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1.
Abdalbasit Adam Mariod Yousif M. Ahmed Bertrand Matthäus Galaledin Khaleel Abdeen Siddig Aied Mohamed Gabra Siddig Ibrahim Abdelwahab 《Journal of the American Oil Chemists' Society》2009,86(12):1181-1188
The proximate analysis of seeds and physicochemical properties of oils extracted from six Sudanese cucurbit seeds Cucumis mello var. agrestis, Cucumis melo var. flexuosus, Cucumis sativus, Citrullus lanatus var. colocynthoides, Cucumis prophetarum, and Luffa echinata were examined by established methods. For each variety, the proximate analysis showed ranges for moisture, protein, and carbohydrates
as 3.70–6.87, 14.50–17.50, and 15.62–28.89% on a dry matter basis, respectively. The oils were extracted by Soxhlet using
petroleum ether, with yields that ranged from 10.9 to 27.10% (wt/wt). The obtained extracted oils were subjected to phyiscochemical,
fatty acid, and tocopherol analysis. The physicochemical characterization of the oil revealed that the refractive indices
and relative densities of the oils fell within the narrow ranges of 1.334–1.442 and 0.874–0.920 g/cm3, respectively. Unsaponifiable matters ranged between 0.8 and 1.2 mg KOH/g, whilst peroxide values (PV) ranged from 2.3 to
4.1 meq/kg. The ranges of the values for free fatty acid (FFA %) were 1.2–4.0%. The predominant fatty acids were 16:0, 18:0,
18:1, and 18:2 with ranges of 8.9–14.2, 6.0–9.4, 14.6–32.1, and 43.6–65.5%, respectively. γ-Tocopherol was the predominant
tocopherol in all samples ranging from 0.8 to 43.2% of the total tocopherols, followed by δ-tocopherol and α-tocopherol. 相似文献
2.
Reza Farhoosh Javad Tavakoli Mohammad Hossein Haddad Khodaparast 《Journal of the American Oil Chemists' Society》2008,85(8):723-729
Pistacia atlantica subsp. mutica (PAM) and kurdica (PAK) kernel oils showed significantly lower unsaturated to saturated fatty acid ratios (6.39, 6.33, respectively) and calculated
oxidizability (Cox) values (3.99, 4.13, respectively) than those of the P. vera L. cv. Ohadi (PVO) kernel oil (8.91, 4.41) samples. The highest peroxide value was observed for the PAK oil (4.07 mequiv kg−1) (PAM, 1.94; PVO, 0.37) samples. Iodine values for the PAM, PAK, and PVO oils were 104.26, 104.77, and 110.66, respectively.
The saponification number of the PVO oil was significantly greater than the PAM and PAK oils, which were statistically not
different. The unsaponifiable contents, which were composed mainly of sterols, ranged from 5.63 to 6.14%. Statistically the
total tocopherols contents of the PAM (818.58 mg α-tocopherol kg−1) and PVO (815.90 mg α-tocopherol kg−1) oils were significantly higher than that of the PAK oil (499.91 mg α-tocopherol kg−1). Total phenolics contents differed significantly, the greatest concentration was for the PAM oil (81.12 mg gallic acid kg−1), followed by the PVO (62.84 mg gallic acid kg−1) and PAK (56.51 mg gallic acid kg−1) oil samples. The wax contents of the oil samples were statistically in the same range, namely 5.67–6.48%. Oxidative stability
data indicated that the PAM oil is the most resistant to the formation of lipid oxidation products, followed by the PAK and
PVO oil samples. 相似文献
3.
J.-F. Butaud P. Raharivelomanana J.-P. Bianchini E. M. Gaydou 《Journal of the American Oil Chemists' Society》2008,85(4):353-356
The sandalwood kernels of Santalum insulare (Santalaceae) collected in French Polynesia give seed oils containing significant amounts of ximenynic acid, E-11-octadecen-9-oic acid (64–86%). Fatty acid (FA) identifications were performed by gas chromatography/mass spectrometry
(GC/MS) of FA methyl esters. Among the other main eight identified fatty acids, oleic acid was found at a 7–28% level. The
content in stearolic acid, octadec-9-ynoic acid, was low (0.7–3.0%). An inverse relationship was demonstrated between ximenynic
acid and oleic acid using 20 seed oils. Results obtained have been compared to other previously published data on species
belonging to the Santalum genus, using multivariate statistical analysis. The relative FA S. insulare composition, rich in ximenynic acid is in the same order of those given for S. album or S. obtusifolium. The other compared species (S. acuminatum, S. lanceolatum, S. spicatum and S. murrayanum) are richer in oleic acid (40–59%) with some little differences in linolenic content. 相似文献
4.
