大豆甾醇

大豆甾醇之所以被誉为“生命的钥匙”，是因为大豆甾醇广泛存在于生物体组织内，具有十分重要的生理功能。很自然地，对甾体科学的研究就成为医学界和制药工业中引人瞩目的领域，其实在化学工业、食品、饲料和生物工程产业中，大豆甾醇也备受国内外科学家的关注，对大豆甾醇的研究和应用目前相当活跃。说起大豆甾醇，有必要先从甾醇谈起，甾醇是甾族化合物的一类，因呈固态又俗称固醇。甾醇的分布很广，各种生物体中几乎都含有这一类甾族化合物。它们以游离、高级脂肪酸酯、苷三种形式存在于动、植物和微生物体内。     

α-亚麻酸甾醇酯检测技术研究

植物甾醇酯是一种新型功能性食品添加剂,具有良好亲脂性和降胆固醇效果。采用薄层色谱法、紫外分析法、红外分析法和气相色谱法相结合的方法对α-亚麻酸甾醇酯产品进行分析检测,为α-亚麻酸甾醇酯和甾醇的分离、定性和定量提供参考。     

微孔草种子油脂肪酸及不皂化物的分析

采用气相色谱法对我国青藏高原特有的野生油料作物微孔草种子油的脂肪酸和不皂化物进行分析。结果表明，其脂肪酸成分以不饱和脂肪酸为主，亚油酸、亚麻酸有较高的含量，三萜醇含有环阿屯酸及其衍生物，4-甲基甾醇以纯叶大戟甾醇和环桉烯醇为主，甾醇以菜油甾醇和β-谷甾醇为主。     

芥菜籽油和亚麻仁油中脂肪酸和不皂化物成分的分析

采用高效液相色谱和气相色谱对芥菜籽油和亚麻仁油中的脂肪酸和甾醇、４—甲基甾醇、三萜醇等不皂化物成分进行了分离、鉴定和测定。     

大豆植物甾醇及其生理功能

文中概述了大豆中植物甾醇的化学结构，在人体内存在形式、吸收、代谢及安全性等。大豆植物甾醇通过抑制胆固醇的吸收和影响胆固醇代谢，达到降低人体胆固醇的效果。     

基于磁性固定化酶的α-亚麻酸植物甾醇酯合成工艺研究

采用固载有Candida rugosa的磁性固定化酶为生物催化剂,并将其用于α-亚麻酸植物甾醇酯的酶促合成。通过响应面分析优化实验条件,得到最佳工艺参数为：固定化酶用量为25.2mg/mL,甾醇底物浓度为146.5μmol/mL,异辛烷为溶剂,55℃反应5h,得到的植物甾醇的酯化率为92.61%。该固定化脂肪酶经过简单的溶剂清洗可以重复使用10次以上,仍能保持71.8%的催化活性。     

某些特油植物资源的脂肪酸类型及用途

按脂肪酸类型介绍特油植物资源，其中包括合长链脂肪酸的Crambe，Limnanthes,Lunaria和Tropaeolum，短链脂肪酸的Cuphea和Lauraceae，羟基脂肪酸的Lesquerella，环氧脂肪酸的Vernonia和Stokesia，以及液体蜡酯的Simmondsia等科、属植物。     

不同产地的紫苏籽油活性成分检测与主成分分析

为评价油品质与营养功能,有效开发不同产地的紫苏籽油,收集19个产地的紫苏籽,分析了油的理化性质,脂肪酸、维生素E、植物甾醇等活性成分的组成及含量。结果发现：紫苏籽油主要含有棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸五种脂肪酸,亚麻酸含量58.8%～70.9%,不饱和脂肪酸含量91.1%～93.8%;紫苏籽油含有△-5燕麦甾醇、菜籽甾醇、β-谷甾醇及环阿廷醇,总甾醇含量67.0mg/100g～94.4mg/100g;紫苏籽油含有α-生育酚、β-生育酚、γ-生育酚,γ-生育酚占总生育酚含量95%左右,总的生育酚含量为63.4mg/100g～99.4mg/100g。通过主成分分析及主成分中各性状载荷分析发现,α-亚麻酸、γ-生育酚、菜籽甾醇是紫苏籽油的特征活性成分,对不同产地的紫苏籽油差异影响较大。对紫苏籽油的12个脂溶性活性成分进行分层聚类热图分析,可将19个产地的紫苏籽油分成6大类。      

