共查询到20条相似文献,搜索用时 215 毫秒
1.
V. Van Hoed G. Depaemelaere J. Vila Ayala P. Santiwattana R. Verhe W. De Greyt 《Journal of the American Oil Chemists' Society》2006,83(4):315-321
The effects of each individual step of the chemical refining process on major and minor components of rice bran oil were examined.
In comparison with common vegetable oils, rice brain oil contains a significantly higher level of several bioactive minor
components such as γ-oryzanol, tocotrienols, and phytosterols. Alkali treatment or neutralization results in a significant
loss of oryzanol. In addition, it gives rise to a change in the individual phytosterol composition. After bleaching, some
isomers of 24-methylenecycloartanol were detected. Because of their relatively high volatility, phytosterols and tocotrienols
are stripped from the rice brain oil during deodorization and concentrated in the deodorizer distillate. At the same time,
oryzanol is not volatile enough to be stripped during deodorization; hence, the oryzanol concentration does not change after
deodorization. Complete refining removed 99.5% of the FFA content. Depending on the applied deodorization conditions, trans FA can be formed, but the total trans content generally remains below 1%. 相似文献
2.
Maria Scharfe Daniel Prange Eckhard Flöter 《Journal of the American Oil Chemists' Society》2022,99(1):43-56
The role of the fatty acid (FA) composition of triglycerides (TAGs) on sterol/sterol ester oleogels has been studied. Minor oil components of three vegetable oils with varying degrees of unsaturation (iodine values, IV) were removed. Typical oil quality parameters were determined before and after the treatment, and oleogels were produced using all six oils. Characteristic gel properties such as transition temperatures, mechanical properties and microstructure were tested. The results were compared regarding the impact of IV and the stripping procedure. Minor components were essentially removed during stripping, resulting in significantly different oil properties such as peroxide value, free FA and viscosity. However, peroxides formed rapidly in stripped flaxseed oil. Gel–sol transition temperatures and enthalpies were higher in gels from untreated oils and decreased with IV in samples with stripped oils. In contrast, the sol–gel transition was suppressed due to minor oil components in untreated oils. The effect of IV on gel formation was much less and linked to a lower solvent viscosity in more unsaturated oils. Nevertheless, gel firmness was significantly higher in oleogels from untreated oils and decreased slightly with IV in stripped oils. That was associated with differences in the arrangement of network building blocks, which was confirmed using atomic force microscopy. This study showed that the FA composition of TAGs has a limited effect on oleogel properties compared to those of minor oil components. The next part of this study focuses on modifying oleogel properties by adding selected minor components to stripped oils at varying concentrations. 相似文献
3.
Solvent efficiency for oil extraction from spent bleaching clay 总被引:1,自引:0,他引:1
C. G. Lee C. E. Seng K. Y. Liew 《Journal of the American Oil Chemists' Society》2000,77(11):1219-1223
Various alcohols and hydrocarbons were used as solvents to extract the residual oil in spent bleaching clay from palm oil
refining. The content of oil and minor components in the spent clay was >40% by weight. The efficiencies of extraction by
the polar alcohols, except for methanol, were higher but with a slower initial rate than the nonpolar hydrocarbons. The free
fatty acids contents, the Totox values (anisidine value+2 x peroxide value), and the color of the alcohol-extracted oil were
also higher than that by the hydrocarbons resulting in poorer quality oils. All the extracted oils, irrespective of the solvent
used, have poorer quality than crude palm oil. However, for regeneration of the residual spent clay, the polar alcohols should
be more suitable as more of the impurities are removed. 相似文献
4.