Ali Moayedi Karamatollah Rezaei Sohrab Moini Behnam Keshavarz 《Journal of the American Oil Chemists' Society》2011,88(4):503-508
Chemical compositions of oils extracted from three wild almond species [Amygdalus scoparia from Beyza, Iran (AZ); A. scoparia from Borazjan, Iran (AJ), and A. hausknechtii from the Firuzabad region, (AH)] and a domestic species, A. dulcis from Estahban, Iran (AD), as a reference, were investigated. Total oil content ranged from 44.4% in AJ to 51.4% in AD. Saponification
numbers were in the range of 173.5 (for AJ) to 192.9 for AD. Oxidative stability, total phenolic contents and total wax contents
were found to be within the ranges 11.7–14.0 h, 33.9–43.2 and 2.05–2.53%, respectively. The main monounsaturated fatty acid
(MUFA) was oleic acid ranging from 66.7% for AH to 69.7% for AZ. The only polyunsaturated fatty acid (PUFA) was linoleic acid
ranging from 18.2% for AZ to 23.0% for AD. The major saturated fatty acid was palmitic acid. MUFA contents and MUFA to PUFA
ratio in the oils from wild almond species as well as those in the domestic one were found at higher levels than those in
the common vegetable oils such as soybean, various nut oils, and also those from the seeds of pomegranate, grape, date and
sesame. Oils from wild almond species investigated here are rich in oleic acid and can be considered as potential vegetable
oils in the human diet. 相似文献
5.
M. Charef Mohamed Yousfi M. Saidi P. Stocker 《Journal of the American Oil Chemists' Society》2008,85(10):921-924
The fruits of two plants from Algeria (Quercus and Pistacia lentiscus) were investigated. The paper reports the chemical characteristics and the fatty acid composition of the oil extracts from
the fruits. The black fruits of P. lentiscus has the highest crude fat of 32.8%, followed by the red fruits with 11.7%, and the lowest value of 9% in Quercus (acorn). The acid value was highest in red fruits of P. lentiscus oil (24.0 mg KOH/g), followed by the black fruits oil and lowest in acorn oil. The relatively high iodine value in the oils
indicates the presence of many unsaturated bonds. Saponification value was highest in the Quercus ilex oil (166.7 mg KOH/g), while the lowest value was in the black fruits of P. lentiscus oil. Gas-liquid chromatography revealed that the three dominant fatty acids found are: palmitic C16:0 (16.3–19.5%), oleic
C18:1 (55.3–64.9%), linoleic C18:2 (17.6–28.4%). The oils contain an appreciable amount of unsaturated fatty acids (78.8–83.5%). 相似文献
6.
Nanzad Tsevegsüren Kurt Aitzetmüller 《Journal of the American Oil Chemists' Society》1996,73(12):1681-1684
Seeds of nine Central Asian species of Boraginaceae were investigated for the first time for their oil content and for the
fatty acid composition of their seed oils by capillary gas chromatography. Levels of γ-linolenic acid ranged from 6.6 to 13.0%
and levels of stearidonic acid ranged from 2.4 to 21.4% of total seed fatty acids. The seed oil ofHackelia deflexa exhibited the highest stearidonic acid content (21.4%) that has been found so far in nature. Other high contents of this
fatty acid were in threeLappula species (17.2 to 18.1%). Seed oils ofCynoglossum divaricatum andAmblynotus rupestris contain considerable amounts ofcis-11-eicosenoic (5.3 to 5.8%) andcis-13-docosenoic acid (7.0 to 9.7%) besides γ-linolenic (10.2 to 13.0%) and stearidonic acid (2.4 to 6.5%), which distinguish
these oils from those of other Boraginaceae genera.
