Possible alternative utilization of Cynara spp.: II. Chemical characterization of their grain oil

The grain oils extracted from six genotypes of Cynara species: two globe artichokes (Cynara scolymus L.), two cultivated cardoons (C. cardunculus L. var. altilis DC.) and two wild cardoons (C. cardunculus L. var. sylvestris Lam.), were analysed in order to ascertain their alimentary value. Oil yield, moisture, acidity, peroxide number, UV spectrophotometry and CIE colour parameters, fatty acids, phytosterols and -tocopherol were determined by standard methods. Cynara species which are most promising in terms of quality and quantity of oil were the cardoons, especially those belonging to the wild cardoon genotypes. Triacylglycerols were the dominant constituents together with very little amounts of phospholipids and glycolipids. The high content of oleic and linoleic acids in a balanced ratio, and the low amount of free acids, peroxides, saturated and linolenic acids ensure a good alimentary quality. Distribution of phytosterols was typical of oil from grain of Asteraceae such as sunflower and safflower. Moreover the optimal -tocopherol content offers a guarantee of stability against oxidation.     

Phytosterol,Squalene, Tocopherol Content and Fatty Acid Profile of Selected Seeds,Grains, and Legumes

The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, squalene, and tocopherols. The objective of the present study was to determine the levels of phytosterols, and squalene, as well as tocopherols (α and β + γ) in selected grains, seeds, and legumes. The method comprised acid hydrolysis and lipid extraction followed by alkaline saponification, prior to analysis by HPLC. In addition, the fatty acid profile of the foods was determined via total lipid extraction, fatty acid derivitisation and GC analysis. In general, β-sitosterol was the most prevalent phytosterol, ranging in concentration from 24.9 mg/100 g in pumpkin seed to 191.4 mg/100 g in peas. Squalene identified in all foods examined in this study, was particularly abundant in pumpkin seed (89.0 mg/100 g). The sum of α- and β+ γ-tocopherols ranged from 0.1 mg/100 g in rye to 15.9 mg/100 g in pumpkin seeds. Total oil content ranged from 0.9% (w/w) in butter beans to 42.3% (w/w) in pumpkin seed and the type of fat, in all foods examined, was predominantly unsaturated. In conclusion, seeds, grains, and legumes are a rich natural source of phytosterols. Additionally, they contain noticeable amounts of squalene and tocopherols, and in general, their fatty acid profile is favorable.     

大豆主要脂肪酸含量近红外模型的建立

为提高大豆脂肪酸品种的育种进程,使用气相色谱法测量289份大豆籽粒样品的脂肪酸含量,并用近红外谷物品质分析仪NIRFIEX N-500采集大豆样品近红外光谱值,采用主成分回归法将化学试验测定的数值与采集的光谱曲线对应拟合整理分析建立定标模型。每种脂肪酸建立11个定标标准,选取决定系数定标Q值中最高的数值为定标模型。结果显示5种脂肪酸定标模型的适宜Q值分别为:棕榈酸0.823 5、硬脂酸0.854 1、油酸0.819 6、亚油酸0.829 1、亚麻酸0.836 3。最后验证结果表明,近红外法测量值与化学试验测定值误差均在1.5%误差范围之内,证明所建立模型质量较好,具有使用价值,可用于大豆育种材料脂肪酸含量的快速测量。     

不同小麦品种籽粒中脂肪酸组分含量及其相关性研究

为了明确小麦品种的脂肪酸及其组分的含量,选取97个小麦品种(系),利用气相色谱仪对其全麦粉脂肪酸组分进行了测定,并初步分析了部分品种(系)的脂肪酸组分含量的分布及其相关性,结果表明,总脂肪酸平均含量为1.91％,其中棕榈酸(C16∶0)、硬脂酸(C18∶0)、油酸(C18∶1)、亚油酸(C18∶2)和亚麻酸(C18∶3)的平均含量依次为0.37％、0.02％、0.27％、1.17％和0.08％,分别占总脂肪酸组成的20％、1％、14％、61％和4％.不饱和脂肪酸(油酸、亚油酸和亚麻酸)在总脂肪酸中所占的比例达到79％;总脂肪酸及其组分含量呈现中间多、两头少的正态分布,变异幅度较大;总脂肪酸含量与棕榈酸、硬脂酸、油酸和亚油酸4种组分含量相关极显著,而与亚麻酸的含量无显著相关.     

