大豆脂肪氧合酶催化合成氢过氧化玉米胚芽油

研究了大豆脂肪氧合酶催化合成氢过氧化玉米胚芽油的反应。考察了溶剂种类、溶剂量、温度、底物浓度对氢过氧化玉米胚芽油得率的影响。较佳反应条件为：5℃下．当溶剂乙醇体积分数为4％,底物浓度100g／L,硼酸-硼砂缓冲液（pH9．0）,反应1．5h后氢过氧化玉米胚芽油得率为53．3％。     

脱脂豆粉催化合成大豆油氢过氧化物

研究了脱脂豆粉催化合成大豆油氢过氧化物的反应。考察了豆粉过筛目数、温度、豆粉浓度、pH值对大豆油氧化的影响。最佳反应条件为豆粉过筛目数80目,豆粉浓度180 g/L,氧化温度10℃,缓冲液pH=9,反应时间3 h,大豆油氢过氧化物产率61.9%。在相同条件下(除反应时间),精酶液催化反应1.5 h达平衡,大豆油氢过氧化物产率54.8%。比豆粉催化最佳产率降低了7.1%。     

玉米秸秆稀酸水解与水解液发酵的实验研究

研究了玉米秸秆的稀酸水解性能,考察了底物浓度、反应温度、反应时间、硫酸浓度和秸秆粒径对水解得率和木糖得率的影响.在硫酸浓度为1.0%、水解温度126℃、水解时间1 h、底物浓度为50～80g/L情况下,玉米秸秆的水解得率为21.7%～24.6%,木糖得率为68.0%-77.1%.所得水解液主要成分为木糖和葡萄糖,经处理后可直接用于微生物的发酵培养.     

接枝共聚改性脱脂豆粉胶粘剂的研究

脱脂豆粉悬浮液经脲预处理后,以APS—NaHSO3氧化还原体系为引发体系,通过自由基聚合,采用BMA接枝共聚改性。研究了反应条件对接枝共聚改性脱脂豆粉胶粘剂的T剥离强度和耐水性的影响,得出较佳工艺条件为:BMA/SPI:50%,APS/BMA:0.6%,NaHSO3/APS:1/1.5,接枝时间:3h,接枝温度:80℃。此条件下的T剥离强度为130.6N/m,约为最小值的两倍,耐水性为50.55%。     

低含量双氧水制备过一硫酸氢钾复合盐的研究

针对目前双氧水氧化法制备过一硫酸氢钾复合盐工艺中所用到的双氧水浓度过高问题,探究出以30%的低质量分数双氧水为原料,对双氧水氧化法制备过一硫酸氢钾复合盐的工艺进行了改进。研究通过单因素实验考察了不同双氧水稳定剂、过氧化反应和中和反应温度、静置结晶时间和原料配比对制备过一硫酸氢钾复合盐的影响,并确定了适宜工艺路线。采用XRD对产品进行表征分析。实验得到适宜工艺条件:采用HEDP为双氧水稳定剂、过氧化反应温度5℃、中和反应温度7℃、静置结晶时间为3 h、n(双氧水)∶n(发烟硫酸)∶n(氢氧化钾)=1∶1.3∶1。在此工艺条件下,制得的过一硫酸氢钾复合盐活性氧质量分数达4.78%,收率达53.5%,稳定性达97.2%。     

克里唑替尼及其中间产物的优化合成研究

优化了克里唑替尼的合成路线,以3-羟基-5-溴-2-硝基吡啶为起始原料,经Mitsunobu反应后,通过酯化引入吡啶环结构,再经过氨基保护作用,发生Suzuki偶联反应得到终产物。以中间产物3为对象,讨论反应温度、反应时间、pH对得率的影响;从单因素考虑,分别在反应温度90℃、反应时间13 h、结晶pH 5.5时得率最高,经测定中间产物得率为89.3%。     

