首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The ability to rapidly measure key FA in oilseed crops would assist in the administration of identity-preserved systems in the grain-handling system or in selection systems in plant-breeding programs. This study shows near-infrared reflectance (NIR) spectroscopy to be a reliable method of determining FA composition in canola, flax, and solin (low-linolenic flax), for oleic acid, linoleic acid, linolenic acid, and iodine value, and to a limited extent for saturated fat. Samples from cultivar trials, harvest surveys, and export shipments were scanned on a NIRSystems 6500 spectrometer (Silver Spring, MD), and calibrations were developed and optimized using modified partial least squares. SE of prediction results for prediction sets of canola, flax, and solin, were, respectively: oleic acid (0.77, 1.03, 0.62%); linoleic acid (0.71, 1.20, 0.37%); linolenic acid (0.42, 0.62, 0.08%); saturated FA (0.23, 0.39, 0.31%); and iodine value (0.63, 0.95, 0.43 units). This paper was previously presented at the 93rd AOCS Annual Meeting & Expo in Montréal, Québec, Canada, May 5–8, 2002, as part of the symposium entitled Use of Spectroscopic Methods to Determine the Fatty Acid Composition of Oils and Oilseeds.  相似文献   

2.
The frying performance of low-linolenic acid soybean oil from genetically modified soybeans was examined. Partially hydrogenated and unhydrogenated low-linolenic acid soybean oils were compared to two partially hydrogenated soybean frying oils. Frying experiments utilizing shoestring potatoes and fish nuggets were conducted. Frying oil performance was evaluated by measuring free fatty acid content, p-anisidine value, polar compound content, soap value, maximal foam height, polymeric material content, and Lovibond red color. The hydrogenated low-linolenic soybean oil (Hyd-LoLn) consistently had greater (P<0.05) free fatty acid content and lower p-anisidine values and polymeric material content than did the other oils. Hyd-LoLn generally was not significantly different from the traditional oils for polar content, maximal foam height, and Lovibond red color. The low-linolenic acid soybean oil (LoLn) tended to have lower soap values and Lovibond red color scores than did the other oils. LoLn had consistently higher (P<0.05) p-anisidine values and polymeric material content than did the other oils, and LoLn generally was not different (P<0.05) from the traditional oils for polar content, maximal foam height, and free fatty acid.  相似文献   

3.
With the aim to utilize a vegetable oil epoxy, a product from a sustainable resource, for improving the properties of polymethacrylic acid (PMAA), the blends of the latter with the epoxy of linseed oil were prepared in solution by mechanical mixing of the requisite amounts of the two components in dimethylsulphoxide. Freestanding films of the blend were cast. The miscibility of the two components was investigated by viscosity, ultrasonic, and density measurements which showed that the two components were semicompatible in solution. The compatibility in solid phase was also examined by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), which revealed that linseed oil epoxy (LOE) and PMAA were incompatible. The films of blend of all compositions were found to be sticky, which was caused by the oozing of LOE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

4.
The composition and physicochemical properties of pecan (Carya illinoensis) kernels and oils from different native trees of the central region of Mexico were investigated. The main compositional characteristic of the kernel was the high lipid content (70–79% w/w on dry basis) with elevated concentration of oleic acid (55–75% w/w). The results confirmed the relationship in the biosynthesis of linoleic and linolenic acids from oleic acid existing in oilseeds. Our results indicate that in pecans such relationship is a function of pecan tree age. The proportion of oleic, linoleic, and linolenic fatty acids determined the oxidative stability, viscosity, and melting/crystallization behavior of pecan oil. In general, these properties in pecan oils were similar or superior to extra-virgin olive oil and unrefined sesame oil. Although all native pecan oils studied showed a significant concentration of oleic acid, a particular group of native Mexican pecan trees produces an oil with a fatty acid composition with the nutritional appeal that consumers demand nowadays (i.e., very high oleic acid, 60–75%), with excellent natural oxidative stability (i.e., induction time for oxidation between 8.5 and 10.8 h), and substantially higher concentrations of α-, γ-, and δ-tocopherol than in pecan varieties previously reported in the literature.  相似文献   

