The following is a sample of the opening report of biopharmaceutical papers compiled by me, hoping to help you.
I. Research background
It was widely cultivated in China in the early 20th century. Onions are rich in flavonoids and are widely used in medicine and food.
Flavonoids have anti-cancer, anti-cardiovascular aging, anti-inflammatory, bactericidal and antihypertensive effects. It is reported that the main flavonoids in onion are flavonol-quercetin and its derivatives, which account for more than 80% of total flavonoids. Because of its phenolic alkyl structure, it has strong antioxidant effect. Many pharmacological studies have shown that quercetin has stronger antioxidant activity, free radical scavenging activity, inhibition of lipoxygenase and cyclooxygenase, and prevention of platelet aggregation than other flavonoids.
Because onion has many health functions, its deep-processed products contain a huge market. Therefore, the in-depth study of onion will provide new clues for the development and utilization of natural drugs such as hypoglycemic, hypolipidemic, antithrombotic, antibacterial and anticancer.
At present, the research on onion mainly focuses on sulfur compounds, but there are few reports on the extraction and application development technology of flavonoids. At present, there are almost no deep-processed onion products in China, and their processing level and products are at a low level such as dehydration.
For example: dried onions and onion powder, and onion salad dressing. Developed countries develop onion flavone capsules, onion convenience foods and other deep-processed products with strong health care functions, which are convenient, nutritious and delicious.
Therefore, through the application of high technology and the optimization of extraction process, extracting flavonoids from onion can improve the utilization rate of raw materials and the added value of products, which is conducive to the improvement of economic benefits. After joining WTO, raw materials such as onions have obvious comparative advantages in international trade because of their low production factors including labor. Over the years, the onion industry in China has mainly faced the international market with raw materials or primary processed products.
At present, the production and sales of onion and its products in China are restricted by three aspects: first, the export and sales of raw materials are greatly restricted by market factors, with low prices and low added value; Second, the application field is not wide, and the export price fluctuates greatly, which leads to the backlog of products, which in turn affects planting and processing; Third, the type of processing varieties is single, and the sales and market are single.
The above three aspects lead to price and income instability, which greatly affects the development of onion industry in China. Especially in onion industry, there are many shortcomings such as unreasonable product structure, single variety, low production level, low extraction rate of flavor substances with main pharmacological functions and low content in products. It is difficult to create new products with high technology content and high added value to meet the market demand, which seriously affects the further development of the industry. Onion, as a high-quality and high-value trade product, is increasingly respected by the food industry. It has developed rapidly abroad and has gradually become one of the main raw materials for China's newly started food industry.
After China's full integration into the international community, it is facing more intense international competition and urgently needs the great development of onion industry. We must actively increase the input of human capital and technology, constantly increase the production of knowledge products, and build the competitiveness of our products by relying on the comparative advantages of foreign trade of onion raw materials.
Through the study of this experiment, firstly, we can lay the foundation and provide the necessary basis for fully and effectively developing and utilizing the functional components of onion. The deep processing of onion and the research and development of functional food should be based on the in-depth and detailed study of its functional components.
Although a lot of work has been done in this field at home and abroad, there are still many contents that need further research and experiments. Through this experimental study, I hope to make some contributions in this respect. Second, increase the added value of onions and bring more benefits to farmers.
Develop deep-processed onion products and cultivate onions? Planting? Storage? Traffic? Deep processing? Packaging? Marketing industry chain drives and develops an industry. It not only improves the added value and economic benefits of onions, but also brings social benefits, providing farmers and growers with opportunities to get rich. This is a long-term feasible and effective way to solve the problems of agriculture, countryside and farmers. Third, it is conducive to the adjustment of industrial structure. Using abundant raw material resources and the relatively low production cost in China to develop deep-processed products suitable for the international market may become a channel to earn foreign exchange through export. So as to change the current situation that agricultural products in China depend on the export of raw materials.
Second, the research status and development trend of this topic.
As a natural healthy and nutritious food, onion is favored by people because of its excellent quality, rich nutrition and easy production and management. Onions were introduced to China from abroad, so the cultivation time of onions in China is relatively short. However, due to strong adaptability, storage and transportation resistance, and the natural conditions in China are very conducive to the growth of onions, the planting history in China is short, but it develops rapidly. Now it has become one of the vegetables with large cultivation area, wide cultivation range and the highest yield in China.
Onion, like ginger and garlic, is a traditional medicinal and edible plant in Asian countries. It contains many physiological active components and has many functions such as health care, prevention and treatment of chronic diseases. In recent years, with the enhancement of people's awareness of their own health care, the naturalness and functionality of food raw materials and additives have been paid more and more attention, which makes people pay more attention to the medicinal and edible characteristics of onions, hoping to extract and enrich their physiological active components to better meet people's needs.
Onion is rich in flavonoids, which have a wide range of physiological activities, and have medical and health care functions such as anticancer, analgesia and immunity improvement.
Clinically, it can be used to prevent and treat diseases such as cerebral arteriosclerosis and poor cerebral circulation. The United States, Japan and some European countries attach great importance to the study of flavonoids in onions because of their high content and extensive physiological activities. However, the domestic research on onion mainly focuses on sulfur compounds, and the pharmacological research on flavonoids, prostaglandins and amino acids needs to be further deepened.
At present, flavonoids are mainly extracted from ginkgo leaves, soybeans, mountain leaves, lotus leaves, celery leaves, cress and peanut shells at home and abroad. In order to further improve the quality of flavonoids and push flavonoids products to a broad market, it is necessary to seek more raw materials, suitable extraction methods and study the best extraction conditions.
Three. Main research contents and expected goals
Main research contents
The technological process of extracting total flavonoids from onion skin by reflux method is as follows:
Wash the onion skin? Drying and pulverizing (sieving with 60 mesh sieve)? Reflux extraction? Excerpts? Suction filtration? Centrifuge? Total flavonoids crude extract? Vacuum drying? Crude flavone
1. Qualitative detection of total flavonoids in onion extract: Through the reduction reaction of magnesium hydrochloride powder, the complexation reaction of metal salt reagent, the reaction of extract with concentrated sulfuric acid, and the reaction with NaOH aqueous solution, it is confirmed that onion extract does contain flavonoids.
2. Quantitative detection of total flavonoids in onion extract: rutin spectrophotometry was used to determine the content of total flavonoids in onion. The yield of flavonoids in the product can be calculated by the following formula, and the yield E(%) of flavonoids is:
Where: c-concentration of total flavonoids extracted from onion skin (mg/ml)
Extraction volume of total flavonoids from v- onion skin (ml)
N- dilution multiple
M-quality of raw materials (g)
3. Effect of crushing particle size on the yield of flavonoids: accurately weigh 65438±0g onion powder with particle sizes of 20 mesh, 40 mesh, 60 mesh and 80 mesh, respectively add 205ml 80% 80% ethanol solution, reflux extract at 70℃ for 2 hours, reflux extract for the second time 1h, combine the extracts, filter, and centrifuge the filtrate at 500Or/8min for 8 minutes. Accurately absorb lml samples respectively, and determine the absorbance A according to the method of establishing standard curve, so as to obtain the yield of flavonoids.
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