蒸汽爆破麦草同步糖化发酵转化乙醇的研究

近年来对木质生物资源同步糖化发酵转化乙醇的研究较多,但是,麦草同步糖化发酵转化乙醇的最佳工艺条件还未确定。文中采用正交试验设计的方法,对在混合酶(纤维素酶Celluclast 1.5 1,β-葡萄糖苷酶Novozym 188)与酿酒酵母菌作用下,稀硫酸催化的蒸汽爆破麦草原料同步糖化发酵转化乙醇的工艺条件进行研究,详细讨论了反应温度、底物质量浓度、发酵液pH值、纤维素酶浓度对乙醇质量浓度和得率的影响。结果表明,工艺条件对乙醇质量浓度和得率的影响程度由高到低依次为:底物质量浓度、纤维素酶浓度、发酵液pH值、反应温度。最佳工艺条件为反应温度35℃,底物质量浓度100 g/L,发酵液pH值5.0,纤维素酶浓度30 FPU/g。在此条件下,随着反应时间的延长,乙醇质量浓度持续上升。反应72 h后,乙醇质量浓度和得率分别达到22.7 g/L和65.8%。     

氢过氧化大豆油还原制备羟基大豆油

用亚硫酸钠还原氢过氧化大豆油制备羟基大豆油,并考察了溶剂种类,溶剂浓度,温度,还原剂亚硫酸钠量及还原时间对反应的影响.在实验条件下,最佳工艺条件为：15℃、以88.2 ％（V/V体系）的乙醇为溶剂、n（Na2SO3）∶n（-OOH）=1.2∶1、反应1.5h.氢过氧化大豆油的转化率达95.8％.     

酶法提取茵陈总黄酮的工艺研究

以酶法提取茵陈中黄酮类化合物,用紫外-可见比色法和芦丁为标准品测定茵陈总黄酮的得率,研究酶用量、pH值、温度、乙醇浓度、提取时间对黄酮得率的影响。最佳工艺条件为纤维素酶的浓度0.10 mg/mL,pH=4.2,温度50℃,乙醇浓度为60%,恒温振荡1.5 h,此条件下黄酮的得率为3.513%。     

氢过氧化异丙苯催化合成工艺

研究相转移催化剂四丁基溴化铵 (TBAB) / [双 (水杨醛 5 磺酸钠 ) 1,2 丙二胺 ]合钴 (Ⅱ )(Co5SO3 NaSALPN) (A)对异丙苯空气氧化的催化作用 ,考察了反应温度、搅拌速度、水的初始浓度及n(TBAB)∶n(A)对氢过氧化异丙苯产率的影响。常压、反应温度 80℃、搅拌速度 12 0 0r/min、水的初始浓度 2 0mol/L、n(TBAB)∶n(A) =15 0∶1等条件下 ,w (氢过氧化异丙苯 ) =2 6 % ,符合工业生产上的要求     

Yield and quality of tofu made form soybeans and soy/peanut blends

The yield and quality of tofu made from blends of soybeans and raw peanuts, partially defatted peanut flour, and defatted peanut flour were investigated. Defatted peanut flour appears to be the most compatible with soybeans for tofu making, followed by partially defatted peanut flour and raw peanuts. Raw peanuts could be incorporated at levels of 10% while partially defatted or defatted peanut flour could be incorporated at a level of 20%: higher levels produced tofu with either poor texture or low yield. SEM images of tofu made from 100% soybeans showed a uniform, continuous, three-dimensional honeycomb-like protein network structure. When 10% of the soybeans was replaced by either raw peanuts; partially defatted peanut flour; or defatted peanut flour, the protein strands that make up the network structure were thicker than those of 100% soybean tofu. When soybeans were replaced with either of the three peanut products at a 30% level, the protein strands of the network structure were either less continuous or appeared perforated.     

Substitution reactions of linoleic acid hydroperoxide isomerase

Linoleic acid hydroperoxide isomerase was extracted from corn germ and partially purified by differential centrifugation. This enzyme catalyzed the isomerization of linoleic acid hydroperoxide.(see article) Isomerase also catalyzed the substitution of various reagents at the carbon bearing the hydroperoxide group. These fatty acid products had the following functional groupings: (see article) where X is either oleoyloxy, ethylthio, or methoxy resulting from the presence of oleic acid, ethanethiol, or methanol, respectively. A crude wheat germ extract containing both lipoxygenase and isomerase enzymes reacted with linoleic acid to yield alpha-ketols, gamma-ketols, and a substitution product, the linoleoyloxy ester of alpha-ketol. Characterization of these products from wheat germ enzymes showed that the substitution reaction was not unique to corn germ. Because anions of the reagents tested are typical nucleophiles, the substitution reactions may proceed by a nucleophilic mechanism as mediated by the isomerase enzyme.     

