高速逆流色谱分离纯化氧化葵花油中三亚油酸甘油酯单氢过氧化物

该文为了获得较高纯度的三亚油酸甘油酯单氢过氧化物,用于"脂肪调控氧化-热反应"制备肉味香精机理的研究。葵花油在70℃下通空气0.72 m3/(kg.h)氧化70 h制备含三亚油酸甘油酯单氢过氧化物的氧化产物,采用液-质联机定性及液相色谱-蒸发光散射检测器面积归一化定量,氧化产物中三亚油酸甘油酯单氢过氧化物质量分数为1.95%。高速逆流色谱分离该氧化产物中的三亚油酸甘油酯单氢过氧化物,较佳的两相溶剂系统为V(正己烷)∶V(二氯甲烷)∶V(乙腈)=4∶1∶3。以上相为固定相,下相为流动相,正向洗脱,流速1.5 mL/min,转速850 r/min,上样5 g,分离时间195 min,一次性得三亚油酸甘油酯单氢过氧化物53 mg,液相色谱-蒸发光散射检测器分析纯度为96.3%,回收率52.3%。     

鸡脂控制氧化-热反应制备鸡肉香精

以过氧化值、茴香胺值和酸值表征鸡脂氧化状态,通过正交实验研究了氧化温度、氧化时间、空气流速等因素对鸡脂控制氧化的影响,确定了以制备肉味香精前体物为目标的鸡脂氧化较优工艺:氧化温度120℃、氧化时间2 h、空气流速0.025 m3/(h.100 g脂肪)。热反应条件固定为加热温度110℃,时间40 m in,w(氧化鸡脂)=1%,感官评价了各氧化鸡脂的热反应产物气味特征,确定了鸡脂控制氧化-热反应制备鸡肉香精的氧化鸡脂工艺指标:过氧化值200~600 mmol氧/kg脂肪,茴香胺值105~330,酸值<4.7 mg KOH/g脂肪。     

以葵花油为原料酶法制备香味料

绿色植物散发的新鲜的青香香气的主要成分是己醛、己烯醛、庚醛、壬烯醛等化合物,它们是植物体内脂肪氧合酶、裂解酶作用下的脂肪酸代谢产物。己醛、己烯醛、庚醛、壬烯醛等脂肪醛类成分现已是批准使用的食用香料,主要通过化学合成方法制备,常用于花香香精、果香香精、肉味香精、蔬菜香精、辛香香精等多种香精产品中。     

二次萃取蒸馏法提取废次烟叶中烟碱的研究

采用二次萃取蒸馏法,提取废次烟叶中的烟碱。废次烟叶经过浸提、萃取、硫酸反萃、二次萃取和减压蒸馏等处理以提取烟碱,用紫外分光光度法分析了烟碱含量。结果表明,较佳的工艺条件为:以4.5 g/L的NaOH溶液浸泡粉碎后的烟叶,置于60℃水浴中振荡3.5 h,过滤得浸提液;滤渣再次浸提,并将两次浸提液合并。调节浸提液pH≥13,用正己烷按照体积比1∶2萃取浸提液3次。有机相用20%硫酸溶液反萃,调节pH≥13后,用正己烷二次萃取,合并有机相,减压蒸馏,以回收有机溶剂,残液即为含量40%的烟碱产品,提取率达75%。     

反胶束萃取精氨酸脱亚胺酶

报道了用反胶束体系萃取精氨酸脱亚胺酶(ADI)的研究结果,为精氨酸脱亚胺酶的分离纯化提供了一种方法。在反胶束体系中采用十六烷基三甲基溴化铵(CTAB)作为表面活性剂,正辛烷和丁醇作为溶剂及助溶剂。考察了水相pH、振荡时间、离子强度、表面活性剂浓度及精氨酸脱亚胺酶质量浓度等因素对精氨酸脱亚胺酶分离纯化效果的影响。实验结果表明,当c(CTAB)=0.01 mol/L,pH=7,振荡时间15 min,体系中用于反萃取的c(NaCl)=0.75 mol/L,且起始粗酶质量浓度控制在30 g/L时,通过辛烷/丁醇/CTAB反胶束体系的萃取和反萃取,ADI酶液萃取率E达到85%,比活达到1.107 U/mg,是起始酶液的4.52倍。     

