentrations of 5-Fluorouracil and Gamma Tocopherol via real-time-PCR. Results: The average number of colonies in the cells treated with 5-Fluorouracil, Gamma Tocopherol and their combination of them was 63±4, 78±3, and 28±2, respectively which significantly decreased in the combination group. In contrast with the control group, the BAX/BCL2 ratio remarkably increased when the cell underwent combinational treatment (p<0.05). Conclusion: 5-Fluorouracil and Gamma Tocopherol reduced HT 29 cell proliferation. Our results suggest that combination therapy with 5- Fluorouracil and Gamma Tocopherol can be considered as a strategy for induction of apoptosis via increasing the BAX/BCL2 ratio. *Corresponding Author: Nadereh Rashtchizadeh; Email: rashtchizadeh@rocketmail.com Please cite this article as: Bazzaz R, Yaghmaei P, Dastmalchi S, Rashtchizadeh N. Apoptosis Induction with Enhancement of BAX/BCL2 Gene Expression Ratio via Combination Therapy in HT29 Colon Cancer Cells. Arch Med Lab Sci. 2020;6:1-7 (e21). https://doi.org/10.22037/amls.v6.33489

Optimization of process variables using response surface methodology for tocopherol extraction from Roselle seed oil by supercritical carbon dioxide

Hibiscus sabdariffa L. (Roselle) seeds are rich in proteins, carbohydrates and unsaturated fatty acids, and are a good source of minerals and antioxidants. Supercritical carbon dioxide (SC-CO2) extraction was applied for extraction of oil from Roselle seed at temperatures of 40 °C to 80 °C and pressures of 20 MPa to 30 MPa. The effects of temperature and pressure on the extraction yield and solubility of oil were determined. Process optimization was carried out using response surface methodology (RSM). A particle size of 300 μm, SC-CO2 flow rate of 5 mL/min and extraction time of 180 min were held constant throughout this study. The overall oil yield increased as pressure and temperature was increased, while a reverse effect was observed at higher temperatures. The optimum extraction conditions for Roselle seed oil corresponded to a pressure of 30 MPa and temperature of 40 °C. According to the analysis of variance (ANOVA), the coefficient of determination R2 for oil yield and gamma tocopherol concentration were 0.9723 and 0.9754, respectively, indicating a good correlation and agreement between the experimental and predicted values.

The Lipide Soluble Vitamin Contents of Some Onobrychis Miller Taxa

The goal of this study is to determine the lipid-soluble vitamin contents in seeds of the some Onobrychis Miller taxa by using HPLC. Samples were collected from the natural habitats. Studied materials were dissolved in acetonitrile/methanol (75/25 v/v) and were injected 50 μL to HPLC instrument (Shimadzu, Kyota Japan). According to data obtained from present study showed that Onobrychis hypargyrea, Onobrychis viciifolia, Onobrychis caput-galli, Onobrychis fallax and Onobrychis oxyodonta var. armena have high lipide-soluble vitamin contents. Present study found that Onobrychis oxyodonta var. armena (1777,27±6,24 µg/g), Onobrychis fallax (916,0±4,51 µg/g) Onobrychis hypargyrea (809,7±5,03 µg/g) and Onobrychis viciifolia (399,7±3,54 µg/g) have highest beta-caroten content. Also, Onobrychis caput-galli has high beta caroten content (73,3±,94 µg/g). on the other hand, it was found that Onobrychis fallax has highest gamma-tocopherol content (1401,2±8,76 µg/g). Onobrychis viciifolia (574,9±2,35 µg/g), Onobrychis caput-galli (410,1±4,56 µg/g), Onobrychis oxyodonta var. armena (267,7±3,68 µg/g), Onobrychis podporea (162,5±2,14 µg/g) werethe other high gamma tocopherol content. Whereas, retinol, retinol acetate and r-tocopherol contents were found absent or trace amounts in the present study.

Determination of tocopherols and physicochemical properties of faveleira (Cnidoscolus quercifolius) seed oil extracted using different methods

Abstract This study aims to evaluate the physicochemical properties and tocopherol content in faveleira seed oil extracted using three methods (Bligh-Dyer, Soxhlet extractor, and cold-pressing). Each of the methods generated different yield percentages, with cold-pressing producing the least amount of oil. However, the cold-pressing method produced better quality oil with more desirable properties, including low acidity (1.56 ± 0.01% oleic acid) and low peroxide value (0.45 ± 0.09 mEq/1000 g). Cold-pressing resulted in higher quantities of tocopherols: 0.59 ± 0.12 mg/100 g of alpha-tocopherol and 20.97 ± 1.15 mg/100 g of beta + gamma-tocopherol. Faveleira seed oil, when extracted by cold-pressing, maintains better physicochemical quality, with the highest beta + gamma-tocopherol content.

