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排序方式: 共有216条查询结果,搜索用时 15 毫秒
1.
Izabella Jackowska Monika Bojanowska Monika Staszowska-Karkut Monika Sachadyn-Król 《International Journal of Food Science & Technology》2019,54(12):3175-3184
Ozonation is an innovative way to preserve high quality of seed during storage and it is an alternative to harmful organophosphorus agents. Disclosure of changes in the rapeseed oil under the influence of oxidative action of ozone on the seeds was the aim of the work and is presented for the first time. Two ozone concentrations and different length of ozonation were applied. The changes in tocopherols, phenolics, flavonoids contents, antiradical activity and oxidative stability were examined. The average vitamin E concentration was 33 mg per 100 g of oil before and 31.7 after ozonation of seeds. The average content of phenolic compounds was 14.3 mg of sinapic acid g−1 and 16.9 after the ozone treatment. Changes in the flavonoids content and antioxidant activity were observed too. Ozonation caused a decrease in the vitamin E concentration which resulted also in reducing the quenching of free radicals and reduction of oil induction time. 相似文献
2.
Miriam A Martinello Mauro Villegas Maria del C Pramparo 《Journal of the science of food and agriculture》2007,87(8):1559-1563
A process of physical refining wheat germ oil using the technique of molecular distillation (MD) is presented in this work. Wheat germ oil was obtained from the germ by solvent extraction using hexane and also by cold pressing. The oil extracted with hexane was degummed and bleached before deacidification in order to modify the parameters of phosphorus and color. The goal in carrying out the stage of physical refining by MD was to preserve the maximum amount of original antioxidative potential obtained from extraction of the crude oil. The effect of evaporation temperature of one‐stage MD on the efficiency of free fatty acid elimination was studied. The antioxidant portion was followed by means of analytic determination of tocopherols by high‐performance liquid chromatography. Tocopherol retention up to 98% was achieved in the oil extracted by pressing, and yields of up to 96% were achieved in the oil extracted with hexane. Copyright © 2007 Society of Chemical Industry 相似文献
3.
Simultaneous HPLC quantification of total cholesterol,tocopherols and β-carotene in Barrosã-PDO veal 总被引:1,自引:0,他引:1
José A. Mestre Prates Mário A. Gonçalves Quaresma Rui J. Branquinho Bessa Carlos M.G. Andrade Fontes Cristina M.P. Mateus Alfaia 《Food chemistry》2006
A simple, rapid and sensitive procedure for the simultaneous determination of total cholesterol, tocopherols and β-carotene in meat is described. The method involves a direct saponification of the meat, a single n-hexane extraction and the analysis of the extracted compounds by normal-phase HPLC, using fluorescence (tocopherols) and UV–Vis photodiode array (cholesterol and β-carotene) detections in tandem. Rates of recovery of spiked meat samples were 93% for cholesterol, 83–86% for (α-, β- and -γ) tocopherols and 89% for β-carotene. Repeatabilities were high (CV < 6%) for all determined compounds, except for δ-tocopherol. This tocopherol, which is not usually present in meat, showed a much lower recovery percentage (73%) and repeatability (12.8%). This methodology was applied for the quantification of total cholesterol, tocopherols and β-carotene in three muscles (longissimus thoracis, longissimus lumborum and semitendinosus) of the Portuguese traditional Barrosã-PDO veal, obtained from autochthonous calves fed extensively during summer (with the least abundant green pastures) and slaughtered in early autumn (October). Barrosã-PDO veal showed median contents of total cholesterol (0.50–0.56 mg/g) and, depending on the analysed muscle, moderate to high contents of α-tocopherol (3.3–3.9 μg/g) and β-carotene (0.07–0.09 μg/g), suggesting an high sensorial and hygienic quality. 相似文献
4.
