Variability of vitamin E content in pumpkin seeds (Cucurbita pepo L)

Pumpkin (Cucurbita pepo L.) seed oil is a common salad oil which is produced in the southern parts of Austria, Slovenia and Hungary. It is dark green and has a high content of free fatty acids. Due to its colour, the oil cannot be used for cooking. The content of vitamin E, especially-tocopherol, is very high. The oil content of the pumpkin seed is about 50%. The seed itself can be eaten. Therefore a pumpkin variety with high vitamin E content is desirable. The aim of this work was to find a variety ofCucurbita pepo which has a high oil yield and a high vitamin E content. A total of 100 breeding lines were tested for their tocopherol content. The tocopherols and tocotrienols are extracted with hexane and analysed by NP-HPLC/FLD with hexane/dioxan (96/4) as eluent, with fluorescence detection at 292/335 nm. The/gg-tocopherol content, which is about 5–10 times as much as that of -tocopherol varies over a broad range (41–620 mg/kg dry pumpkin seeds).- and-tocopherol are found at low levels.     

Validation of a method for simultaneous quantification of total carotenes and tocols in vegetable oils by HPLC

A normal-phase HPLC method for analysis of carotenes, tocopherols and tocotrienols has been developed and validated. In this work we presented a modification to the official AOCS method for analysis of tocols which allowed simultaneous quantification of the three groups of compounds, including carotenes. Analytes were separated using a gradient mobile phase (hexane and isopropanol) and with a gradient flow rate (1–2 mL min⁻¹). The column effluent was monitored by Photo Diode Array detector (PDA) set at 292 nm (tocols) and 455 nm (β-carotene) and by fluorescence detector set at an excitation wavelength of 290 and 330 nm emission. Inter- and intra-run accuracies and precision of the analytical method were better than ±15%. The lower limit of quantification was 5.0 mg L⁻¹ for the tocols and 0.1 mg L⁻¹ for carotenes. The method has been applied for the quantification of these compounds in Amazon oils.     

Tocol and β-glucan levels in barley varieties and in pearling by-products

In order to verify a different genotype potential in barley varieties, in terms of tocols and β-glucans, and to demonstrate that pearling by-products have interesting amounts of these bioactive compounds, their content was investigated in 36 barley varieties and in the pearling by-products of a commercial hulled barley stock. The β-glucan content ranged from 2.64 g/100 g dw (dry weight) for Vanessa to 8.05 g/100 g dw for Ludine, with an average value of 3.95 g/100 g dw and 50% of the compounds were in the range between 3.45 and 4.36 g/100 g dw. The total tocol amount ranged from 50.3 mg/kg dw (Ladoga) to 88.6 mg/kg dw (Maggiodoro), with a mean value of 69.1 mg/kg dw and with most genotypes (50%) having a content between 62 and 75 mg/kg dw. Adagio and Sabel were the best source of vitamin E activity, expressed as Tocopherol Equivalents. In the pearling by-products there was no enrichment of β-glucans, on the contrary, a seven and a fivefold increase was observed for tocopherols and tocotrienols, respectively.     

Tocopherols in espresso coffee: Analytical method development and validation

The present paper reports the development and validation of an analytical micro-method for tocopherols quantification in espresso coffee by normal-phase HPLC with fluorescence detection. The proposed method consists in a liquid–liquid extraction with n-hexane:ethyl acetate, followed by a clean-up with dimethylformamide to eliminate co-eluting interferences. The method showed good intra- and inter-day precisions (coefficient of variation < 6.5%), good accuracies (98 ± 6%), and high correlation coefficients (r > 0.999) for standards subjected to the entire procedure. Only α- and β-tocopherols were identified in the brews. The detection and quantification limits were 0.5 and 1.4 ng/ml, for α-tocopherol, and 0.4 and 1.1 ng/ml, for β-tocopherol, respectively. A mean total tocopherol content (α + β) of 3.5 ± 0.9 μg in commercial espresso coffee blends (30 ml) was detected. The proposed method requires low solvent consumption and proved to be sensitive, precise and accurate.     

