氧化羟丙基淀粉浆料性能研究

探讨氧化羟丙基淀粉浆料性能。利用氧化和羟丙基化复合变性制备了氧化羟丙基淀粉浆料,测试了黏度、取代度及pH值等因素对氧化羟丙基淀粉浆料及浆纱性能的影响。结果表明:氧化羟丙基淀粉浆料具有高浓低黏浆料特性,其黏度热稳定性和成膜性良好;在一定范围内,随着氧化剂用量的增加,黏度逐渐下降,浆膜断裂强度和断裂伸长率降低,耐磨性增加;随着取代度的增加,浆液黏度热稳定性提高,浆膜断裂强度和断裂伸长率都增加,水溶速度加快,浆液黏附力增大;取代度达到0.3的氧化羟丙基淀粉表现出良好的浆膜性能、黏附性能及对纯棉纱良好的浆纱效果。认为:取代度为0.3的氧化羟丙基淀粉具有较好的上浆性能。     

Expression and purification of goat lactoferrin from Pichia pastoris expression system

ABSTRACT:  The recombinant goat lactoferrin (rGLF) was expressed in the methylotropic yeast Pichia pastoris using pGAPZαC vector, GAP as promoter, and Zeocin as the selective marker. After transformation of the GLF-pGAPZαC into Pichia pastoris X-33 expression host, the GLF-pGAPZαC vector was integrated into the GAP promoter locus of Pichia pastoris X-33 chromosome. The rGLF was expressed and secreted into the broth using α-factor preprosequence. SDS-PAGE and PAS staining analysis indicated that the rGLF could be purified to electrophoretic homogeneity by heparin-Sepharose 6 Fast Flow affinity chromatography and glycosylated by the expression host. The yield of purified rGLF was approximately 2.0 mg/L of culture broth. The N-terminal sequence was identical to the native goat lactoferrin (nGLF). The iron-binding behavior, papain-inhibiting property, and thermal stability of the purified rGLF were comparable to nGLF. This is the 1st report of intact goat lactoferrin expression using the P. pastoris system.     

Investigation of hygienic quality and freshness of marketed fresh seafood in Northern Taiwan

To survey the hygienic quality and freshness of fresh fish and shellfish, 533 specimens of fish and shellfish were collected from fishing piers, traditional markets and supermarkets (including warehouses) in northern Taiwan during the winter (January-February) and summer (July-August) seasons for hygienic quality and freshness examinations. The indicators included total bacterial count, fecal coliform, Escherichia coli, volatile basic nitrogen (VBN) and K value judged from ATP-related compounds. It was found that the hygienic quality and freshness of fish and shellfish decreased in summer, especially for clam and mussel. The ratio of unacceptable hygienic quality or freshness of fish and shellfish was the highest in fecal coliform, followed by E. coli and others. The fecal coliform count in products from the traditional markets was the highest, followed by those from supermarkets and fishing piers. Secondary contamination seems to be the most important problem for hygienic quality and freshness of fish and shellfish.     

采用同时蒸馏提取法分析不同加工时期金华火腿香味成分

腌制时间对金华火腿的风味与质量十分重要 ,文中采用同时蒸馏提取法比较了成熟火腿(发酵 1a)和生火腿 (未经发酵 )中的风味成分 ,分别得到了 77种和 62种化合物。结果显示 ,成熟火腿中的醛醇类物质 (3 4种 )尤其是烯醛和烯醇的种类和数量明显多于生火腿 (1 5种 )。同时 ,文中还讨论分析了各类组分及它们的风味贡献。     

黑粒小麦麸皮中花色苷的提取及性质研究

为了对我校自主培育的黑粒小麦麸皮中花色苷进行开发利用,本试验以黑粒小麦麸皮为原料,进行了花色苷的提取条件和理化性质的研究。结果表明,用pH 1.0、40%的乙醇作提取剂,在料液比为1∶20(g/mL)、70℃条件下浸提80 min,提取效果最好,花色苷得率为14.5%;该花色苷可见光范围内的最大吸收波长为525 nm,pH对其影响明显,温度影响不大,60℃以内比较稳定。Mg2+、K+和Al3+对该花色苷有很好的增色、稳定作用,Ca2+和Fe2+对其稳定作用影响不大,Cu2+、Zn2+和Fe3+使其明显褪色。该花色苷耐氧化性、耐还原性差,耐光性好。蔗糖、柠檬酸对其有明显的褪色作用,苯甲酸钠在低质量浓度(<0.1 mg/mL)时对其基本无影响,在高质量浓度(>0.2 mg/mL)时有一定的褪色作用,盐对其有一定的增色、稳定作用。     

白栎淀粉的特性

采用X射线衍射仪、粒度仪、差示扫描量热仪(DSC)、分光光度计、质构仪等对白栎淀粉的结构及性质进行研究,并与玉米淀粉进行比较。结果表明:白栎淀粉颗粒粒径较小,平均粒径为3.15μm,结晶结构属A型,直链淀粉含量18.90%,糊化温度为72.3～84.7℃;白栎淀粉溶解性和膨润力高于玉米淀粉;白栎淀粉糊具有透明度低、凝沉性大、冻融稳定性差、黏度小、酶解率较高的特点;质构分析表明白栎淀粉糊凝胶强度较大,质地和口感较好。     

车前子总黄酮的纯化及其成分的液相质谱联用分析

采用DPPH自由基清除法和邻苯三酚自氧化抑制法对车前子黄酮初提液的不同溶剂萃取液的体外抗氧化能力进行了比较,发现正丁醇萃取液具有与初提液相近的抗氧化能力,说明用正丁醇能萃取出大部分有效成分.并比较了AB-8、D101、NKA-2、NKA-9四种大孔吸附树脂对车前子黄酮的吸附及解吸性能,以选择合适的车前子黄酮纯化工艺.将纯化液进行液质联用分析其组成.结果表明,AB-8型树脂吸附和解吸率最高,适合萃取后的车前子黄酮的纯化,纯化后黄酮含量可从4%提高到30%以上.采用液质联用技术分析纯化液,确定其主要成分为苯乙醇苷类毛蕊花苷、异毛蕊花苷、大车前苷和黄酮类物质野漆树苷.     

直接利用净化海水生产酱油

通过净化海水并作为酿造酱油用水的整个生产研究,结果表明米曲霉能够在三角瓶、通风制曲等生产过程中正常生长,其外观、孢子数、发芽率和自来水酿造的无明显差别,培养过程减少细菌总数44.8%、发酵过程减少28.1%;海水酱油的各项指标均符合GB18186-2000《酿造酱油》标准要求,而且感官指标更佳;说明利用净化后的海水代替自来水进行酱油生产是可行的,并直接节约生产成本每吨70元,出品率提高3%左右,具有显著经济效益.     

绿色壁垒对我国纺织业的影响

概述了绿色壁垒的由来,分析了纺织品贸易绿色壁垒对我国纺织品出口的负面影响,提出了国内纺织业应对绿色壁垒的对策.