R.?Zadernowski M.?NaczkEmail author R.?Amarowicz 《Journal of the American Oil Chemists' Society》2003,80(1):55-58
The free tocopherol content in whole berries of six sea buckthorn cultivars grown in northeastern Poland and Belorussia was
determined with HPLC. The total free tocopherol content in oil from whole berries was 101.4–128.3 mg/100 g of oil. α-Tocopherol
was the predominant tocopherol of sea buckthorn berries, and only traces of γ-tocopherol were detected in the oil. α- and
δ-Tocopherols constituted 62.5–67.9% and 32.1–37.5% of total tocopherol, respectively. The total free tocopherol content in
oil of sea buckthorn cv. Nadbaltycka increased during maturation from 40.4 to 109.8 mg/100 g of oil. Green berries contained
a marked amount of γ-tocopherol, but its content rapidly declined to traces when the color of berries turned from green to
olive-yellow. 相似文献
5.
Oxidative stability of high-fatty acid rice bran oil at different stages of refining 总被引:2,自引:0,他引:2
The contents of natural antioxidants and the oxidative stability of rice bran oils at different refining steps were determined.
Tocopherols and oryzanols were constant in crude and degummed oils but decreased in alkali-refined, bleached and deodorized
oils. The process of degumming, alkali-refining, bleaching and deodorization removed 34% of the tocopherols and 51% of the
oryzanols. During storage of deodorized oil for 7 wk, 34% of the tocopherols and 19% of the oryzanols were lost. The maximum
weight gain, peroxide value and anisidine value were obtained from alkali-refined oil during storage. The order of oxidation
stability was crude ≥ degummed > bleached = deodorized > alkali-refined oil. 相似文献
6.
Pekka Manninen Päivi Laakso Heikki Kallio 《Journal of the American Oil Chemists' Society》1995,72(9):1001-1008
This study demonstrates the usefulness of capillary supercritical fluid chromatography (SFC) for the characterization of triacylglycerols
of edible oils and fats. Triacylglycerols were separated according to the acyl carbon number and the degree of unsaturation
on a 25% cyanopropyl/25% phenyl/50% methylpolysiloxane stationary phase. Valuable information concerning the triacylglycerol
composition of berry oils was obtained, despite the overlapping of certain triacylglycerol peaks. Simultaneous analysis of
fat-soluble vitamins and triacylglycerols is not practical by capillary SFC with flame-ionization detection because of the
low concentration of naturally-occurring fat-soluble vitamins in edible oils. Therefore, higher loading of the sample, which
led to overloading of triacylglycerols, was required to get reasonable peaks for fat-soluble vitamins. The method was applied
to the characterization of triacylglycerols and tocopherols in sea buckthorn pulp and seed oil, and cloudberry seed oil without
any sample purification prior to SFC. In addition, the stationary phase proved useful for separating the more complex mixtures
of triacylglycerols found in milk fat and in fish oil. 相似文献
7.
T. Gallina Toschi M. F. Caboni G. Penazzi G. Lercker P. Capella 《Journal of the American Oil Chemists' Society》1993,70(10):1017-1020
Eight samples of cashew nut oil were assayed, and the component triacylglycerols, fatty acids and several unsaponifiable compounds
were analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC). Total lipid amount, unsaponifiable
percentage, fatty acids, sterols, triterpene alcohols and tocopherols are reported here. The combination of GC and HPLC enhanced
the resolution of compound classes. 相似文献
8.
G.?Perretti E.?Finotti S.?Adamuccio R.?Della Sera L.?MontanariEmail author 《Journal of the American Oil Chemists' Society》2004,81(12):1119-1123
The aim of the present study was to highlight the main differences between seed oils produced from conventionally cultivated
crops and organically cultivated ones and processed using mild extraction procedures. The composition and the nutritional
and health aspects of both types of sunflower seed oils were compared and were analytically tested to determine the macroscopic
differences in proximate composition, the main differences in the minor components, the main quality parameters, the in vitro antioxidant activity, and the presence of trans-ethylene steroisomers in FA. No significant trends were found in the oil samples for TAG and FA composition, but remarkable
differences were found in the composition of minor components and in the main chemical and analytical quality properties.