5.
Blending of two polymers in solution is a simple and cost‐effective technique to improve upon the physical and mechanical properties of the component polymers through synergism. To obtain maximum synergy in their properties, the component polymers should be miscible with each other on molecular scale. Polymer blends of complex physicomechanical properties are being actively investigated. Poly(methacrylic acid) (PMAA), a commercial polymer, yields transparent, hard, brittle, and water‐sensitive films. It has been blended with natural polymers like dextran, collagen, and gelatin to obtain films with improved physical and mechanical characteristics. Polyesteramides, which are easily synthesized from vegetable seeds oil, a sustainable resource, have found application in surface coatings. These oligomeric products do not make free standing films in the ambient condition. The polyesteramides from vegetable seeds oil can be used to obtain blend with PMMA of improved mechanical and water absorption properties. In this study, linseed oil polyesteramide (LOPEA) and dehydrated castor oil polyesteramide (DCPEA), the source oils with different unsaturation in their fatty acid chains, were blended with PMAA through mixing in solution in the ratio DCPEA/LOPEA: PMAA as 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, and 20/80. In the first instance, the miscibility of the two components was investigated in solution by viscosity and ultrasonic measurements and in solid phase through differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Moisture absorption by the blend was also studied. DCPEA and LOPEA show immiscibility with PMAA in solution phase while LOPEA with more unsaturation in the fatty acid chain of the oil was found more immiscible than DCPEA. DCPEA shows a narrow miscibility window in the solid phase while LOPEA was found immiscible with PMAA in the solid phase too. Uptake of moisture was found to be markedly reduced in the blends of DCPEA/LOPEA with PMAA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1367–1374, 2007:  相似文献   

6.
Pan-heating of low-linolenic acid and partially hydrogenated soybean oils   总被引:1,自引:0,他引:1  
Genetically modified low-linolenic acid soybean oil (LL-SBO) was compared to partially hydrogenated soybean oil (PH-SBO). Samples were heated on a Teflon pan at ∼180°C until a selected end point of ≥20% polymer content was reached. High-performance size-exclusion chromatography analysis indicated the PH-SBO contained >20% polymer after 20 min of heating, whereas the LL-SBO sample contained >20% polymer after 10 min. Supercritical fluid chromatography analysis indicated degradation rates of 0.161±0.011 min−1 for LL-SBO and 0.086±0.004 min−1 for PH-SBO. The volatile compounds were identified and quantitated with static head-space-GC-MS. 1-Heptene (239.9 ppm) and hexanal (1486.1 ppm) were present at the greates concentration among the volatile compounds in LL-SBO. The volatile compounds present in the greatest concentrations in heated PH-SBO were hexanal (376.9 ppm) and pentane (82.1 ppm). After 10 min of heating, the LL-SBO oil FFA value (2.66%), p-anisidine value (386.5 abs/g oil), Food Oil Sensor reading (18.75), and color intensity (Y=4.0, R=1.0) were significantly greater than those of PH-SBO after 14 min of heating (4.28%, 298.5 abs/g oil, 16.08, Y=1.0, R=0.1, respectively). There was a significant difference in the degradation rates between LL-SBO and PH-SBO (P<0.05). The PH-SBO was more stable than the LL-SBO.  相似文献   

