The tea industry in China has experienced rapid development in the past two decades. The area of tea plantations has been expanding to more than 40 million mu. The area of tea production in a large number of provinces is still rising rapidly, resulting in the increase of the annual output of more than 100,000 tons or even 200,000 tons. Behind the increase in area output, exports of China have grown very slowly over the past decade, eventually maintaining at around 300,000 tons, sometimes falling. Under the background of unbalanced production and marketing of tea, the deep processing of tea has attracted more and more attention of the industry.
Although the amount of tea used for deep processing is not much in our country every year, but the benefits are not low. "Our deep processing industry today uses less than 7-8% of the total tea output of middle and low-grade tea, which is one third of the total tea output value of China. The economic benefit of tea industry has a great space to improve, and deep processing shoulders the responsibility and hope for the development of tea industry.
At present, the final products of tea deep processing are mainly tea beverage, instant tea powder, tea polyphenols, theophylline, theanine and so on. According to the difference of final products, the following processes are usually used: raw material juicing or water extraction, solvent extraction (extracting its soluble components), filtration and centrifugation (removing suspended particles and impurities), precipitation, extraction, ion exchange, adsorption, chromatography, etc. (extracting functional components). The final steps are vacuum distillation concentration and solvent recovery, spray or freeze-drying.
Defects of traditional technology:
In the stage of filtration and centrifugation, the traditional separation and extraction methods mainly adopt mechanical filtration, high-speed centrifugation and chemical treatment. The clarification effect is not good, the product quality is poor, and the transparency of tea liquid is not good. It makes the cold solubility of instant tea and tea extracts is poor.
When heat treatment is used in the concentration stage, the loss of heat-sensitive substances will be caused and the process change will be difficult to control.
The selectivity of precipitant or solvent extraction to the target is not good, the yield of products is low, the investment of equipment is high, and the recovery of precipitant and solvent is difficult.
If the above technology is used to extract functional components from tea, the comprehensive utilization rate of tea is low and the purity of the product is not high.
High energy consumption, heavy pollution and high cost.
Membrane Separation Technology
Membrane separation technology, a high and new technology for tea deep processing, can improve the separation and classification of effective components in tea extract without changing the color, aroma and taste of the target product. On the other hand, it can solve the problems of aroma loss, high energy consumption and three wastes caused by high temperature concentration.
Advantages of membrane separation process:
Membrane filtration has high precision, high clarity and stability, which solves the problem of "muddy after cold". Tea polyphenols, theophylline, theanine and other active ingredients are less lost, and the purity of the product is improved.
It is a kind of green environmental protection technology without adding chemicals, pollution-free and residue-free.
After ultrafiltration, the content of protein, tannin and pectin in the filtrate decreases greatly, the purity of the active ingredients is improved, and the cleaning cycle and service life of the filtrate are prolonged.
The matching membrane concentration process is a non-phase change process at room temperature, which avoids the shortcomings of traditional evaporation concentration process, such as high energy consumption, high fragrance loss, high product viscosity and easy backmixing.
The application of membrane integration technology in clarification, separation, classification and concentration of tea extract has become a new green and energy-saving technology in the field of tea deep processing.
As a listed company in the field of membrane separation, Jiangsu Jiuwu Hi-tech Co., LTD has accumulated rich project experience in the deep processing of tea. According to the different end products of customers (including tea beverage, instant tea powder, tea polyphenols, theophylline, theanine, etc.), the optimum membrane integration process can be designed, and a set of equipment with higher cost performance ratio for tea deep processing can be developed.