紫薯花青素的提取优化及稳定性分析

超声波法萃取下,用酒石酸酸化乙醇溶液作为提取剂提取紫薯花青素,探讨不同金属离子、酸度、温度等对紫薯色素的稳定性影响。实验结果表明,其提取的最优条件为:0.5%酒石酸-95%乙醇溶液(50∶50,V/V)作为提取剂、物料比为1∶50、超声(40 Hz)提取30 min。提取率达到1.003 mg/g;在5~60℃温度范围内紫薯花青素稳定性良好,pH为1~4色泽良好,金属离子Cu2+、Ag+、Fe3+影响紫薯色素稳定性。     

巴戟天中原花青素的提取工艺及其稳定性

研究乙醇浓度、料液比、提取时间和提取温度对巴戟天中原花色素提取效果的影响,优选提取工艺,并考察原花青素稳定性。最佳提取工艺为45%乙醇,料液比1∶25,60℃,提取30 min,提取液的平均吸光度为0.666,RSD=2.7%,n=6,结果表明该提取工艺重复性良好。野生巴戟天和种植巴戟天中原花色素含量分别为0.192%和0.186%。巴戟天中原花青素具有较好的耐光性、耐糖性、耐盐性,在低温、Na+、Mg2+、Ca2+条件下稳定,而在强酸、强碱、高温、H2O2、Na2SO3、Ba2+、Zn2+和Cu2+及Fe3+中不稳定。     

1-苯基氨基脲的合成研究

以盐酸苯肼和尿素为原料,用水作溶剂,在浓硫酸催化下合成1-苯基氨基脲。研究了原料摩尔比、浓硫酸和溶剂量、反应时间、催化剂用量对产品质量和收率的影响,确定了最佳工艺反应条件:n(盐酸苯肼)∶n(尿素)∶n(浓硫酸)∶V(水)=1∶1.2∶0.2∶500 mL,盐酸苯肼与催化剂的比例为1∶10(mol/g),反应时间10 h。放大实验的收率达到92%以上。     

南瓜黄色素的提取工艺优化及稳定性研究

用95%乙醇提取南瓜黄色素,并考察了光照、温度、pH值、金属离子及常用食品添加剂等对其稳定性的影响。结果表明:南瓜黄色素的最佳提取条件为:料液比1∶11g/mL,95%乙醇提取3.5h、pH6.0,提取温度60℃。南瓜黄色素溶液在强光和高温下不稳定,对pH值波动、大部分金属离子和食品添加剂溶液中表现稳定,但溶液中的Fe3+和十二烷基磺酸钠(SDS)对该色素有较大影响。     

加速溶剂萃取(ASE)技术提取海南萝芙木活性成分

考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。     

微波辐射法提取米糠中的肌醇研究

以盐酸、尿素为提取剂,脱脂米糠为原料,采用微波浸提、离子交换和微波水解从米糠中提取肌醇,并探讨其工艺条件。结果表明(1)微波浸提植酸较佳的工艺条件:功率为80 W,浸提时间5min,浸提温度55℃,中和方式二步法,离子交换流量(10~15)mL/min;(2)微波水解植酸制备肌醇的较佳工艺条件:V(甘油)∶V(水)=1∶1,植酸浓度0.5 mol/L,盐酸浓度0.05 mol/L,微波功率为120 W,辐射时间80 min。微波法从米糠中提取肌醇能显著缩短提取时间、降低成本,提高肌醇得率,并且具有操作简单,快速方便,环保友好等特点。     

蝇蛆壳中提取甲壳素工艺研究

以蝇蛆壳为原料提取甲壳素,并用盐酸除无机盐、氢氧化钠除蛋白质、次氯酸钠脱色.实验确定较佳工艺条件为:除无机盐,m(蝇蛆壳)∶V(HCl)=1 g∶5 mL(c(HCl)=2 mol/L),室温反应2 h;除蛋白质,m(蝇蛆壳)∶V(NaOH)=1 g∶5 mL(w(NaOH)=2%),室温下反应6 h.经质量分数为0.5%的NaClO室温3 h脱色后得到白色的甲壳素,收率30%(以干燥蝇蛆壳质量计).     