7.
The objective of this study was to evaluate the effects of adding flaxseed oil (FO) to feed on the incorporation of n‐3 PUFA in tilapia heads. Tilapia were given diets with increasing levels of FO (0.00, 1.25, 2.50, 3.75 and 5.00% for treatments A, B, C, D and E, respectively), as a source of LNA for 150 days. The proximate composition of the heads indicated high nutritional value and 40 FA (fatty acids) common to all treatments were identified in total lipids. Intake of LNA caused storage of LNA and sequential desaturation‐elongation to eicosapentaenoic acid (EPA) and DHA. With increasing levels of FO in the diet, the content of LNA in tilapia heads increased (1.7 and 14.0% for diets A and E, respectively), as well as the contents of EPA (0.1 and 0.9% for diets A and E, respectively) and DHA (0.5 and 1.8% for diets A and E, respectively). Adding FO to tilapia feed markedly increased the total content of n‐3 PUFA (3.0 and 21.1% for diets A and E, respectively), decreased the total content of n‐6 PUFA (41.3 and 24.9% for diets A and E, respectively), and consequently resulted in a decrease in the n‐6/n‐3 ratio (13.8 and 1.2 for diets A and E, respectively). Therefore, feeding tilapia with FO is a good way of valorizing this part of the fish by creating a valuable nutritional food source.  相似文献   

8.
Ethylene diamine polyesteramide (Ed‐PEA) was synthesized from N, N‐bis (2‐hydroxy ethyl) linseed oil fattyamide and ethylene diamine tetra acetic acid through condensation polymerization. It was further treated with toluylene 2,4‐diisocyanate (TDI) in different weight percentage to obtain urethane‐modified polyesteramide (Ed‐UPEA). The structural elucidation of Ed‐PEA and Ed‐UPEA were carried out by FTIR, 1H‐NMR, and 13C‐NMR spectroscopic techniques. Thermal studies of these resins were carried by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The coatings of urethane‐modified polyesteramide were prepared on mild steel strips and their anticorrosive behavior of in acid, alkali, water, and xylene were investigated. Thermal stability performance suggests that the system could be safely used upto 200°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

9.
亚麻油改性特-辛基酚醛树脂的合成及性能研究   总被引:1,自引:0,他引:1  
利用亚麻油与松香对辛基酚醛树脂进行改性合成改性辛基酚醛树脂。对改性产品进行了GPC、FT-IR的表征分析及其软化点、脂肪烃溶解性和溶剂溶解性能等的研究。实验表明,亚麻油与松香质量比在20%~40%之间时,所得产品分子量(Mn)6 000~10 000,分子量分布范围(PD I)小于4,庚烷容纳度在10~20 mL/2 g,软化点大于110℃,是平版印刷油墨用的一种新型高分子聚合物。  相似文献   

10.
Hash browns (HB) were fried (Teflon-coated pan, ∼180°C) with low-linolenic acid (LL-SBO) and creamy partially hydrogenated soybean oils (PH-SBO). High-performance size-exclusion chromatography of the oil extracted before heating indicated a relatively low polymer content (LL-SBO, 3.8%; PH-SBO, 1.6%), although the oil remaining in the pan after frying had a much greater polymer content (38.8%, LL-SBO; 17.5%, PH-SBO). The percentage of altered TAG in the LL-SBO sample (extracted from HB) was 34.4% after frying, whereas the PH-SBO had 33.2% altered TAG (as determined by supercritical fluid chromatography). In the LL-SBO pan-fried HB samples (not the extracted oil), 2-pentanone, hexanal, 2-hexenal, trans-2-heptenal, 2-pentylfuran, and trans-2-octenal were found, whereas the major volatile compounds in the HB fried with PH-SBO included hexanal, trans-2-hexenal, and trans-2-heptenal. Hexanal was the most abundant volatile compound in both HB samples (LL-SBO, 2.7 ppm; PH-SBO, 0.3 ppm). There were significant differences in the polymer content, hexanal content, p-anisidine values, and Foodoil sensor readings between LL-SBO and PH-SBO (P<0.05). The PH-SBO sample was more stable than the LL-SBO sample. Moreover, the LL-SBO oil sample in the pan after frying had the greater increase in polymer content.  相似文献   