酶解-溶剂提取银杏叶活性成分工艺条件

研究了酶法与溶剂提取相结合提取银杏叶中活性成分银杏黄酮的工艺条件。通过正交试验找出纤维素酶法及溶剂提取的最佳工艺条件,通过紫外分光光度检测及紫外扫描进行产物分析。纤维素酶的最佳提取工艺条件为纤维素酶浓度40 U/mL,酶解pH值4.8,酶解温度55℃,酶解时间90 m in。溶剂提取的最优工艺条件为无水乙醇∶粗提液(体积比)=1∶10,石油醚∶粗提液(体积比)=3∶1,乙酸乙酯∶粗提液(体积比)=2∶1。酶解-溶剂提取是一种安全高效的提取方法。     

盐湖卤水萃取提硼试验研究

以西藏某盐湖卤水浓缩液为研究对象,对影响萃取和反萃取的诸多因素如料液酸度、萃取剂配比、萃取和反萃取时间、反萃取剂浓度、相比等进行了详细试验研究,获得了混合醇提硼适宜的萃取条件：原料液pH=3,混合醇萃取剂与磺化煤油的体积比V（2-乙基-1,3-己二醇）∶V（异辛醇）∶V（磺化煤油）=3∶7∶10,相比为1.0,萃取时间为 10 min;反萃取条件：反萃取剂浓度为0.3 mol/L,相比为1.0,反萃取时间为10 min。在此工艺条件下,萃取率＞96%,反萃取率＞95%。另外,在本原料液体系中,以二元醇与一元醇的混合醇作为萃取剂萃取硼,萃取效果远好于一元醇。     

乙醛酸法合成香兰素过程研究

以乙醛酸与愈创木酚为原料合成香兰素,分别对其缩合反应、氧化反应做了考察。结果表明,缩合反应较优反应条件为:物料滴加加入,反应温度为35℃,反应时间为6 h,n(乙醛酸)∶n(愈创木酚)∶n(氢氧化钠)=1∶2∶3,未反应愈创木酚先用甲苯萃取,再用氢氧化钠溶液反萃取,用于下次反应;氧化反应较优反应条件为:硫酸铜为氧化剂,n(硫酸铜)∶n(3-甲氧基-4-羟基扁桃酸)=2.4∶1,反应温度为95℃,反应体系pH=13,反应时间为7 h,氧化剂使用双氧水再生。缩合产物收率达到89.5%,氧化产物收率达到98.2%,香兰素精品收率可达到80%,纯度>99.8%,高于以往文献报道。     

乙醛酸法合成香兰素过程研究

以乙醛酸与愈创木酚为原料合成香兰素,分别对其缩合反应、氧化反应做了考察。结果表明,缩合反应较优反应条件为:物料滴加加入,反应温度为35℃,反应时间为6 h,n(乙醛酸)∶n(愈创木酚)∶n(氢氧化钠)=1∶2∶3,未反应愈创木酚先用甲苯萃取,再用氢氧化钠溶液反萃取,用于下次反应;氧化反应较优反应条件为:硫酸铜为氧化剂,n(硫酸铜)∶n(3-甲氧基-4-羟基扁桃酸)=2.4∶1,反应温度为95℃,反应体系pH=13,反应时间为7 h,氧化剂使用双氧水再生。缩合产物收率达到89.5%,氧化产物收率达到98.2%,香兰素精品收率可达到80%,纯度99.8%,高于以往文献报道。     

1,4-双(辛烷基)哌嗪萃取体系萃取模拟电镀废水中的Co2+

将1,4-双(辛烷基)哌嗪、白油和乙酸异辛酯配制成萃取体系。利用该萃取体系萃取模拟电镀废水中的Co~(2+)。最佳萃取方案为:m(模拟电镀废水)∶m(萃取体系)=1∶1,m[1,4-双(辛烷基)哌嗪]∶m(白油)∶m(乙酸异辛酯)=1.00∶3.00∶0.50,萃取时间10 min,萃取pH值6.0。1,4-双(辛烷基)哌嗪萃取体系对Co~(2+)的饱和萃取量为221.2 mg/L。当pH值为5.5～6.5时,Co~(2+)的萃取率大于75.0%。另外,采用1,4-双(辛烷基)哌嗪萃取体系时,Co~(2+)的质量浓度范围较为宽泛。     

