二氧化硅在菜籽油吸附脱磷中的应用及其对酚酸的影响

为了精炼后的油中尽可能多地保留菜籽多酚,首先通过傅里叶红外光谱分析(Fourier infrared spectrum,FT-IR)和差示扫描量热分析(differential scanning calorimetry,DSC)对二氧化硅(SiO2)和磷脂酰乙醇胺(PE)以及它们的复合物进行表征分析,然后以菜籽油为研究...     

磷脂脂肪酸技术在不同土地管理方式下土壤微生物多样性研究的应用

磷脂脂肪酸方法是一种新兴的土壤微生物生态学研究方法,磷脂脂肪酸的种类和数量可以用来表征土壤微生物的群落结构和组成。施肥和耕作等土地管理方式可影响土壤生物理化特性,进而直接或间接的影响土壤微生物群落的多样性。文章主要介绍了磷脂脂肪酸方法及其在施肥和耕作等土地管理措施下土壤微生物多样性研究中的应用。     

微波预处理对油菜籽及其低温压榨油脂肪酸含量的影响

为了解微波预处理对油菜籽及菜籽油脂肪酸含量的影响,评价其产生反式脂肪酸的风险,以8个省14产地的57份油菜籽样品为材料进行微波预处理,并对微波前后的油菜籽进行压榨,得到冷榨菜籽油。采用优化后的气相色谱法快速测定油菜籽和菜籽油中脂肪酸组成和含量,考察油菜品种、油菜产地以及微波预处理对油菜籽脂肪酸含量的影响。结果发现,与国标方法相比,优化后样本分析时间缩短一半以上,显著提高分析通量。研究发现,产地对油菜籽和冷榨菜籽油脂肪酸组成和含量影响较小,品种对菜籽和冷榨菜籽油脂肪酸组成和含量影响较大。不同品种的油菜籽和对应冷榨菜籽油中的脂肪酸含量差异极显著（P＜0.01）。高芥酸菜籽的花生一烯酸、芥酸的平均含量分别是低芥酸菜籽的6.89倍和64.50倍,油酸的平均含量仅为低芥酸菜籽的71.48%。同一品种不同产地的油菜籽与对应的冷榨菜籽油中的脂肪酸含量之间,不存在显著性差异。微波预处理不会显著影响油菜籽和菜籽油中的脂肪酸组成和含量水平,同时也不会产生反式脂肪酸等风险因子,微波处理后,产生反式脂肪酸的风险较低。     

甘蓝型油菜脂肪酸碳链延长酶BnaA.FAE1与BnaC.FAE1的底物特异性分析

为提供信息改良油料种子脂肪酸,研究脂肪酸碳链延长酶1（FAE1）的底物特异性,将甘蓝型油菜A、C基因组的BnaA.FAE1和BnaC.FAE1分别在亚麻荠种子中表达。其转基因种子中山嵛酸与芥酸含量的比值（C22:0/C22:1）分别为0.18和0.88,表明BnaA.FAE1对单不饱和脂肪酸亲和力较高,而BnaC.FAE1则对饱和脂肪酸亲和力较高,这种差异在各转基因世代表现稳定。通过分析T3转基因家系种子中酰基辅酶A（Acyl-CoAs）的组成,进一步证明了上述结论。但是在拟南芥中分别异源表达上述基因,并没有观察到类似的底物特异性差异。在甘蓝型油菜祖先种,白菜型油菜和甘蓝种子中调查其C22:0/C22:1比值,同样未发现其FAE1底物特异性存在差异。综上认为BnaA.FAE1和BnaC.FAE1在亚麻荠中存在底物特异性。     

Nitrogen applications modify seed and oil yields and fatty acid composition of winter mustard

