木醋液制备及形成机理研究进展

生物质能具有来源广泛、绿色无污染、可再生和低廉易得等优点，开发高附加值产品对生物质资源多元化利用和解决能源危机具有重要的战略意义。木醋液是生物质热解制炭工艺中的高价值酸性副产物，已被广泛应用于农业、林业、畜牧业、工业和医药业等多个领域，均显现出正面的促进作用。本文综述了木醋液制备工艺、理化性质、分离方法及形成机理的研究进展，从生物质组分（半纤维素、纤维素和木质素）热解的角度阐述了木醋液中主要有机化合物的形成机理。木醋液颜色呈浅黄色或红褐色，密度为1.00~1.13g/cm³，pH为2.27~3.32，有机酸含量为2.07%~13.82%，热解温度170~350°C下制得的木醋液的物理及化学性质满足日本农用木醋液标准。文章指出木醋液富含酸类、酚类、酮类、呋喃类、醛类、醇类、酯类和醚类有机物，酸类化合物（主要是乙酸）和酚类化合物（主要是愈创木酚）使木醋液具备优良的抗微生物活性和抗氧化活性，并且酚类化合物使其具有烟熏气味的独特性质。联合不同单一分离法精制木醋液的效果最佳，可适用于不同领域的多种用途。在生物质热解过程中，游离水、吸附水和结合水随着温度升高依次析出，半纤维素、纤维素和木质素再分解成挥发性有机物质与水，共同冷凝后形成木醋液。但是，传统热解工艺制备得到木醋液的产率低及温度对成分含量的影响显著是限制木醋液发展的主要瓶颈。水热法是一种新兴的木醋液制备技术，其产率高，焦油成分少，包含的有机化合物种类更多。此外，从生物油中直接萃取也可快速制备含有相同有机组分的木醋液。因此，本文提出未来研究应着重于开发和研究高效且便捷的木醋液制备技术、分离技术及其机理，同时结合先进的催化技术与膜分离技术，以便利于制备高品质木醋液和直接地应用于不同领域，早日实现木醋液的规模化应用。     

脱臭馏出物中植物甾醇的回收和精制

以脱臭馏出物为原料，采用甲醇酯化、结晶分离、溶剂重结晶净化精制工艺，对回收和精制植物甾醇的过程进行了研究. 实验结果表明，应用该工艺从油脂脱臭馏出物中提取的植物甾醇含量大于95%，过程总收率达80%以上，为从脱臭馏出物中提取植物甾醇的工业化生产提供了技术依据.     

蒸馏-色谱法分析煤焦油中萘含量的研究

煤焦油中萘含量是焦油出厂检验的一个重要指标,针对色谱法分析煤焦油中萘含量时会堵塞色谱柱的问题,研究了用蒸馏-色谱法分析煤焦油中萘含量。采用自制的煤焦油蒸馏及馏出物保温装置,收集350℃前馏出物,以四氢萘作为内标物,通过气相色谱法分析出馏出物中的萘含量,进而计算出煤焦油中萘含量。试验结果表明：该方法具有良好的准确度和精密度,并且能够防止煤焦油堵塞色谱毛细管柱。     

裂解法测定沥青蜡含量应注意的问题及对策

通过比对试验,介绍了沥青蜡含量测定过程中应注意的问题,如裂解蒸馏的速率、馏出物初馏时间、馏出物取样量、冷洗剂加入量、漏斗孔径、抽滤过程真空度及在操作过程中可以采取的预防措施,使试验结果更准确.     

木醋液中醋酸含量的测定

木醋液中醋酸含量因干馏热解原料、工艺、贮存周期的不同而存在差异。本文针对秸秆干馏热解产生的木醋液中总有机酸含量,分别用化学和仪器分析方法对其进行测定,所得结果基本吻合。     

木醋液多酚研究进展

在前期统计木醋液有机酸类成分组成的基础上,从木醋液酚类成分、木醋液多酚的提取和生物活性等角度综述木醋液多酚的研究现状。热解温度对木醋液总酚浓度有影响。采用pH值梯度萃取分离法可以获得木醋液多酚。木醋液多酚主要为儿茶酚、甲基儿茶酚、根皮酚等多酚类化合物。木醋液多酚具有抗氧化等生物活性,在医药、食品、化妆品等领域具有开发价值。     

