Method for extracting levodopa from cat beans

Abstract

The invention provides a method for extracting levodopa from cat beans. The method comprises the following steps: flattening the cat beans and putting the cat beans into a reaction kettle with a water solution containing dissolved ammonium hydrogen carbonate, ammonium sulfate, tannic acid and sodium pyrosulfite; pressurizing with carbon dioxide; raising the temperature and extracting to obtain an extracting solution and cat bean dreg; precipitating the extracting solution by utilizing chitosan and filtering; after primarily separating impurities, decompressing and concentrating filtrate; separating out a crude product; eluting the crude product with an ethanol solution; recycling eluted ethanol and taking a filter cake; purifying the filter cake by adopting a traditional refining process; standing and separating out crystals; filtering to obtain the crystals; drying the crystals to obtain the levodopa with the content of no less than 99 percent and the yield of no less than 3 percent. Compared with a traditional acid water-resin process, a product of the extracting method provided by the invention is equivalent and the yield of the product can be improved to 3 percent from previous 2.5 percent; the emission amount of wastewater containing acid and alkali is reduced by 95 percent or more, and 60 percent of labor force can also be saved.

Description

technical field [0001] The invention relates to the technical field of agricultural product processing, in particular to a method for extracting levodopa from cat beans. Background technique [0002] Cat bean, also known as dog claw bean, white quinoa bean, and dog bean, is a plant of the genus Chenopodium in the family Fabaceae. Stizotobium cochi nchinensis (Lour).Tang et Wang, is a special medicinal and edible resource plant in Guangxi. Its origin is South Asia, and it is also distributed in rocky mountains at an altitude of 800-1400m in Southwest my country and South China, and Guangxi is the main producing area. Cat beans contain natural levodopa (levodopa.L--dopa), which has important application value. Cat beans have high nutritional value, rich in protein, rich in nitrogen-free extracts, and the conventional nutritional components are close to that of broad beans for feeding. After detoxification treatment, they can be used as concentrated feed. Quinoa plants mai...

AI Technical Summary

Problems solved by technology

The more prominent problem of the acid water-resin method is that the extraction process consumes a large amount of hydrochloric acid, which requires particularly high acid resistance of the equipment, resulting in short service life of the equipment, quick update, and high production costs; another obvious disadvantage of the acid water-resin method is : The production process produces a large amount of acidic wastewater, and after neutralization, a large amount of protein precipitates are precipitated. The COD is as high as 10,000 mg / L, which seriously exceeds the national discharge standard of COD less than 100 mg / L. Therefore, this type of sewage treatment facility requires large investment and environmental protection. The cost is extremely high, the pressure on environmental protection increases, and the product cost is high

The disadvantage is that after the particles and colloidal ions in the extract are adsorbed and deposited on the membrane surface or in the membrane pores to a certain extent, the membrane pores are quickly blocked and become smaller, and the permeation flow and separation characteristics of the membrane are irreversibly changed. Phenomenon, the membrane permeability and transmittance are almost 0, and the membrane needs to be regenerated frequently, so that the service life of the filter membrane is very short, and the filter membrane needs to be updated frequently, and the cost is very high

The disadvantages are: 1. When the salt concentration deviates, the protein will denature or precipitate out of the solution, and the crude product obtained has poor stability and high viscosity, which is not conducive to subsequent operations

2. A large amount of high-concentration COD is produced, which makes sewage treatment difficult and expensive

Its disadvantages: 1. High requirements for equipment anti-corrosion, huge investment, short service life of equipment, high depreciation rate

2. The purity of the product is not high

Its disadvantages: many impurities, low content

Its disadvantages: low product yield and product content

This process is currently commonly used by enterprises, and its disadvantages are: a large amount of acidic waste liquid with high concentration of COD is produced, which seriously pollutes the environment, and the facilities required for processing such waste liquid are huge and the treatment cost is extremely high

Currently, the processing and production of levodopa using cat beans generally has the defects of complicated procedures, low extraction rate, and low purity of levodopa.