Bestimmung von Tocopherolen in Ölen und Fetten: Einfluß des Tocopherol-Gehaltes von Erdnuß- und Sojaöl auf den Oxydationsverlauf dieser Öle beim Erhitzen I

Determination of Tocopherols in Oils and Fats: Influence of the Tocopherol Content of Ground-nut and Soybean Oils on the Course of Oxidation of these Oils on Heating I A sensitive method for the quantitative determination of α, γ and δ tocopherols in edible oils and fats was worked out. The tocopherols are isolated from unsaponifiable matter by thinlayer chromatography and ultimately each of them was determined photometrically from the red colour formed with iron chloride and bathophenanthroline. The effect of reduction in tocopherol content, resulting from the heating of oils, on the course of the oxidation of oil was followed, among others, with the help of 4-hexylresorcin. The blue dyestuff formed by this reaction was synthesized and identified as trimethin dye.     

Tocopherole — Antioxidative Wirkung bei Fetten und Ölen

Tocopherols — Antioxidative Effect on Oils and Fats The main reason for the deterioration of fats and oils is a chemical reaction between the oxygen and the double bonds which are contained in the unsaturated fatty acids. In the course of the autoxidation intermediate peroxides affect the vitamines sensitive to oxidation. They lower the content of physiologically valuable essential fatty acids. The oxidation stability of oils and fats depends on the natural content of tocopherols as well as on the composition of the fatty acid. The effect of the added tocopherols depends on the natural content of tocopherols. Lipids with lower contents can be stabilized very well with antioxidants consisting of tocopherols. Here animal fats as well as synthetical lipids are considered which in particular are used in cosmetic industry and in the field of pharmacy but also in food industry. Vegetable oils contain, due to their nature, high contents of tocopherols which are partly removed or oxidised during raffination and storage. Therefore adding antioxidants containing tocopherols is adviseable. Also an addition of reducing substances as for instance ascorbylpalmitate is recommended. Moreover antioxidant systems should consist of heavy metal chelating substances.     

Dünnschicht- und Gaschromatographie von Tocopherolen

Thin-Layer end Gas Chromatography of Tocopherols Oilseeds, to which an internal standard of tocopherol was given, were extracted for tocopherols with ethanol under conditions inhibiting oxidation using an Ultra-Turrax homogenizer. After filtration the ethanolic extract is briefly saponified and the unsaponifiable matter containing the tocopherols extracted into n-hexane. Then the hexane-fraction is washed alkalifree with water, dried over Na₂SO₄, concentrated and applied on a silicagel GF₂₅₄-plate, which is developed with dichloromethane. With co-chromatographed reference-tocopherols on the margins of the TLC-plate the presence of tocopherolquinones can be checked in UV-light, whereas the bands of tocopherols and tocotrienols are located by spraying the margins with Emmerie and Engel-reagent. The corresponding zones were scrapped off the plate, the silicagel extracted with 15 × 1 ml ethanol, the ethanol evaporated to dryness and the residue derivatised to trimethylsilylethers. Gaschromatography on 3 m SE-52/XE-60 or 1.5 m SE-30 columns gave a good separation of tocopherols and tocotrienols. Simultaneous qualitative and quantitative determination of tocopherols by GLC combined with the possibility of automation makes this analytical procedure superior to TLC and colorimetry of tocopherols. About 500 tests with different oilseeds in the range between 50-800 mg lipid and 20-2000 μg of total tocopherol/sample gave a recovery of 60% at a coefficient of variation of approximately 6%.     

Schnellmethode zur quantitativen Bestimmung individueller Tocopherole in Ölen und Fetten

A Rapid Method for the Quantitative Determination of Individual Tocopherols in Oils and Fats Oils and fats were two times frozen from acetone solution at ?80°C under protection by ascorbyl palmitate. Tocopherols (T) and tocotrienols (T₃) present in the filtered extract are separated into their homologues by one-dimensional TLC on pre-coated silica gel plates, the extract having been streaked and developed three times in the n-hexane/ethyl acetate system 92.5:7.5. Complete separation of the positional isomers β-T and γ-T is accomplished as well whereas β-T₃ and γ-T are assumed to form identical bands. Suitable spray- and detection systems including new found coloring ones are described for the qualitative estimation of the chromatograms. Values are given for the content of individual tocopherols T/T₃ of 24 commercial plant oils (bands measured by Emmerie-Engel procedure).     

