Separating Tocotrienols from Palm Oil by Molecular Distillation

Crude palm oil contains approximately 1% minor components, including carotenoids and vitamin E (tocopherols and tocotrienols), which contribute to the stability and nutritional properties of palm oil. Palm oil is considered one of the best sources of vitamin E. The vitamin E content in palm oil is unique because it is composed of tocotrienols rather than tocopherols. Palm fatty acid distillate (PFAD) is the volatile organic material recovered as a valuable by-product in the deodorization of palm oil. Several processes have been proposed for recovering tocopherols and tocotrienols from PFAD. For this separation process, it is necessary to develop a processing procedure to extract the valuable tocotrienols and other minor components from PFAD using molecular distillation. Molecular distillation occurs at low temperatures and reduces the problem of thermal decomposition. High vacuum also eliminates oxidation that might occur in the presence of air. The rate of evaporation is controlled by the rate at which the molecules escape from the free surface of the liquid and condense on the condenser. The effects of feed-flow rate and temperature of distillation on extraction of minor components from PFAD are based on concentrations, distribution coefficients, and relative volatilities. The separation of tocotrienols from PFAD approached maximum values at low temperatures and fell drastically as temperature increased. For the optimum conditions for the extraction of tocotrienols with high yield and purity, it is necessary to determine the effect of processing variables on the extraction of minor components (i.e., tocotrienols, α-tocopherol) from the PFAD in terms of concentrations in the liquid and vapor phases, to reveal the behavior of target components in the evaporation process, and to determine the evaporation and volatility properties of tocotrienols and other minor components from PFAD.     

Vitamin E in foodstuff: Nutritional,analytical, and food technology aspects

Vitamin E is a group of isoprenoid chromanols with different biological activities. It comprises eight oil-soluble compounds: four tocopherols, namely, α-, β-, γ-, and δ-tocopherols; and four tocotrienols, namely, α-, β-, γ, and δ-tocotrienols. Vitamin E isomers are well-known for their antioxidant activity, gene-regulation effects, and anti-inflammatory and nephroprotective properties. Considering that vitamin E is exclusively synthesized by photosynthetic organisms, animals can only acquire it through their diet. Plant-based food is the primary source of vitamin E; hence, oils, nuts, fruits, and vegetables with high contents of vitamin E are mostly consumed after processing, including industrial processes and home-cooking, which involve vitamin E profile and content alteration during their preparation. Accordingly, it is essential to identify the vitamin E content and profile in foodstuff to match daily intake requirements. This review summarizes recent advances in vitamin E chemistry, metabolism and metabolites, current knowledge on their contents and profiles in raw and processed plant foods, and finally, their modern developments in analytical methods.     

Chemistry and biology of vitamin E

Our understanding of the role of vitamin E in human nutrition, health, and disease has broadened and changed over the past two decades. Viewed initially as nature's most potent lipid-soluble antioxidant (and discovered for its crucial role in mammalian reproduction) we have now come to realize that vitamin E action has many more facets, depending on the physiological context. Although mainly acting as an antioxidant, vitamin E can also be a pro-oxidant; it can even have nonantioxidant functions: as a signaling molecule, as a regulator of gene expression, and, possibly, in the prevention of cancer and atherosclerosis. Since the term vitamin E encompasses a group of eight structurally related tocopherols and tocotrienols, individual isomers have different propensities with respect to these novel, nontraditional roles. The particular beneficial effects of the individual isomers have to be considered when dissecting the physiological impact of dietary vitamin E or supplements (mainly containing only the alpha-tocopherol isomer) in clinical trials. These considerations are also relevant for the design of transgenic crop plants with the goal of enhancing vitamin E content because an engineered biosynthetic pathway may be biased toward formation of one isomer. In contrast to the tremendous recent advances in knowledge of vitamin E chemistry and biology, there is little hard evidence from clinical and epidemiologic studies on the beneficial effects of supplementation with vitamin E beyond the essential requirement.     

