Deep eutectic solvent-based liquid-phase microextraction coupled with reversed-phase high-performance liquid chromatography for determination of α-, ß-, γ-, and δ-tocopherol in edible oils.

For simultaneous analysis of four fat-soluble tocopherols (α-, ß-, γ-, and δ-) in edible oils, an efficient and green method using deep eutectic solvent-based liquid-phase microextraction (DES-LPME) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The DESs formed by different quaternary ammonium salts and ethanol were used as the extractants. Tetrabutylammonium chloride (TBAC)-ethanol DES at a molar ratio of 1:2 achieved the best extraction efficiency. Under the optimized conditions, the detection limits were in the range of 2.1-3.0 ng mL-1. The intra-day and inter-day repeatability were in the ranges of 3.9-5.3% and 4.8-7.1%, respectively, and the recoveries for the real samples varied from 80.7% to 105.4%. The developed method was successfully employed for the determination of all four tocopherol homologues with an RP-HPLC system containing a COSMOSIL π-NAP column in five edible oils collected locally. Graphical abstract.

Involvement of metabolites in early defense mechanism of oil palm (Elaeis guineensis Jacq.) against Ganoderma disease.

Understanding the mechanism of interaction between the oil palm and its key pathogen, Ganoderma spp. is crucial as the disease caused by this fungal pathogen leads to a major loss of revenue in leading palm oil producing countries in Southeast Asia. Here in this study, we assess the morphological and biochemical changes in Ganoderma disease infected oil palm seedling roots in both resistant and susceptible progenies. Rubber woodblocks fully colonized by G. boninense were applied as a source of inoculum to artificially infect the roots of resistant and susceptible oil palm progenies. Gas chromatography-mass spectrometry was used to measure an array of plant metabolites in 100 resistant and susceptible oil palm seedling roots treated with pathogenic Ganoderma boninense fungus. Statistical effects, univariate and multivariate analyses were used to identify key-Ganoderma disease associated metabolic agitations in both resistant and susceptible oil palm root tissues. Ganoderma disease related defense shifts were characterized based on (i) increased antifungal activity in crude extracts, (ii) increased lipid levels, beta- and gamma-sitosterol particularly in the resistant progeny, (iii) detection of heterocyclic aromatic organic compounds, benzo [h] quinoline, pyridine, pyrimidine (iv) elevation in antioxidants, alpha- and beta-tocopherol (iv) degraded cortical cell wall layers, possibly resulting from fungal hydrolytic enzyme activity needed for initial penetration. The present study suggested that plant metabolites mainly lipids and heterocyclic aromatic organic metabolites could be potentially involved in early oil palm defense mechanism against G. boninense infection, which may also highlight biomarkers for disease detection, treatment, development of resistant variety and monitoring.

Chemical and Antioxidant Properties of Wild Edible Mushrooms from Native Nothofagus spp. Forest, Argentina.

This study addresses issues regarding chemical and bioactive properties of nine wild edible mushrooms from native Nothofagus forest from Patagonia, Argentina. Macronutrients, sugars, fatty acids, tocopherols, organic acids, phenolic compounds and antioxidant properties were determined. Protein was found in high levels and varied between 3.35 g/100 g dw in Cyttaria hariotii and 22.29 g/100 g dw in Lepista nuda. All of them presented mannitol and trehalose as main sugars. Mannitol was significantly higher in Ramaria patagonica, although absent in Fistulina endoxantha, whereas trehalose predominated in Aleurodiscus vitellinus, Hydropus dusenii, Cortinarius magellanicus, C. hariotii, Grifola gargal and L. nuda, ranging from 1.15 to 10.26 g/100 g dw; it was absent in R. patagonica. The major fatty acid found was linoleic acid, followed by oleic acid and palmitic acid. All species presented oxalic and fumaric acids, while some also had malic, quinic and citric acids. Tocopherols composition was variable. Cortinarius magellanicus presented significantly higher contents of both α-tocopherol and ß-tocopherol. R. patagonica presented the best results in all the antioxidant activity assays (EC50 values ≤ 1 mg/mL) and the highest content of phenolic compounds presenting gallic, p-hydroxybenzoic, p-coumaric and cinnamic acids. This study constitutes the first report on chemical composition and nutritional value of most of these edible mushroom species. Furthermore, it provides important information necessary to characterize and define the use of these species as gastronomic delicacies, functional foods and sources of bioactive compounds.

Some rape/canola seed oils: fatty acid composition and tocopherols.

Seed samples of some rape and canola cultivars were analysed for oil content, fatty acid and tocopherol profiles. Gas liquid chromotography and high performance liquid chromotography were used for fatty acid and tocopherol analysis, respectively. The oil contents of rape and canola seeds varied between 30.6% and 48.3% of the dry weight (p<0.05). The oil contents of rapeseeds were found to be high compared with canola seed oils. The main fatty acids in the oils are oleic (56.80-64.92%), linoleic (17.11-20.92%) and palmitic (4.18-5.01%) acids. A few types of tocopherols were found in rape and canola oils in various amounts: α-tocopherol, γ-tocopherol, δ-tocopherol, ß-tocopherol and α-tocotrienol. The major tocopherol in the seed oils of rape and canola cultivars were α-tocopherol (13.22-40.01%) and γ-tocopherol (33.64-51.53%) accompanied by α-T3 (0.0-1.34%) and δ-tocopherol (0.25-1.86%) (p<0.05). As a result, the present study shows that oil, fatty acid and tocopherol contents differ significantly among the cultivars.

Subcritical extraction of flaxseed oil with n-propane: Composition and purity.