Anwendung des Tocopherolmusters zur Erkennung von Fett- und Ölvermischungen

Utilization of the Tocopherol pattern for Recognition of Fat and Oil Adulterations The determination of the tocopherols is one of the possibilities for purity control because many oils and fats have a characteristic natural tocopherol-content with a typical tocopherolpattern. It is shown, that there are some problems in the determination by HPLC (preparing of the samples, identification). A classification of the oils and fats is given, which demonstrates not only the possibilities but also the limits for purity control.     

Physiologische Bedeutung unverseifbarer Komponenten von Nahrungsfetten

Physiological Importance of Unsaponifiable Components in Dietary Fats For evaluation of the physiological relevance of dietary fats both their fatty acid pattern and unsaponifiable components should be considered. According to fat source these components include sterols (phytosterols, cholesterol), lipopigments, fat soluble vitamins, antioxidants and different sensoric substances. In lipid metabolism the non polar fraction, mainly tocopherols and phytosterols, decrease the ratio of total-/HDL-cholesterol. In rat experiments the erythrocyte membrane-stabilizing effect of α- and γ-tocopherol was not found for β-sitosterol and ubiquinones. Tocopherols stabilize also hepatocytes by protecting the membrane fatty acids against oxidation disableing cells to maintain their physiological structure as well as function. Similar effect is to be considered also for ubiquinones. Main function of the unsaponifiable substances is their antioxidant capacity resulting from redox potentials of several components. α-and γ-tocopherol, when added in equimolar amounts, inhibit the in vitro lipid peroxidation. In this time and temperature dependent function γ-tocopherol reveals a higher potency than α-tocopherol. On the other hand, in vivo lipid peroxidation (rat liver mitochondria and testes) is less when β-tocopherol was administered compared to γ-tocopherol. Highest potency was found for mixtures with both tocopherols in combination with ubiquinones and β-sitosterol. Unsaponifiable components of dietary fats together with the fatty acid pattern are important for prevention and therapy of fat metabolism disorders. They also can regulate lipid peroxide formation in vitro and in vivo.     

Bioactive compounds in unsaponifiable fraction of oils from unconventional sources

The aim of the research was to characterize bioactive components of unsaponifiable fraction of selected unconventional oils. Nine oils were analyzed as far as the content of tocopherols, squalene, phenolic compounds, and sterols were concerned. Tocopherols and squalene were analyzed by HPLC coupled with diode array detector and fluorescent detector (HPLC‐DAD‐FLD). The content of sterols in oils was determined by GC coupled with MS (GC‐MS). The total amount of phenolic compounds in oils was determined by the colorimetric methods using Folin–Ciocalteau phenol reagent. The examined oils were characterized by differentiated amount of particular forms of tocopherols. The oil obtained from the seeds of amaranth was the richest source of squalene (over 52 mg/g oil). The presence of 22 different compounds of sterols were identified, whereas β‐sitosterol was found in the largest amount. Total amount of sterols in the oils ranged from 90 (walnut) to 850 mg/100 g (evening primrose). Significant differentiation of total amount of phenolic compounds was observed in the examined oils. Evening primrose oil showed the highest amount of phenolic compounds (679 mg/kg). The presented results prove that plant oils obtained from nonconventional sources are a potential source of bioactive compounds.     

Vergleich der Vitamin- und Antioxidans-Wirkung der verschiedenen Tocopherole bei den wichtigsten Pflanzenölen

Comparison of Vitamin Activity and Antioxidant Activity of Various Tocopherols from Important Vegetable Oils Unsaponifiables of most vegetable oils contain tocopherols in varying amounts and ratios. All these tocopherols do not have the same action. It is known that vitamin E activity is in the decreasing order for α-, β-, γ- and δ-tocopherols whereas antioxidant activity increases in the same order. Accordingly, an oil which is rich in vitamin E is not necessarily the most stable one. The tocopherols occuring most commonly are α- and γ-tocopherols. Influence of various refining steps on the tocopherol content is discussed briefly.     

Zum Nachweis von Sesamöl

Proof of Sesam Oil A high-performance liquid chromatographic (h.p.l.c.) method for the simultaneous determination of sesamol, sesamol, sesamin and tocochromanols is described. Oils, fats or the unsaponifiable components of food (sesamol not determinable) are dissolved in n-hexan. The separation is carried out on a column of Li Chrosorb Si 60 (5μm, 25 × 0.4 cm) with 1,4-dioxan-n-hexan (6 + 94) or ethyl acetat-n-hexan (10 + 90) as mobile phase (1 ml min^?1) and fluorimetric detection at 330 nm (exitation at 295 nm). Several sesam-seed oils and food containing sesam-seed were analysed. The data presented illustrate that apparently unspoilt and non-refined sesam oils contain characteristic amounts of sesamolin, sesamin and tocopherols, only traces of sesamol were found in these oils.     

