Pectinase enzyme is a polysaccharide chain polymerized by α-1,4 glycosidic bonds of galacturonic acid at different esterification degrees. It often possesses side chains composed of rhamnose, arabinose, galactose, xylose, trehalose, celery sugar, etc. Part or all of its free carboxyl groups will combine with calcium, potassium, and sodium ions, especially boron compounds.
The structure of the pectin molecule varies with plant species, tissue parts, growth conditions, etc. The overall structure can be divided into smooth and whisker zones, mainly composed of three structural regions: HGA, RG-I and RG-II. RG-II often exists in the form of dimers. Pectinase enzyme is one of the four major enzyme preparations in the world. It is the general term for pectinase decomposing enzymes. It mainly includes four categories: propectinase, pectin esterase, polygalacturonase and pectin lyase.
1. Extraction of fruit and vegetable juice
The current juice extraction methods are mainly pressurized extraction and filtration, and plant cell walls are first destroyed during juice processing. Most plant cell walls are primarily composed of cellulose, hemicellulose and pectin. The structure of cell walls is relatively compact, and it is difficult to break them by mechanical or chemical methods alone fully.
2. Juice clarification
Fruit juice pectinase can randomly hydrolyze the glycosidic bonds of pectic acid and other polygalacturonic acid molecules to generate oligogalacturonic acid with a smaller molecular weight, making its viscosity drop rapidly, making it easier to squeeze and filter and improve the pulp juice yield, ae well as the clarification effect of juice.
Pectin lyase has a good clarification effect on apple juice, but the impact on grape juice is not apparent. Due to the requirement of haze-like turbidity, citrus juice should be treated with endogalacturonase without pectinesterase. Since the pectin lyase can avoid methanol production, it can also prevent the partially de-esterified pectin from forming precipitation with calcium ions. It can also control the loss of esters that constitute the aromatic components of various fruits. Therefore, studies have shown that if pectinase preparations are used in fruit and vegetable juice and fruit wine processing, it is best to contain more pectin lyase.
3. Improve the nutritional content of fruit and vegetable beverages
Using pectinase to produce fruit and vegetable juice improves the juice yield and retains the nutrients in the fruit and vegetable juice. First of all, the solid soluble content of fruit and vegetable juice is significantly increased, and these soluble solids are composed of soluble protein and polysaccharides and other nutrients. The preservation rate of carotene in fruit and vegetable juice is also significantly improved. The juice's glucose, sorbose and fructose content after enzyme treatment increased significantly, the sucrose content decreased slightly, and the total sugar content increased.
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