Influence of added menadione (vitamin K3) on dissolution and dimerization of tocopherols and autoxidation of triacylglycerols during storage of plant oils

Abstract

The effect of added menadione (vit. K3) to stored rapeseed and soybean oil on the dissolution and dimerization of natural tocopherols and autoxidation of triacylglycerols was studied. Commercial rapeseed and soybean oils with added menadione and pure oil were stored at +20 degrees C in brown and transparent glass bottles. During storage their peroxide value, changes of the content of fatty acids and dissolution of tocopherols were measured. Destruction of individual tocopherols in tested oils with added menadione stored in both dark and transparent glass bottles were greater than in the oil samples without menadione. However, the degradation of individual tocopherols was different in each oil. Addition of menadione to the rapeseed and soybean oils resulted in the accelerated process of autoxidation of these oils. The oxidative state of the oils was lower in the oils stored in transparent bottles than in the oils stored in brown bottles. The prooxidant activity of menadione was additionally activated by light. Menadione added to the vegetable oils influenced the dissolution of natural tocopherols as well as their dimerization. It is conduced that addition of menadione to vegetable oils decreases their nutritive value.

Identification of α-Tocotrienolquinone Epoxides and Development of an Efficient Molecular Distillation Procedure for Quantitation of α-Tocotrienol Oxidation Products in Food Matrices by High-Performance Liquid Chromatography with Diode Array and Fluorescence Detection

“…The lower enrichment factors of the analytes in lard were due to the higher evaporator temperature, which led to a higher proportion of interfering volatile components in the distillate. The recovery rates of the tocochromanols found in our experiment are comparable to those determined in other studies involving molecular distillation or solvent extraction of tocochromanols. ,,, However, no information on the enrichment factors or the recovery rates of the tocopherol oxidation products is given for the conventional extraction procedures for tocopherol oxidation products such as solvent extraction, solid phase extraction, or saponification. ,,,, Some authors assumed recovery rates similar to those determined for T. , Applying trypsin incubation and solvent extraction, Faustman et al . determined recovery rates of internal deuterated standards of α-T, α-TQ, α-TQ-4a,5-E, and α-TQ-7,8-E to be 95–111%.…”

“…However, data from the literature are contradictory for the formation of tocochromanol dimers and trimers in oxidized lipid matrices. Some previous studies do indicate the formation of tocochromanol dimers and trimers in lipid matrices, ,, but these results are not in agreement with those of Yamauchi and coauthors, who showed that α-T suppresses the formation of methyl linoleate hydroperoxides in methyl linoleate and that the main oxidation products of α-T are epoxy-8a-hydroperoxy-α-tocopherones and 8a-alkylperoxy-α-tocopherones, which convert to α-TQE and α-TQ. The α-T dimers and trimers are formed only in a reaction mixture containing large amounts of α-T.…”

“…18,20,27,29 However, no information on the enrichment factors or the recovery rates of the tocopherol oxidation products is given for the conventional extraction procedures for tocopherol oxidation products such as solvent extraction, solid phase extraction, or saponification. 17,21,23,24,26 Some authors assumed recovery rates similar to those determined for T. 18,20 Applying trypsin incubation and solvent extraction, Faustman et al 22 determined recovery rates of internal deuterated standards of α-T, α-TQ, α-TQ-4a,5-E, and α-TQ-7,8-E to be 95−111%. Furthermore, no data from the literature are available for the extraction efficiency of tocochromanol oxidation products by molecular distillation.…”

“…Other authors determined α-TQ and α-TQEs formed in beef and fish during storage at 4 and 10 °C. 22,23 Pirisi et al 19 investigated α-TQ and 5-formyl-γ-tocopherol (5-FγT) formed during photolysis in olive oil and model triacylglycerols, and Gogolewski et al 21 examined the formation of dimeric oxidation products of tocopherols in plant oils under storage conditions.…”

“…The generation of tocochromanol oxidation products, especially oxidation products of α-T, have chiefly been studied in model systems. , Obviously because of problems associated with the complex food matrices and comparatively low concentrations of the oxidation products formed, only a few papers describe the isolation and detection of T oxidation products formed in food under food processing or storage conditions. − Murkovic et al, Rennick and Warner, and Verleyen et al studied the formation of α-TQ and α-tocopherolquinones epoxides (α-TQEs) in vegetable oils and model triacylglycerols under frying conditions. Other authors determined α-TQ and α-TQEs formed in beef and fish during storage at 4 and 10 °C. , Pirisi et al investigated α-TQ and 5-formyl-γ-tocopherol (5-FγT) formed during photolysis in olive oil and model triacylglycerols, and Gogolewski et al examined the formation of dimeric oxidation products of tocopherols in plant oils under storage conditions.…”