Fruits and vegetables are one of the indispensable foods in our daily lives, with the improvement of living standards and the transformation of consumption structure, fruit and vegetable processing products such as beverages are more favored by the public. In the processing process, it is inseparable from the participation of enzymes, pectinase is an important new type of enzyme in the field of industrial production, and is widely used in fruit and vegetable beverages, which can be used for the extraction, clarification, and improvement of juice yield.
1. Pectinase structure and source
The pectin molecule is a polysaccharide chain composed of galactolic acid with different degrees of esterification in α-1,4 glycoside bonds, often with rhamnose, arabinose, galactose, xylose, trehalose, celery sugar and other side chains, free carboxyl group partially or completely combined with calcium, potassium, sodium ions, especially with boron compounds. The structure of the pectin molecule varies according to the different types of plants, tissue sites, growth conditions, etc., and can be divided into two parts: smooth region and hairy region, which are mainly composed of three structural regions of hga, rg-i and rg-ii, of which rg-ii often exists in the form of dimers. Pectinase (pectinase) is one of the world's four major enzyme preparations, is a general term for the decomposition of pectinase, mainly including protoprine, pecsterase, polygalacturonase and pectinase lyase four categories.
Application of pectinase
1 fruit and vegetable juice extraction
At present, the extraction method of fruit juice is mainly pressurized and filtered, and the plant cell wall is first destroyed during fruit juice processing. Most plant cell walls are mainly composed of cellulose, hemicellulose and pectin substances, etc., and the structure of the cell wall is relatively tight, and it is difficult to fully break it by mechanical or chemical methods alone.
2 juice clarifications
Pectinase can randomly hydrolyze glycoside bonds inside pectinic acid and other polygalacturonic acid molecules to generate oligolactic acid with small molecular weight, so that its viscosity decreases rapidly, it is easy to squeeze and filter, improve the juice juice yield, and improve the clarification effect of fruit juice.
Pectin lyase (pl) has a good clarifying effect on apple juice, but not significantly on grape juice. For citrus juice, due to the requirement of fog turbidity, it should be treated with polygalacturonic acid endo-pg without pectinase (pe). Because pectin lyase can avoid the production of methanol, partially deesterified pectin can also avoid the formation of precipitates with calcium ions, and the loss of esters that make up various aromatic components of fruits can also be avoided. Therefore, studies have shown that pectinase preparations for fruit and vegetable juice and fruit wine processing are best to contain a larger amount of pectin lyase (pl).
3 Improve the nutritional composition of fruit and vegetable drinks
The use of pectinase to produce fruit and vegetable juice not only improves the juice yield, but also retains the nutrients in the fruit and vegetable juice. First of all, the soluble solid content of fruit and vegetable juice is significantly improved, and these soluble solids are composed of soluble proteins and polysaccharides and other nutrients, and the preservation rate of carotene in fruit and vegetable juice is also significantly improved. The glucose, sorbise and fructose content of the enzyme-treated juice increased significantly, the sucrose content decreased slightly, and the total sugar content increased.
At present, the industrial application of pectinase in China is still in a relatively lagging state, in order to improve the use rate of pectinase, simplify the product purification process and achieve the purpose of continuous production, the pectinase fixed on the cheap carrier has become an important topic of international research. Xiaobian suggests that you must choose a large brand when choosing an enzyme preparation manufacturer, and avoid choosing a small manufacturer to cause harm to yourself.