The organically grown samples had a higher total antioxidant activity compared with the conventional samples. Trans FA were found only in the conventional oils. 相似文献
9.
Effect of natural antioxidants in virgin olive oil on oxidative stability of refined,bleached, and deodorized olive oil 总被引:1,自引:0,他引:1
M. Teresa Satue Shu-Wen Huang Edwin N. Frankel 《Journal of the American Oil Chemists' Society》1995,72(10):1131-1137
The factors influencing the oxidative stability of different commercial olive oils were evaluated. Comparisons were made of
(i) the oxidative stability of commercial olive oils with that of a refined, bleached, and deodorized (RBD) olive oil, and
(ii) the antioxidant activity of a mixture of phenolic compounds extracted from virgin olive oil with that of pure compounds
andα-tocopherol added to RBD olive oil. The progress of oxidation at 60°C was followed by measuring both the formation (peroxide
value, PV) and the decomposition (hexanal and volatiles) of hydroperoxides. The trends in antioxidant activity were different
according to whether PV or hexanal were measured. Although the virgin olive oils contained higher levels of phenolic compounds
than did the refined and RBD oils, their oxidative stability was significantly decreased by their high initial PV. Phenolic
compounds extracted from virgin olive oils increased the oxidative stability of RBD olive oil. On the basis of PV, the phenol
extract had the best antioxidant activity at 50 ppm, as gallic acid equivalents, but on the basis of hexanal formation, better
antioxidant activity was observed at 100 and 200 ppm.α-Tocopherol behaved as a prooxidant at high concentrations (>250 ppm) on the basis of PV, but was more effective than the
other antioxidants in inhibiting hexanal formation in RBD olive oil.o-Diphenols (caffeic acid) and, to a lesser extent, substitutedo-diphenols (ferulic and vanillic acids), showed better antioxidant activity than monophenols (p- ando-coumaric), based on both PV and hexanal formation. This study emphasizes the need to measure at least two oxidation parameters
to better evaluate antioxidants and the oxidative stability of olive oils. The antioxidant effectiveness of phenolic compounds
in virgin olive oils can be significantly diminished in oils if their initial PV are too high. 相似文献
10.
Marina Heinonen Katri Haila Anna-Maija Lampi Vieno Piironen 《Journal of the American Oil Chemists' Society》1997,74(9):1047-1052
The effects of low concentrations of β-carotene, α-, and γ-tocopherol were evaluated on autoxidation of 10% oil-in-water emulsions
of rapeseed oil triacylglycerols. At concentrations of 0.45, 2, and 20 μg/g, β-carotene was a prooxidant, based on the formation
of lipid hydroperoxides, hexanal, or 2-heptenal. In this emulsion, 1.5, 3, and 30 μg/g of γ-tocopherol, as well as 1.5 μg/g
of α-tocopherol, acted as antioxidants and inhibited both the formation and decomposition of lipid hydroperoxides. Moreover,
at a level of 1.5 μg/g, γ-tocopherol was more effective as an antioxidant than α-tocopherol. At levels of 0.5 μg/g, both α-
and γ-tocopherol significantly inhibited the formation of hexanal but not the formation of lipid hydroperoxides. Oxidation
was effectively retarded by combinations of 2 μg/g β-carotene and 1.5 μg/g γ- or α-tocopherol. The combination of β-carotene
and α-tocopherol was significantly better in retarding oxidation than α-tocopherol alone. While γ-tocopherol was an effective
antioxidant, a synergistic effect between β-carotene and γ-tocopherol could not be shown. The results indicate that there
is a need to protect β-carotene from oxidative destruction by employing antioxidants, such as α- and γ-tocopherol, should
β-carotene be used in fat emulsions. 相似文献