13 research outputs found
Dolichol: A Component of the Cellular Antioxidant Machinery
Dolichol, an end product of the mevalonate pathway, has been proposed a biomarker of aging, but its biological role, not to mention its catabolism, has not been fully understood. UV-B radiation was used to induce oxidative stress in isolated rat hepatocytes by the collagenase method. Effects on dolichol, phospholipids-bound polyunsaturated fatty acids (PL PUFA) and known lipid soluble antioxidants [coenzyme Q (CoQ) and α-tocopherol] were studied. The increase in oxidative stress was detected by a probe sensitive to reactive oxygen species (ROS). Peroxidation of lipids was assessed by measuring the release of thiobarbituric acid reactive substances (TBARS). Dolichol, CoQ and α-tocopherol were assessed by high-pressure liquid chromatography (HPLC), PL PUFA by gas-liquid chromatography (GC). UV-B radiation caused an immediate increase in ROS as well as lipid peroxidation and a simultaneous decrease in the levels of dolichol and lipid soluble antioxidants. Decrease in dolichol paralleled changes in CoQ levels and was smaller than that in α-tocopherol. The addition of mevinolin, a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoAR), magnified the loss of dolichol and was associated with an increase in TBARS production. Changes in PL PUFA were minor. These findings highlight that oxidative stress has very early and similar effects on dolichol and lipid soluble antioxidants. Lower levels of dolichol are associated with enhanced peroxidation of lipids, which suggest that dolichol may have a protective role in the antioxidant machinery of cell membranes and perhaps be a key to understanding some adverse effects of statin therapy
Thermal processing in a roaster for selected legumi-nous seeds intended for food production
Celem pracy była ocena możliwości wykorzystania obróbki cieplnej w prażaku nasion grochu i fasoli do wytwarzania nowych produktów będących zamiennikami orzeszków ziemnych. Badania obejmowały procesy nasycania (nawilżania) nasion różnymi wodnymi roztworami soli, cukru i melasy, a następnie prażenie ich w założonych zakresach temperaturowo-czasowych. Tak preparowane nasiona poddane zostaną ocenie sensorycznej. Wyniki badań i ich analiza wykazały, iż odpowiednio dobrane metody przygotowania i nasycania (nawilżania) nasion, a następnie obróbka cieplna w prażaku w temperaturze 150-160°C, dają możliwość otrzymania, nowych, atrakcyjnych i wysokobiałkowych produktów.The purpose of the work was to evaluate the possibilities of using thermal processing of pea and bean seeds in a roaster to make new products constituting substitutes for peanuts. The scope of the research covered seed saturation (humidification) processes using various water solutions of salt, sugar and molasses, and then roasting within the assumed temperature-time ranges. Seeds prepared in this way will be subject to sensory evaluation. Research results and their analysis have proven that properly selected methods for seed preparation and saturation (humidification), and then thermal processing in a roaster at the temperature of 150-160°C, allow to obtain new, attractive, highprotein products
Double Bond Stereochemistry Influences the Susceptibility of Short‑Chain Isoprenoids and Polyprenols to Decomposition by Thermo‑Oxidation
Alcohols are common constituents of
living cells. They are usually assigned a role in the adaptation
of the cell to environmental stimuli, and this process
might give rise to their oxidation by reactive oxygen
species. Moreover, cellular isoprenoids may also undergo
various chemical modifications resulting from the physicochemical
treatment of the tissues, e.g., heating during food
processing. Susceptibility of isoprenoid alcohols to heat
treatment has not been studied in detail so far. In this study,
isoprenoid alcohols differing in the number of isoprene units
and geometry of the double bonds, β-citronellol, geraniol,
nerol, farnesol, solanesol and Pren-9, were subjected to
thermo-oxidation at 80 °C. Thermo-oxidation resulted in the
decomposition of the tested short-chain isoprenoids as well
as medium-chain polyprenols with simultaneous formation
of oxidized derivatives, such as hydroperoxides, monoepoxides,diepoxides and aldehydes, and possible formation of oligomeric derivatives. Oxidation products were monitored by GC-FID, GC-MS, ESI-MS and spectrophotometric methods. Interestingly, nerol, a short-chain isoprenoid with a double bond in the cis (Z) configuration, was more oxidatively stable than its trans (E) isomer, geraniol. However, the opposite effect was observed for medium-chain polyprenols, since Pren-9 (di-trans-poly-cis-prenol) was more susceptible to thermo-oxidation than its all-trans isomer, solanesol. Taken together, these results experimentally confirm that both short- and long-chain polyisoprenoid alcohols are prone to thermo-oxidation