丙烯酰胺残留单体的提取及测定

采用异丙醇和甲醇的混合溶液对应用于化妆品行业的丙烯酰胺交联共聚物乳液中残留单体丙烯酰胺(AM)进行提取,得到较佳提取方案为:V(甲醇)∶V(异丙醇)=1∶1,超声30 min。并利用高效液相色谱对提取液中的AM进行测定,得出色谱条件为:流动相V(甲醇)∶V(水)=4∶96,流速1.0 mL/min,检测波长220 nm。在此色谱条件下测试回收率为99.02%~99.62%,相对标准偏差为1.44%。     

勿忘我花色素的性质研究

研究了勿忘我花色素的可见吸收光谱、光稳定性、热稳定性、酸碱度对色素的影响以及金属离子和几种食品添加剂对色素的影响。结果表明:勿忘我花色素品质较好,有广阔的开发前景。     

葡萄籽中原花色素的微波提取工艺研究

以微波作为外加物理场,采用乙醇-水为提取剂时,利用单因素优选和正交实验筛选探索提取葡萄籽中原花色素的适宜提取工艺条件。通过实验发现适宜的提取条件为:提取剂乙醇的浓度为60%,料液比为1∶8,微波功率为650 W的条件下加热80 s,然后在40℃下浸泡3 h,此时原花色素的提取率为4.52 mg/g。     

C.I.颜料红48:2表面改性的研究

2B酸重氮化与2,3酸偶合,30分钟后,填加阴离子表面活性剂,用氯化钙进行色淀化得标题颜料。分散剂MF、扩散剂NNO、聚丙烯酸、红油使颜料的鲜艳度、着色力和透明度提高,色光有所变化;MF、NNO和聚丙烯酸使颜料的流动性提高;红油、十二烷基磺酸钠使流动性下降;阴离子表面活性剂可提高颜料在二甲苯中的分散性。     

酞菁染料包覆TiO2制备红外反射颜料

采用酞菁染料(直接耐晒翠蓝GL)包覆金红石型TiO2制备蓝色系列红外热反射复合颜料,研究了TiO2的包覆工艺,获得了较优的工艺条件如下:m(BaCl2)∶m(TiO2)=0.2,反应温度80 ℃,反应液pH=8.将此复合颜料制成涂料,研究了涂料的红外反射、隔热及耐酸碱性能.结果显示,含此蓝色复合颜料的涂层其红外反射率高...     

Specific determination of malonaldehyde by N-methyl-2-phenylindole or thiobarbituric acid

Reactivity of a commercially available test kit (LPO-586), based on N-methyl-2-phenylindole, toward aldehydes was characterized and compared with that of thiobarbituric acid (TBA). In hydrochloric acid, LPO-586 produced a violet pigment with malonaldehyde (MA) but not with other tested aldehydes. In methane sulfonic acid, LPO-586 produced the violet pigment with MA and 4-hydroxynonenal (HNE), but not with other tested aldehydes. Pigment formation with MA was not inhibited by other aldehydes, but that with HNE was inhibited by alka-2,4-dienals. TBA produced a red pigment with MA but not with other tested aldehydes in hydrochloric acid or in acetate with ethylenediaminetetraacetic acid (EDTA). Both the LPO-586 test in hydrochloric acid and the TBA test in hydrochloric acid or in acetate with EDTA can be used for specific measurement of MA in oxidized lipid samples.     

Thiobarbituric acid reaction of aldehydes and oxidized lipids in glacial acetic acid

Thiobarbituric acid (TBA) reaction of several aldehydes and oxidized lipids in glacial acetic acid was performed. All the samples were freely soluble in the solvent used. Saturated aldehydes produced a stable yellow pigment with an absorption maximum at 455 nm, a red pigment derived from malonaldehyde at 532 nm, and an orange pigment due to dienals at 495 nm. The absorbance maximum was 7–9 per μmol for saturated aldehydes, 27.5 per μmol for malonaldehyde and about 2 per μmol for dienals. Autoxidation of unoxidized lipids increased progressively in glacial acetic acid. When the TBA test was performed under nitrogen, autoxidation of unoxidized lipids was inhibited completely. While saturated aldehydes produced no yellow pigment under nitrogen, oxidized lipids produced a considerable amount of stable yellow pigment. The value for absorbance at 455 nm as a function of autoxidation time paralleled those of peroxide values. The absorbance of most oxidized lipids at 455 nm was higher than at 532 nm. Yellow pigment formation in the TBA test under nitrogen could not be ascribed to free saturated aldehydes but rather to unspecified closely related substances. The stable yellow pigment was found to be an excellent indicator of lipid oxidation.     