植物甾醇脂肪酸酯酶法合成及热力学特性研究进展

植物甾醇脂肪酸酯作为一种降胆固醇的有效成分而受到人们的重视。文章详细介绍了国内外酶催化合成植物甾醇脂肪酸酯的研究进展,同时介绍了植物甾醇脂肪酸酯的热力学行为,为开发添加植物甾醇酯的功能性食品提供理论依据。     

甘肃胡麻地方品种种质资源品质分析

对甘肃116 个胡麻地方品种种质资源的粗脂肪含量、5种脂肪酸含量及碘价等主要品质性状进行测定分 析,对品质性状间的相关性进行了研究。结果表明,甘肃胡麻地方种质资源粗脂肪含量,棕榈酸、硬脂酸、油酸、亚 油酸、亚麻酸含量及碘价的平均值分别为37. 48%、5. 90%、5. 32%、29. 05%、10. 94%、48. 76%和175. 60。粗脂肪 含量普遍较低,油酸和亚麻酸含量高。5种脂肪酸中棕榈酸、亚麻酸、亚油酸含量变异较小,硬脂酸和油酸变异较 大;不同品质性状间的相关关系和相关程度不同,粗脂肪含量与亚油酸含量有极显著的正相关,与硬脂酸含量有极 显著的负相关;亚麻酸与棕榈酸、硬脂酸、油酸、亚油酸含量均呈极显著的负相关关系,与碘价呈极显著的正相关关 系;棕榈酸与油酸含量有显著的正相关,硬脂酸与油酸含量有极显著的正相关,油酸与碘价呈极显著负相关。初步 筛选出一批高油分、高油酸、高亚麻酸的优良种质。     

Chemical composition and profile characterisation of pumpkin (Cucurbita maxima) seed oil

Seeds of a Tunisian variety (Béjaoui) of pumpkin (Cucurbita maxima) were analysed for their main chemical composition and for their oil properties. Expressed on dry weight basis, seed moisture was 8.46%, whereas contents of proteins, fibre, ash, fat, and total sugars established at 33.92%, 3.97%, 21.97%, 31.57%, and 0.11% respectively. Gas chromatography revealed that the major fatty acids were oleic, linoleic, and palmitic acids (44.11%, 34.77%, and 15.97% respectively). Seed oil was also found to be rich in tocopherols with a predominance of δ-tocopherol (42.27%). The sterol marker β-sisosterol accounted for 39.6% of total sterols contained in seed oil of this variety. Six phenolic acids (protocatechuic, caffeic, syringic, vanillic, p-coumaric and ferulic) were detected, the syringic acid being predominant (7.96 mg/100 g). As a whole, based on its seed oil features, pumpkin may be considered as a valuable source for new multi-purpose products for industrial, cosmetic, and pharmaceutical utilisation.     

Fatty Acids, Sterols, Phenols and Antioxidant Activity of Phoenix theophrasti Fruits Growing in Crete, Greece

In the present study we report the chemical composition of the Cretan Phoenix theophrasti Gr. fruits, in comparison with dates, from its close relative Phoenix dactylifera L. for their nutritional value and their potential exploitation as a source of bioactive components such as phytosterols, lipids and polyphenols. The non polar dichloromethane (CH₂Cl₂) extract of the fruits was analysed by several techniques (TLC, CC, GC and GC-MS) and was found to consist mainly from fatty acids, hydrocarbons and phytosterols. Palmitic acid was the most abundant fatty acid, 12.49% of total saponifiables, while β-sitosterol was the most prevalent phytosterol, 29.46% of total unsaponifiable lipid fraction. The polar methanolic extract was examined for its total phenolic content, by the Folin–Ciocalteu assay, as well as for its antioxidant activity through DPPH assay, in comparison with previous studies on the fruits of several Phoenix dactylifera varieties. This fraction was found to possess strong antioxidant activity despite its lower content of phenolic compounds in comparison with previously studied Phoenix dactylifera specimens.     