Effect of processing on sphingolipid content in soybean products

Soybeans are believed to be a rich source of sphingolipids, a class of polar lipids that has received attention for their possible cancer-inhibiting activities. The effect of processing on the sphingolipid content of various soybean products has not been determined. Glucosylceramide (GlcCer), the major sphingolipid type in soybeans, was measured in several processed soybean products to illustrate which product(s) GlcCer is partitioned into during processing and where it is lost. Whole soybeans were processed into full-fat flakes, from which crude oil was extracted. Crude oil was refined by conventional methods, and defatted soy flakes were further processed into alcohol-washed and acid-washed soy protein concentrates (SPC) and soy protein isolates (SPI) by laboratory-scale methods that simulated industrial practices. GlcCer was isolated from the samples by solvent extraction, solvent partition, and TLC and was quantified by HPLC. GlcCer remained mostly within the defatted soy flakes (91%) rather than in the oil (9%) after oil extraction. Only 52, 42, and 26% of GlcCer from defatted soy flakes was recovered in the acid-washed SPC, alcohol-washed SPC, and SPI products, respectively. All protein products had a similar GlcCer concentration of about 281 nmol/g (dry wt basis). The minor quantity of GlcCer in the crude oil was almost completely removed by water degumming.     

An analysis scheme for estimation of crude oil quality

A seed analysis scheme was designed to rapidly estimate the quality of extracted oil. Factors of crude oil quality evaluated were: free fatty acids, oxidative status (Totox value), color, and phosphatides (soybean) or wax (sunflower). Soybean and sunflower seeds subjected to extended storage at varying moisture contents were sampled at incremental time periods to yield fifty storage-damaged samples of each oilseed. Oil was extracted from 50-g lots of each sample and analyzed for the crude oil quality factors according to standard methods. Alternative instrumental and chemical analyses of the quality factors were correlated with the standard methods. Hexanal content, measured by headspace-gas Chromatographie analysis of the ground full-fat meal, was correlated to the oxidative status. Crude oils recovered by rapid extraction, using sonication, and desolventation were monitored by spectrophotometry for color correlation. Free fatty acid content was determined by titration methods and monitored by spectrophotometry. Modified turbidimetric methods estimated the phosphatides (soybean) or wax (sunflower seed) contents. The analysis scheme provides for the rapid estimation of oil quality as impacted by various pre- and post-harvest events that cause deterioration of oilseeds. The mention of firm names or trade products does not imply that they arc endorsed or recommended over other firms or similar products not mentioned.     

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%。     

Evidence of an Enzymatic Source of Off Flavors in “Lipoxygenase-Null” Soybeans

The utilization of soybean products as food ingredients and foods is often limited by their beany-grassy flavor. Eliminating seed lipoxygenase (LOX) isozymes 1, 2 and 3 reduces the amounts of volatile off-flavor compounds in stored soybeans and soy products significantly, but they are not completely eliminated. The present work presents evidence that lipoxygenase-null (LOX-null) soybeans contain a LOX-like enzyme that is responsible for the off-flavors in LOX-null soybeans. Volatiles production in triple LOX-null soybeans was terminated by heat treatment, which suggests an enzymatic cause to the off-flavors. The source is LOX-like in that the volatile compounds produced are similar to LOX-generated products of polyunsaturated fatty acids. Oxygen was consumed when a LOX-null protein solution was incubated with crude soybean oil suggesting that the enzyme catalyzed oxygen consuming reactions. The generation of flavor compounds was inhibited by the typical LOX inhibitors propyl gallate and nordihydroguaiaretic acid (NDGA). The enzyme appears to be more active with phosphatidylcholine than with other lipid substrates. The cause of the off-flavors in LOX-null beans appears to have enzyme-like characteristics. This is the first report of the initial characterization of this LOX-like enzyme.     

