霉菌型豆豉和纳豆中异黄酮含量的比较研究

目的:比较纳豆和豆豉中异黄酮含量的组成变化。方法:利用超声波提取,采用高效液相色谱法测定,色谱柱填料为Hypersil ODS2(4.6 mm×250 mm,5μm),流动相为甲醇(A)-水(B)进行梯度洗脱,检测波长为255 nm。结果:豆豉与纳豆相比较,豆豉中大豆苷、黄豆黄苷、染料木苷、大豆甙元、黄豆黄素、染料木素的含量分别为11,未检出,25,320,65,380μg/g;纳豆中中大豆苷、黄豆黄苷、染料木苷、大豆甙元、黄豆黄素、染料木素的含量分别为330,73,410,12,3.3,28μg/g。结论:豆豉中甙元的含量高,纳豆中糖苷的含量高。     

Stabilization and Target Delivery of Nattokinase Using Compression Coating

ABSTRACT

The aim of the work is to develop a new formulation in order to stabilize a nutraceutical enzyme Nattokinase (NKCP) in powders and to control its release rate when it passes through the gastrointestinal tract of human. NKCP powders were first compacted into a tablet, which was then coated with a mixture of an enteric material Eudragit® L100-55 (EL100-55) and Hydroxypropylcellulose (HPC) by direct compression. The activity of the enzyme was determined using amidolytic assay and its release rates in artificial gastric juice and an intestinal fluid were quantified using bicinchoninic acid assay. Results have shown that the activity of NKCP was pressure independent and the coated tablets protected NKCP from being denatured in the gastric juice, and realized its controlled release to the intestine based on in vitro experiments.     

纳豆菌的研究和应用

主要介绍了近年来对纳豆菌、纳豆以及纳豆激酶的一些研究进展,并论述了研究和应用开发纳豆菌产品的前景和存在的问题.     

纳豆芽孢杆菌的开发与利用

介绍了纳豆芽孢杆菌的起源和特点,重点阐述了纳豆及纳豆芽孢杆菌的生理功效及其在食品加工、微生态制剂和纳豆激酶、抗菌素等方面的应用现状,并对今后的发展趋势进行了展望。     

Growth characteristics of Bacillus subtilis (natto) in milk

In this paper, Bacillus subtilis (natto) was incubated to develop a possible functional ingredient in ice cream. A lab‐scale culture revealed that incubation in the sterilised milk without dilution and concentration at 37°C for 28 h could obtain ideal growth characteristics of Bacillus subtilis (natto), especially with continuous aeration. Following freezing operation of the cultured milk, survival content of Bacillus subtilis (natto) was at 49–92%, while nattokinase activity was conserved at 62–98% comparing with the initial contents, which indicating a potential for application of natto functional ingredient in frozen milk products.     

Improvement of the stability of nattokinase using γ-polyglutamic acid as a coating material for microencapsulation

In this study, nattokinase (NK) was microencapsulated in high-molecular-weight Na-γ-PGA, and the amount of NK added to the Na-γ-PGA was in the ratio of 1:1 and 2:1 w/w, which was designated as NK-100 and NK-200, respectively. The temperature and pH stability of microencapsulated NK were found to be higher than those of the free form. Free NK lost its overall initial activity after treatment at a temperature above 60 °C or at a pH less than 5.0 for 1 h. NK-100 and NK-200 retained 35% and 60% of their activities after exposure to an acidic condition of pH 4.0 and possessed 18% and 25% activity after treatment at 60 °C for 1 h, respectively. Furthermore, NK-100 and NK-200 exhibited more protective bioactivity than free NK did in storage stability tests. This simple and versatile approach can be potentially applied to the microencapsulation of various biomolecules for drug-delivery applications.     

产纳豆激酶的枯草芽孢杆菌基因工程菌发酵条件的响应面优化

采用实验室前期构建的能够高产纳豆激酶的枯草芽孢杆菌基因工程菌株,对其液体发酵条件进行优化。通过单因素实验和响应面Box-Behnken模型优化液体发酵培养参数,五因素三水平的响应面分析表明最佳发酵培养条件为:蛋白胨26.05 g/L,葡萄糖29.29 g/L,MgSO4 1.5 g/L,CaCl2 0.74 g/L,NaCl 10 g/L,pH 9.0,接种量3 %。在最优发酵培养条件下,纳豆激酶最高酶活达到2 186.17 IU/mL,比优化前提高了269 % ,这表明响应面法优化枯草芽孢杆菌工程菌能够明显的提高纳豆激酶活性,为该菌株规模化生产纳豆激酶提供了基础应用参考。     

纳豆激酶液体发酵条件的优化

以纳豆枯草芽孢杆菌 (Bacillussubtillisnatto ,BSN)为实验菌株 ,对其液体发酵生产进行了研究。实验考察了发酵条件 (温度、接种量、起始pH、装液量 )和培养基成分 (碳源、氮源、金属离子等 )对纳豆激酶产量的影响 ;在优化发酵条件和培养基的基础上 ,进行了 5L发酵罐放大实验 ,产酶量为 2 2 5 0IU/mL。     

纳豆激酶的研究进展

纳豆激酶有很强的溶血栓能力，跟传统的一些溶栓剂相比，具有安全性好、成本低、口服有效等优点，极有可能开发为新一代的溶栓剂。本文介绍了纳豆激酶的分离纯化技术、生化特性；并对纳豆激酶的活性测定方法、影响纳豆激酶稳定性的因素及提高纳豆激酶酶产量的几种途径等最新研究成果进行了综述。     

纳豆激酶基因在毕赤酵母中的表达条件研究

通过设计正交试验,对重组Pichiapastrois酵母利用YEPD培养基表达纳豆激酶基因的发酵条件进行了研究,确定最适条件:pH值6·0,培养温度30℃,培养时间36h,诱导时间84h,甲醇添加量1·0%,其中培养温度为主要影响因素。在该条件下进行重组子的培养及诱导表达,SDS-PAGE电泳结果表明外源蛋白的表达量占菌体蛋白的10%。