Fatty Acid Content of Seed at Different Development Stages in Canola on Different Soil Types with Low Organic Matter

Abstract

Physical and chemical properties of vegetable oils and consequently their use, depend on the composition of fatty acids that accumulate in storage lipids during seed development. The objective of this study was to determine the combined effects of seed development stages and organic matter content of soil on oil fatty acid composition of canola. The experiments were carried out under field conditions on four soils with different organic matter contents. To evaluate seed oil content and fatty acid composition of canola, we harvested plants at six growth stages (GS), GS 75, GS 79, GS 83, GS 87, GS 92 and GS 99 including development of seed, ripening and senescence. The synthesis of oil and fatty acids were largely influenced by seed maturity and soil type. Seeds had maximum content of stearic and palmitic acids at GS 75 (50% of pods reach final size). The seed yield, oil content of seeds and oleic acid percentage of seed oil significantly increased with increasing rate of soil organic matter in canola. This study addresses the organic matter content in poor soils should be ameliorated not only to obtain higher crop yields but also quality production.     

一种快速大量提取禾谷类作物幼苗期总RNA的方法

为探索一种快速、大量提取禾谷类作物总RNA的方法,利用改良的热酚法提取禾谷类作物(玉米、水稻和小麦)幼苗期不同组织的总RNA,该方法在2.5 mL的离心管中进行,在提取缓冲液中增加了巯基乙醇,对传统的操作步骤进行了优化.提取的RNA质量较高,纯度检测表明RNA样品OD260/OD280在1.8～2.1之间,含量约为10 μg/μL.RT-PCR和Northern杂交结果表明RNA可以满足进一步分子操作的需要.     

油菜籽油分及脂肪酸同时测定的气相色谱快速方法

本文拟定了对菜籽油分与脂肪酸组分同时测定的气谱快速方法,基于使用氢氧化四甲铵为催化剂,酯交换在汽化室以热解方式进行,可使油分定量地转换成脂肪酸甲酯。甲酯总峰面积的大小,可作为含油量的量度,与外标作比较,求得菜籽的含油率;再对各脂肪酸甲酯的峰面积作归一化法处理,便可求得各脂肪酸的含量;与油重法和IUPAC庚烷法测定结果相比较,其相对误差分别为±3％和±3—10％,符合快速分析的要求。     

不同制粉方法对燕麦粉货架期的影响

为了解不同制粉方式对燕麦粉货架期的影响,以炒制燕麦粉、燕麦片粉、超微燕麦粉为研究对象,以脂肪酸值和丙二醛含量为评价指标,应用Arrhenius相关模型及热力学理论和统计学原理,比较了三种制粉方式生产的燕麦粉货架期。结果表明,三种燕麦粉的脂肪酸值和丙二醛含量均随贮藏时间延长呈上升趋势;50℃贮藏比40℃贮藏上升更明显,燕麦片粉上升的最快。燕麦粉发生氧化产生游离脂肪酸和丙二醛在40℃和50℃均遵循0级反应动力学,根据Arrhenius动力学模型和统计学原理,预测炒制燕麦粉、燕麦片粉、超微燕麦粉在常温(20℃)下的货架期分别为304d、140d、204d。     

不同地域茶叶EGCG含量差异研究

本文比较研究了长沙高桥镇、云南思茅和福建福安三地茶叶EGCG含量,以及东山峰不同海拔高度茶叶EGCG的含量。研究结果表明:湖南东山峰为加工高EGCG茶的适宜地域,其中东山峰海拔800m左右的EGCG含量最高。     