Current technologies in the extraction,enrichment and analytical detection of tocopherols and tocotrienols: A review

During the past few years the scientific and medical community has been confronted with a continual interest in vitamin E with the interest prompted by new discoveries. Tocopherols and tocotrienols, commonly known as vitamin E, are extremely invaluable compounds and have various nutritional functionalities and benefits to human health. Great deals of research projects have been launched in order to develop effective methods for the extraction of vitamin E. By and large, three distinct extractive methods are usually employed: supercritical fluid extraction (SFE), molecular distillation, and adsorption methods. These methods are sensitive to different experimental conditions, such as pressure, temperature, and flow rate with noticeable effects on the efficiency of the extraction and enrichment of vitamin E. This review has covered the most commonly adapted extraction methods and has probed into the extraction yields under variable operational parameters.     

Determination of vitamin e in foods — a review

The vitamin E group includes tocopherols and tocotrienols and their isomers, esters, and derivatives. They differ not only in biopotencies as antisterility agents but also in activities in other physiological and chemical relationships. Unlike vitamins A and D, foods (vegetable oils) are among the richest sources of vitamin E, and assay methods for vitamin E include food applications more often than for the former vitamins. Phys‐icochemical methods are replacing bioassays for vitamin E and tocopherol wherever possible because of greater specificity and less variability, time, and, sometimes, expense. Unless careful purifications and isolations are carried out and some of the relative vitamin E activities of components are calculated, bioassays are still required for total vitamin E activity. The vitamin E group is separated by column, paper, thin‐layer, gas‐liquid, and high‐pressure liquid chromatography (HPLC): Gas‐liquid chromatography has been more successfully used for vitamin E than for other fat‐soluble vitamins. Recently developed HPLC methods for vitamin E are sensitive and apparently require less cleanup of extracts and less time than former methods; HPLC may prove to be the most useful technique for vitamin E in foods, especially if other fat‐soluble vitamins can be determined simultaneously on the same sample extract.     

Vitamin E and its anticancer effects

Abstract

Vitamin E is a lipid soluble vitamin comprising of eight natural isoforms, namely, α, β, δ, γ isoforms of tocopherol and α, β, δ, γ isoforms of tocotrienol. Many studies have been performed to elucidate its role in cancer. Until last decade, major focus was on alpha tocopherol and its anticancer effects. However, major clinical trials using alpha-tocopherol like SELECT trial and ATBC trial did not yield meaningful results. Hence there was a shift of focus to gamma-tocopherol, delta-tocopherol and tocotrienol. Unlike alpha-tocopherol, gamma-tocopherol and delta-tocopherol can scavenge reactive nitrogen species in addition to reactive oxygen species. Antiangiogenic effect, inhibition of HMG CoA reductase enzyme and inhibition of NF-κB pathway make the anti-cancer effects of tocotrienols unique compared to other vitamin E isoforms. Preclinical research on non-alpha tocopherol isoforms of vitamin E showed promising data on their anticancer effects. In this review, we deal with the current understanding on the potential mechanisms involved in the anticancer effects of vitamin E and the controversies in this field over last three decades. We also highlight the need to conduct further research on the anticancer effects of non-alpha-tocopherol isoforms in larger population and clinical setting.     

Is organically produced wheat a source of tocopherols and tocotrienols for health food?

Forty organically grown spring and winter wheat genotypes were investigated for content and compositions of tocopherol and tocotrienol. The selected genotypes belonged to five different genotypic groups, i.e. landraces, old cultivars, modern cultivars, spelt wheat, and primitive wheat. The total tocochromanols content (21.9–37.3 mg/kg) wheat were in similar ranges as previously reported for conventionally grown wheat. The vitamin E activity varied among the genotypic groups and corresponded to 12–25% of the recommended daily intake. Primitive wheat was found to contain the highest percentage of tocotrienols (74%). Content of tocochromanols and vitamin E activity are known to decrease by heating. Organic wheat is more commonly consumed as whole and sprouted grain when compared to conventional wheat and might therefore be a good source of tocochromanols in health food. The large variation in tocopherols and tocotrienols in the investigated wheat genotypes indicated a great potential for the development of specific wheat genotypes with health promoting properties in future breeding programmes.     