This paper was presented as a poster at 10th Minisymposium and Workshop on Plant Lipids, Sept. 3–6, 1995, in Berne, Switzerland. 相似文献
7.
Hyun H. Oh Keum T. Hwang Min K. Shin Hee K. Lee Sung Z. Kim 《Journal of the American Oil Chemists' Society》2007,84(6):549-555
Seed and oil contents, and fatty acid compositions of oils of 20 caneberries grown in Korea were determined. Fatty acid compositions
of the oils were analyzed using GC for the extracted and methylated oils from the berry seeds. The seeds comprised 4–10% (w/w)
of the wet berries and accounted for 26–62% of the dry berries. Moisture and oil contents of the berry seeds were 8–17 and
13–28% (dry basis), respectively. More than 90% of the total fatty acids in the oils from the berry seeds were unsaturated.
Linoleic and linolenic acids comprised 49–70 and 13–34%, respectively, of the oils in the berry seeds. 相似文献
8.
Farooq Anwar Rehana Naseer M. I. Bhanger Samia Ashraf Farah Naz Talpur Felix Adekunle Aladedunye 《Journal of the American Oil Chemists' Society》2008,85(4):321-330
The physico-chemical characteristics of the seeds and seed oils of four citrus species, Mitha (Citrus limetta), Grapefruit (Citrus paradisi), Mussami (Citrus sinensis), and Kinnow (Citrus reticulata) were investigated. The hexane-extracted oil content of citrus seeds ranged from 27.0 to 36.5%. The protein, fiber and ash
contents were found to be 3.9–9.6%, 5.0–8.5%, and 4.6–5.6%, respectively. The extracted oils exhibited an iodine value of
99.9–110.0; refractive index (40 °C), 1.4639–1.4670; density (24 °C), 0.920–0.941 mg/mL; saponification value, 180.9–198.9;
unsaponifiable matter, 0.3–0.5%; acid value (mg KOH/g of oil), 0.5–2.2 and color (1-in. cell) 1.4–3.0R + 15.0–30.0Y. The oils
revealed a good oxidative stability as indicated by the determinations of specific extinctions at 232 and 270 nm (2.3–4.4
and 0.6–0.9, respectively), p-anisidine value (2.2–3.2) and peroxide value (1.6–2.4 mequiv/kg of oil). The citrus seed oils mainly consisted of linoleic
acid (36.1–39.8%). Other prominent fatty acids were palmitic acid (25.8–32.2%), oleic acid (21.9–24.1%), linolenic acid (3.4–4.4%),
and stearic acid (2.8–4.4%). The contents of tocopherols (α, γ, and δ) in the oil were 26.4–557.8, 27.7–84.1, and 9.1–20.0 mg/kg,
respectively. The results of the present study demonstrated that the seeds of citrus species investigated are a potential
source of valuable oil which might be utilized for edible and other industrial applications. 相似文献
9.
Olives were collected from various districts of Turkey (North and South Aegean sub-region, Bursa-Akhisar, South East Anatolia
region) harvested over seven (2001–2007) seasons. The aim of this study was to characterize the chemical profiles of the oils
derived from single variety Turkish olives including Ayvalik, Memecik, Gemlik, Erkence, Nizip Yaglik and Uslu. The olive oils
were extracted by super press and three phase centrifugation from early harvest olives. Chosen quality indices included free
fatty acid content (FFA), peroxide value (PV) and spectrophotometric characteristics in the ultraviolet (UV) region. According
to the FFA results, 46% (11 out of 24 samples) were classified as extra virgin olive oils; whereas using the results of PV
and UV, over 83% (over 19 of the 24 samples) had the extra virgin olive oil classification. Other measured parameters included
oil stability (oxidative stability, chlorophyll pigment, pheophytin-α), cis–trans fatty acid composition and color index. Oxidative stability among oils differed whereas the cis–trans fatty acid values were within the national and international averages. Through the application of two multivariate statistical
methods, Principal component and hierarchical analyses, early harvest virgin olive oil samples were classified according to
the geographical locations categorized in terms of fatty acid profiles. Such statistical clustering gave rise to defined groups.
These data provide evidence of the variation in virgin olive oil quality, especially early harvest and cis–trans isomers of fatty acid profiles from the diverse agronomic conditions in the olive growing regions of Turkey. 相似文献
10.