Predicting Jatropha curcas seed-oil content, oil composition and protein content using near-infrared spectroscopy—A quick and non-destructive method

The potential of near-infrared reflectance spectroscopy (NIRS) to estimate the oil content, fatty acid composition, and protein content of Jatropha curcas seeds was studied. Seventy-four intact kernels from various sources were scanned by NIRS. All samples were analyzed for oil content (hexane extractions), fatty acid composition (gas chromatography), and protein content (Kjeldahl). Calibration equations were developed for oil content, individual fatty acids (oleic C18:1, linoleic C18:2, stearic C18:0 and palmitic C16:0), and protein content. The performance of the calibration equations was evaluated through external and cross-validation. The results showed that NIRS was a reliable, accurate and nondestructive technique to estimate oil and protein contents, as well as oleic and linoleic fatty acid concentrations in J. curcas kernels; NIRS provides a rapid, simple, and cost-effective alternative method for screening intact J. curcas kernels.     

靛酚蓝比色法测定植物全氮含量方法的改进

改进苯酚测定植物全氮含量的方法。验证结果表明：溶液中的铵盐与显色液反应后,在690 nm附近有最大吸收峰,在0～300 mg/L的氮浓度ρN范围内,吸光度A690与ρN成正比,其相关系数R2＝0.998 2,所形成的颜色稳定长达6 h,干扰元素少;样品测定精密度在2%以内,加标回收率在97%～100%。改进后,待测液中氮浓度的测定范围提高了3倍,且不需调整pH值,并建立了测定植物全氮含量的相应方法。     

三角褐指藻 LPAAT基因在酵母中表达对脂肪酸的影响

从三角褐指藻（Phaeodactylum tricornutum）中克隆到1 632bp的溶血磷脂酸酰基转移酶(LPAAT)全长cDNA,其中包含的开放阅读框被命名为PtLPAAT。在毕赤酵母中异源表达PtLPAAT基因,诱导培养45h时随机选取的3个酵母转化子总脂肪酸含量分别提高了2.68%、11.14%、31.28%;诱导培养72h时同样的转化子总脂肪酸含量分别提高11.59%、18.72%、46.63%。用薄层层析法分离48h后的酵母菌体的甘油三酯,并用气相色谱法测定其脂肪酸,结果显示：与非转基因对照菌株相比,其油酸提高了0.9倍、亚油酸提高了5倍。用荧光定量PCR检测发现PtLPAAT基因的表达量随三角褐指藻油脂不断积累逐渐升高。表明在酵母中表达PtLPAAT基因不仅能够明显地提高其脂肪酸含量,而且还能选择性结合不饱和脂肪酸到甘油三酯中。     

7种油用山茶果实经济性状及籽油成分分析

以7种主栽油用山茶为材料,研究了不同山茶果实经济性状、茶油脂肪酸组成及角鲨烯、β-谷甾醇和维生素E等生物活性物质含量间的差异。结果表明：7种主栽油用山茶的果实经济性状、脂肪酸组成、角鲨烯、β-谷甾醇和维生素E含量均存在较大差异,其中小果油茶的鲜出籽率（60.07％）、干出籽率（37.47％）、鲜果含油率（10.76％）最高;浙江红山茶的出仁率（64.99％）、种仁含油率（60.23％）和干籽含油率（38.47％）最大,油酸（82.69％）和单不饱和脂肪酸（83.18％）含量最高、多不饱和脂肪酸（5.96％）含量最低,是高油酸品种选育的理想材料;7种山茶籽油中的角鲨烯、β-谷甾醇和维生素E等3类生物活性物质含量高低依次为β-谷甾醇＞角鲨烯＞维生素E,其中博白大果油茶的角鲨烯、β-谷甾醇和维生素E含量最为丰富,这可为3类活性物质利用提供潜在植物源树种。相关分析表明,β-谷甾醇含量与出仁率、干籽含油率呈显著负相关,角鲨烯、维生素E与果实经济性状相关不显著。