摘要：纳豆是由黄豆通过纳豆菌（枯草杆菌）发酵制成的豆制品，具有良好的保健功效。为获得高纤溶活性纳豆，本实验对纳豆培养条件进行优化。通过改变纳豆的培养时间，对不同培养时间的纳豆进行活性测定，确定最佳培养时间；将大豆粉碎，豆粉过筛，选出20~40目和60~80目的豆粉，并与整豆同时进行纳豆培养，比较纤溶活性，确定最佳粒度；通过改变培养过程中的通气量和含水量，确定氧气和水份对活性的影响。结果显示，纳豆的最佳培养时间为2~3d即48~72h；20~40目豆粉为最适宜的豆粉粒度；增加通气量可增加代谢产物纤溶活性；而10g干豆粉加水量在5~10mL之间时，活性较好，10g干豆粉加水量为10mL时的活性略大于加水量为5mL时。此研究优化了原有的纳豆培养条件，为纳豆的生产工艺改进提供了理论基础。49320

毕业论文关键词：纳豆、纤溶活性、培养条件、优化

Culture Conditions Optimization of Natto

Abstract: Natto with good health care efficacy was made by natto bacteria fermenting soybean. In order to obtain natto with high fibrinolytic activity, culture conditions of Natto were optimized. The best culture time was determined by testing the fibrinolytic activity of natto cultivated under different time. The effect of particle size on the fibrinolytic activity were determined by selecting different culture medium (the whole soybean, the soybean powder through 20-40 mesh sieve and 60-80 mesh sieve). The effects of the oxygen and water on the fibrinolytic activity were determined by changing ventilatory capacity and moisture. The results showed that the best culture time was 2-3 days (48-72 hours).The optimum particle size of soybean powder was through 20-40 mesh sieve. Increasing the ventilatory capacity could enhance the fibrinolytic activity of natto. When 5-10mL water was added to 10g dry bean powder, the fibrinolytic activity of natto was high. The fibrinolytic activity of natto was higher adding 10mL water than 5mL. The study optimized the existing culture conditions of natto and provided a theoretical basis for natto. production. 

Keywords: Natto; fibrinolytic activity; culture condition; optimization

目录

前言 1

1.材料与方法 2

1.1实验材料 2

1.2试剂 2

1.3培养基 2

1.4实验仪器 2

1.5实验方法 3

2.结果与分析 5

2.1确定最佳培养时间 5

2.2豆粉培养基含水量对纳豆活性的影响 5

2.3豆粉粒度对纳豆纤溶活性物质的影响 6

2.4通气量对菌株代谢的影响 8

3.讨论 10

致谢 11

参考文献 12

前言

纳豆是由黄豆通过纳豆菌（枯草杆菌）发酵制成豆制品，具有黏性，气较臭，道较甜[1]。纳豆具有抗菌、降血压、抗血栓、抗氧化、预防癌症等多种生理调节功能[2-3]。纳豆菌为革兰氏阳性菌，属细菌科芽孢杆菌属，好氧型，其原始菌株与枯草芽孢杆菌相同，是枯草芽孢杆菌的一个亚种[4-5]。纳豆距今已有近2000的历史，盛行于日本，被认为是日本人长寿的“秘方”[6]。它的传统制法是将蒸熟的黄豆用稻草包裹起来，稻草浸泡在100℃的沸水中以杀菌消毒，并保持在湿度比较高的地方发酵1-2d[7-8]。稻草上常见的枯草杆菌（纳豆菌）因可产生芽孢而耐热度高，杀菌过程不受破坏，高温培养速度快也能抑制其他菌种，并使黄豆发酵后产生黏稠的丝状物。