Protein,ash, lutein and tocols distribution in einkorn (Triticum monococcum L. subsp. monococcum) seed fractions

The distribution of protein, ash, lutein, tocopherols and tocotrienols in the germ, bran and endosperm portions was studied in seeds of two einkorn accessions and one bread wheat. The two einkorns showed a higher content of most compounds, but the distribution within the kernel was similar in both species. The germ fraction showed the highest concentration of protein, lutein, α-tocopherol, β-tocopherol and total tocols. Ash, α-tocotrienol and β-tocotrienol levels were highest in the bran fraction, although significant quantities were detected also in the germ and, for tocotrienols, in the flour.     

Interactions between tocopherols,tocotrienols and carotenoids during autoxidation of mixed palm olein and fish oil

Electron spin resonance (ESR) and spin trapping detection of radical formation showed that the oxidative stability of palm olein/fish oil mixtures increased with the amount of palm olein. Mixtures with red palm olein were less stable than were mixtures with yellow palm olein. Addition of ascorbyl palmitate and citric acid gave further reduction of radical formation, whereas no effect was observed by adding lecithins. Storage of palm olein/fish oil mixtures (4:1) at 30 °C confirmed that red palm olein mixtures were less stable than were yellow palm olein mixtures. Ascorbyl palmitate together with citric acid improved the stability in both cases. The concentrations of α-tocopherol and α-tocotrienol decreased during storage, whereas β-, γ-, and δ-tocotrienols were unaffected. Ascorbyl palmitate reduced the losses of α-tocopherol and α-tocotrienol. The rate of loss of carotenoids was independent of the presence of fish oil and, except for an initial fast drop, also of the presence of ascorbyl palmitate.     

Functional lipid characteristics,oxidative stability,and antioxidant activity of macadamia nut (Macadamiaintegrifolia) cultivars

Phytochemical compounds (tocopherols, tocotrienols, and squalene) were measured in seven macadamia cultivars harvested from four locations on Hawaii island to establish whether these compounds enhance the oxidative stability of roasted kernels. Cultivars that had the greatest oxidative stability also had high total lipid-soluble antioxidant capacity. Tocopherols [delta (δ), gamma (γ), alpha (α)] were not detected in most macadamia nut samples, but macadamia kernels contained significant amounts of tocotrienols (31–92 μg/g oil) and squalene (72–171 μg/g oil) for all cultivars tested. This is the first report of variation for three tocotrienol homologs (δ-, γ-, α-T3) and total antioxidant capacity in macadamia nut cultivars. No statistical correlations were found between oxidative stability and tocopherol, tocotrienol, and squalene concentrations. However, two cultivars (HAES 294 and HAES 835) were identified with superior oxidative stability, suggesting that the kernel quality of these cultivars is more stable during storage.     

Legumes are valuable sources of tocopherols

Grain legumes contain numerous phytochemicals useful for their nutritional or nutraceutical properties, such as tocopherols, involved in the prevention of cardiovascular disease and eye pathologies. In this work, tocopherols were quantified in soybean, chickpea, lentil, pea, common bean, broad bean, and three lupin species. In all samples, the gamma congener was the most abundant tocopherol, followed by minor quantities of alpha-tocopherol (with the exception of common bean lacking in this congener) and delta-tocopherol (with the exception of Lupinus angustifolius and Lupinus mutabilis). Beta-tocopherol and tocotrienols were never detected. Some samples of soybean, pea, white lupin and chickpea contained over 10 mg/100 g seeds of total tocopherols. In order to estimate the nutritional value, the vitamin E activity was calculated. Chickpea, soybean and, to a lesser extent, lupin, broad bean and pea may contribute in a relevant way to the daily intake of this vitamin.     

