新型氨基甲酸乙酯人工抗原的制备与表征

目的合成新型氨基甲酸乙酯(ethylcarbamate,EC)人工抗原并对其效果进行表征分析。方法用4-(二苯基羟甲基)苯甲酸对EC衍生化合成半抗原,用核磁氢谱(proton nuclear magnetic resonance, NMR)、核磁碳谱和质谱法(massspectrometry,MS)对其结构进行表征;用活化酯法将EC半抗原与牛血清蛋白(bovine serum albumin, BSA)偶联得到EC人工抗原。用紫外光谱和荧光光谱法对人工抗原进行表征并计算偶联比,用考马斯亮蓝法测定蛋白含量,间接竞争酶联免疫法鉴定其免疫活性。结果 EC半抗原结构与理论结构一致,半抗原与BSA成功偶联,偶联比为13:1,冻干粉的蛋白含量为0.695 mg/mg,用该新型人工抗原免疫小鼠,得到的抗血清效价为1:10000,且特异性较好。结论该新型氨基甲酸乙酯半抗原具有较好的免疫活性。     

低聚半乳糖糖基化法降低牛乳αs1-酪蛋白抗原性和免疫原性

用等电点沉淀法从牛乳中提取酪蛋白,根据αs-酪蛋白对尿素溶液溶解特性从酪蛋白中提取αs-酪蛋白,并用阴离子交换层析使αs1-酪蛋白与αs2-酪蛋白分离。用低聚半乳糖通过在一定条件下的美拉德反应对αs1-酪蛋白进行糖基化处理,通过竞争ELISA实验检测αs1-酪蛋白糖基化产物的抗原性。结果表明,该糖基化产物的抗原抗体结合常数Kd较αs1-酪蛋白上升3.7倍,即低聚半乳糖糖基化处理使αs1-酪蛋白的抗原性得到显著降低。用动物实验和非竞争ELISA实验检测αs1-酪蛋白糖基化产物的免疫原性,结果显示免疫原性降低19%,该实验证实对降低牛乳αs1-CN抗原性和免疫原性具有显著效果,为开发较理想的、切实可行的新脱敏奶粉生产技术提供了科学依据。     

单板层积材力学性能研究

经三种不同的外部条件处理后,使用无损检测设备(FFT)和力学试验机对杉木单板层积材试件静曲强度和弹性模量进行测量。结果表明,试件含水率在纤维饱和点以下时,无损检测方法(FFT)测得的弹性模量和力学试验机测得的静曲强度和弹性模量具有较优的线性相关性;在试件纤维饱和点以上,无损检测方法测得的弹性模量和力学测得的弹性模量有较优的线性相关性,而与静曲强度无线性相关性;单板层积材的静曲强度和弹性模量随着含水率的增加而降低。     

ISOLATION AND IN VITRO HYDROLYSIS OF GLOBULIN G1 FROM LENTILS (LENS CULINARIS, MEDIK)

The major globulin fraction from lentil seeds was investigated with respect to in vitro hydrolysis by trypsin and chymotrypsin. Globulin was isolated by a NaCl-ascorbate extraction procedure and purified by DEAE-cellulose chromatography and gel filtration chromatography on Sepharose CL-6B. The purity and identification of the protein were performed by PAGE. The native globulin, with a molecular weight of 375 kD, was resolved by SDS-PAGE into twelve polypeptides with molecular weights ranging from 61 to 14.5 kD. Native and heated globulin G1 was hydrolyzed with trypsin and chymotrypsin. SDS-PAGE indicated that native globulin was more resistant to digestion than heated protein. Amino acid analysis of the major globulin revealed that glutamic acid was present in the largest concentration, followed by aspartic acid, arginine and leucine. As is also the case for other legumin-like globulins, lentil G1 was deficient in sulfur-containing amino acids.     