G. R. List K. Warner P. Pintauro M. Gil 《Journal of the American Oil Chemists' Society》2007,84(5):497-501
Partially hydrogenated soybean oils (90–110 IV) were prepared by electrochemical hydrogenation at a palladium/cobalt or palladium/iron
cathode, moderate temperature (70–90 °C) and atmospheric pressure. The trans fatty acid (TFA) contents of 90–110 IV products ranged from 6.4 to13.8% and the amounts of stearic acid ranged from 8.8 to
15.4% (the higher stearic acid contents indicated that some reaction selectivity had been lost). The solid fat values and
melting point data indicated that electrochemical hydrogenation provides a route to low-trans spreads and baking shortenings. Shortenings produced by conventional hydrogenation contain 12–25% trans fatty acids and up to 37% saturates, whereas shortening fats produced electrochemically had reduced TFA and saturate content.
Electrochemical hydrogenation is also a promising route to low-trans spread and liquid margarine oils. Compared to commercial margarine/spread oils containing 8–12% TFA, the use of electrochemical
hydrogenation results in about 4% TFA.
Names are necessary to report factually an available data: the USDA neither guarantees nor warrants the standard of the product,
and the use of the name USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
11.
Seed oils from six legume cultivars of Phaseolus vulgaris, grown in the Kingdom of Lesotho, were extracted and their physicochemical properties and FA compositions were determined
in order to compare their dietary lipids with those in P. vulgaris cultivars grown in other parts of the world. The oil content of the beans was very low, ranging from 1.5 to 2.0% (w/w). The
acid values ranged from 11.0 to 19.2 mg KOH/g, whereas a combination of the PV and the p-anisidine values in Holm's equation gave oxidation values that ranged from 11.0 to 15.0. Thus, considerable enzymatic hydrolysis
and oxidation had taken place in the beans during storage. Iodine values ranged from 80.5 to 92.3 (Wijs method), indicating
moderate unsaturation in the oils. However, capillary GC analysis, supported by proton NMR analysis of the FAME, gave a total
unsaturation range from 79.67 to 84.24%. The dominant FA were α-linolenic acid (36.47–48.81%) and linoleic acid (20.96–36.10%),
with appreciable amounts of palmitic acid (14.33–18.23%). This FA composition pattern is quite similar to the FA distribution
reported for low oil-bearing legume seeds. Thus, notwithstanding the different climatic and soil conditions, the general properties
of lipids in the southern African legume cultivars were quite similar to those of lipids in P. vulgaris cultivars grown in other parts of the world. The high content of α-linolenic acid in the cultivars of P. vulgaris could very likely play a beneficial role in reducing the risk of coronary heart disease among the large populations consuming
them in the southern African region. 相似文献
12.
F. Jahaniaval Y. Kakuda M. F. Marcone 《Journal of the American Oil Chemists' Society》2000,77(8):847-852
This paper reports the fatty acid and triacylglycerol (TAG) compositions of five Amaranthus accessions (RRC1011, R149, A.K343, A.K432, and A. K433) representing two species and a cross between one of these and a third species. Seed oils of these were analyzed by
gas chromatography and reversed-phase high-performance liquid chromatography, and their compositional properties compared
with buck-wheat (Fagopyrum esculentum), corn (Zea mays), rice bran (Oryza sativa), soybean (Glycine max L. Merr.), sesame (Sesamum indicum), quinoa (Chenopodium quinoa), and cottonseed (Gossypium hirsutum) oils. All Amaranthus accessions were relatively high in palmitic (21.4–23.8%) and low in oleic (22.8–31.5%) and linolenic (0.65–0.93%) acids when
compared to most of the grain and seed oils. The fatty acid composition of Amaranthus accessions K343, K433, and K432 (group I) were different from R149 and RRC1011 (group II) in mono and polyunsaturated fatty
acids, but the saturate/unsaturate (S/U) ratios were very similar. All Amaranthus accessions were similar in TAG type, but showed slight differences in percentage. High similarities in UUU, UUS, and USS
composition were observed among Amaranthus K343, K433 and K432, and between R149 and RRC1011. The fatty acid compositions of Amaranthus oil (group I) and cottonseed oil were similar, but their TAG compositions were different. The grain and oilseed oils were
different from each other and from the Amaranthus accessions oils in terms of fatty acid composition, S/U, and TAG ratios. The UUU, UUS, and USS percentages were very diverse
in grain and seed oils. The percentages of squalene in the TAG sample from the Amaranthus accessions were 8.05% in K343, 11.10% in K433, 11.19% in K432, 9.96% in R149, and 9.16% in RRC1011. Squalene was also tentatively
identified in quinoa and ricebran oils at levels of 3.39 and 3.10%, respectively. 相似文献
13.