Isolation and quantitation of lectins from vegetable oils

The factor(s) responsible for the unexplained atherogenicity of peanut oil remain to be elucidated. To this end, we developed a technique to determine if lectin was present in the oil and to quantitate its concentration. This technique was applied to other vegetable oils including corn, soybean, and sunflower. Crude, unprocessed corn and soybean oils were also analyzed for lectin content. The crude oils contained from 858 to 2983 μg lectin per kg, while the refined oils contained 24 to 55 μg/kg of biologically active lectin. The identities of the isolated lectins were confirmed by electrophoresis on SDS-polyacrylamide gels. The biological significance of the presence of lectin in these oils remains to be determined.     

Components of the hardening flavor present in hardened linseed oil and soybean oil

The characteristic hardening flavor which develops in hardened linseed and soybean oils during storage has been coned from hardened linseed oil by stripping with nitrogen. After separating the volatile substances by adsorption chromatography on silica, the fraction containing the hardening flavor has been converted into 2,4-dinitrophenylhydrazones (DNPHs) and separated by means of partition chromatography. On regeneration of the fractions of DNPSs obtained, the characteristic hardening flavor was observed in one specific band. Both by hydrogenation and by oxidation of the free carbonyl the carrier of the flavor was found to be an unsaturated aldehyde; however, not of the α-β unsaturated type. Further separation of the regenerated carbonyls by means of gas-liquid chromatography (GLC) points to a C₉-aldehyde. After synthesis of the 4-,5- and 6-cis- andtrans-nonenals, comparison made it probable that the carrier of the hardening flavor is a mixture of 6-cis and 6-trans-nonenal, the latter of which has the greatest share in the hardening flavor. In order to confirm the location of the double bond in the carrier of the hardening flavor a recent isolation technique was applied. The volatile substances from hardened linseed oil were first separated via GLC. After conversion of the carbonyls in question into their DNPHs, the latter have been separated by means of thin-layer chromatography (TLC). By means of IR-analysis and oxidation with osmium tetroxide of the pure derivative, the principal carrier of the hardening flavor has been identified as 6-trans-nonenal.     

Minor components responsible for flavor reversion of soybean oil

Edible refined, bleached and deodorized (RBD) soybean oil was fractionated by silicic acid column chromatography to identify minor components responsible for flavor reversion. Minor components from oil eluted with diethyl ether/n-hexane (1:1) were compared with those from corn and canola oils. All vegetable oils contain free fatty acids, diglycerides and sterols as major ingredients in this fraction. However, unusual triglycerides consisting of 10-oxo-8-octadecenoic acid and 10-and 9-hydroxy octadecanoic acids were detected in RBD and crude soybean oils.     

Using SPME-GC/MS to Evaluate Acrolein Production in Cassava and Pork Sausage Fried in Different Vegetable Oils

This work presents the quantification of acrolein in cassava and pork sausage fried (temperature of 170 °C) in five different vegetables oils: canola, palm, sunflower, soybean and corn using a method of solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry. The results showed that the highest concentration of acrolein was found in samples fried in sunflower oil and canola oil. The concentration of acrolein in pork sausage (3.7 and 2.0 ng/g/g) was lower than in cassava (10.2 and 3.8 ng) when fried in sunflower and soybean oils, respectively. In contrast, when the denser oils (canola and palm) were used for frying, the concentration of acrolein in pork sausage (6.3 and 3.8 ng/g) was higher than in cassava (3.7 and 2.8 ng/g). Using corn oil, the concentrations of acrolein in both cassava and sausage were similar (approximately 5 ng/g). The viscosity of the oil, the fatty acid composition, especially the level of saturated and unsaturated fatty acids from the food, and oil uptake are factors that influence the acrolein concentration found in fried food.     

环氧葵花油的合成及其对PVC性能的影响

采用无溶剂工艺合成了环氧葵花油,并利用转矩流变仪、差示扫描量热仪等进一步研究了其对聚氯乙烯（PVC）热稳定性、增塑效果的影响。结果表明,反应温度为60 ℃、反应时间为5 h、过氧化氢和葵花油摩尔比为2:1、催化剂用量为原料总质量的3 %时,环氧葵花油的环氧值达到了6.78 %;环氧葵花油与钙锌稳定剂并用具有协同作用,可以增强PVC的长期热稳定性,效果比环氧大豆油更好;环氧葵花油还能使PVC的玻璃化转变温度、硬度、拉伸强度降低,断裂伸长率升高,可以作为PVC增塑剂使用。