菜籽油不皂化物中甾醇成分的分析

采用制备型高效液相色谱法将菜籽油不皂化物分离为甾醇、４－甲基甾醇、三萜醇和烃四类。甾醇部分经乙酰化后，由气相色谱法分析，并采用硝酸银硅胶制备薄层色谱法和高效液相色谱法进一步分离。分得的主要组分经薄层、气相色谱、溶点、红外光谱和质谱鉴定，并分离得到β－谷甾醇，菜油甾醇，菜籽甾醇和△５－燕麦甾醇等纯品。被认定的有２４－亚甲基胆甾醇、豆甾醇、△７－豆甾烯醇和△７－燕麦甾醇。     

微波和脱皮处理菜籽对油中活性成分的影响

以高、中、低芥酸和硫甙含量菜籽为原料,微波和脱皮预处理后分别冷榨制油。结果表明,同一品种菜籽不同处理方式对基本品质并无影响,但油中植物甾醇和维生素E含量均存在明显差异,且含量大小依次为低芥酸低硫甙菜籽＞中芥酸中硫甙菜籽＞高芥酸高硫甙菜籽。利用SPSS (统计产品与服务解决方案,Statistical Product and Service Solutions)方差分析,探讨4种不同处理方式与3种不同原料对菜籽油中维生素E和植物甾醇的影响。结果表明,不同处理方式对双低菜籽油中α、γ维生素E和△5-燕麦甾醇影响差异显著,对菜籽甾醇、菜油甾醇和β-谷甾醇影响不显著;同一种处理方式下,不同原料对维生素E和植物甾醇都存在显著差异。微波处理后油中维生素E和植物甾醇含量最高,且低芥酸低硫甙菜籽更适宜通过微波处理提高油的品质。     

Analysis of bioaccessibility of campesterol,stigmasterol, and β-sitosterol in maize by in vitro digestion method

The content of campesterol, stigmasterol, and β-sitosterol in raw and cooked Big Flint Maize (BFM), Pop Corn Maize (PCM) and Red Maize (RM) were analyzed by using a chemical method and using in vitro digestion of cooked samples. RM contained 15.14, 8.36, and 72.19 mg/100 g campesterol, stigmasterol, and β-sitosterol, respectively, which were higher compared to in BFM and PCM. Samples cooking resulted in 6–48% increase in phytosterol content, while cooked RM had the highest phytosterol content. Using the in vitro digestion method, 44–61% reduction in phytosterol content was observed in contrast to the chemical method. The difference bioaccessible campesterol and β-sitosterol contents among varieties was insignificant, except for stigmasterol in RM. The bioaccessibility of campesterol was 44–56% higher than those of stigmasterol and β-sitosterol, and it was higher in BFM and PCM. In conclusion, phytosterol contents estimated in different maize samples using in vitro digestion can be another determinative for the ultimate content and reveals the necessity to consider with chemical method of determination.     

用气相色谱-质谱联用法分析澳洲坚果幼叶的挥发性成分

利用气相色谱-质谱联用的方法(GC-MS)对澳洲坚果幼叶的挥发性成分进行了定性定量分析。在不同极性的色谱柱和不同程序性的升温条件下,采用正己烷和乙酸乙酯对澳洲坚果幼叶进行分步萃取,分离鉴定出45种挥发性成分,包括烃及其衍生物27种,酮3种,醛2种,醇3种,酸2种,酯8种共六大类物质。其中,不饱和脂肪酸(亚麻酸、棕榈酸)、植物甾醇、酚类等物质,不仅具有一定的营养价值,还具有降血压血脂、抗氧化抗癌等保健功能。     

Distribution and composition of phytosterols and steryl ferulates in wheat grain and bran fractions

Phytosterols and steryl ferulates are bioactive compounds accumulating in the bran and germ of wheat. However, little is known regarding their localisation and composition in the bran layers of the kernel. The aim of this study was to determine the distribution of phytosterols and steryl ferulates in the wheat grain and in the different layers of bran. The wheat fractions, produced by conventional debranning, aleurone separation and a novel electrostatic process, were analysed for phytosterol contents using GC–FID and for steryl ferulate contents using HPLC–UV. The compounds were identified by GC– and LC–MS. Phytosterols and steryl ferulates were concentrated in the bran layers. The steryl ferulates were accumulated in the intermediate layers, whereas the phytosterols were more evenly distributed in the intermediate layers and aleurone cell contents. The phytosterol composition varied within the wheat kernel, while the steryl ferulate composition was similar in different fractions. Sitosterol and campestanyl ferulate were the main compounds. The highest levels of phytosterols (up to 2117 μg/g) and steryl ferulates (up to 703 μg/g) were found in the pearling, aleurone and certain bran fractions. The phytosterol-rich fractions could be utilised in cereal foods to enhance the intake of health-promoting compounds from natural sources.     

