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Secondary Oxidation Products (secondary + oxidation_products)
Selected AbstractsOxidative stability of Echium plantagineum seed oil bodiesEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2010David A. Gray Abstract Echium plantagineum seed contains a highly polyunsaturated oil (approximately 14% linoleic acid, 10% ,-linolenic acid, 33% ,-linolenic acid and 14% stearidonic acid); almost half of the fatty acids are omega-3 fatty acids, so there is an interest in the possible health benefits of this oil, which, once extracted, is prone to oxidation. For the first time in reported literature, oil bodies (OBs), the organelles that store the oil in mature seed, were recovered from E. plantagineum seeds. The oxidative stability of these organelles ex vivo, dispersed in an aqueous continuous phase, was tested against processed E. plantagineum oil emulsions stabilised with either SDS or Tween 20. For both primary and secondary oxidation products the OBs were the most stable form of dispersed oil, and the dispersed systems were all more stable than bulk E. plantagineum oil after incubating at 40°C for 7 days. The possible reasons for the enhanced chemical stability of E. plantagineum OBs are explored in this paper. Practical applications: OBs, the natural store of oil in oilseeds, can be recovered from seeds intact and are relatively stable to oxidation ex vivo. Echium seed OBs, enriched in physiologically active omega-3 fatty acids, therefore offer an attractive alternative to traditional oil extraction methods and overcome the need to encapsulate the omega-3 rich oil. [source] Effects of tocopherols and tocotrienols on the inhibition of autoxidation of conjugated linoleic acidEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 4 2010Soon-Nam Ko Abstract The effect of eight vitamin E homologues, i.e. ,-, ,-, ,-, and ,-tocopherol and ,-, ,-, ,, and ,-tocotrienol, on the inhibition of autoxidation of conjugated linoleic acid (CLA) were investigated. The oxidation was carried out in the dark for 21 days at 50,°C and monitored by peroxide values (PV) and TBA values. The levels of the individual vitamin E homologues in CLA during storage were determined by HPLC. ,-Tocopherol exhibited the highest antioxidant activity among the homologues tested in this study when the antioxidant activities of the individual homologues in CLA were compared by PV. The order of antioxidant activity of eight homologues was ,-tocopherol,>,,-tocopherol,=,,-tocotrienol , ,-tocotrienol,>,,-tocopherol,=,,-tocotrienol,>,,-tocopherol,=,,-tocotrienol. The degradation rates of , -tocopherol and , -tocotrienol were faster than those of the other homologues, whereas ,-tocopherol had the highest stability in CLA during storage. All homologues exhibited an antioxidant activity by inhibiting the formation of secondary oxidation products. It appears that ,-tocotrienol and ,-tocotrienol have significantly higher antioxidant activities for secondary oxidation in CLA than ,-tocopherol and ,-tocopherol. Meanwhile, the other homologues, namely ,-tocopherol, ,-tocotrienol, ,-tocopherol, and ,-tocotrienol, exhibited similar antioxidant activity for secondary oxidation in CLA. [source] Combined effects of thymol, carvacrol and grapefruit seed extract on lipid oxidation and colour stability of poultry meat preparationsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 11 2009Annalisa Lucera Summary The combined effects of thymol, carvacrol and grapefruit seed extract (GFSE) on lipid oxidation and colour stability of poultry meat preparations packaged in air or modified atmospheres (MAP: 5% O2; 30% CO2; 65% N2) were investigated using a simplex centroid mixture design. Lipid oxidation was evaluated through measurement of secondary oxidation products (malonaldehyde, MDA) and general appearance with visual assessment and instrumental measurement of colour. Thymol and carvacrol, as individual antioxidants, retarded the oxidation process by maintaining MDA values below 2 mg kg,1 meat. The effect of GFSE was less than thymol and carvacrol. Redness (a*) decreased in all treatments during storage but this reduction was more evident in the control and in samples containing GFSE than in thymol and carvacrol. Although colour acceptability decreased with time, all meat preparations packaged in air maintained desirable appearance better than samples in MAP. Also, off-odours developed faster in the samples packaged in MAP than in aerobically packaged samples. [source] Oxidation process of oils with high content of linoleic acyl groups and formation of toxic hydroperoxy- and hydroxyalkenals.JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2005A study by 1H nuclear magnetic resonance Abstract The oxidation process of sunflower and corn oils at 70 °C with circulating air has been studied by means of 1H nuclear magnetic resonance (NMR). The changes produced in the two oils are compared not only in relation to the rate of degradation of acyl groups but also with reference to both the rate of formation and degradation of primary oxidation products as well as the rate of formation of secondary oxidation products such as aldehydes. Special attention is paid to the evolution of the different kinds of aldehydes formed throughout the process. The great ability of these oils to produce geno- and cytotoxic aldehydes under the above conditions is proved. Moreover, peroxide and anisidine values of corn oil throughout its oxidation process have also been determined and the results obtained have been compared with those provided by the 1H NMR spectra, showing good agreement. Copyright © 2005 Society of Chemical Industry [source] Effect of light and oxygen transmission characteristics of packaging materials on photo-oxidative quality changes in semi-hard Havarti cheesesPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2002Grith Mortensen Abstract Changing transmission characteristics of food packaging materials by colouring the materials may be a suitable way of reducing photo-oxidative quality changes. This study proved that packaging in black laminates provided the best protection of Havarti cheese, followed by a white laminate. However, transparent packaging materials did not protect the product in the critical wavelength range, i.e. 400,500,nm, and changes in colour and odour were already notable after few hours of exposure to fluorescent light. Additionally, secondary oxidation products, hexanal, 1-pentanol, and 1-hexanol, were formed in cheese packaged in transparent or semi-transparent packaging materials. The expected effects of oxygen transmission were difficult to evaluate, due to high residual oxygen levels in the packages. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||