Winter mustard (Brassica juncea L.) is not a common crop in the Southeastern United States. With increased interest in biodiesel production, there has been corresponding interest in mustard in this region. The objective of this study was to evaluate the effect of N fertilization (0, 50, 100, 150 kg N ha⁻¹) on productivity, oil content, and oil composition of winter mustard ‘Pacific Gold’ grown at three locations in Mississippi (Stoneville, and two locations at Verona, namely Verona silt loam (Verona-SL) and Verona clay (Verona-C)). Nitrogen did not affect oil content (percent oil). Seed and oil yields (kg ha⁻¹) increased with N application relative to the unfertilized control. At the Verona-C location, the concentration of oleic acid was higher in the 50 kg N ha⁻¹ treatment. At Stoneville, linolenic acid concentration was higher in the 150 kg N ha⁻¹ and lower in the 100 kg/N ha⁻¹ treatment, while it was not different in the other treatments. Overall, the yield of the fatty acids (FA) palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, arachidic, eicosanoic, behenic, erucic, lignoceric, and nervonic acid increased with higher N rates (100 or 150 kg N/h). The highest yield of FA in the two Verona locations were achieved in the 100 kg N ha⁻¹, while greatest yield of FA at Stoneville was achieved in the highest N rate (150 kg N ha⁻¹). Means of mustard oil yields in our study in the higher fertility treatment ranged from 737 to 1094 kg ha⁻¹. This study demonstrated winter mustard production in Mississippi and possibly other areas in the Southeastern United States can be successful and could provide seed and oil yields comparable to yields from other production areas.     

Natural infraspecific variation in fatty acid composition of Cuphea (Lythraceae) seed oils

Fatty acid analyses of seed lipids were performed for 28 populations representing three widely distributed Cuphea species. Locality and climatic data for all samples were also compiled. The objectives of this study were to examine the extent of variation in seed oil composition among the wild populations, and to discover any patterns of relationship between fatty acid composition of seed oils and environmental factors. While we found the dominant fatty acid in the oil of each species remained consistent over the environmental and geographical ranges of the samples in the present study, variation as high as 30.6% in the amount of the dominant fatty acid produced was observed. Correlation analysis between fatty acid composition and the individual environmental factors of latitude, elevation or temperature showed no consistent pattern of influence. However, when considered together, the interaction of all three, and especially latitude and elevation, contributed significantly to the variation among populations. Environmental data at microhabitat level and through controlled environmental experiments will be needed for more precise understanding of factors affecting Cuphea seed oil composition at the population level.     

山皂荚籽不饱和脂肪酸含量的测定

本实验测定山皂荚籽中粗脂肪的质量含量为41.0g/kg.分析脂肪酸组成。实验结果表明,山皂荚籽主要含有不饱和脂肪酸,占脂肪酸总成分的82.7%,其中以亚油酸相对含量最高为56.31。     

甘蓝型油菜主要脂肪酸的主基因+多基因遗传分析

以低芥酸油菜品系APL01与高芥酸品种M083杂交所获得的6个基本世代（P1、P2、F1、B1、B2和F2）为材料，利用主基因+多基因混合遗传模型对油菜主要脂肪酸进行遗传分析，结果表明：棕榈酸和廿碳烯酸均由2对加性-显性-上位性主基因+加性-显性多基因控制，棕榈酸的主基因以显性效应为主，加性效应较小，廿碳烯酸的主基因加性效应与显性效应并重。硬脂酸、油酸、亚油酸和亚麻酸均由2对加性-显性-上位性主基因+加性-显性-上位性多基因控制，硬脂酸的主基因以加性效应为主，显性效应较小，主基因的遗传率为75.00%~92.45%，多基因的遗传率较小；控制油酸的2对主基因的加性效应值分别为14.38和9.92，显性效应值分别为-2.24和-0.44，上位性效应以加加上位为主，主基因的遗传率较大，为81.93%~92.68%，多基因的遗传率较小；控制亚油酸及亚麻酸的主基因加性效应均大于显性效应，上位性效应中以加加上位和显显上位为主。芥酸由2对加性-显性主基因控制，加性效应为-12.27和-8.83，显性效应值较小，分别为0.35和1.69，无上位性效应，也无多基因存在，主基因的遗传率较大，为92.54%~96.72%。     

Influence of species, cutting date and cutting interval on the fatty acid composition of grasses