乙烯基类单体改性铬鞣革屑水解产物制备复鞣填充剂的研究

以制革厂产生的固体废弃物铬鞣革屑为原料 ,在不脱铬的情况下对铬鞣革屑进行水解 ;用乙烯基类单体对铬鞣革屑水解产物进行改性 ,制备皮革用复鞣填充剂 ;对改性产品以茚三酮法进行分析 ,对铬鞣革屑水解产物及其改性产品进行IR分析和氨基酸分析。结果表明 :乙烯基类聚合物分子链以共价键在胶原蛋白水解产物的分子链 (即多肽链 )上发生了接枝 ;所制备的复鞣剂是一种含铬的蛋白复鞣填充剂 ,经其复鞣后的坯革 ,具有较好的伸长率和伸展高度     

分离纯化酒花黄腐酚初探

为了简化工艺,降低纯化黄腐酚的成本,将粉碎后的酒花先用超临界CO2萃取,收集酒花萃余物,以甲醇(乙醇)作为提取剂,对酒花萃余物进行超声波提取;浓缩的萃取液,与硅藻土混合均匀,先后经2种洗脱液洗脱,将收集到的第2种洗脱液经过滤膜过滤、低温浓缩干燥处理后,即可得到黄腐酚纯品,纯度为86.2%。纯化后的黄腐酚为黄色粉末状固体,经重结晶纯度可达97.8%以上。     

粮谷中残留硝基苯的固相萃取前处理方法研究

根据不同种类粮谷的特点,低脂肪含量的样品采用正己烷直接提取的模式,高脂肪含量的样品先用乙腈作为提取剂,然后进行液-液分配,使硝基苯转移至正己烷相,正己烷提取液再利用固相萃取技术进行净化和浓缩处理;固相萃取选择氧化铝作为主要填料,用5ml正己烷和5ml乙酸乙酯-正己烷(6 4)淋洗杂质,最后乙酸乙酯进行洗脱并浓缩至5ml,使样品的浓缩和净化同步进行,解决了前处理过程中不能浓缩的问题,并用气相色谱-质谱进行了验证.实验本着简单、有效及节省成本的原则,利用固相萃取技术,解决了硝基苯净化和浓缩的问题,建立了一套理想的前处理方法,具有处理后杂质干扰少、实用性强等特点,通过对方法回收率进行验证,说明该方法准确、可靠,符合前处理要求.     

Chemical composition and some properties of modified buffalo milk for infant feeding

A proposed formula for modifying buffalo milk for infant feeding was described. Buffalo milk was diluted with four parts of whey that was produced by addition of citric acid or lemon juice to milk and neutralization with sodium bicarbonate. The chemical composition and the properties of the proposed formula were compared with raw buffalo milk, human milk and buffalo milk modified by the ordinary method. The proposed formula was characterised by low casein/whey protein N comparable to human milk and by curd tension.     

Chemical composition and some properties of modified buffalo milk for infant feeding.

A proposed formula for modifying buffalo milk for infant feeding was described. Buffalo milk was diluted with four parts of whey that was produced by addition of citric acid or lemon juice to milk and neutralization with sodium bicarbonate. The chemical composition and the properties of the proposed formula were compared with raw buffalo milk, human milk and buffalo milk modified by the ordinary method. The proposed formula was characterised by low casein/whey protein N comparable to human milk and by curd tension.     

酶预处理和酸水解制备糯玉米淀粉纳米晶及其表征

采用糖化酶对糯玉米原淀粉进行预处理,通过X射线衍射(XRD)确定糖化酶预处理的最佳用量,再对酶预处理淀粉进行硫酸酸水解,制备糯玉米淀粉纳米晶,采用傅里叶变换红外光谱（FT-IR）、扫描电子显微镜(SEM)、粒径测量和Zeta电位分析等对淀粉纳米晶进行表征。结果表明,用1000U/(g淀粉)活性的糖化酶对糯玉米原淀粉处理2h,再结合酸水解2天,得到粒径约100nm、分散性好、产率为24.1%的糯玉米淀粉纳米晶;相较于仅硫酸酸水解处理,酶预处理结合酸水解法制备糯玉米淀粉纳米晶的反应时间缩短了3天,产率提高了70.9%,淀粉纳米晶的Zeta电位达-22.3 mV。     