Tocopherols in rose hips (Rosa spp.) during ripening

BACKGROUND: Rose hips are used as a food ingredient and in health products. They are rich in various bioactive compounds such as carotenoids and vitamin C, but data on their vitamin E content (tocopherols and tocotrienols) are limited. In this study, four different species ofRosa were analysed for tocopherol and tocotrienol content during ripening in three different years. RESULTS: Only α‐ and γ‐tocopherol were found in the fleshy parts of the rose hips, and the tocopherol content and vitamin E activity varied depending on date of harvesting, species and year. The amount of vitamin E activity differed between species of Rosa and years, whereas the changes during ripening were relatively small. CONCLUSION: The choice of species must be considered if tocopherol content is to be optimised when rose hips are used as a food ingredient. Copyright © 2012 Society of Chemical Industry     

Breadmaking and Storage of Various Wheat Fractions Affect Vitamin E

The vitamin E loss during baking of two types of industrially baked breads was studied. Neither scalding nor fermentation reduced the vitamin E content. However, the sour dough preparation and dough-making resulted in 20-60% reduction in the content of tocopherols and tocotrienols. In addition the vitamin E yield in the doughs and the French bread when using two different extraction methods were compared. The two methods showed similar results for flours and doughs, but indicated differences after the baking stage. Storage stability of wholemeal flour, white flour, bran and germ of wheat were also investigated. Storage at 20°C for 12 mo decreased vitamin E activity of the various wheat fractions by 28-40%.     

米糠油及其脱臭馏出物中生育酚和生育三烯酚的分析检测

对米糠油及其脱臭馏出物中生育酚及生育三烯酚含量进行检测分析,结果表明,米糠来源和米糠油精炼工艺对米糠油及其脱臭馏出物中α、β、γ、δ-生育酚和生育三烯酚的含量有显著影响。米糠毛油中生育三烯酚占维生素E总量的60%～70%,脱臭馏出物中生育三烯酚占维生素E总量的25%～40%,米糠油脱臭馏出物维生素E总量中生育三烯酚的含量较米糠毛油有较大的损失。通过对米糠油脱臭馏出物不皂化物的分析检测可知,米糠油脱臭馏出物中主要甾醇的种类为豆甾醇、菜油甾醇、谷甾醇,总甾醇含量很少,仅为0.32%;除此之外,还有少量日耳曼甾醇、羊毛甾醇、3,5-二烯豆甾烷等。     

硅胶和硝酸银硅胶柱层析分离生育酚与生育三烯酚

本文以乙醚正己烷混合溶液为淋洗液，探讨了硅胶柱层析和硝酸银硅胶柱层析分离生育三烯酚和生育酚的效果。结果表明：通过改变淋洗液中乙醚含量可以将生育酚和生育三烯酚大部分分离；硝酸银硅胶柱层析分离生育三烯酚和生育酚的效果明显高于硅胶柱层析，其洗脱液中生育三烯酚可占VE总量的90％以上，最高达98．47％。     

Tocopherols and tocotrienols in plants and their products: A review on methods of extraction,chromatographic separation,and detection

Vitamin E consists of four tocopherols (α-, β-, γ-, and δ-tocopherol) and four tocotrienols (α-, β-, γ-, and δ-tocotrienols), collectively referred to as tocochromanols or tocols. Tocols are well-known for potent antioxidant, anticancer, anti-inflammatory, immuno-stimulatory and nephroprotective properties. For human nutrition, diet is the major source of tocols (vitamin E) in the body. Thus, there is a need to analyze the different forms of tocols in the diet for the recommendations and to monitor the intake in the body accurately. Several methods have been developed for effective extraction, selective chromatographic separation and sensitive detection of tocols in food. Major advancements also have been made in the field of mass spectrometry for high throughput analysis of primary and secondary metabolites in fruits, vegetables, and grains. This review discusses the theoretical aspects and modern developments in methods of extraction, chromatographic separation, and detection of tocols in plants and their products. Additionally, future research challenges in this perspective are also identified.     