The content and composition of sterols and sterol esters in sunflower and poppy seed oils 总被引:1,自引:0,他引:1
Anna Johansson 《Lipids》1979,14(3):285-291
The composition and proportion of free sterols and sterol esters in crude sunflower and poppy seed oils were determined, using
preparative thin layer chromatography followed by gas chromatography with cholesterol as an internal standard. Free sterols
and sterol esters were also isolated in a liquid fraction obtained by low temperature crystallization (−80 C) of the oils
and enriched with minor lipid classes. This enrichment procedure provided a liquid fraction suitable for studies of minor
components in the oils. However, selectivity towards sterol esters was observed since sterols esterified to very long chain
fatty acids (C20–C24) were preferentially retained in the precipitate. The proportions of free and esterified sterols were found to be 0.34 and
0.28%, respectively, in the sunflower oil, whereas the corresponding figures for poppy seed oil were 0.33% and 0.05%. Sunflower
oil was characterized by a relatively high percentage of Δ7-sterols, preferentially obtained in the esterified fraction, and
by very long chain saturated fatty acids of sterol esters. The sterols in poppy seed oil were composed almost entirely of
campesterol, stigmasterol, sitosterol and Δ5-avenasterol, although their percentage distributions were remarkably different
in the free and esterified fraction. 相似文献
5.
Gilbert Otto Fruhwirth Thomas Wenzl Rosemarie El‐Toukhy Franz Siegfried Wagner Albin Hermetter 《European Journal of Lipid Science and Technology》2003,105(6):266-274
Plant oils provide a rich source of dietary polyunsaturated fatty acids (PUFAs) and mostly lipophilic antioxidants. PUFAs are both in their free form and as components of glycerolipids preferred targets of free radical‐induced oxidation, leading to the formation of highly atherogenic compounds. Thus, stabilization of polyunsaturated lipids by radical scavengers in the oils is important in order to avoid pathophysiological side effects of these essential components of our diet. To determine lipid oxidizability and its inhibition by endogenous antioxidants, we developed a simple fluorescence technique. It is based on solubilisation of the oils in aqueous buffer, labeling of the resulting emulsions with a suitable reporter fluorophore, which reflects lipid oxidation, and continuous monitoring of the decomposition process. Using this method, we found that oxidizability of the oils depended only to a limited extent on the content of lipophilic antioxidants. In addition, a smaller fraction of polar (phenolic) compounds showed comparable protective effects, especially in pumpkin seed oil, which is a non‐refined product therefore containing antioxidative components that are removed from most other edible oils during processing. Therefore, the contribution of these “minor” compounds has to be taken into account when potential biological effects of plant oils are evaluated. 相似文献
6.
Kornkanok Aryusuk Jiraporn Puengtham Supathra Lilitchan Narumon Jeyashoke Kanit Krisnangkura 《Journal of the American Oil Chemists' Society》2008,85(5):475-479
The effects of minor components in crude rice bran oil (RBO) including free fatty acids (FFA), rice bran wax (RBW), γ-oryzanol,
and long-chain fatty alcohols (LCFA), on alkali refining losses were determined. Refined palm oil (PO), soybean oil (SBO)
and sunflower oil (SFO) were used as oil models to which minor component present in RBO were added. Refining losses of all
model oils were linearly related to the amount of FFA incorporated. At 6.8% FFA, the refining losses of all the model oils
were between 13.16 and 13.42%. When <1.0% of LCFA, RBW and γ-oryzanol were added to the model oils (with 6.8% FFA), the refining
losses were approximately the same, however, with higher amounts of LCFA greatly increased refining losses. At 3% LCFA, the
refining losses of all the model oils were as high as 69.43–78.75%, whereas the losses of oils containing 3% RBW and γ-oryzanol
were 33.46–45.01% and 17.82–20.45%, respectively. 相似文献
7.
The endogenous minor components from canola, rice bran, sesame and palm oils including selected phospholipids, and various
combinations of tocopherol isomers were tested during frying using canola oil triacylglycerols as the frying medium. Thermo-oxidative
degradation was assessed by measurement of the total polar components, the rate of volatile carbonyl compounds and 4-hydroxynonenal
formation. All the tested minor components protected to a different extent canola triacylglycerides from thermo-oxidative
degradation during frying. No significant differences were observed in the protection of the triacylglycerides among all the
tested tocopherol isomers and their mixtures. Irrespective of the composition of tocopherol homologous, an increase in the
added amounts above 1,000 μg/g did not improve protection. Minor components isolated from rice bran and sesame oils offered
better protection during canola triacylglycerides frying than endogenous minor components isolated from canola oil. When 0.2%
phosphatidylcholine or phosphatidylethanolamine was added to the canola triacylglycerides, the amount of formed polar components
decreased twice as compared to the tocopherol isomers. Accordingly, by optimizing the composition and the concentration of
the endogenous minor components, the frying performance of oil can be significantly enhanced. 相似文献
8.