11.
The fatty acid and triacylglycerol composition of pili nut (Canarium ovatum) oil and fractions were analyzed by gas chromatography and reversed-phase high-performance liquid chromatography, respectively. The oil obtained by solvent extraction was low in polyunsaturated fatty acids and high in saturates. The polyunsaturated fatty acid (18∶2 and 18∶3) contents were less than 11%, whereas palmitic (16∶0) and stearic acid (18∶0) were 33.3 and 10.9%, respectively. The saturated fatty acid level of the low-melting fraction oil was reduced from 44.4 to 35.5% and the total unsaturated fatty acid levels were increased from 55.6 to 65% by fractional crystallization. Triacylglycerol analysis showed that the high-melting fraction (HM) from pili nut oil consisted of POP, POS, and SOS+SSO (P=palmitic acid, O=oleic acid, and S=stearic acid) in the proportion of 48.6, 38.8, and 8.7%, respectively. The physicochemical properties of the HM fraction were studied using differential scanning calorimetry and pulsed nuclear magnetic resonance. The results showed that the melting range and solid fat content of the HM fraction were very similar to those isolated from cocoa butter and olive oil. The content of POP played an important role in determining the melting range of the HM fraction. It is suggested that this HM fraction may have applications as a cocoa butter substitute in confectionery products.  相似文献   

12.
The use of maleinized linseed oil (MLO) as a potential biobased plasticizer for poly(lactic acid) (PLA) industrial formulations with improved toughness was evaluated. MLO content varied in the range 0–20 phr (parts by weight of MLO per hundred parts by weight of PLA). Mechanical, thermal and morphological characterizations were used to assess the potential of MLO as an environmentally friendly plasticizer for PLA formulations. Dynamic mechanical thermal analysis and differential scanning calorimetry revealed a noticeable decrease in the glass transition temperature of about 6.5 °C compared to neat PLA. In addition, the cold crystallization process was favoured with MLO content due to the increased chain mobility that the plasticizer provides. PLA toughness was markedly improved in formulations with 5 phr MLO, while maximum elongation at break was obtained for PLA formulations plasticized with MLO content in the range 15–20 phr. Scanning electron microscopy revealed evidence of plastic deformation. Nevertheless, phase separation was detected in plasticized PLA formulations with high MLO content (above 15–20 phr MLO), which had a negative effect on overall toughness. © 2017 Society of Chemical Industry  相似文献   

13.
A modified low-temperature solvent crystallization process was employed for the enrichment of polyunsaturated fatty acids (PUFA) in borage and linseed oil fatty acids. The effects of solvent, operation temperature, and solvent to free fatty acid (FFA) ratio on the concentration of PUFA were investigated. The best results were achieved when a mixture of 30% acetonitrile and 70% acetone was used as the solvent. With an operation temperature of −80°C and a solvent to FFA ratio of 30 mL/g, γ-linolenic acid (GLA) in FFA of saponified borage oil can be raised from 23.4 to 88.9% with a yield of 62.0%. At a yield of 24.9%, α-linolenic acid in linseed oil can be increased from 55.0 to 85.7%. The results of this work are comparable to the best results available in the literature.  相似文献   

14.
15.
Oil and triglyceride contents and fatty acid composition were determined for seeds in nine taxa belonging to the genusCoincya (Brassicaceae) on the Iberian Peninsula (Spain and Portugal). The oil content ranges from 11.1 to 24.6%, triglycerides from 68.7 to 88.5%. The major fatty acids were erucic (24.6–30.5%), linolenic (17.7–27.7%), linoleic (13.9–24.6%) and oleic acid (12.3–21.8%).  相似文献   

