linoleic-acid and 2-tert-butylhydroquinone

Trilinolein, with or without additives, was placed in glass ampoules and subjected to thermal treatment at 180 °C or 240 °C for 8h. Thermal treatment of trilinolein at 180 °C and 240 °C produced twice the amount of trans nonconjugated linoleic acids (NLAs) compared to conjugated linoleic acids (CLAs), and nitrogen stream reduced the amount of both trans NLA and CLA products. The presence of additives resulted in the suppression or induction of trans NLAs and CLAs, depending on the type of additive, the concentration of the additive, and the heating temperature. Our analysis indicates that TBHQ is an effective additive for reducing trans NLA formation and inducing trans CLA formation in frying oil. Glutathione and L-cysteine at 0.1% may also be used as additives for frying oil. At suitable concentrations, Fe(3+) and Al(3+) ions derived from oils can reduce trans NLAs and induce trans CLAs during frying.

Topics: Butylated Hydroxyanisole; Butylated Hydroxytoluene; Chromatography, Gas; Cooking; Cysteine; Hot Temperature; Hydroquinones; Isomerism; Linoleic Acid; Linoleic Acids, Conjugated; Trans Fatty Acids; Triglycerides; Vitamin E

Effects of synthetic phenolic antioxidants (BHA, BHT, and TBHQ) on the methylene blue (MB) sensitized photooxidation of linoleic acid as compared with that of alpha-tocopherol have been studied. Their antioxidative mechanism was studied by both ESR spectroscopy in a 2,2,6,6-tetramethylpiperidone (TMPD)-methylene blue (MB) system and spectroscopic analysis of rubrene oxidation induced by a chemical source of singlet oxygen. Total singlet oxygen quenching rate constants (k(ox-Q)+k(q)) were determined using a steady state kinetic equation. TBHQ showed the strongest protective activity against the MB sensitized photooxidation of linoleic acid, followed by BHA and BHT. TBHQ (1 x 10(-3) M) exhibited 86.5% and 71.4% inhibition of peroxide and conjugated diene formations, respectively, in linoleic acid photooxidation after 60-min light illumination. The protective activity of TBHQ against the photosensitized oxidation of linoleic acid was almost comparable to that of alpha-tocopherol. The data obtained from ESR and rubrene oxidation studies clearly showed the strong singlet oxygen quenching ability of TBHQ. The k(ox-Q)+k(q) of BHA, BHT, and TBHQ were determined to be 3.37 x 10(7), 4.26 x 10(6), and 1.67 x 10(8) M(-1) s(-1), respectively. The k(ox-Q)+k(q) of TBHQ was within the same order of magnitude of that of alpha-tocopherol, a known efficient singlet oxygen quencher. There was a high negative correlation (r(2) = -0.991) between log (k(ox-Q)+k(q)) and reported oxidation potentials for the synthetic antioxidants, indicating their charge-transfer mechanism for singlet oxygen quenching. This is the 1st report on the kinetic study on k(ox-Q)+k(q) of TBHQ in methanol as compared with other commonly used commercial synthetic antioxidants and alpha-tocopherol.

Topics: alpha-Tocopherol; Antioxidants; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Electron Spin Resonance Spectroscopy; Hydroquinones; Kinetics; Light; Linoleic Acid; Methylene Blue; Naphthacenes; Oxidation-Reduction; Photochemistry; Photolysis; Singlet Oxygen

We describe the synthesis of some 3-tert-butyl-4-hydroxyphenyl D-glycopyranosides by reaction of tert-butylhydroquinone with beta-D-pentaacetyl-glucose, beta-D-pentaacetyl-galactose, 2-acetamido- and 3,4,6-tri-O-acetyl-2-butanamido-2-deoxy-beta-D-glucopyranosyl chlorides as well as the formation of anomeric 3-tert-butyl-4-hydroxyphenyl 4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-eno-pyranosides by reaction between tert-butylhydroquinone and 3,4,6-tri-O-acetyl-D-glucal. All compounds, except 3-tert-butyl-4-hydroxyphenyl alpha- and beta-D-glucopyranosides, inhibited lipid peroxidation with a degree of potency comparable to that of tert-butyl hydroxyanisole.

Topics: Acetylation; Animals; Antioxidants; Ascorbic Acid; Benzenesulfonates; Glucose; Glycosides; Hydroquinones; Iron; Linoleic Acid; Lipid Peroxidation; Microsomes, Liver; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Rats; Structure-Activity Relationship