Ludger Brühl 《European Journal of Lipid Science and Technology》1997,99(12):428-432
The analysis of free fatty acids (FFA) and diacylglycerols (DG) by GLC may be used to detect the deacidification of oils. Free fatty acids are removed from the oil during neutralization or physical refining, while the corresponding DG remain in the oil. This will change the ratio of FFA to DG. For analysis, oils with tricaprin as internal standard are silylated and injected on-column onto a short high-temperature capillary column. Extracted oils showed higher amounts of FFA and DG than pressed oils from the same batch of seeds. There are only minor changes in the ratio of FFA to DG according to the yield of pressing or due to washing the oil. 相似文献
9.
Minor constituents of palm oil 总被引:5,自引:5,他引:0
Crude palm oil contains about 1% of minor components including carotenoids, tocopherols, sterols, triterpene alcohols, phospholipids,
glycolipids and terpenic and paraffinic hydrocarbons. The nutritionally important components such as carotenes and tocopherols
also improve stability of the oil. Although a highly valued product, carotene unfortunately is bleached or destroyed in refining
because suitable recovery technology is not available. Thermal degradation of carotene, previously suspected of giving rise
to undesirable chemicals, now is known to furnish mainly harmless hydrocarbons, most of which are removed by the deodorization
step in refining. Tocopherols, being natural antioxidants, need to be carefully preserved during milling, refining, fractionation
and modification of palm oils. The accumulation of tocopherols in the palm fatty acid distillate promises to provide a new
source for the recovery of this valuable substance. The role played by phospholipids is frequently misunderstood because they
can act in two ways, i.e. as an antioxidant synergist and a surface active agent to disperse impurities in oil. In crude palm
oil the phospholipid content is small, because most of it is removed during milling; the phosphorus content is due mainly
to inorganic phosphorus. Among the sterols, cholesterol constitutes too small a percentage to be of much concern. Sterols,
triterpenoids and terpenoid hydrocarbons are also potentially useful side products should recovery technology become available.
Other newly characterized minor and trace components also are discussed. 相似文献
10.
Ketinun Kittipongpittaya Atikorn Panya David Julian McClements Eric A. Decker 《Journal of the American Oil Chemists' Society》2014,91(3):453-462
Association colloids such as phospholipid reverse micelles could increase the rate of lipid oxidation in bulk oils. In addition to phospholipids, other surface active minor components in commercial oils such as free fatty acids may impact lipid oxidation rates and the physical properties of reverse micelles. In this study, the effects of free fatty acids on changes in the critical micelle concentration (CMC) of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) in stripped corn oil (SCO) were determined by using the 7,7,8,8-tetracyanoquinodimethane solubilization technique. Different free fatty acids including myristoleic, oleic, elaidic, linoleic and eicosenoic were added at 0.5 % by wt along with the DOPC into the bulk oils. There was no significant effect of free fatty acids with different chain length, configuration and number of double bonds on the CMC value for DOPC in bulk oil. However, increasing concentrations of oleic acid (0.5 to 5 % by wt) caused the CMC value for DOPC in bulk oils to increase from 400 to 1,000 μmol/kg oil. Physical properties of DOPC reverse micelles in the presence of free fatty acids in bulk oils were also investigated by the small angle X-ray scattering technique. Results showed that free fatty acids could impact on the reverse micelle structure of DOPC in bulk oils. Moreover, free fatty acid decreased pH inside reverse micelle as confirmed by the NMR studies. The oxidation studies done by monitoring the lipid hydroperoxide and hexanal formation revealed that free fatty acids exhibited pro-oxidative activity in the presence and absence of DOPC. Different types of free fatty acids had similar pro-oxidative activity in bulk oil. 相似文献
11.