柱层析法制备高纯磷脂酰胆碱

对三氧化二铝柱层析法富集大豆磷脂酰胆碱(PC)过程中产生的溶血磷脂的分离及分析进行了探讨,用高效液相色谱法对PC进行了定性和定量分析。食品级大豆浓缩磷脂经丙酮脱油、乙醇萃取后,进行三氧化二铝柱层析,经95%乙醇洗脱,制备高纯磷脂酰胆碱,同时实现了柱洗脱中间产物溶血磷脂与PC的分离,所得产品中PC纯度接近100%。     

辣椒红素对照品的制备

建立从辣椒中分离制备高纯度辣椒红素对照品的方法———辣椒粉先经丙酮超声提取,皂化后,硅胶柱色谱进行粗分。制备型高效液相色谱(RP-HPLC)采用丙酮/水(体积比85∶15)进行分离纯化。通过UV、ESI-MS、1H-NMR和13C-NMR对所分离的辣椒红素进行结构鉴定,分析型HPLC进行纯度测定。从辣椒中制得的辣椒红素对照品纯度为99.3%。     

大豆降胆固醇活性肽的初步分离纯化

研究了大豆降胆固醇活性肽的初步分离纯化,用Alcalase碱性蛋白酶水解大豆分离蛋白得到的酶水解物经过大孔吸附树脂脱盐,并用不同浓度的乙醇以疏水性大小洗脱,得出浓度为75%的乙醇洗脱物具有最高的降胆固醇活性,将此洗脱物再经过SephadexG15凝胶过滤色谱进行分子量分级,得到了部分纯化的大豆降胆固醇肽,其最高降胆固醇活性肽是分子量大多在1000以下的小肽,抑制率为81.26%。     

麦胚降血糖肽的分离纯化及鉴定

建立麦胚降血糖肽的分离纯化方法及鉴定活性多肽的结构组成。采用胰蛋白酶酶解麦胚蛋白,得到降血糖多肽,并进行降血糖动物实验。超滤获得高活性组分,离子交换吸附实验选择最佳的树脂,并对麦胚降血糖肽进行离子交换吸附分离,SephadexG-25和SephadexG-15分离,再经过反相高效液相色谱（reverse phase-high performance liquid chromatography,RP-HPLC）分离高活性成分。最后采用高效液相色谱-电喷雾-质谱（HPLC-electrospray ionization-mass spectrometry,HPLC-ESI-MS）鉴定活性多肽的结构组成。结果显示酶解麦胚蛋白对α-葡萄糖苷酶的抑制性IC50为10.98?mg/mL,能够缓解糖尿病小鼠的症状。超滤获得分子质量小于5?kDa的高活性组分,IC50为1.60?mg/mL。732型阳离子交换树脂的分离效果最好,2.5%氨水的洗脱率为98.13%,通过动态离子交换吸附分离后,活性显著提高,IC50为0.30?mg/mL。通过SephadexG-25和SephadexG-15分离得到高活性组分,经RP-HPLC分离得到8?个组分（峰）,其中1号峰的活性和含量都最高,IC50为0.098?mg/mL。HPLC-ESI-MS结果显示m/z?274.45的丰度比较高,经离子碎片拼接,共有7?种多肽,其中二肽有1?种,三肽有6?种。本研究对于开发具有降血糖功效的新型功能性食品有一定的作用。     

Clean-up procedure with ion-exchange mini column in the analysis of flusulfamide in agricultural products by HPLC

A clean-up procedure with an ion-exchange column in the analysis of flusulfamide by HPLC was examined. Pesticide in the sample was extracted with methanol following liquid-liquid partition with ethyl acetate. The ethyl acetate fraction was cleaned up with silica gel column chromatography. The eluate from the silica gel column was further cleaned up with SAX + PSA mini column, then determined by HPLC. Carotenoids and interfering peaks were removed by washing the combined mini columns with 10 mL of 20% acetone-containing n-hexane and 5 mL of acetone, and flusulfamide was eluted with 35 mL of acetone.     

