Alkaline pectinase

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Pectinase refers to enzymes that decompose pectin, the main component of plants. Pectinase is widely distributed in higher plants and microorganisms, depending on its substrate. It can be divided into three categories. Two of them (pectinesterase and polygalacturonase) are found in higher plants and microorganisms, and another (pectin lyase) is found in microorganisms, especially certain pathogenic microorganisms that infect plants.

Figure 1. Protein structure of pectinase.

Introductions

Pectinase is an enzyme that breaks down pectin, which is a polysaccharide found in plant cell walls. Usually called pectinase, they include pectinase, pectinase and polygalacturonase, which is one of the most widely studied and most widely used commercial pectinase. This is useful because pectin is a gelatinous matrix that binds plant cells together and embeds other cell wall components (such as cellulose fibrils). Therefore, pectinase is commonly used in processes that involve the degradation of plant materials, such as speeding up the process of extracting juice from fruits including apples and tomatoes. Since the 1960s, pectinase has also been used in wine production. The function of pectinase in brewing is twofold. First, it helps to decompose plant (usually fruit) raw materials, so it helps to extract flavor from it. Secondly, the presence of pectin in the finished wine can cause turbidity or slight turbidity. Pectinase can be used to decompose pectin and make wine clear. Pectinase is also used for degumming. Adding chelating agents or pretreating plant materials with acids can enhance the effect of enzymes.

Classifications

Pectinases include two types, one type can catalyze the depolymerization of pectin, and the other type can catalyze the hydrolysis of esters in pectin molecules. Among them, the enzymes that catalyze the depolymerization of pectin substances are divided into enzymes that act on pectin (polymethylgalactose, uronidase, aldate lyase or pectin lyase) and enzymes that act on pectic acid (polygalactose). Aldase, polygalacturonic acid lyase or pectate lyase). The enzymes that catalyze the hydrolysis of esters in pectin molecules include pectin esterase and pectin acyl hydrolase.

Functions

Pectinase is metabolized and produced by aspergillus niger. It is prepared by deep fermentation of liquid and modern biological extraction and drying technology. It can hydrolyze pectin to produce water-soluble pectin, pectic acid and β- Galacturonic acid. Pectinase is widely used to prevent the turbidity of fruit and vegetable juices after squeezing the juice, can effectively degrade soluble and insoluble pectin and hemicellulose, etc., prevent and remove the flocculation of fruit and vegetable juices to achieve clarification It is also very effective in reducing the viscosity of juice, improving filtration efficiency, and extending the life of the filter membrane.

Application

Pectinase is the most important enzyme in fruit processing. Using pectinase to treat broken fruits can speed up the filtration of juice and promote clarification. Using other enzymes and pectinase together, the effect is more obvious. For example, Qinlan uses a compound enzyme system of pectinase and cellulase to prepare pumpkin juice, which greatly improves the juice yield and stability of pumpkin juice. The ultrastructure of pumpkin pulp cells was observed by scanning electron microscope, which showed that the destructive effect of single pectinase preparation or cellulase preparation on pumpkin pulp cell wall is far less than that of compound enzyme system. It has been reported that a new type of fruit and vegetable processing enzyme-porridge enzyme (containing pectinase, cellulase, hemicellulase and protease, etc.), which can improve the juice yield and clarity of fruit and vegetable juices.

Optimum environment

As with all enzymes, pectinases have an optimum temperature and pH at which they are most active. For example, a commercial pectinase might typically be activated at 45 to 55 °C and work well at a pH of 3.0 to 6.5. Pectinase is commonly used in fruit industries to speed up fruit juice extraction.