Samuel Owusu Yeboah Yulita Chebotip Mitei Jane Catherine Ngila Ludger Wessjohann Juergen Schmidt 《Journal of the American Oil Chemists' Society》2011,88(10):1539-1549
The lipid components of three Cameroonian seed oils, ke tchock (Aframomum arundinaceum), njangsa (Ricinodendron heudelotii) and calabash nutmeg (Monodora myristica), have been investigated. Gas chromatography (GC)–mass spectrometry (MS) fatty acid (FA) analysis showed M. myristica seed oil to be dominated by linoleic (49.29%) and oleic (37.17%) acids; R. heudelotii was mainly linoleic (58.73%), followed by stearic (15.00%) and oleic (14.21%) acids; A. arundinaceum was predominantly oleic (65.76%) and palmitic (20.36%) acids. Electrospray ionization (ESI)-Fourier transform ion cyclotron
resonance (FTICR)-MS analysis showed seven major triacylglycerol (TAG) classes for M. myristica, with C54:5, C54:4 and C54:6 dominating. R. heudelotii had eight major TAG classes with C54:8, C54:7 and C54:6 being most abundant. A. arundinaceum also had eight major TAG classes with C52:2, C54:3 and C50:2 dominating. 13C nuclear magnetic resonance (NMR) analysis of the TAGs showed that both sn-1,3 and sn-2 positions were predominantly occupied by linoleoyl and oleoyl chains. High-performance liquid chromatography (HPLC) fluorescence
detector (FLD) analysis showed that M. myristica contained only α- and β-tocopherols (195.40 and 73.95 μg/g, respectively), R. heudelotii contained mainly γ-tocopherol (289.40 μg/g), and A. arundinaceum had mainly γ- and β-tocopherols (236.78 and 124.93 μg/g, respectively). GC–MS analysis of the unsaponifiable matter showed
that β-sitosterol was the most abundant phytosterol in all three seed oils. The absolute amounts of 4-desmethylsterols were
196.15, 608.71 and 362.15 μg/g for M. myristica, R. heudelotii and A. arundinaceum seed oils, respectively. These compositional and structural studies provide justification for the use of all three seed oils
in food products. 相似文献
14.
Kenneth D. Carlson Robert Kleiman 《Journal of the American Oil Chemists' Society》1993,70(11):1145-1148
Nasturtium (Tropaeolum majus L.) oil contains the highest levels of erucic acid of known seed oils (75–80%). A significant portion of the acid is attached
to the 2-position of the glycerol, and trierucin is a major component (ca. 50%) of the oil. Seeds from eleven varieties of commercially available garden nasturtium (T. majus) were screened for oil content, erucic acid levels and fatty acid distribution. Oil contents ranged fromca. 6 to 11%, and erucic acid levels in the oils ranged from 62 to 80%. One sample ofT. speciosum was also analyzed, and contained 28% oil, fatty acids from C16 to C28 and triglycerides up to C72. 相似文献
15.