木醋液多酚研究进展

在前期统计木醋液有机酸类成分组成的基础上,从木醋液酚类成分、木醋液多酚的提取和生物活性等角度综述木醋液多酚的研究现状。热解温度对木醋液总酚浓度有影响。采用pH值梯度萃取分离法可以获得木醋液多酚。木醋液多酚主要为儿茶酚、甲基儿茶酚、根皮酚等多酚类化合物。木醋液多酚具有抗氧化等生物活性,在医药、食品、化妆品等领域具有开发价值。     

PVA/木醋液/PVA复合膜的制备和表征

制备了5种聚乙烯醇(PVA)/木醋液/PVA复合膜,并分别对其力学性能和透光率进行表征。研究结果表明PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的平均厚度较小(0.67 mm);PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的拉伸强度较大(82.47 Mpa);PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的断裂伸长率较小(17.5%)。PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的透光率较好。PVA/木醋液/PVA复合膜在木醋液抑菌膜领域具有开发价值。     

MD-S80短程蒸馏设备传质性能研究

采用MD-S80短程蒸馏设备分离邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二丁酯(DBP),考察了蒸馏温度、蒸馏压力、刮膜转速、进料速率等实验条件对蒸馏的影响.研究表明降低蒸馏温度、刮板转速和进料速率都有利于轻组分在馏出物富集,但馏出物减少;提高蒸馏压力有利于轻组分在馏出物中富集,但馏出物减少.     

木醋液的制备及精制研究进展

以农林废弃物为原料,干馏法制备粗木醋液。探讨了木醋液的内涵和外延。综述了生物质热解机制、粗木醋液的制备工艺条件优化及精制方法。以液体为主要产物的热解温度一般在700℃以下。静置法和木炭或活性炭吸附法及过滤法的联用,是常见的粗木醋液精制生产方法。脱色脱味精制木醋液的研发,在医药等领域具有开发价值。     

邵东玉竹营养成分分析

对邵东玉竹的营养成分进行了分析研究。结果表明,邵东玉竹中含糖成分较高,达到了8.14 g/100 g。粗纤维的含量是3.84 g/100 g,灰分和蛋白质的含量分别是1.74 g/100 g和3.32 g/100 g。玉竹中所含氨基酸不但种类较多,且氨基酸含量丰富,所测的17种氨基酸含量在0.18~0.96 g/100 g之间,总氨基酸的含量为12.51 g/100 g,其中人体必须氨基酸的含量为3.14 g/100 g。此外,玉竹中含有丰富的人体必需微量元素Fe、Cu、Zn和Mn。     

杨桃花中的氨基酸和微量元素的测定与分析

利用氨基酸自动分析仪和火焰原子吸收光谱法测定了杨桃花中的17种氨基酸和6中微量元素.结果表明,氨基酸含量为14.88%,其中必需氨基酸占总氨基酸的比值为36.56%,必需氨基酸与非必需氨基酸的比值为57.63%.杨桃花中Cu、Zn、Mn、Fe、Mg、Ca 6种微量元素含量分别是7.03,37.78,435.78,90....     

Chemical composition of the cellular biomass of yeasts

This work is aimed at analyzing yeast strains, possibly used in animal feeding, obtained by batch cultivation from cheese whey as main carbohydrated substrate. For that purpose 10 yeast strains selected for its biomass production capacity were chemically analyzed. From the results, it can be observed that the chemical composition of the strains is quiet variable, showing in all cases high protein content, good solubility and enzymatic digestibility. In all of them, the RNA content is low, being this important if the biomass is utilized in human feeding. On the other hand, they have an adequate content of essential amino acids, although the sulphur amino acids content is deficient. Among the tested yeasts, Kluyveromyces marxianus var. lactis (No. 10) stands out for the good relationship it has between protein and RNA content, as well as for the detection of methionine among its essential amino acids.     