16.
The influence of temperature during seed development on the fatty acid composition of oilseed rape (Brassica napus L.) was studied in one low-linolenic and one conventional canola cultivar. The cultivar Regent produces seed oil with ∼20% linoleic acid (C18:2) and ∼8% linolenic acid (C18:3), whereas Stellar is relatively high in C18:2 (∼25%) and low in C18:3 (∼2.5%). Both cultivars were grown in the field, and the fatty acid compositions of the seed oils were monitored throughout the period of seed development. In the field, the content of saturated (C16:0+C18:0) and monounsaturated (C18:1) fatty acids in the seed oil increased when seed developed under high temperatures. C18:3 levels were higher in seed harvested at sites with lower average daily temperatures. The low C18:3 trait of the cultivar Stellar was relatively stable over environments. Both temperature and duration of exposure to the temperature during seed development affected the fatty acid composition of the seed in a controlled environment study. Plants subjected to a high-temperature treatment (30/25°C day/night) for 40 d produced seed with the lowest C18:3 content and the highest levels of C16:0+C18:0 and C18:1. This was observed in both cultivars.  相似文献   

17.
简要介绍了亚麻籽油的来源、特性与传统应用,着重介绍了亚麻籽油在化妆品中的应用.亚麻籽油作为一种特殊天然功能油脂,在各种保湿护肤护发化妆品中用作营养和保湿剂.作为Omega -3系必需脂肪酸补充剂,不仅应用于具有特殊疗效的肤用化妆品中缓解或治疗皮肤问题,还应用于发用化妆品中发挥促进生发的功效.最后对亚麻籽油如何更好地应用于我国化妆品行业进行了展望.  相似文献   

18.
Catalytic transfer hydrogenation (CTH) of safflower oil was studied using aqueous ammonium formate as hydrogen donor and palladium on carbon as catalyst in a closed vessel under controlled microwave irradiation conditions. The method offered good selectivity in complete reduction of linoleic acid to monounsaturated acid with a slight increase in stearic acid compared to other reported catalytic transfer hydrogenation methods. Selectivity was achieved by using microwave-assisted CTH without employing an emulsifier or high ratios of water to oil.  相似文献   

19.
The oil extracted from the fat-storage organ (fat body) of the bullfrog (Rana catesbeiana) was characterized for its fatty acid composition. The main fatty acids were palmitic (18.1%), stearic (4.1%), myristic (2.7%), oleic (31.7%), and linoleic (12.9%) acids. Long-chain polyunsaturated fatty acids were also present in significant amounts, i.e., eicosapentaenoic (1.5%) and docosahexaenoic (4.7%), and were probably derived from the fish meal content of the diet. A partially fractionated oil was extracted from the homogenized and frozen fat body with an oleic acid content of 43.2%. The natural alkaloid boldine, added at 0.5 mg/g oil level, improved the oxidative stability by a factor ranging from 1.7 to 2.4, as assessed by the Oil Stability Index method between 90 and 110°C. The stabilization effect of boldine was higher than that of naringenin, morin, and quercitin and for the synthetic antioxidant butylated hydroxytoluene at the same concentration level.  相似文献   

20.
This study analyzed the effects of different concentrations of flaxseed oil (FO) on the proximate composition and the contents of alpha-linolenic acid (LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), and docosahexaenoic (DHA, 22:6n-3) fatty acids in the liver of cultured Nile tilapia (Oreochromis niloticus). During the five-month culture period, tilapias were given diets with incremental concentrations of FO (0.00%; 1.25%; 2.50%; 3.75%, and 5.00%) as a replacement of sunflower oil (control). There was no significant difference in moisture and ash content in the liver between treatments. Protein values ranged from 12.1% (treatment II) to 13.9% (treatment V) and total lipids ranged from 5.6% (treatment V) to 7.2% (treatment II). There was no significant difference between most treatments. Fatty acid methyl esters (FAMEs) were quantitatively analyzed by capillary gas chromatography against a C(23:0), internal standard. Variations in concentrations (in mg g(-1) of total lipids) of fatty acids between treatment I and treatment V ranged from 4.2 to 51.2 (LNA), from 0.2 to 2.3 (EPA), and from 10.6 to 56.2 (DHA), respectively. This experiment demonstrated that increasing amounts of LNA in feed may markedly increase the amounts of LNA, EPA, and DHA in the liver of Nile tilapia.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号