C. Rukmini M. Vijayaraghavan P. G. Tulpule 《Journal of the American Oil Chemists' Society》1982,59(10):415-419
Mesta seed oil (Hibiscus sabdariffa), like cottonseed oil, contains cyclopropenoid fatty acids (2.9%) and epoxy fatty acids (2.6%) in addition to normal fatty
acids found in vegetable oils.Cleome viscosa (Capparidaceae) seed oil is rich in linoleic acid (70%) and free from any abnormal chemical constituents. Nutritional and
toxicological evaluations of these two oils were done by multigeneration breeding studies by feeding the respective oils and
groundnut oil as control at 10% level in a 20% protein diet with adequate vitamins and minerals. These studies revealed that
rats fed mesta oil had inferior growth and reproductive performance and also had altered liver metabolism. Rats fedC. viscosa oil did not show any abnormal growth or reproductive performance or altered liver lipid levels. Thus, these studies indicate
that raw or refined mesta oil may not be suitable for human consumption whereasC. viscosa oil can be used safely by humans. 相似文献
12.
Nadhir Gourine Mohamed Yousfi Isabelle Bombarda Boubakeur Nadjemi Emile Gaydou 《Journal of the American Oil Chemists' Society》2010,87(2):157-166
The composition and antioxidant activities of Pistacia atlantica Desf. essential oil were investigated. Qualitative and quantitative differences in compositions and in antioxidant activities
of male and female leaf essential oils were observed during the season. The essential oils obtained by hydrodistillation were
analysed by GC and GC–MS. The oils were rich in monoterpenes hydrocarbons and oxygenated sesquiterpenes. The main components
of male essential oil were α-pinene/α-thujene, spathulenol and bicyclogermacrene. The major component of female essential oil was δ-3-carene. The seasonal variation showed that most of the main components of the oils reached theirs highest values in September.
The antioxidant activity of the oil was investigated in vitro using two assays: DPPH· (2,2-di-phenyl-1-picrylhydrazyl) free radical-scavenging and FRAP (Ferric Reducing Antioxidant Power). The highest antioxidant
capacity to scavenge free DPPH radicals was reached in the month of June for male oils and during the months of September–October
for the female oils. The high reducing power for male oil was observed during the month of June and for the female oil it
was in August. The female oil was more active than the male oil. The antioxidant capacity of the female oil was almost ten
times higher than Ascorbic acid in the FRAP assay. 相似文献
13.
Yasushi Endo Hiromi Endo Kenshiro Fujimoto Takashi Kaneda 《Journal of the American Oil Chemists' Society》1991,68(10):769-771
Edible refined, bleached and deodorized (RBD) soybean oil was fractionated by silicic acid column chromatography to identify
minor components responsible for flavor reversion. Minor components from oil eluted with diethyl ether/n-hexane (1:1) were
compared with those from corn and canola oils. All vegetable oils contain free fatty acids, diglycerides and sterols as major
ingredients in this fraction. However, unusual triglycerides consisting of 10-oxo-8-octadecenoic acid and 10-and 9-hydroxy
octadecanoic acids were detected in RBD and crude soybean oils. 相似文献
14.
Rosario Zamora Gemma Gómez M. Carmen Dobarganes Francisco J. Hidalgo 《Journal of the American Oil Chemists' Society》2002,79(3):261-266
One hundred nine oil samples were separated chromatographically to obtain oil fractions with a decreased TAG content but with
enhanced levels of the minor components that define oil genuineness and quality. The oils, which included virgin olive oils
from different cultivars and regions of Europe and north Africa and refined olive, “lampante” olive, refined olive pomace,
hazelnut, rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils, were fractionated on a silica gel
column with hexane/diethyl ether as the mobile phase eluent. The method was highly reproducible, and the fraction obtained
contained about 15% unmodified TAG and 85% polar compounds, which included polymeric TAG, oxidized TAG, DAG, MAG, and FFA,
in addition to other minor polar components of the oils. The presence of these compounds, in an enriched fraction, should
provide information about the thermal, oxidative, and hydrolytic alterations of the oils, as well as many compounds of interest
in determining oil genuineness. The results indicate that these fractions can provide more information than the original oils
for NMR or other spectroscopic studies used in the determination of oil quality. 相似文献
15.