Trimethylsilyl Derivatization/Gas Chromatography as a Method to Determine the Free Fatty Acid Content of Vegetable Oils 总被引:1,自引:0,他引:1
Peter J. Wan Michael K. Dowd Audrey E. Thomas Boyce H. Butler 《Journal of the American Oil Chemists' Society》2007,84(8):701-708
Thirty-one samples of vegetable oils were analyzed for free fatty acid (FFA) concentration by titration against sodium hydroxide
and by trimethylsilyl (TMS) derivatization followed by gas chromatography (GC). In preliminary experiments, two silylation
chemistries and three GC stationary phases were tested for TMS fatty acid ester formation and separation. No ideal combination
of conditions was identified; however, hexamethyldisilazane with an acid catalyst and a non-polar J & W DB-5 column were chosen
for comparison of the two approaches. Over the range of FFA values studied (0.04–12%), the results from the two methods were
highly correlated (R > +0.996) and were generally in good agreement. However, values from the chromatographic method were slightly lower than
values obtained by titration for the crude oil samples (which had higher FFA levels). For oils with >0.4% FFA, the GC approach
was slightly less reproducible (average coefficient of variance of ~3%) compared with the titration approach (average coefficient
of variance of ~1.4%). For oils with <0.4% FFA, the coefficients of variance were higher (8–9%) and comparable between the
methods.
Use of a company or product name by the Department does not imply approval or recommendation of the product to the exclusion
of others which may also be suitable. 相似文献
16.
Liliana N. Ceci Amalia A. Carelli 《Journal of the American Oil Chemists' Society》2010,87(10):1189-1197
The relation between oxidative stability and composition in 58 virgin olive oils from different cultivars and Argentinian
regions was studied over four harvest years. The oxidative stability of the oils was assessed using the OSI index (110 °C,
20 L/h air flow). A multiple linear regression model is proposed using OSI values as the dependent variable (multiple R = 0.933, p = 1 × 10−15), with positive contributions of the independent variables: fatty acid composition [oleic acid/(linoleic acid + linolenic
acid), 55.3%, p = 1 × 10−15], total polyphenols (24.1%, p = 1.8 × 10−9), carotenes (4.8%, p = 6.1 × 10−5), β-tocopherol (1.9%, 6.0 × 10−3) and other compounds (13.9%). Highly significant correlation was observed between oxidative stability indexes estimated by
the compositional model and those experimentally determined by Rancimat method (b = 0.981, R = 0.924). Chlorophylls and Δ-5-avenasterol contributions to the model were non-significant when variables related with fatty
acids and polyphenols were included. The results suggest that the fatty acid composition and the polyphenol content are the
main factors that affect the oxidative stability of olive oils. The proposed model allows the estimation of the oxidative
stability in olive oils independently of the cultivar. The model was obtained also taking into account samples that lie out
of the international legal limits in some compositional values due to natural variations. 相似文献
17.
Interprovenance variation was examined in the composition of Moringa oleifera oilseeds from Pakistan. The hexane-extracted oil content of M. oleifera seeds harvested in the vicinity of the University of Agriculture, Faisalabad (Punjab, Pakistan), Bahauddin Zakariya University
(Multan, Pakistan), and the University of Sindh, Jamshoro (Sindh, Pakistan), ranged from 33.23 to 40.90%. Protein, fiber,
moisture, and ash contents were found to be 28.52–34.00, 6.52–7.50, 5.90–7.00, and 6.52–7.50%, respectively. The physical
and chemical parameters of the extracted M. oleifera oils were as follows: iodine value, 67.20–71.00; refractive index (40°C), 1.4570–1.4637; density (24°C), 0.9012–0.9052 mg/mL;
saponification value, 177.29–184.10; unsaponifiable matter, 0.60–0.83%; color (1-in. cell), 1.00–1.50 R+20.00–30.00Y; smoke
point, 198–202°C; and acidity (% as oleic acid), 0.50–0.74. Tocopherols (α, γ, and δ) accounted for 114.50–140.42, 58.05–86.70,
and 54.20–75.16 mg/kg, respectively, of the oils. The induction periods (Rancimat, 20 L/h, 120°C) of the crude oils were 9.64–10.66
h and were reduced to 8.29–9.10 h after degumming. Specific extinctions at 232 and 270 nm were 1.80–2.50 and 0.54–1.00, respectively.
The major sterol fractions of the oils were campesterol (14.13–17.00%), stigmasterol (15.88–19.00%), β-sitosterol (45.30–53.20%),
and ͤ5-avenasterol (8.84, 11.05%). The Moringa oils were found to contain high levels of oleic acid (up to 76.00%), followed by palmitic, stearic, behenic, and arachidic
acids up to levels of 6.54, 6.00, 7.00, and 4.00%, respectively. Most of the parameters of M. oleifera oils indigenous to different agroclimatic regions of Pakistan were comparable to those of typical Moringa seed oils reported in the literature. The results of the present analytical study, compared with those for different vegetable
oils, showed M. oleifera to be a potentially valuable oilseed crop. 相似文献
18.