The effects of colorifico on lipid oxidation,colour and vitamin E in raw and grilled chicken patties during frozen storage

Colorifico is a spice consisting essentially of a mixture of annatto (Bixa orellana) and corn flour. The effects of colorifico addition (0.4 g/100 g) to chicken meat on the development of lipid oxidation, colour stability, and degradation of bixin and vitamin E was investigated in raw and grilled patties during storage at −18 °C for 120 days. Colorifico was able to provide a more stable and intense red and yellow colour in both raw and grilled chicken patties when compared to the meat without spice. Lipid oxidation was delayed by colorifico in the grilled patties until 30 days of storage; however, no effect was observed in the raw patties. Vitamin E content was significantly higher in raw meat with colorifico and heat treatment resulted in relatively less loss when compared to the meat without spice; however, during storage both presented the same degradation pattern. Bixin content was stable during storage but not after grilling. The observed antioxidant mechanism suggests that vitamin E, probably the tocotrienols, is acting along with bixin to protect the unsaturated lipids from oxidation.     

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, especiallyγ-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 α-tocopherol varies over a broad range (41–620 mg/kg dry pumpkin seeds).β- andδ-tocopherol are found at low levels.     

Effects of Tocols and β-Glucan on Serum Lipid Parameters in Chickens*

Cereal grain diets affect serum lipids by their soluble fibre and tocotrienols. Chickens were fed diets containing an oat bran fraction or waxy hulless barley that were enriched or depleted in β-glucan and/or tocotrienols. Serum cholesterol and triacylglycerides and enzymes of cholesterol metabolism were measured. Weight gains appeared to be lower in birds on oat bran fraction-containing diets and higher in those on barley-containing diets supplemented with β-glucanase. All diets containing oat bran fraction or barley lowered serum total cholesterol and low-density-lipoprotein (LDL) cholesterol relative to the corn control diet. LDL cholesterol was reduced more by oat bran fraction supplemented with tocotrienols than by either oat bran fraction or tocotrienols alone. LDL cholesterol levels were the same for all barley-based diets. Activities of β-hydroxy-β-methylglutaryl coenzyme A (HMG CoA) reductase and cholesterol 7α-hydroxylase were inversely affected by the diets. Oat bran fraction plus tocotrienols, barley and solvent-extracted barley decreased HMG CoA reductase by 50% and increased cholesterol 7α-hydroxylase by 100%; other diets caused lesser effects. It was concluded that both β-glucan and tocotrienols affected cholesterol levels and metabolism, and the effects were additive or less. Removal of β-glucan from barley diets abolished or diminished effects on enzyme activities but did not alter effects on cholesterol levels, indicating the possibility of another component in barley that affected cholesterol levels. © 1997 SCI.     

Comparisons of protein, lipid, phenolics, γ-oryzanol, vitamin E, and mineral contents in bran layer of sodium azide-induced red rice mutants

BACKGROUND: The bran part of red rice grain is concentrated with many phytochemicals, including proanthocyanidins, oryzanol and vitamin E, that exert beneficial effects on human health, but it contains low levels of essential minerals such as Fe and Zn. In the present study, the protein, lipid, phytochemicals and mineral contents in bran samples were compared among red rice SA‐586 and its NaN₃‐induced mutants. RESULTS: The plant heights of NaN₃‐induced mutants were decreased. The contents of protein, lipid, total phenolics, total flavonoids, total anthocyanins, total proanthocyanidins, total γ‐oryzanol, total tocopherols and total tocotrienols also varied among the tested mutants. The brans of mutants M‐18, M‐56 and M‐50 contained more proanthocyanidins, γ‐oryzanol, vitamin E than that of SA‐586, respectively. M‐54 accumulated more Fe content (588.7 mg kg^?1 bran dry weight) than SA‐586 (100.1 mg kg^?1 bran dry weight). CONCLUSIONS: The brans of M‐18, M‐50 and M‐56 are good sources of proanthocyanidins, vitamin E and γ‐oryzanol, respectively, while the bran of M‐54 is rich in Fe. Thus these mutants could be used to produce high‐value phytochemicals or Fe byproducts from bran during rice grain milling or as genetic resources for rice improvement programs. Copyright © 2011 Society of Chemical Industry     

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.     