Ketinun Kittipongpittaya Atikorn Panya Leqi Cui David Julian McClements Eric Andrew Decker 《Journal of the American Oil Chemists' Society》2014,91(11):1955-1965
Association colloids formed by surface active minor components play an important role in the oxidative stability of bulk oils. To imitate the formation of nanostructures in refined oils, multiple surface active minor components including phospholipids, free fatty acids, diacylglycerols and sterols were added to stripped corn oil. The critical micelle concentration (CMC) of the mixed components was determined. The impact of mixed minor components at below and above their CMC on oxidative stability of bulk oil and on antioxidant activity of α-tocopherol and Trolox was investigated. The CMC of the mixed surface active components in bulk oil was 20 µmol/kg oil in the presence of 383 ± 2 ppm of water. 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) played an important role on the formation of association colloids since it was the most important component in forming the association colloids as confirmed by CMC and fluorescence probe studies. The association colloids formed by the mixed components showed prooxidative activity in bulk oil as determined by monitoring the formation of lipid hydroperoxide and hexanal. The activity of α-tocopherol or Trolox was not changed by mixed components association colloids. These results suggest that association colloids both physically and chemically impacted the oxidative stability and activity of antioxidants in bulk oil. 相似文献
16.
T. K. Mag 《Journal of the American Oil Chemists' Society》1973,50(7):251-254
The treatment of crude edible oils with sodium hydroxide solutions is the standard refining procedure in the industry. Refining
with NaOH removes free fatty acids, some phosphatides, proteinaceous matter and some colored material. Up to now experience
has shown that most oils cannot be deodorized satisfactorily unless they have been caustic-refined. In the past, when most
crude oils contained several per cent of free fatty acids, caustic-refining offered itself as a particularly suitable means
of preparation for further processing. In recent years the free fatty acid content of crude oils has been, in most cases,
only a fraction of 1%, which could very readily be removed in the process of deodorization. A prerequisite for this would
be to remove by some other means those substances that interfere with satisfactory deodorizing. It has been found that the
process of bleaching can be used for this purpose if the oil is pretreated with 0.1–0.5% phosphoric acid and bleached at 325–350
F. The amount of bleaching clay required depends on the type of oil and its quality, but with many oils up to 2% clay is satisfactory.
The amount of phosphoric acid necessary also depends on the type of oil.
One of nine papers presented in the symposium “Processing of Edible Oils,” AOCS Meeting, Ottawa, September 1972. 相似文献
17.
Makoto Miyazaki Min-Zhao Huang Naoya Takemura Shiro Watanabe Harumi Okuyama 《Lipids》1998,33(7):655-661
Previously, we demonstrated that several vegetable oils that included low-erucic rapeseed oil markedly shortened the survival
time (by ∼40%) of stroke-prone spontaneously hypertensive (SHRSP) rats as compared with perilla oil, soybean oil, and fish
oil. We considered that a factor other than fatty acids is toxic to SHRSP rats, because the survival time-shortening activity
could not be accounted for by the fatty acid compositions of these oils. In fact, a free fatty acid (FFA) fraction derived
from lipase-treated rapeseed oil was found to be essentially devoid of such activity. A high-oleate safflower oil/safflower
oil/perilla oil mixture exhibited a survival time-shortening activity comparable to that of rapeseed oil, but the activity
of this mixed oil was also reduced by lipase treatment. A partially hydrogenated soybean oil shortened the survival time by
∼40%, but a FFA fraction derived from lipase-treated partially hydrogenated soybean oil shortened it by 13% compared with
soybean oil. Fatty acid compositions of the rapeseed oil and a FFA fraction derived from lipase-treated rapeseed oil were
similar, but those of hepatic phospholipids of rats fed the oil and FFA were slightly but significantly different. These results
support the interpretation that the survival time-shortening activity exhibited by some vegetable oils is due to minor components
other than fatty acids, and that an active component(s) were produced in or contaminated soybean oil during the partial hydrogenation
processes. 相似文献
18.