Phenolic compounds of ‘Galega Vulgar’ and ‘Cobrançosa’ olive oils along early ripening stages

In this study, the lipophilic and hydrophilic phenol composition of virgin olive oils (VOO) obtained from olives from two of the most important Portuguese cultivars (‘Galega Vulgar’ and ‘Cobrançosa’), harvested at different ripening stages and under two irrigation schemes (rain fed and irrigated), was evaluated. Phenolic alcohols (hydroxytyrosol and tyrosol), phenolic acids and derivatives and flavonoids (luteolin and apigenin), as well as tocopherols were quantified. Lipophilic (>300mgkg−1) and hydrophilic phenols (>600mgkg−1) were present in high contents in both VOO, for early ripening stages. Gamma-tocopherol content is higher in ‘Galega Vulgar’ VOO. Total phenols showed a decrease between ripening index 2.5 and 3.5. The dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA), also known as oleacein, was the major phenolic compound identified in both oils. The concentration of free hydroxytyrosol and tyrosol in both VOO is very low while their esterified derivatives, like 3,4-DHPEA-EDA and p-HPEA-EDA, are much more abundant.

Prenatal polycyclic aromatic hydrocarbon (PAH) exposure, antioxidant levels and behavioral development of children ages 6–9

PurposePrenatal polycyclic aromatic hydrocarbon (PAH) exposure has been shown to increase DNA adduct levels and to affect neurodevelopment. Micronutrients may modify the adverse effect of PAH on neurodevelopment. Thus, we examined if micronutrient concentrations modified the association between PAH exposure and neurodevelopmental outcomes. Methods151 children from a birth cohort who had micronutrient concentrations measured in cord blood and completed the Child Behavioral Checklist (CBCL), between the ages of 6 and 9 years, were evaluated. Prenatal airborne PAH exposure was measured by personal air monitoring. The betas and 95% CI for the associations of antioxidant concentrations and PAH exposure with each of the outcomes of CBCL raw score and dichotomized standardized T-score (based on clinical cutpoints) were estimated, respectively, by multivariable poisson and logistic models. ResultsChildren below the median for alpha-tocopherol and gamma-tocopherol concentrations, compared to those above, were more likely to have thought problems, aggressive behavior and externalizing problems (p<0.05). Lower carotenoid concentration was associated with more thought problems (MVβ=0.60, p<0.001) and externalizing problems (MVβ=0.13, p<0.05) for the same contrast. No statistically significant associations were observed between retinol concentrations and neurodevelopmental symptoms. Overall, no consistent patterns were observed when we examined the interaction between antioxidants (e.g., alpha-tocopherol) and PAH in relation to CBCL symptoms (e.g., internalizing and externalizing problems, p<0.05). ConclusionsLower alpha-tocopherol, gamma-tocopherol and carotenoid levels may adversely affect healthy neurodevelopment, even after accounting for PAH exposure. Future research to confirm these findings are warranted given the importance of identifying modifiable factors for reducing harmful PAH effects.

Storage stability of Jatropha curcas L. oil naturally rich in gamma-tocopherol

Jatropha curcas L. is an interesting tropical oil crop for biodiesel production. However, seed conservation until oil extraction may be a problem under high temperature and humidity. In this study, Jatropha curcas L. seeds grown in Mozambique and presenting 160mg/kg of gamma-tocopherol in their oil were stored for 42 days, in dark, at 35°C and 75% or 92% relative humidity (RH). Along storage, the oil was extracted and analysed in terms of fatty acid composition, tocopherol content, acidity, initial and final oxidation products (monitored by K232 and K270 values, respectively).Jatropha seeds presented an initial water content of 8.4% and an oil content of 45.7% (dry basis). The oil was rich in oleic (41.2%) and linoleic (38.8%) acids.Along 42 days of storage, the acidity increased from 0.8% to 7.4% and 25.3% and K270 increased from 0.07 to 0.25 and 0.46 in oils from seeds stored at 75% and 92% RH, respectively. Simultaneously, a decrease in gamma-tocopherol content was observed, which was more pronounced at 92% RH than at 75% RH (96% decrease versus 57% decrease). Gamma-tocopherol showed to protect the oil against oxidation principally during the second stage of oxidation. During the storage at 35°C, the fatty acid composition of the oils from seeds kept either at 75% or 92% of humidity, did not significantly vary throughout the test.