Improved method for quantitating and obtaining the unsaponifiable matter of fats and oils

A quantitative method for saponifying and isolating the unsaponifiable matter (UM) from fats and oils is detailed. The method, which is a modification of a previously described procedure, is faster, uses about half the solvent, and is easier to execute. The minimum time needed to completely saponify a large number of fats and oils is established and conditions for removing contaminating soap from the extracted UM are described. Evidence presented shows some fats and oils to be incompletely saponified using previously indicated time-temperature conditions. The method compares favorably with the AOAC method, but is not applicable to the analysis of marine oils.     

Brüdenöl aus Soja- und Rapsöl als Tocopherolen-Quelle

Post Deodorization Condensates from Soya and Rape Oils as a Source of Tocopherols For refining of different kinds of plant oils the same industrial installations are used. The qualitative and quantitative composition of tocochromanols obtained from post deodorization condensates depends on the refined oil. The influence of the quantity of refined oils in the process on quantitative changes of tocopherols in the condensates was investigated. We found, that for the eventual obtaining of tocopherol concentrates from them, it is better to use soya post deodorization condensate. The maximum concentration of tocopherols in soya condensate was found after deodorization of approximately 26 tons of the oils at an installation yield of about 3.5 tons per hour.     

The Antioxidant Functions of Tocopherol and Tocotrienol Homologues in Oils,Fats, and Food Systems

This review paper is focused on the relative antioxidant activities of tocopherols and tocotrienols in oils and fats and certain food systems. α-Tocopherol generally showed better antioxidant activity than γ-tocopherol in fats and oils, but at higher concentrations γ-tocopherol was found to be a more active antioxidant. The results of studies on the optimum antioxidant concentrations of tocopherols in oils and fats indicated that the optimal level for α-tocopherol is usually lower than other tocopherols, meaning less α-tocopherol is needed for maximum antioxidant protection. There are comparatively very few studies related to the antioxidant activities of tocotrienols in oils and fats. It has been stated that generally γ-tocotrienol has higher antioxidant effect than α-tocotrienol, and tocotrienols may be better antioxidants than their corresponding tocopherols in certain oils and fats systems. Studies on the antioxidant activity of various tocopherols in food systems are varied and cannot be uniformly evaluated because experiments have generally focused on different foods and used various methods for the detection of antioxidant activities. Depending on the food system, in certain cases tocopherols were better antioxidants than synthetic antioxidants such as butylhydroxy toluene (BHT) or butylhydroxy anisole (BHA). However, in certain other food systems the synthetic antioxidants were more effective to increase the shelf life and the stability of foods than those containing tocopherols.     

Column Chromatographic Determination of Unsaponifiable Matter in Fats and Oils

A column chromatographic method for determination of unsaponifiable matter (UM) in fats and oils has been developed. The procedure involves saponification of the oil and elution or UM through a mixed bed consisting of an upper layer of calcium oxide and a lower layer of basic aluminium oxide, using diethyl ether as the eluting solvent and finally quantitation of UM by weight. The method eliminates tedious and time-consuming extraction steps and the consequent problems due to possible emulsion by hydrolysis, UM contents of fats and oils can be determined with very good to excellent accuracy. The relative standard deviation for 6.0 per cent to 0.5 per cent of UM in oils is in the range of 0.5–2.0. The method is simple, readily adaptable, fairly rapid and is equally applicable to soap samples.     

Determination of tocopherols and sterols by capillary gas chromatography

A method is described for simultaneously determining tocopherols and sterols in fats and oils by quantitative capillary gas chromatography. Samples containing ca. 100 mg of lipid were saponified in capped tubes with aqueous KOH by heating for 8 min at 80 C; the unsaponifiable fraction was extracted with cyclohexane, freed of solvent, derivatized to form the trimethylsilyl ethers of both tocopherols and sterols, and chromatographed on a 50 m×0.25 mm glass capillary column coated with Dexsil 400. Most of the individual tocopherols and common sterols were well separated, although interfering peaks were seen in some samples, which for better specificity should be subjected to an initial purification. For most samples, however, the simplified sample preparation, without preliminary purification, was adequate when combined with capillary gas chromatography. Recovery, method and gas liquid chromatographic precision, and applications are discussed.     