4种鸡汤中游离氨基酸的组成及呈味贡献对比分析

将鸡肉煮汤,经离心、冷冻干燥后,利用氨基酸自动分析仪进行游离氨基酸的测定及呈味分析,研究了北京油鸡、三黄鸡、奔跑鸡、散养鸡的鸡汤中游离氨基酸的种类及对呈味的贡献。4种鸡汤中均鉴定出17种游离氨基酸,其中必需氨基酸7种,含量最高的是组氨酸。总氨基酸含量最高的是散养鸡汤(46.47 g/L),最低的是三黄鸡汤(16.86 g/L)。必需氨基酸总含量最高的是散养鸡汤(10.02 g/L),最少的是三黄鸡汤(3.88 g/L)。4种鸡汤中苦味氨基酸各为9种,鲜味2种,甜味5种,鲜味氨基酸质量分数最高的为三黄鸡汤(18.42%),甜味氨基酸质量分数最高的为奔跑鸡汤(30.41%)。根据氨基酸滋味活性值(TAV)得出,北京油鸡汤中对滋味有贡献的氨基酸为11种,三黄鸡汤6种,奔跑鸡汤10种,散养鸡汤11种。通过电子舌主成分分析(PCA)和判别指数,表明差异最小的是奔跑鸡汤和三黄鸡汤,最大的是散养鸡汤和北京油鸡汤。     

Roles of amino acids,protein, and fiber in leaf-feeding resistance of corn to the fall armyworm

The free amino acids have been shown by isolational work and choice bioassays to be more important than all other factors evaluated in defining leaf-feeding resistance of corn (Zea mays L.) to fall armyworm (FAW) [(Spodoptera frugiperda J.E. Smith)] larvae. 6-MBOA (6-methoxybenzoxazolinone) and maysin, toxins present in corn, were shown not to be significant factors for leaf-feeding resistance to first-instar FAW larvae because of their low concentrations in the whorl. Amino acid analysis showed that while the ratios of the essential amino acids in susceptible (S) and resistant (R) lines were similar, there were differences in the nonessential amino acids, particularly aspartic acid, which was higher in R lines. Also, the ratio of essential amino acids to nonessential amino acids was important, being too low in expressed whorl leaf juice (obtained from V₈–V₁₀ growth stage plants) to support larval growth, although juice was stimulatory in choice tests. The total protein content of whorls in S lines was about 15% higher than in R lines, but the significance of this difference is uncertain, because nutritional tests showed that larval growth increased with total protein only up to 12% protein. Sugars were only slightly stimulatory. Thus, the amino acids along with higher hemicellulose content of R lines, established by us earlier, appear to explain much of the basis of resistance in corn to larval leaf-feeding of the FAW.     

高效液相色谱法测定发酵酱油中的氨基酸含量及分析

采用高效液相色谱法分析了两种发酵酱油中的氨基酸。结果表明,低盐固态发酵酱油与高盐稀态发酵酱油中均含有丰富的氨基酸,8种必需氨基酸含量比例分别达到46.05%与41.45%。虽然低盐固态发酵酱油的总氨基酸与必须氨基酸的含量高于高盐稀态发酵酱油,但高盐稀态发酵酱油中呈味氨基酸特别是甜味和鲜味氨基酸的含量较高,从而使高盐稀态发酵酱油滋味更加鲜美。     

亚致死浓度氟啶虫胺腈对桃蚜体内能量物质的影响

[目的]明确氟啶虫胺腈亚致死浓度对桃蚜体内能量物质的影响,旨在为氟啶虫胺腈对靶标害虫的解毒代谢机理提供更多的理论参考。[方法]通过GC-MS分析法,测定氟啶虫胺腈亚致死浓度(LC10和LC30)胁迫下,桃蚜体内脂肪酸、氨基酸及可溶性糖的组成及含量变化。[结果]氟啶虫胺腈亚致死浓度作用下,桃蚜体内的总脂肪酸含量显著降低,除了LC10处理组的豆蔻油酸,LC30处理组的花生烯酸和神经酸,药剂处理组各脂肪酸含量均显著低于对照处理组;总氨基酸含量LC10处理组显著低于对照处理组,LC30处理组显著高于对照处理组,与对照处理相比,LC10处理组未检测到蛋氨酸,而LC30处理组除了检测到对照组中所有游离氨基酸外,另外检测到谷氨酸;与对照组相比,药剂处理组总可溶性糖含量均有所增加,但LC10处理组与对照组无显著性差异,LC30处理组显著高于对照处理组。[结论]氟啶虫胺腈亚致死浓度作用下,桃蚜体内的脂肪酸、氨基酸及糖类组成及含量均会发生不同程度的变化,上述能量物质在一定程度上参与了桃蚜对氟啶虫胺腈的解毒代谢过程,但具体的解毒代谢过程有待进一步研究。     