Alpha-tocopherol and gamma-tocopherol concentration in vegetable oils

Vegetable oils are the richest dietary sources of vitamin E. Vitamin E determination levels in foods are of great importance to adjust the ingestion of nutrients by the population. The purpose of this paper is to determine the concentration of alpha-tocopherol and gamma-tocopherol in vegetable oils and compare the alpha-tocopherol value to the nutritional requirement of vitamin E. The analysis was performed using High Performance Liquid Chromatography. The values expressed as mg/kg for alpha and gamma-tocopherol were, respectively, 120.3±4.2 and 122.0±7.9 in canola oil; 432.3±86.6 and 92.3±9.5 in sunflower oil; 173.0±82.3 and 259.7±43.8 in corn oil; 71.3±6.4 and 273.3±11.1 in soybean oil. A significant difference was encountered between the alpha-tocopherol concentrations in vegetable oils. Similar results were found for gamma-tocopherol, except for corn and soybean oils. It was concluded that the soybean oil was not considered a source of vitamin E. The canola and corn oils were considered sources, and the sunflower oil was considered an excellent source.

Dietary Alpha-Tocopherol Affects Tissue Vitamin E and Malondialdehyde Levels but Does not Change Antioxidant Enzymes and Fatty Acid Composition in Farmed Atlantic Salmon (Salmo salar L.)

In this study the effect of increasing dietary alpha tocopherol on vitamin E tissue concentrations, lipid peroxidation (malondialdehyde), antioxidant enzymes, and fatty acid composition has been investigated in farmed Atlantic salmon. To this end fish (initial body weight ~ 193 g, n = 70 per group) were fed diets based on fish oil (27.5 %), fish meal (15.0 %), wheat gluten (20.6 %), and soy protein concentrate (24.0 %) for 14 weeks. Diets were supplemented with 0 (negative control), 150, and 400 mg/kg vitamin E as all-rac alpha-tocopheryl acetate. Dietary vitamin E did not affect feed conversion efficiency ratio but significantly (p < 0.05) increased alpha-tocopherol concentrations in salmon plasma, liver, and fillet (n = 8 per group each). The increase in fillet alpha-tocopherol was accompanied by a considerable decrease (p < 0.01) in malondialdehyde concentrations at the higher supplementation level. Furthermore, we observed an antagonistic interaction between alpha- and gamma-tocopherol in plasma at the highest supplementation level, since high dietary alpha-tocopherol reduced plasma gamma-tocopherol concentrations. Liver antioxidant enzymes, including glutathione peroxidase and superoxide dismutase, remained largely unchanged in response to dietary alpha-tocopherol. Dietary alpha-tocopherol did not affect eicosapentaenoic acid and docosahexaenoic acid concentrations in salmon fillet. Present data suggest that alpha-tocopherol supplementations beyond dietary recommendations may further improve flesh quality and nutritional value of Atlantic salmon fillet as far as malondialdehyde and vitamin E concentrations are concerned.

A practical study on the feasibility of alpha and gamma-tocopherol quantification for distinguishing Iberian pig feeding systems

This study was undertaken to test the feasibility of using alpha and gamma-tocopherol quantification in fat and muscle to establish a correct classification of Iberian pigs according to their feeding background in practical situations. Samples were obtained over three different seasons from the four categories of pigs described in the Industry Quality Policy (FREE-OUT “bellota” ; FREE-OUT-FEED “recebo” ; FEEDOUT “campo” ; and FEED-IN “cebo” ). Linear discriminant functions were calculated with data obtained from seasons 1 and 2 and validated. The classification of fat and muscle samples from season 3 in the four feeding categories according to the calculated discriminant functions achieved an average of 76% success rate in distinguishing the true origin of pig samples. Quantification in muscle seemed to have higher prediction ability. Regression equations to quantify weight gained depending on the gamma-tocopherol concentration had higher R 2 values for muscle than for fat (R 2 = 0.81 vs. 0.62). Merging of the feeding categories established by the Quality Policy could raise the accuracy of the alpha and gamma-tocopherol quantification method to up to between 89% and 98%.