Human practice

In daily life, yogurt is often use as a flavor drink. It has a better taste than milk, and it is easier to absorb the nutrients, better regulate the human intestinal bacteria situation. After fermentation, the fatty acids in yogurt can be increased twice as much as the raw materials. These changes make yogurt easier to digest and absorb, and the utilization of nutrients can be improved. Yogurt is fresh milk as raw materials, add a certain proportion of sucrose, after high temperature cooling and sterilization , then add a pure lactic acid bacteria culture into a kind of dairy products, taste sweet and smooth, rich in nutritious, in the fermentation process lactobacillus can also produce human nutrition must be a variety of vitamins, such as VB1, VB2, VB6, VB12 and so on. Its nutritional value is better than fresh milk and a variety of milk powder.

However, in our review of the relevant literature, we found that many by-products were produced during the fermentation process of yogurt production, including lactic acid as a representative by-product. In the fermentation process of Yogurt, the production of lactic acid will have a certain inhibitory effect on the growth of bacteria, but lactic acid is also an indispensable symbol of fermentation products. Therefore, the real-time monitoring of lactic acid in the production of yogurt plays an important a role that can not be ignored, which can ensure the texture of yogurt fermentation.

Through referring to a large number of documents, we understand the actual production of yogurt in some cases, careful thinking and summing up the existing situation, and we obtained our experimental plan. In order to make our experiment more practical, we conduct business visits, many of our yogurt fermentation process.

For Silver

1. Shanxi Zhendong group

In order to understand the production process of lactic acid and the actual yield of lactic acid, we went to the company to observe the whole process of fermentation.

After some discussions, we chose to go to the Shanxi Zhendong group to have a field trip. It’s aim to understand the actual situation of lactic acid in fermentation production. Inside the enterprise, we went into the factory and watch the whole process of food fermentation. During that time, we communicated with the employees about some problems we encountered in our experiment. In addition, we were trying to find out the ways to solve these problems in actual production. For example, how to prevent the material in industrial production from being polluted.

After a few days, we entered the Enterprise Quality Inspection Department, followed by the Quality Supervision Department staff to do a series of experiments, understand the quality of the enterprise process and the need to check the project. In the process of quality inspection we feel that the quality of treatment is still time-consuming and laborious, but also may cause some pollution to the fermentation broth. We and our business managers described our projects in detail, and they were very interested in our actual products and reported with great enthusiasm.

In the following days, we entered the quality inspection department of the company, and followed the staff of the quality supervision department of the company, and followed the staff of the quality supervision department to do a series of experiments to understand the process of quality inspection and the items to be checked. In the process of quality inspection, we feel that the process of quality inspection is still time consuming and laborious, and may cause some pollution to the fermentation liquid. We described our project in great detail with business executives who were very interested in our actual product and responded with great enthusiasm.

2. Fujian Normal University beer factory

In the process of reviewing the literature, we also found that a certain amount of lactic acid was produced during the yeast fermentation, which had a strong inhibitory effect on the whole fermentation system..

We have cooperated with Fujian Normal University. Under the guidance of the students of Fujian Normal University, we have visited the beer factory inside the college to learn about the whole production line of beer production and the function of each step. In the course of the visit, we retrieved a portion of the beer fermentation liquid to observe the experiment, and used chemical methods to detect the lactic acid content in the fermentation process.

3. North Eastern University yogurt production base

All of the members in our team visited the yogurt base of North Eastern University to learn the actual process of lactic acid fermentation.

With the development of technology, many people have small yogurt machine to make their homemade yogurt. But at the Northeastern University yogurt production site, team members learned how to plant the fermentation tank for yogurt fermentation. During the visit, in the teacher's introduction, the students understand the operating principle of every step of the fermentation tank, as well as lactic acid in the production of real yogurt in the symbolic significance.

4. BGI(Beijing Genomics Institute)

In order to understand the principles of the experiment, and the actual situation of the gene industry, we came to the Beijing Genomics Institute to visit the field and have a deep communication with their staff.

At BGI, the staff introduced us to some of the existing businesses of the BGI, and we visited the gene pool. In the study of the project, we ask the staff of the specific research mechanism of gene sequencing, and the existing gene sequencing technology and many other problems. The staff answered our questions. During the visit, we briefed them on our events and explained some of the problems we encountered in the experiment, the company's internal staff explained to us the possible causes of these problems, and expressed willingness to give us some help in the experiment.

The gold part

1.The professional teacher instructs the meeting

We have invited four professional professors to have a talk with our team members. They are professor Chen Ding, professor Ren Sheng, professor Teng Fei, professor Lijun Liu.

We presented our complete experimental project to the professors in the form of PPT. During the presentation, professors asked us some questions about our experimental project, and we had an in-depth communication with our teachers to better optimize our program.

In the course of the discussion, the professors raised two questions: how long will our testing system work, and how many bacteria can be detected in the number of the threshold value. We did not discuss such issues in depth until then.

In view of the questions raised by the teacher, we have a series of discussions and finally completed the optimization of the experiment. In the final protocol, we use the enzyme-based instrument to detect the luminescence time of the whole system. According to the data can be obtained: in the engineering bacteria od=0.6,10 minutes, the fluorescence value of GFP can reach the highest value, and the distance detection time is short, easy to operate easily detected.

2.Information collage in NEU

To better complete our project, we went to the information collage of North Eastern University to deeply understand how to how to use electrical components to achieve the conversion between photoelectric, fluorescent protein detection.
We discussed our project with teacher Yanan Zhang and Riqing Lu from information collage. We presented our idea of using fiber to detect fluorescence. Professors affirmed our project and suggested improvements to our project from a professional point of view.
We originally decided to use Photoresistors to complete the entire experiment device, but in the process of communication with the teacher, we found that photoresistors for light intensity of the range is very wide, fluorescent protein emitted by the light is very faint, it is difficult to achieve photoresistors photoelectric conversion.
After adopting the professor's suggestion, we have made some changes in the original project, and fully perfected our experiment project. In the process of communication with students in the information Academy, we fully understand the practical use and parameters of optical fiber, and have a better understanding of the various properties of optical fiber, and optimized our experimental program. We also cooperated with the Information Institute, which provided us with theoretical guidance in the process of optical fiber conversion and helped us complete the whole process of the experiment.

3.Interview for the manager of the base of yogurt

After visiting the yogurt base, we interviewed the manager of the base-teacher Jiang Liu and Zhenbo Cui. During the meeting with the teacher, we learned that in the actual production process, workers often using acid-base titration method to detect the acidity of yogurt, in this way to reflect the concentration of lactic acid . But this method is complicated in actual production. Therefore, we raised out the idea of build a real time system to detect the concentration of lactic acid after in-depth discussion with teachers. The teachers on the professional perspective analyse the feasibility of the whole project, feel that there is a strong display space.
In our actual experiment, we found that the expression level of lactic acid manipulator is relatively low, can not express fluorescent protein GFP efficiently. In the teacher's advice, we introduced the E. coli group sense system,and use the group sense system to amplify the signal of the entire device. It better express GFP and the sensitivity of the detection was extremely high.