Rapid method for the quantitative determination of individual tocopherols in oils and fats

Oils and fats are frozen two times from acetone solution at -80 C under protection by ascorbyl palmitate. Tocopherols (T) and tocotrienols (T₃) present in the filtered extract are separated into their homologues by one-dimensional thin layer chromatography on precoated silica gel plates in the n-hexane/ethyl acetate system 92.5:7.5. Complete separation of the positional isomers β-T and γ-T is accomplished as well, whereas β-T₃ and γ-T are assumed to form identical bands. Suitable spray- and detection systems including new found coloring ones are described for the qualitative estimation of the chromatograms. The content of individual tocopherols (T and T₃) of 24 commercial vegetable oils is quantitatively determined using the Emmerie-Engel procedure.     

A Novel and Efficient Synthesis of Tocopheryl Quinones by Homogeneous and Heterogeneous Methyltrioxorhenium/Hydrogen Peroxide Catalytic Systems

A convenient and efficient application of heterogeneous poly(4‐vinylpyridine), poly(4‐vinylpyridine N‐oxide), and polystyrene/methylrhenium trioxide systems for the selective oxidation of tocopherols and tocopherol derivatives to the corresponding ortho‐ and para‐tocopherylquinones is described. Environment friendly, easily available, and low‐cost hydrogen peroxide (H₂O₂) was used as the oxygen atom donor. The antiviral activity of the newly synthesized tocopherylquinones and their parent tocopherols against influenza A virus is also reported. On the basis of the biological assay, the activity of tocopherols against influenza virus is higher than that showed by the corresponding tocopherylquinones, thus suggesting, for the first time, a drawback effect of the oxidative metabolism on the antiviral activity of these compounds.     

Analysis of tocopherols by gas-liquid and high-performance liquid chromatography: a comparative study

Selected normal-phase HPLC and GLC methods for the analysis of tocopherols in vegetable oils were evaluated critically. Repeatability, accuracy and/or recovery were determined for both methods and compared to data mentioned in the official methodology. The best accuracy and repeatability was obtained for the normal-phase HPLC technique based on the AOCS official method Ce 8-89, which can probably be explained by the short and easy sample preparation. Tocopherol levels of sixteen fully refined vegetable oils were determined by both, GLC and HPLC. Regression analysis showed that tocopherol levels obtained by GLC were about 6.1% higher than the corresponding HPLC data. Although the reported recovery of the GLC method was good, it seems that an additional TLC separation has to be introduced in the sample preparation to avoid peak overlap between tocopherols and some interfering substances present in the unsaponifiable fraction.     

Studies of unsaponifiables in several vegetable oils

The unsaponifiable fractions of soybean, cottonseed, coconut, olive, and avocado oils have been studied in detail. The oils differed in the contents of total unsaponifiables, squalene, tocopherols, and sterols and also in the composition of the tocopherol and sterol fractions. The presence of absence of individual unsaponifiable components may help in establishing the identity of each of the investigated oils and in detecting of admixture by another oil.     

Einfluß von Bestandteilen der Raffinationsfettsäuren für Geflügel auf die Mastleistung von Broilern

Influence of Acid Oil Components on Broiler Performance The German feedingstuffs regulations (FMV) only feature limited quality criteria for acid oils to be used in poultry, i.e. inorganic acids, impurities insoluble in petrol ether and unsaponifiable matter. Producers of these products and the trade have generally tended to include further quality criteria into their specifications, such as oxidation characteristics, the content of linoleic and linolenic acid and a guaranteed absence of castor oil, dark cotton seed oil and crude marine oils. To avoid the use of products which do not correspond to the definition of the FMV for acid oils and which might have dilaterious effects on poultry, more attention should be paid especially to the content of polymers arising e. g. from distillation residues and used fried fats. The influence of unsaponifiable matter and polymerized fatty acids in acid oils on the growth performance of broilers, as determined in trials with male birds and accompanying analytical investigations, is described. Footing on these results, proposals are made to extend the specifications for feeding oils to be used in poultry compounds.     

Occurrence of 3-oxo triterpenes in the unsaponifiable matter of some vegetable fats

Fourteen vegetable oils were examined and 3-oxo triterpenes are present in the unsaponifiable matter of shea (Butyrospermum parkii), illipe (Shorea stenoptera), mango kernel (Mangifera indica), kokum (Garcinia indica) and phulwara (Madhuca butyracea) fats but not in cocoa butter, dhupa fat (Vateria indica), soybean, peanut, mustard, corn, palm, coconut or mowrah (Madhuca latifolia) fats.Lipids.