辛烯基琥珀酸淀粉微胶囊化浓缩鱼油的研究

主要研究采用辛烯基琥珀酸淀粉喷雾干燥微胶囊化浓缩鱼油时,几种碳水化合物和食用酵母对其溶剂浸油率、氧化稳定性以及鱼腥异味的影响。实验结果,采用多聚糊精替代20%的辛烯基琥珀酸淀粉可有效降低溶剂浸油率;采用15%的食用酵母就能完全消除鱼腥异味,而且还能显著地提高氧化稳定性。     

二醋酸纤维素片丙酮浆液中TiO2的X-射线荧光光谱分析

应用X-射线荧光光谱法测试了二醋酸纤维素片丙酮浆液中的TiO2,并进行了与燃烧法的对比分析及其不确定度的评定.结果表明该法的RSD为1.15%,扩展不确定度为0.028%,分析时间100s,检测结果与燃烧法的吻合,适合批量二醋酸纤维素片丙酮浆液TiO2的快速分析.     

内标液相色谱-串联质谱法测定蜂蜜中氯霉素、甲砜霉素和氟苯尼考残留

目的建立液相色谱-串联质谱法测定蜂蜜中氯霉素、甲砜霉素和氟苯尼考的分析方法。方法以氯霉素-D5为内标,样品用乙酸乙酯提取,提取液在45℃氮气吹至近干,残渣用2mL水溶解,溶解液过Oasis HLB柱净化,洗脱液在45℃氮气吹干, 50%甲醇水溶液定容,后经正己烷脱色脱脂、PSA粉末吸附净化,高速离心过膜后用串联四极杆检测。样液经过Agilent Eclipse XDB-C₁₈色谱柱分离,甲醇-水流动相梯度洗脱,多反应监测扫描模式检测。采用内标法定量。结果氯霉素在0.1~4.0μg/kg、甲砜霉素和氟苯尼考在0~40.0μg/kg呈良好的线性关系,相关系数大于0.999,回收率为93.7%~109.7%,RSD为0.7%~11.4%,检出限为0.03~0.09μg/kg,定量限为0.1~0.3μg/kg。结论该方法准确、检出限低、重现性好,适用于蜂蜜中氯霉素、甲砜霉素和氟苯尼考残留的检测。     

超高效液相色谱法检测饮料中纳他霉素的含量

建立用超高效液相色谱测定饮料中纳他霉素含量的方法。用甲醇溶液提取样品中的纳他霉素,UPLC分析,外标法定量。采用BEHShieldRP18色谱柱,检测波长为303nm,以乙酸铵和乙腈为流动相,进行等度洗脱。该方法操作简单快捷,方法准确度和稳定性好。     

Simultaneous determination of N-methylcarbamate pesticides and their metabolites in agricultural products

We investigated the determination of N-methylcarbamate pesticides and their metabolites in agricultural products by HPLC with post-column fluorescence detection after clean-up with an SPE cartridge. The homogenate of agricultural products was extracted with acetone. The crude extract was partitioned between 5% sodium chloride solution and dichloromethane, and the dichloromethane layer was concentrated to dryness. The residue was dissolved with a mixture of acetone and n-hexane, and purified by using Supelclean ENVI-Carb SPE, Bond Elut Extraction Cartridge PSA and SAX in series with a mixture of acetone and n-hexane. N-Methylcarbamate pesticide was analyzed by HPLC with post-column reaction and fluoresce detection. N-Methylcarbamate pesticide in citrus fruits and various kinds of agricultural products could be analyzed accurately by the presented method. Recoveries of N-methylcarbamate pesticides added to several agricultural products at the level of 0.10 ppm were mostly in the range of 60-110%. The limit of detection was 0.005 ppm.