Changes in the content and composition of vitamin E in damp barley stored in airtight bins

The effect of airtight storage on the content and composition of vitamin E was studied in damp barley at 20 and 28% moisture. Airtight storage with an external supply of carbon dioxide was compared with conventional airtight storage with or without an expansion sack. In two additional models, the grain was also treated with 1% ammonia (NH3). The tocopherols and tocotrienols in the grain were analysed using high pressure liquid chromatography with fluorescence detection. The changes in vitamin E during airtight storage were determined by the moisture content of the barley. In barley at 20% moisture, the vitamin E content increased until mid-April and after 10 months the final levels were similar to those at harvest (55–65 mg kg^?1) except in the bin treated wih ammonia. In barley at 28% moisture, vitamin E breakdown processes prevailed from the beginning of airtight storage and led to an unsatisfactory level of this vitamin in the grain. In barley, α-tocotrienol was clearly the dominating isomer. The relative distribution of the isomers in barley at 20% moisture was stable during the airtight storage. For 28% moisture barley in most of the experimental models, the fraction of tocopherol isomers increased at the cost of the tocotrienols. It was concluded that the higher moisture content and a lower pH apparently favoured saturation of the side chains of the trienols. Treatment of barley with 1% ammonia gas resulted in a general decrease in the total vitamin E content and a simultaneous increase in the relative fraction of α-tocotrienol. Therefore, α-tocotrienol appeared to be more resistant to ammonia treatment than are the other isomers. For barley at 20% moisture content, the type of silo arrangement had hardly any effect on the vitamin E concentration or on the proportions of the isomers. For the barley at 28% moisture content, an external supply of CO₂ appeared to have a preservative effect on vitamin E content.     

Development of vitamin E-enriched functional foods: stability of tocotrienols in food systems

Tocotrienols are members of the vitamin E family that provide many nutritional benefits. Developing tocotrienol-fortified functional foods introduces vitamin E into consumers diets without changing their food habits. The purpose of this study was to compare the stability of tocotrienols in bulk form and six food matrices at a fixed dose (40 mg kg⁻¹) under accelerated and conventional storage conditions. The delta- and gamma-tocotrienol content was measured using HPLC, and the sensory attributes were evaluated using triangle and hedonic tests. Tocotrienol in bulk powder was less stable under stressed conditions than in bulk oil, with the powders having approximately 40% and 80% reduction in δ- and γ- after storage and bulk oil with no significant degradation. HPLC analysis demonstrated that tocotrienol content remained unchanged in dry mix lemonade, yogurt, raw and UHT milk, and margarine over time; however, complete degradation of γ- and partial degradation (up to 50%) of δ-tocotrienol was observed in bread during ambient and stressed storage conditions. A significant decrease in the δ-tocotrienol relative concentration was also observed in HTST processed milk samples. Tocotrienol addition was not perceived, and no significant difference in the product attributes and overall liking was reported in the discrimination sensory testing.     

Effects of feeding various tocotrienol sources on plasma lipids and aortic atherosclerotic lesions in cholesterol-fed rabbits

Tocotrienols exert hypocholesterolaemic and antioxidant effects, and may hence have anti-atherogenic properties. Therefore, the aim of this study was to investigate the cholesterol-lowering and anti-atherogenic effects of tocotrienols in cholesterol-fed rabbits. Rabbits were fed a basal diet (control) supplemented with γ-tocotrienol, γ-tocotrienyl acetate, mixed tocotrienols or α-tocotrienol for 12 weeks. All treatments resulted in significant increases in plasma tocotrienols. None of the treatments, however, had significant effects on serum lipids or size of atherosclerotic lesions. A trend towards a decrease in plasma cholesterol was observed following γ-tocotrienol treatment (−22%) after 6 weeks. The decrease was mainly attributable to a reduction in LDL cholesterol (23%), whereas HDL cholesterol increased (14%). This trend was mirrored in a non-significant reduction in lesion area (20%). Our results demonstrate that tocotrienols are absorbed, but have little effect on plasma lipids and atherosclerosis in cholesterol-fed rabbits.