Evaluation of Camelina sativa oil as a feedstock for biodiesel production

The oilseed crop Camelina sativa (camelina) has lower production costs than oilseed rape in some climates. For this reason, the production of biodiesel-grade methyl ester from camelina oil was evaluated. The evaluation included quality assessment of esters produced in laboratory and pilot plant, an examination of methods of improving ester low-temperature properties, and vehicle trials. Laboratory esterifications gave ester yields similar to rape-seed oil. Six 350 kg batches of unrefined camelina oil with acid values from 3 to 6 were esterified in a pilot plant. Ester-specific properties were satisfactory with one exception; the iodine number of 155 far exceeded the value of 120 required by the relevant EU standard. Fuel-specific properties of the camelina methyl esters were largely within specification, though low-temperature behaviour could be a problem in some climates. This problem could be overcome by the use of suitable pour-point depressants or by blending with diesel oil. In vehicle tests, the reduction in fuel economy with camelina ester was similar to that with biodiesel from other feedstocks. The high iodine number of camelina methyl ester did not lead to a more rapid deterioration of the lubricating oil. However, it was concluded that further engine trials would be needed before the use of camelina ester as an undiluted vehicle fuel could be recommended.     

外源添加糖及氨基酸对咖啡果皮酒风味和感官品质的影响

为探究不同外源添加物对咖啡果皮酒风味和感官品质的影响,本研究添加4种可发酵糖（葡萄糖、果糖、麦芽糖和蔗糖）和2种可发酵氨基酸（精氨酸和谷氨酸）发酵生产咖啡果皮酒。以顶空固相微萃取-气相质谱法结合感官评价,分析外源添加物对咖啡果皮酒风味和感官品质的影响。结果表明:共检出9大类75种风味组分,以酯类和醇类为主;添加可发酵糖能显著增加咖啡果皮酒醇类组分（23.99%~121.24%）,添加可发酵氨基酸咖啡果皮酒能增加酯类组分（25.77%~28.18%）,而添加可发酵糖咖啡果皮酒酯类组分显著减少（10.81%~69.94%）;方差齐性检验P=0.206>0.05,在α=0.05的水平上各外源添加物果酒风味组分没有显著性差异,事后两两比较P=(0.371~0.989)>0.05,说明样品间差异不显著,但PCA分析（PC1:96.01%,PC2:3.13%）能将其完全区分;使用模糊数学法感官评判发现,添加精氨酸所酿造的果酒综合得分最高（92.40）,更加适合人们的口味,整体风格显著,协调性好,谷氨酸添加次之（80.80）,果糖和蔗糖所酿造的咖啡果皮酒综合评分一致（78.20）,添加麦芽糖果酒得分最低（74.20）。综上所述,添加氨基酸可改善咖啡果皮酒风味和口感,发酵糖改善效果不如氨基酸。     

Extraction of lipids from flax processing waste using hot ethanol

The cuticle of flax stems contains lipids that provide a protective barrier to pathogens and control moisture loss. These lipids include wax esters and long chain fatty alcohols or policosanols. Cuticle fragments generated during several different fiber processing operations retain these lipid compounds that represent a potential co-product. Samples of flax shives (i.e., lignified core tissues), processing dust, and cuticular fractions recovered from enzyme retting waste water were extracted on a laboratory scale with hot ethanol to remove the lipid compounds. Ethanol extracts were analyzed by gas chromatography to determine the amount and type of lipids recovered. The results demonstrated that hot ethanol effectively extracted the lipid compounds from cuticle fragments in all these samples. When the extract was cooled, the longer chain wax esters (i.e., chain length of 44 carbon atoms or larger) precipitated and could be separated from the shorter chain lipid components (i.e., fatty alcohols and aldehydes less than 44 carbons). Similar results were obtained using absolute ethanol or 95% ethanol (aqueous). This technique provides a very economical method to recover lipid fractions as potential value-added co-product from flax processing waste.     

pH control for dyebath reuse in dyeing of polyamide with binary mixtures of acid dyes

Hydrolyzable organic esters were compared with ammonium sulphate as an acid donor for the pH control in dye-bath-reuse system of acid dyes mixtures. The ability of pH control, levelness, dyeing properties and reproducibility in dye-bath-reuse system were investigated comparatively. Hydrolyzable organic esters showed higher exhaustion and color yield than ammonium sulphate. In addition, hydrolyzable organic ester exhibited very low conductivity less than 0.5 mS, while ammonium sulphate give high conductivity. However, we could not observe any difference in levelness of dyed samples between two kinds of acid donors in laboratory scale dyeing. Over 10 cycles of reuse, hydrolyzable organic esters showed higher reproducibility than ammonium sulphate. No deterioration of the color fastness and levelness occurs over 10 cycles of reuse.