大豆脂肪氧合酶酶促合成亚油酸氢过氧化物

研究了水相体系中大豆脂肪氧合酶酶促合成亚油酸(LA)氢过氧化物的反应,最佳反应条件为底物质量浓度4 11g/L,pH=9,5℃,反应时间120min,亚油酸氢过氧化物产率80%。当m(LA)∶m(surfactant)=1∶1时,Tween系列、CTAB、AOT、AEO4、OAPCG、S8390均能加速反应,其中AEO4使反应时间缩短至30min,产率提高12%。一些盐可以明显地加快反应进程,其中柠檬酸钠使反应时间缩短至15min。外源Fe3+在反应体系中的浓度为0 5μmol/L或外源Fe2+为5nmol/L时反应速度显著提高,消除了滞后期。     

以葵花油为原料酶法制备香味料

从豆粕中浸提脂肪氧合酶粗酶液。葵花油皂化制备脂肪酸。通过单因素实验和正交实验研究了温度、时间、脂肪酸质量浓度、酶、空气流速、pH等因素对于脂肪酸氧化的影响,确定了获得较高过氧化值(79.56 mmol/kg)氧化产物的氧化工艺:酶液100 mL〔m(豆粕)∶m(水)=1∶5浸提制备〕,ρ(脂肪酸)=84 g/L,氧化温度10℃,缓冲液pH=9、空气流速0.12 m3/h,氧化时间6 h。经同时蒸馏萃取,氧化产物被降解并萃取出生成的香成分,萃取液浓缩得香味料,具有青香、油脂香香气特征,收率为320 g/kg葵花油。经气-质联机分析,香味料主要由己醛、反-2-壬烯醛、2,4-癸二烯醛、反-4-壬烯醛等C5~C11的挥发性饱和或不饱和脂肪醛组成。     

Effect of Natural and Pretreated Soybean Hulls on Enzyme Production by Trichoderma reesei

The enzyme induction utility of soybean hulls (SBH), consisting in excess of 50 wt% non-starch polysaccharides (NSP) cellulose, hemicellulose, and pectin, was studied through cultivation of the carbohydrase-producing fungus Trichoderma reesei Rut C-30. Shake flask systems of T. reesei were grown in a medium consisting of defatted soybean flour as a nitrogen source and SBH, some of which were untreated and others pretreated by liquid hot water, alkaline, and supercritical carbon dioxide, as carbon source. Cellulase, xylanase, and polygalacturonase activities were measured for the systems, and the natural hull systems were found to yield optimum enzyme production. Controlled batch fermentation experiments were carried out to compare enzyme production resulting from media with Avicel^® (FMC BioPolymer, Philadelphia, PA, USA) versus natural SBH with and without soybean flour as the nitrogen source. Soybean hull fermentations were also performed at several pH levels to observe the effects on enzyme production. Soybean hulls induced comparable levels of cellulase, and higher levels of xylanase and polygalacturonase, than Avicel^®. With SBH, cellulase and xylanase production were enhanced at higher pH levels (6.0), and polygalacturonase was enhanced at lower pH levels (4.0–4.5). Enzyme production was largely unaffected by the presence of soybean flour as the nitrogen source.     

微波辐射相转移催化下合成大豆油蔗糖多酯

用微波辐射技术,以大豆油脂肪酸乙酯和蔗糖为原料,十六烷基三甲基溴化铵作相转移催化剂,用两步法合成大豆油蔗糖多酯。用响应曲面分析法中的Box-behnken模型对影响大豆油蔗糖多酯产率的3个主要因素(催化剂质量分数、微波功率、反应时间)进行了优化。优化出的最佳合成条件为:微波功率433W,反应时间33min,x(催化剂)=2.3%。在该条件下蔗糖多酯的产率达88.81%,酯化度达6.5。     

Soybean lipoxygenase is active on nonaqueous media at low moisture: a constraint to xerophilic fungi and aflatoxins?