Lipid components,fatty acid distributions of triacylglycerols and phospholipids in rice brans

Endogenous tocochromanols in extracted lipids from rice brans of the five cultivars were determined by high-performance liquid chromatography, and were investigated in relation to the fatty acid (FA) distribution of triacylglycerols (TAG) and phospholipids (PL). The dominant tocols were α-tocopherol and γ-tocotrienol, followed by α-tocotrienol and with much smaller amounts of γ-tocopherol and δ-tocotrienol. The lipids of these rice brans comprised mainly TAG (80.6–86.0 wt.%), free FA (4.2–9.0 wt.%), and phospholipids (5.5–6.7 wt.%), whilst other components were also detected in minor proportions (0.2–2.1 wt.%). The PL components included phosphatidyl choline (31.8–46.8 wt.%), phosphatidyl ethanolamine (25.0–38.9 wt.%) and phosphatidyl inositol (20.2–23.2 wt.%). Comparison of these different cultivars showed, with a few exceptions, no significant differences (P > 0.05) in FA distribution. FA distribution of TAG among the five cultivars was evident in the rice brans: unsaturated FA were predominantly concentrated at the sn-2 position and saturated FA primarily occupying the sn-1 or sn-3 position. These results suggest that the tocopherol content, lipid component, and FA distribution in rice brans are not dependent on the cultivation areas during the growing season.     

Lipid components,fatty acids and triacylglycerol molecular species of black and red rices

Extracted lipids obtained from black and red rices were analysed by high-performance liquid chromatography (HPLC), for endogenous tocochromanols. The molecular species and fatty acid (FA) distribution of triacylglycerols (TAG) isolated from these total lipids were analysed by a combination of AgNO₃ thin-layer chromatography (TLC) and gas chromatography (GC), and were investigated in relation to the content of endogenous tocochromanols. With a few exceptions, the predominant tocols were γ-tocotrienol and α-tocopherol, followed by α-tocotrienol (red) and γ-tocopherol (black) with much smaller amounts of β-, δ-tocopherols and δ-tocotrienol. The lipids of these rices were comprised mainly of TAG (76.4–80.5%), free FA (7.2–9.8%), and phospholipids (3.5–3.6%), whilst other components were present in minor proportions (0.1–4.1%). The principal FA components were palmitic (16:0), oleic (18:1n − 9) and linoleic (18:2n − 6) acids. Fifteen different TAG molecular species were detected and quantified by successive applications of AgNO₃-TLC and GC. The major TAG components were S₂M (7.0–7.8%), SM₂ (12.6–12.9%), M₃ (15.7–16.5%), SMD (23.5–23.7%), SD₂ (5.7–5.8%), M₂D (9.3–9.8%), MD₂ (8.1–8.6%) and D₃ (5.8–7.4%) (where S, M, D, and T denote a saturated FA, a monene, a diene, and a triene, respectively). The results suggested that these rice lipids contain large amounts of nutraceuticals with proven positive health effects.     

Discrimination between arabica and robusta coffee species on the basis of their tocopherol profiles

The tocopherol profiles of arabica and robusta coffee beans, both green and roasted, were ascertained. A solid-liquid micro-extraction method was used, and the quantification performed by normal-phase HPLC/diode-array/fluorescence detection. Regarding green arabicas, the mean contents were 2.7 ± 0.4 mg/100 g, for α-tocopherol, and 8.0 ± 0.9 mg/100 g, for β-tocopherol. For green robustas, mean values of 1.7 ± 0.3 and 2.1 ± 0.3 mg/100 g were found for α- and β-tocopherol, respectively. Generally, more than 90% of tocopherols remained after the roasting procedure, except for β-tocopherol in robustas, whose mean degradation was approximately 25% when expressed as dry weight. No γ-tocopherol was detected in any sample. The results show that tocopherol profile could be useful in the discrimination of arabica and robusta coffees (either green or roasted).     

Tocopherols and tocotrienols as free radical-scavengers in refined vegetable oils and their stability during deep-fat frying

The aim of this study was to assess the effect of total tocopherols and tocotrienols of refined vegetable oils on oil radical-scavenging activity and to investigate the stability of the various homologues during the deep-fat frying of French fries. Eight different refined vegetable oils were investigated, having variable levels of natural tocopherols and tocotrienols. A direct correlation between the radical-scavenging capacity of the oils, measured by the DPPH test, and the total content of natural tocopherols and tocotrienols was found. Frying experiments showed that the stability of the different tocopherols and tocotrienols present in the refined vegetable oils basically depend on two factors: the fatty acid composition of the oil, in particular polyunsaturated fatty acid content, and the kind of tocopherol and tocotrienol homologues present. The more oxidizable the oil, on the basis of fatty acid composition, the more stable were the tocopherolic antioxidants. Among the different homologues, γ-tocotrienol in palm super olein proved to be the least stable during the deep-fat frying, thus preserving the other homologues.     