Flaxseed (Linum usitatissimum L.) oil was obtained via subcritical n-propane fluid extraction (SubFE) under different temperatures and pressures with an average yield of 28% and its composition, purity and oxidative stability were compared to oils obtained via conventional solvent extraction methods (SEMs). When the oxidative stability was measured by differential scanning calorimetry, the oil was found to be up to 5 times more resistant to lipid oxidation as compared to the SEM oils. Direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis showed characteristic and similar TAG profiles for SubFE and SEMs oils but higher purity for the SubFE oil. The flaxseed oil content of ß-tocopherol, campesterol, stigmasterol and sitosterol were quantified via GC-MS. SubFE showed to be a promising alternative to conventional SEM since SubFE provides an oil with higher purity and higher oxidation stability and with comparable levels of biologically active components.

Tocopherol and tocotrienol contents of different varieties of rice in Malaysia.

BACKGROUND: The present study examined the contents of tocopherols and tocotrienols and their distribution in 58 different varieties of whole rice cultivated in Malaysia. The analytical method used was saponification of samples followed by dispersive liquid-liquid microextraction and reverse phase high-performance liquid chromatography. RESULTS: The total vitamin E contents of different varieties of whole rice ranged between 19.36 and 63.29 mg kg⁻¹. Contents of vitamin E isomers varied among rice varieties both within and between grain color groups. Black-pigmented rice showed significantly higher mean contents of α-tocopherol, ß-tocopherol and α-tocotrienol than non-pigmented rice and red-pigmented rice. Red-pigmented rice had significantly lower mean contents of γ-tocotrienol and total vitamin E than non-pigmented rice. The mean contents of δ-tocotrienol and total vitamin E in non-pigmented rice, however, were similar to those in black-pigmented rice. γ-Tocotrienol was the predominant form of vitamin E isomer in all analyzed varieties. The Pearson correlations among vitamin E isomers and total vitamin E content of whole rice were also studied. CONCLUSION: This study provides information on vitamin E content of different rice varieties that would be beneficial for decision making in genetic breeding of bioactive compound-rich rice varieties.

Comparative study of lipophilic and hydrophilic antioxidants from in vivo and in vitro grown Coriandrum sativum.

Coriander is commonly used for medicinal purposes, food applications, cosmetics and perfumes. Herein, the production of antioxidants in vegetative parts (leaves and stems) of in vivo and in vitro grown samples was compared. In vitro samples were clone A- with notorious purple pigmentation in stems and leaves and clone B- green. Seeds were also studied as they are used to obtain in vivo and in vitro vegetative parts. Lipophilic (tocopherols, carotenoids and chlorophylls) and hydrophilic (sugars, ascorbic acid, phenolics, flavonols and anthocyanins) compounds were quantified. The antioxidant activity was evaluated by radical scavenging activity, reducing power and lipid peroxidation inhibition. The in vivo sample showed the highest antioxidant activity mainly due to its highest levels of hydrophilic compounds. Otherwise, in vitro samples, mainly clone A, gave the highest concentration in lipophilic compounds but a different profile when compared to the in vivo sample. Clones A and B revealed a lack of ß-carotene, ß- and δ-tocopherols, a decrease in α-tocopherol, and an increase in γ-tocopherol and clorophylls in comparison to the in vivo sample. In vitro culture might be useful to explore the plants potentialities for industrial applications, controlling environmental conditions to produce higher amounts of some bioactive products.

Temperature dependence of autoxidation of perilla oil and tocopherol degradation.

Temperature dependence of the autoxidation of perilla oil and tocopherol degradation was studied with corn oil as a reference. The oils were oxidized in the dark at 20, 40, 60, and 80 degrees C. Oil oxidation was determined by peroxide and conjugated dienoic acid values. Tocopherols in the oils were quantified by HPLC. The oxidation of both oils increased with oxidation time and temperature. Induction periods for oil autoxidation decreased with temperature, and were longer in corn oil than in perilla oil, indicating higher sensitivity of perilla oil to oxidation. However, time lag for tocopherol degradation was longer in perilla oil, indicating higher stability of tocopherols in perilla oil than in corn oil. Activation energies for oil autoxidation and tocopherol degradation were higher in perilla oil (23.9 to 24.2, 9.8 kcal/mol, respectively) than in corn oil (12.5 to 15.8, 8.8 kcal/mol, respectively) indicating higher temperature-dependence in perilla oil. Higher stability of tocopherols in perilla oil was highly related with polyphenols. The study suggests that more careful temperature control is required to decrease the autoxidation of perilla oil than that of corn oil, and polyphenols contributed to the oxidative stability of perilla oil by protecting tocopherols from degradation, especially at the early stage of oil autoxidation.

Characterization of a potential nutraceutical ingredient: pomegranate (Punica granatum L.) seed oil unsaponifiable fraction.

The chemical fingerprinting of the unsaponifiable fraction of different Punica granatum seed oils was performed in order to evaluate their potential as a functional food ingredient. Qualitative and quantitative determinations of tocopherol, aliphatic alcohol (including policosanol), squalene, phytosterols and triterpene contents were performed by GC-MS. A high yield (3.1-4.2%) of unsaponifiable matter was obtained and consistent levels of squalene (up to 800 mg/kg) and policosanol (118-185 mg/kg) were noticed. ß-sitosterol (up to 8069 mg/kg) and cycloartenol (5916-7766 mg/kg) were predominant in phytosterol and triterpene fractions, while ß- and δ-tocopherol were the most abundant vitamin E forms. Some minor variations were noticed between samples. From the results obtained, it can be suggested that the seed oil of P. granatum can be considered an interesting alimentary source of substances of nutraceutical value involved in the modulation of cholesterol metabolism.