Previous workers have reported that certain products of the lipoxygenase pathway are detrimental either to the development and growth of Aspergillus species or to aflatoxin production by these organisms. Since Aspergillus often thrives on “dry” stored grains, depending on the level of the relative humidity, we sought to determine if lipoxygenase could catalyze the oxidation of linoleic acid on these “dry” substrates equilibrated at various relative humidities. A desiccated model system, previously adjusted to pH 7.5, was composed of soybean extract, linoleic acid, and cellulose carrier. The model system was incubated for up to 24 h at four relative humidities ranging between 52 and 95% to determine the extent of oxidation catalyzed by lipoxygenase, compared with heat-inactivated controls. Oxidation in the active samples was much greater than in the controls at all relative humidities, and oxidation was principally enzymatic as demonstrated by chiral analysis of the linoleate hydroperoxides formed. The main product was 13S-hydroperoxy-9Z,11E-octadecadienoic acid, accompanied by a significant percentage of 9S-hydroperoxy-10E,12Z-octadecadienoic acid. Since the products became more racemic with time of incubation, autoxidation appeared to be initiated by the lipoxygenase reaction in dry media. Additionally, the biological relevance of lipoxygenase activity was tested under these xerophilic conditions. Thus, enzyme-active and heat-inactivated defatted soy flour amended either with or without 3.5% by weight linoleic acid was inoculated with fungal spores and incubated at 95% relative humidity. Although fungal growth occurred on all treatments, samples inoculated with Aspergillus parasiticus showed significantly less aflatoxin in the enzyme-active samples, compared to inactivated flour. Addition of linoleic acid had little effect, possibly because the defatted soy flour was found to contain 1.7% residual linoleic acid as glyceride lipid.     

Lipase‐catalyzed ethanolysis of soybean oil in a solvent‐free system using central composite design and response surface methodology

BACKGROUND: In this work we describe the synthesis of ethyl esters, commonly known as biodiesel, using refined soybean oil and ethanol in a solvent‐free system catalyzed by lipase from Thermomyces lanuginosus. Central composite design and response surface methodology (RSM) were employed to optimize the biodiesel synthesis parameters, which were: reaction time, temperature, substrate molar ratio, enzyme content, and added water, measured as percentage of yield conversion. RESULTS: The optimal conditions obtained were: temperature, 31.5 °C; reaction time, 7 h; substrate molar ratio, 7.5:1 ethanol:soybean oil; enzyme content, 15% (g enzyme g⁻¹ oil); added water, 4% (g water g⁻¹ oil). The experimental yield conversion obtained under these conditions was 96%, which is very close to the maximum predicted value of 94.4%. The reaction time‐course at the optimal values indicated that 5 h was necessary to obtain high yield conversions. CONCLUSION: A high yield conversion was obtained under the optimized conditions, with relative low enzyme content and short time. Comparison of predicted and experimental values showed good correspondence, implying that the empirical model derived from RSM can be used to adequately describe the relationship between the reaction parameters and the response (yield conversion) in lipase‐catalyzed biodiesel synthesis. Copyright © 2008 Society of Chemical Industry     

Analysis of autoxidized fats by gas chromatography-mass spectrometry: V. Photosensitized oxidation

The role of singlet oxygen in oxidation was studied by analyzing hydroperoxide isomers in unsaturated fats and esters by gas chromatography-mass spectrometry (GC-MS). On oxidation photosensitized with methylene blue at 0 C, methyl oleate produced a 50–50% mixture of 9- and 10-hydroperoxides, linoleate a mixture of 66% conjugated (9+13) and 34% unconjugated (10+12) hydroperoxides, and linolenate a mixture of 75% conjugated (9+12+13+16) and 25% unconjugated (10+15) hydroperoxides. Cottonseed, safflower, and corn oil esters showed, as in soybean esters, the presence of varying amounts of 12-hydroxy esters derived from the corresponding hydroperoxide at low peroxide values. Since these oils do not contain linolenic acid, a likely source of the 12-hydroperoxide is linoleic acid by photosensitized oxidation. Several lines of evidence support the conclusion that singlet oxygen may contribute to the unique hydroperoxide composition of vegetable oil esters at low levels of oxidation. In the presence of photosensitizers such as methylene blue and chlorophyll, the unique hydroperoxide composition (high levels of 10- and 12-hydroperoxides) obtained in soybean esters was similar to that produced by oxidation at low peroxide values. In contrast, a normal hydroperoxide composition was produced, as expected from the fatty acid composition of soybean oil esters, when singlet oxygen quenchers such as β-carotene and α-tocopherol were used and when the esters were treated with carbon black to remove natural photosensitizers. GC-MS analyses of the derived unsaturated alcohols provided indirect evidence for 12-hydroperoxy-9,13-diene in soybean esters as expected by photosensitized oxidation of linoleate. Presented at the AOCS Meeting, San Francisco, California, April 29–May 3, 1979. The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.