Two experiments were conducted to evaluate the effects of species, cutting date and cutting interval on the concentration of fatty acids in temperate grasses. The first experiment compared eight species, harvested in late autumn and summer. Levels of individual fatty acids were distinctive for some species, with low levels of C18:1 in Dactylis glomerata L. and high levels of C18:2 in Phleum pratense L. Differences in individual fatty acids could not be used to differentiate fescues and ryegrasses. However, fatty acid profiles could be used to differentiate species when material was managed similarly (i.e. at the same cut). There were large species × cut interaction effects, showing that management factors will be as important as plant breeding in manipulating fatty acid levels. Cultivars belonging to one Lolium perenne L. gene pool were identified as having significantly higher α-linolenic acid and total fatty acids in late-season (November) material.
The second experiment compared three ryegrass species over a growing season, with three or five cuts. All species had high concentrations of fatty acids and a high proportion of α-linolenic acid during vegetative growth (late April). Fatty acid levels declined markedly in all species after this date, recovering by autumn. Kunth Lolium multiflorum Lam. and Lolium  ×  boucheanum had higher levels of total fatty acids and α-linolenic acid in the early and late season when compared with perennial ryegrass. Fatty acid levels (particularly C18:2 and C18:3) declined when the regrowth interval was extended from 20 to 38 d.
These studies demonstrate opportunities to change the composition of ruminant products through breeding and management of grasses for altered levels of fatty acids.     

Genetic variability in the response of fatty acid composition to minimum night temperature during grain filling in sunflower

It is not known if the response of the oil fatty acid composition to temperature is similar among sunflower hybrids, especially among traditional hybrids. The objective of this work was to asses the genetic variability of the response of the oil fatty acid composition to temperature during the period 100–300 °C day after flowering among sunflower hybrids. Seven traditional hybrids and a high oleic hybrid were grown in several locations of Argentina. With the same hybrids two experiments were carried out in growth chambers where the plants were exposed to different day–night temperatures during grain filling. From these field and growth chamber experiments wide ranges of variation of temperature and oil fatty acid compositions for each hybrid were obtained. The concentration of oleic acid in sunflower oil showed a sigmoidal response to minimum night temperature from 100 to 300 °C day after flowering, increasing almost lineally within a given range of temperature. Outside this range, the concentration of this fatty acid remained merely constant. The same mathematical expressions characterized the response of oleic acid concentration to temperature in both, traditional and high oleic hybrids. The same expression also described the response of other fatty acids to temperature in all the hybrids. Differences between hybrids were observed for the minimum and maximum concentration of oleic acid and also for the maximum slope and range of the response. Since the sum of oleic + linoleic acids increased with temperature, increasing temperature reduced the concentration of saturated fatty acids and behenic acid. Genetic variability in the response of these fatty acids to temperature was observed. The results presented here show that it is possible to obtain sunflower oils of very different qualities combining the genetic variability in the response of the fatty acid composition to temperature and the climatic diversity under which sunflower is cultivated.     

Influence of cultivar and cutting date on the fatty acid composition of forage crops for grazing beef production in Argentina

The fatty acid composition and total lipids of various forage crops at different cutting dates and seasons, which are used in forage grazing beef production in Argentina, were determined. Three experiments were carried out at the Agricultural Experimental Station of INTA, Anguil, La Pampa, Argentina Samples of alfalfa from three different cultivars with different dormancy groups (G4‐5, G6‐7 and G8‐9) and samples of ryegrasses Bill, Florida and Queue, wheats Charrua and Guapo, and triticale Don Santiago cultivars were taken at different cutting dates and analysed for total lipids and fatty acid composition. Significant differences on the fatty acid composition, the ratios 18:3n‐3/18:2n‐6 and polyunsaturated fatty acids (PUFA) due to cultivar, cutting date and season were found. Taking into account the importance of 18:2n‐6 and 18:3n‐3 fatty acids as substrates for the conjugated isomers of 18:2n‐6 (CLA) and n‐3 PUFA concentrations in beef, the fatty acid composition of forages needs to be considered in forage grazing beef production systems. Data variation in both total lipids and individual fatty acid proportions in forages should be taken into account to establish the potential to cultivate crops for a higher content of n‐3 PUFA and hence the opportunity to deliver more n‐3 PUFA and CLA into beef.