Christina Borch-Jensen Benny Jensen Kim Mathiasen Jørgen Mollerup 《Journal of the American Oil Chemists' Society》1997,74(3):277-284
The seed oils from Dimorphoteca pluvialis and Ricinus communis contain hydroxy fatty acids. Dimorphoteca pluvialis contains Δ-9-hydroxy-10t, 12t-octadecadienoic acid (dimorphecolic acid) and R. communis contains Δ-12-hydroxy-9c-octadecenoic acid (ricinoleic acid). The oils were derivatized and analyzed to determine the content of hydroxy fatty acids.
The trimethylsilyl fatty acid methyl ester (TMS-FAME) derivatives were analyzed by capillary gas chromatography (GC), and
the free fatty acid (FFA) derivatives and the oils were analyzed by capillary supercritical fluid chromatography (SFC). Further,
mass spectroscopy of the TMS-FAME derivatives was performed to check the purity of the derivatives. The results from the GC
analyses of TMS-FAME corresponded to the results found by SFC analysis of the FFA. The content of ricinoleic acid in the glycerolipids
of R. communis was 87.7 wt%, and the content of dimorphecolic acid in D. pluvialis was 54.0 wt%. The methods were evaluated with respect to the cost, ease, and time needed for sample preparation and analysis. 相似文献
19.
W. S. Choo E. J. Birch J. P. Dufour 《Journal of the American Oil Chemists' Society》2007,84(8):735-740
Flaxseed oils are used in stir-frying in parts of China. In this study, flaxseed oils were heated at approximately 150 °C
as a thin film in a frying pan for 3 and 6 min, respectively. Pan-heating caused loss of tocopherols, plastochromanol-8, phenolic
acids and chlorophyll pigments. There was a significant decrease in the linolenic acid resulting in a concomitant relative
increase in palmitic, stearic, oleic and linoleic acids in the oils after pan heating. Positive CIELAB “b*” color value, which indicates yellowness and levels of β-carotene and lutein in these oils showed a 42–56% and 8–53% decrease,
respectively. Peroxide values, p-anisidine values, percentage of conjugated dienoic acid, specific extinction at 232 and 270 nm and food oil sensor readings
of these oils showed significant increases to levels exceeding good oil quality indices. Acid values only showed one to twofold
increase from fresh oil values of 0.65–2.23 mg KOH/g of sample. These results indicate that significant levels of oxidation
products would be present in flaxseed oils after pan heating. The flaxseed oil with a lower amount of PUFA appeared to be
more degraded suggesting that the major factor affecting the oxidative stability of the flaxseed oils during pan-heating was
not the degree of unsaturation but was dependent on the complex interaction between the fatty acids and minor constituents
in the oils.
Presented at the American Oil Chemists’ Society 97th Annual Meeting & Expo, St. Louis, MO, 30 April–3 May, 2006. 相似文献
20.
Nongnuch Sutivisedsak Bryan R. Moser Brajendra K. Sharma Roque L. Evangelista Huai N. Cheng William C. Lesch Robert R. Tangsrud Atanu Biswas 《Journal of the American Oil Chemists' Society》2011,88(2):193-200
Four common beans (black, kidney, great northern, and pinto) were extracted with hexane and found to contain about 2% triacylglycerols.
The fatty acids in these bean oils were mainly linolenic (41.7–46 wt%), linoleic (24.1–33.4 wt%), palmitic (10.7–12.7 wt%)
and oleic (5.2–9.5 wt%). Because of the high levels of polyunsaturated fatty acids, the bean oils had iodine values between
174 and 177 g/100 g (compared to 130 g/100 g for soybean oil). Yet, the bean oils exhibited high oxidative stability due to
the presence of high amounts of tocopherols (2,670–2,970 ppm). The bean oils had lower pour points (−18 to −11 °C) compared
to −9 °C for soybean oil. Among the four bean oils, kidney bean oil had the highest acid value (15.4 mg KOH/g) and kinematic
viscosities over a wide range of temperatures. 相似文献