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Modern methods to determine vitamin E in foods and feeds
53-58Views:84Highly specific and sensitive, the proposed fluorometric method for determining α-tocopherol is robust and fairly fast. It
has been tested in parallel with a conventional thin layer chromatographic method on foods and feeds. The only necessary
cleanup is the usual saponification. The unsaponificable fraction can be extracted with ethyl ether or, preferably, with
Extrelut columns. Reagents and their solvents are added to the isooctane solution before each successive reaction and are
then eliminated by partition with water. The α-tocopherol (α-T) derivative always remains in isooctane. The first step is
nitrosation and elimination of tocopherols and tocotrienols other than α-isomers. α-T is then oxidized to α-tocored (α-TR)
with a mixture of sulfuric acid, ferric chloride, and iodine bromide. Α-TR is then condensed to a new reagent: 4,5-dimethylo-
phenylenediamine. The phenazine formed is strongly fluorescent. Iodine and bromine add to the double bonds of α-
tocotrienol present and quench the fluorescence of its phenazine. -
Sour cherry seed as an industrial gamma tocopherol source
27-33Views:152In our experiments sour cherry kernels were investigated. The kernels of different sour cherry cultivars were originated from Újfehértói Gyümölcstermesztési Kutató és Szaktanácsadó Nonprofit Közhasznú Kft. Tocopherol profile, oil yields and nutritional value were stood in focus of examinations.
We started processes preparing of sour cherry kernels. After the preparation recovered non-polar fraction was investigated. We worked with formerly developed chromathographic system, which is capable to separate different tocopherol isomers efficiently. We measured concentration of each tocopherol isomers and registered those and their relation in different oil samples.
According to received data, alpha-, gamma- and delta-tocopherol appeared in samples, but beta-tocopherol could not be detected. It became clear that level of gamma-tocopherol is far higher than alfa- or gamma-isomer, it is concentration exceeded 1–1.5 mg ml-1.