Saeed Mirzaee Ghazani Guadalupe García-Llatas Alejandro G. Marangoni 《Journal of the American Oil Chemists' Society》2013,90(5):743-756
The minimal refining method described in the present study made it possible to neutralize crude canola oil with Ca(OH)2, MgO, and Na2SiO3 as alternatives to NaOH. After citric acid degumming, about 98 % of the phosphorous content was removed from crude oil. The free fatty acid content after minimal neutralization with Ca(OH)2 decreased from 0.50 to 0.03 %. Other quality parameters, such as peroxide value, anisidine value, and chlorophyll content, after traditional and minimal neutralization were within industrial acceptable levels. The use of Trisyl silica and Magnesol R60 made it feasible to remove the hot-water washing step and decreased the amount of residual soap to <10 mg/kg oil. There were no significant changes in chemical characteristics of canola oil after using wet and dry bleaching methods. During traditional neutralization, the total tocopherol loss was 19.6 %, while minimal refining with Ca(OH)2, MgO, and Na2SiO3 resulted in 7.0, 2.6, and 0.9 % reductions in total tocopherols. Traditional refining removed 23.6 % of total free sterols, while after minimal refining free sterols content did not change. Both traditional and minimal refining resulted in almost complete removal of polyphenols from canola oil. Total phytosterols and tocopherols in two cold-pressed canola oils were 774 and 836 mg/100 g, and 366 and 354 mg/kg, respectively. The minimal refining method described in the present study was a new practical approach to remove undesirable components from crude canola oil meeting commercial refining standards while preserving more healthy minor components. 相似文献
19.
Removal of dioxins and PCB from fish oil by activated carbon and its influence on the nutritional quality of the oil 总被引:1,自引:0,他引:1
Jeroen Maes Bruno De Meulenaer Peter Van Heerswynghels Wim De Greyt Gauthier Eppe Edwin De Pauw Andre Huyghebaert 《Journal of the American Oil Chemists' Society》2005,82(8):593-597
Fish oils are well-known sources of nutritionally valuable components such as the n-3 FA EPA and DHA as well as the fat-soluble
vitamins A, D, and E. However, some fish oils can be contaminated with considerable amounts of dioxins and dioxin-like PCB.
The most important challenge during fish oil refining is to remove these contaminants without altering the levels fining is
to remove these contaminants without altering the levels of nutritionally valuable compounds and the oxidative status and
stability of the oil. Treatment with an apolar adsorbent, e.g., activated carbon (AC), seems to be the most efficient process
today. Very little information about the adsorption of different dioxin and PCB congeners is available. Four grades of AC
were evaluated for their efficiency in removing these compounds. In addition, the effects of the treatment on the nutritional
and oxidative quality of the oil were evaluated. After treatment of contaminated cod liver oil [5.4 ppt toxic equivalents
(TEQ) polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), 18.1 ppt TEQ dioxin-like PCB] with 0.5% AC, almost all PCDD/F and up to 80% of the dioxin-like
PCB could be removed. AC showed low affinity for mono-ortho PCB (<30% removal), which could be explained by their noncoplanar structure. Removal efficiencies were dependent on the grade
and percentage of AC used. The treatment of contaminated cod liver oil caused no important effects on oil quality or FA composition
in the conditions tested. 相似文献
20.
Minor components are the non‐triacylglycerol constituents of oil and constitute up to 5% of the total lipid composition. Though minor in composition, they can exert major influence on the performance of oil during frying. The effect of the minor components on frying performance depends on their chemical nature, composition and amount in the oil. Among these minor components tocopherols, phytosterols, phospholipids, γ‐oryzanol, lignans, phenolics, and carotenoids are the most important. Here, their effect on the frying performance of edible oils is discussed. 相似文献