Composition and antioxidative activities of supercritical CO2-extracted oils from seeds and soft parts of northern berries

The present study investigated the composition and the antioxidative activities of oils from the seeds and the soft parts of a range of northern berries extracted by supercritical CO₂. The seed oils of the species of Rubus, Vaccinium, Empetrum, Fragaria and Hippophaë were rich in linoleic (18:2n-6, 34-55% of total fatty acids) and ??-linolenic (18:3n-3, 29-45% of total) acids with n-6:n-3 ratios of 1:1-1:2. The seed oils of the species Ribes contained, in addition to linoleic and ??-linolenic acids, ??-linolenic (18:3n-6) and stearidonic (18:3n-4) acids. In seed oils from European rowanberry (Sorbus aucuparia L.) and snowball berry (Viburnum opulus L.), linoleic and oleic (18:1n-9) acids together exceeded 90% of the total fatty acids. The sea buckthorn (SB) pulp oil had palmitoleic (16:1n-7), palmitic (16:0) and oleic acids as the major fatty acids. The SB pulp oil and snowball berry seed oil were rich in ??-tocopherol (120 and 110 mg/100 g oil, respectively), whereas raspberry seed oil contained a high level of ??-tocopherol (320 mg/100 g oil). Seed oils of cranberry (180 mg/100 g oil), Arctic cranberry (190 mg/100 g oil) and lingonberry (120 mg/100 g oil) are rich sources of ??-tocotrienol. The berry seed oils and the SB pulp oil showed varying peroxyl radical scavenging efficacies (300-2300 ??mol ??-tocopherol equivalent per 100 g oil) and inhibitory effects on perioxidation of microsomal lipids (250-1200 ??mol trolox equivalent per 100 g oil) in vitro. The peroxyl radical scavenging activity positively correlated with the total content of tocopherols and tocotrienols of the oils (r = 0.875, P = 0.001). The SB seed oil and pulp oil were active in scavenging superoxide anions produced by xanthine-xanthine oxidase system and inhibited Cu²⁺-induced LDL oxidation in vitro. The SB oils also protected purified DNA and rat liver homogenate from UV-induced DNA oxidation in vitro. The current research suggests potential of supercritical CO₂-extracted oils from northern berries as nutraceuticals and ingredients of functional foods.     

Effect of cooking and drying on the thermal conductivity of rice

The transient line source technique was used to determine the thermal conductivity of rice during cooking and drying of cooked rice. A temperature range of 50‐70°C, moisture content of 10‐70% (wet basis), bulk (packing) density range of 500‐850 kg/m³ and porosity range of 0.265‐0.7 were studied. Thermal conductivity increased with increasing temperature, moisture content and bulk density, and the values were in the range 0.082‐0.543 W/m °C. This value is comparable with the literature values for granular and gelatinized starch. The data on the effect of phase change due to gelatinization have also been included. The experimental values were statistically analyzed and empirical polynomial equations were developed in terms of temperature, bulk density, porosity and moisture content of rice during cooking and drying the cooked material.     

Lipids and phytosterol oxidation products in commercial potato crisps commonly consumed in Sweden