紫红色四季报春花色素的提取及稳定性研究

以紫红色四季报春花为原料提取色素,并对该色素的稳定性进行研究。结果表明,适宜的提取溶剂为pH=1的95%乙醇溶液,该色素在382 nm处有最大吸收峰;该色素热稳定性差,有较强的耐光性,耐氧化性,还原性差,在酸性条件下不稳定;金属离子Na+、K+、Mg2+、Zn2+对色素的影响较小,而Fe3+对该色素稳定性的影响较大;常用食品添加剂(葡萄糖、蔗糖、可溶性淀粉和柠檬酸)对该色素色泽无不良影响。     

Desorption of soy oil lutein from rice hull cristobalite with polar solvents

The effectiveness of sequential isopropanol/hexane washes of increasing polarity for desorbing soy oil pigment (lutein) from alkaline and acid rice hull ash was studied. Increasing the polarity promoted desorption of pigment. However, the amount of pigment desorbed with each extraction decreased after washing with 2% isopropanol. More lutein was desorbed as the amount of adsorbed lutein increased. Desorption from acid ash was greater than that from alkaline ash, which may be due to the absence of potassium from acid ash. The data suggest that the adsorption sites, occupied by lutein, are not all equally accessible to isopropanol, probably because of the irregular structure of the ash.     

一串红色素的提取及其稳定性研究

研究了一串红色素的提取原理和方法,并对该色素的稳定性进行了验证。结果表明：该色素在酸性条件下对热、光均具有良好的稳定性,具有开发应用价值。     

A Quantitative study of polymeric dispersant adsorption onto oxide-coated titania pigments

Polyacrylic acid salts and similar copolymers are used extensively in the coatings industry to disperse oxide-coated titania pigments. The effect of polymer adsorption onto the pigment can vary widely depending on polymer composition, pigment surface treatment, and solution properties such as pH and ionic strength. This investigation examines the effect of molecular weight on the adsorbed layer thickness and stabilizing action of polyacrylic acid dispersants. In order to understand the stabilization mechanism, a DLVO model was used in which the surface treatment layer of the pigment and the adsorbed layer thickness of the dispersant were taken into account. It was found that only this level of detail could account for the degree of stability found in pigment suspensions. Layer thickness and adsorption isotherms indicate that the dispersant molecules do not adsorb completely flat to the pigment surface but with enough loops and tails to provide some electrosteric stabilization.     

桑椹红色素提取试验

本试验从桑椹原浆中提取桑椹红色素 ,并对其理化性质开展研究。结果表明 ,在所采用工艺条件下 ,桑椹红色素浸膏得率 11% ;桑椹红色素属花青素类色素 ,在酸性条件下 ,对温度、光照和食品添加剂的影响 ,显现出较稳定的特征。还对桑椹红色素浸膏的营养成分作了测试分析     

Characteristics of the thiobarbituric acid reactivity of human urine as a possible consequence of lipid peroxidation

A 532 nm red pigment formed in the thiobarbituric acid (TBA) assay of human urine was characterized after separation of the pigment by high-performance liquid chromatography. The yield of the red pigment was some-what higher at pH 2 than at pH 5; its development was not inhibited by ethylenediaminetetraacetic acid. The characteristics of the pigment were similar to those of the pigment derived from standard malonaldehyde. The amount of the pigment formed was roughly equal to the content of malonaldehyde derivatives estimated as 1-(2,4-dinitrophenyl)pyrazole. Pigment formation was significantly enhanced byt-butyl hydroperoxide (t-BuOOH) and ferric ions, which may be due to pigment formed from aldehydes other than malonaldehyde; the presence of these aldehydes was confirmed by the formation of the corresponding 2,4-dinitrophenylhydrazones. The amount of pigment produced from 24-h urine samples of 12 healthy subjects was estimated to be 26–95 nmol/kg, and 65–182 nmol/kg in the presence oft-BuOOH. These values are lower than those for urine of rabbit or rat. The TBA reactivity in the absence and presence oft-BuOOH of human urine was not related to age or sex. The TBA reactivity of human urine collected in the afternoon and in the evening was higher than that of urine collected in the morning.