Nutrient Composition of Larval Nectar Secretions from Three Species of Myrmecophilous Butterflies

A comparative chemical analysis of the larval nectar secretions and hemolymph from three unspecifically and facultatively ant-attended lycaenid species (Polyommatus coridon, P. icarus, and Zizeeria knysna) was performed by using high-performance liquid chromatography techniques. Sucrose was the main sugar component in all three species. In half of the samples of P. coridon, it was accompanied by glucose, whereas other sugars occurred only rarely. In P. icarus and Z. knysna, melezitose was the second-most important component, followed by fructose and glucose. Total sugar contents were 43.6 ± 14.8 g/l (mean ± SD) for P. coridon, 74.2 g/l for P. icarus, and 68.3 ± 22.6 g/l for Z. knysna. Up to 14 different identified amino acids were found in P. coridon nectar, with a total content of 9.7 ± 3.4 g/l. Leucine was always the major component (contributing 50% of overall amino acid content). Other important amino acids were tyrosine, proline, arginine, and phenylalanine. P. icarus nectar contained up to six amino acids with a total content of 1.2 g/l, dominated by tyrosine and phenylalanine. Z. knysna nectar contained alanine and proline, with only 0.3 ± 0.17 g/l total content. In the hemolymph of all species, up to 16 different amino acids occurred relatively regularly, with histidine dominating, followed by serine and proline. The amino acid pattern in hemolymph was considerably different from that of the nectar secretions. Larval diet weakly influenced P. coridon nectar sugars, and with a semisynthetic diet, a more homogeneous amino acid pattern was detected. Comparison with reports from other lycaenid species shows that secretions rich in amino acids are related to intimate, often obligate ant associations, whereas facultative, unspecific myrmecophiles rely on carbohydrates.     

猪牛鸡肉酶解液中游离氨基酸及呈味特性的对比分析

为对比分析猪肉、牛肉与鸡肉酶解液中游离氨基酸的组成及含量,采用氨基酸自动分析仪分析检测猪肉、牛肉与鸡肉酶解液中的游离氨基酸,通过计算味道强度值(TAV)确定各游离氨基酸对猪肉、牛肉与鸡肉酶解液滋味的贡献率。 结果表明,鸡肉酶解液中鲜味和甜味氨基酸质量分数以及味道强度值均大于猪肉和牛肉酶解液,3种酶解液中味道强度值最大的均为组氨酸,其次为苯丙氨酸,均为呈苦味氨基酸,可见猪、牛、鸡肉酶解液整体滋味以苦味为主。     

Quality of US Soybean Meal Compared to the Quality of Soybean Meal from Other Origins

Quality of soybeans and soybean meals (SBM) from non-US and US origins were compared. The US SBM was more consistent with higher digestibility (by KOH solubility), lower fiber and better quality of protein (by essential amino acid levels) than SBM of other major export origins (Argentina, Brazil and India). Protein quality carried through from whole soybeans to SBM, for a given origin. While the protein content was higher for the SBM from Brazil, the percentage of total digestible amino acids was highest for the SBM from the US and China. The US SBM had the highest content (total) of five essential amino acids for both poultry and swine feed uses, which when coupled with higher digestibility, would give US meal an advantage in rations balanced on amino acids. The mean particle size for all SBM from all origins was within the desirable range specified by nutritionists. The US soybeans were lower in protein than Brazilian soybeans, but higher than Argentine soybeans. The crude protein disadvantage of US soybeans was offset by higher concentrations of the essential amino acids in the lower protein soybeans. The US soybeans were lower in oil content than soybeans from either of the South American origins. Average protein and oil contents of US soybeans were consistent with the 2003 and 2004 annual soybean quality surveys. The US SBM held an advantage in digestibility and concentration of key amino acids in all three studies.