The stability of frying oils and fried foods is mainly affected by the fatty acids present and by the types and levels of minor components such as phytosterols and tocopherols. This study assessed the current status of lipid composition and the occurrence of oxidised phytosterols as a parameter of lipid oxidation in potato crisps available in the Swedish market. Fatty acid composition and concentrations of tocopherols, sterols and phytosterol oxidation products (POPs) were determined in 16 commercial potato crisp samples of two types, distinguished by a high or low fat content. The fatty acid composition in most samples was dominated by saturated and monounsaturated fatty acids. The sum of α-tocopherol and γ-tocopherol content varied from undetectable levels to 10.2 mg/100 g potato crisps, with α-tocopherol dominating. Among the tocotrienols, α-tocotrienol and γ-tocotrienol were present in almost equal proportions, while δ-tocotrienol was present in all samples but in smaller amounts. Fatty acid composition, tocopherol and tocotrienol content, showed that all potato crisp samples were prepared in palm oil or a blend of palm oil and unspecified fats and oils. Total sterol content ranged from 10.2 to 93.1 mg/100 g sample, with β-sitosterol being the major sterol in all samples. The content of POPs ranged from 0.05 to 0.68 mg/100 g potato crisps. In general, there were no significant differences in content of POPs between high and low fat samples, and generally no correlations could be established between content of POPs and fatty acid, tocopherol, tocotrienol, and sterol content among the potato crisp samples.     

LED lighting and seasonality effects antioxidant properties of baby leaf lettuce

We report on the application of supplementary light-emitting diode (LED) lighting within a greenhouse for cultivation of red, green and light green leaf baby lettuces (Lactuca sativa L.) grown under natural illumination and high-pressure sodium (HPS) lamps (16-h; PPFD-170 μmol m⁻² s⁻¹) during different growing season. Supplementary lighting from blue 455/470 nm and green 505/530 nm LEDs was applied (16-h; PPFD-30 μmol m⁻² s⁻¹). Our results showed that to achieve solely a positive effect is complicated, because metabolism of antioxidant properties in lettuce depended on multicomponent exposure of variety, light quality or seasonality. The general trend of a greater positive effect of supplemental LED components on the vitamin C and tocopherol contents was in order: 535 > 505 > 455 > 470 nm; on the total phenol content: 505 > 535 = 470 > 455 nm; on the DPPH free-radical scavenging capacity: 535 = 470 > 505 > 455 nm; on the total anthocyanins: 505 > 455 > 470 > 535 nm. Further investigations are needed for understanding the mechanism and interaction between antioxidants and light signal transduction pathways.     

天然维生素E乙酸酯的制备

VE的乙酸酯有比VE更强的化学稳定性及更多药用价值。本文介绍了用天然VE酯化制备VE乙酸酯的试验结果。优化后得到优化的工艺条件为(原料50克)：乙酸酐用量为9．0ml、反应时间为5．5小时、催化剂(三乙胺)用量为5．0ml、反应温度为60℃。VE酯化率为94.93％。     

Mediterranean non-cultivated vegetables as dietary sources of compounds with antioxidant and biological activity

Non-cultivated vegetables whose basal leaves have been traditionally consumed in Spain were evaluated for their potential in human nutrition, considering vitamin C, organic acids, tocopherols, phenolics and flavonoids, and antioxidant activity. As far as we know, this is the first report on organic acids and vitamin C of Anchusa azurea and Apium nodiflorum, on tocopherols of Aazurea, Beta vulgaris, Chondrilla juncea, Rumex papillaris, Rumex pulcher, Silybum marianum and Taraxacum obovatum, as well as on the antioxidant capacity of most of them. Data revealed that the mentioned non-cultivated vegetables are good sources of bioactive compounds. R. pulcher, R. papillaris and Papaver rhoeas are rich in vitamin C, Sonchus oleraceus and R. papillaris in tocopherols. R. pulcher, P. rhoeas and A. azurea showed promising antioxidant properties, which are related to their high levels of phenolic and flavonoids. Some species presented high levels of oxalic acid. Therefore, people with a trend of developing kidney calculus should avoid eating these greens (especially S. marianum, S. oleraceus and Beta maritima) and choose species with low oxalic acid content such as T. obovatum and Cichorium intybus. The traditional consumption of these species after boiling and rejecting the water may decrease the amount of oxalic acid.     

高效液相色谱法测定食品中维生素E的研究进展

该文综述了维生素E的发现、研究发展、医疗保健功效以及各种食品中维生素E的高压液相色谱分析方法等。     

脂溶性维生素对多种慢性疾病治疗作用的研究进展

综述脂溶性维生素抗炎、抗氧化等生物活性对糖尿病、骨质疏松、慢性肾脏病等慢性疾病治疗作用的研究进展。