Pectinase is a general term for a group of enzymes that can catalyze the degradation of pectin substances. Pectin substances are usually found in higher plants, such as vegetables, fruits, corn, soybeans, etc., and are one of the components of non-starch polysaccharides.

Pectinase degradation of pectin substances plays an important role in industrial production. Through treatment, pectinase effectively degrades polygalacturonic acid and rhamnolic acid in pectin and converts them into sugar and other useful compounds, thus solving the problem of spoilage and deterioration of processed food.

As one of the world’s four major enzyme preparations, pectinase is widely used in the food industry, such as juice clarification, juicing, brewing and oil extraction. With the rapid rise of China’s industry, the market demand for pectinase is also increasing, and its application value is inestimable. This paper mainly discusses the application of pectinase in food and other industrial production, in order to provide a strong theoretical guidance for the in-depth research and exploration of pectinase.

Overview of pectinase

Pectinase is widely distributed in higher plants and microorganisms. According to statistics, microbial pectinase accounts for 25% of the total global sales of food enzymes.

Overseas research on pectinase began in the 1930s, and industrialized production began in the 1950s. Domestic research began in 1967, and industrialized production began in the late 1980s. With the development of fruit cultivation and processing industry in China, the development and application of pectinase is going deeper and deeper.

According to the different ways of galacturonic acid, pectinase can be divided into protopectinase, pectin esterase and pectin cleavage enzyme. It is well known that microbial enzymes are susceptible to factors such as substrate, temperature, concentration and pH when acting, so pectinases also show subtle differences according to the effects of physical and chemical factors.

According to its optimal pH value, pectinase can be divided into acidic pectinase and alkaline pectinase. At present, the research and application of more acidic pectinase, mainly used for fruit juicing and juice clarification, the enzyme action of the optimal pH value in the acidic range, the study of alkaline pectinase can expand the scope of application of pectinase.

Application of pectinase in food industry

With the continuous development of the industry, pectinase is getting more and more attention from the market, especially in the food industry, it is widely used, such as used in juice clarification, juicing, brewing, tea and coffee fermentation and improving animal feed, etc., which brings great convenience to people’s production and life.

Juice clarification
Research on pectinase clarification of fruit juice can be traced back to the 1930s, when it was believed that the main cause of turbidity of fruit and vegetable juices is pectin; while research on the principle of fruit juice clarification began in the 1960s.

Researchers postulated a simplified model for pectinase clarification of apple juice, which essentially involves enzymatic hydrolysis of pectin and non-enzymatic electrostatic flocculation.

When the pectin in fruit and vegetable juice is partially hydrolyzed under the action of pectinase, some of the positively charged protein particles that are encapsulated in it are exposed and collide with other negatively charged particles, and then aggregated, which leads to flocculation.

In the settlement process of flocculent, pectinase adsorbs and entangles other suspended particles in the juice, which can be removed by centrifugation and filtration, thus achieving the purpose of clarification.

Researchers on the application of pectinase clarification of sugarcane juice research, found that sugarcane juice in the pectin-like substances is caused by the suspension of sugarcane juice colloidal particles of one of the main triggers; adding pectinase can be specifically hydrolyzed pectin-like substances, so that other colloidal substances in the system due to the loss of pectin’s protective effect and precipitation precipitation precipitation, to achieve the clarification of the juice.

Improve the juice yield of fruit and vegetable juice
General fruit and vegetable cell wall contains a large number of pectin, cellulose, starch, protein and other substances. After crushing the pulp is very viscous, resulting in pressing the juice is very difficult and low juice yield, and enzymatic technology can overcome the above shortcomings.

Pectinase is usually used to accelerate juice and flavor extraction and to remove pectin. Pectinase not only catalyzes the depolymerization of pectin, effectively reduces viscosity, improves pressing performance, increases juice yield and soluble solids content, but also increases the aromatic components of the juice, reduces the production of pomace, and facilitates subsequent processing.

It has been reported that the utilization of enzymatic technology can increase the juice yield of different fruits and vegetables by 10% to 35%, with the specific values varying according to the pectin content in different fruits and vegetables and the differences in pressing methods. In the process of making lychee juice concentrate, the staff treated lychee meat with pectinase to remove insoluble solids and increase the juice yield, and the resulting vacuum-concentrated lychee juice was able to maintain its nutritional and sensory qualities for six months at -20 ℃.

Used to improve the juice yield of fruit and vegetable juice enzyme technology is generally divided into two kinds: one is the pulp impregnation technology, that is, in the broken fruit and vegetable pulp add pectinase, the role of a period of time after the juice; the second is the complete liquefaction technology, that is, in the pulp to add pectinase and cellulase, and then the use of both synergistic effect of the fruit and vegetable cell wall as far as possible to completely degrade.

But the liquefaction technology is easy to cause the juice flavor deterioration, browning, etc., at the same time, this enzyme technology requires a higher amount of enzyme additives, increasing the production cost. Therefore, in actual production, the two are often used in combination to greatly improve the yield of fruit and vegetable juice.

Improvement of wine quality
The use of pectinase in the winemaking industry can increase the extraction of natural pigments, improve the color and flavor of wine, increase the aroma of wine, and produce sparkling wine, which has an important role in improving the quality of wine.

Researchers study the effect of pectinase on the main components of red wine, the results show that the addition of pectinase has almost no effect on the sugar and acid content of the grape juice, but it can reduce the viscosity of the juice, which is conducive to the solubilization of pigments; samples with the addition of pectinase fermented more vigorously and rapidly than samples without the addition of pectinase, and it can reduce the amount of volatile acid generation, increase the dry leachate content of the original wine and the total phenol content, and improve the quality of the wine.

Tea and coffee fermentation
Alkaline pectinase-producing microorganisms are utilized to remove the sticky skin of coffee beans during coffee fermentation, and alkaline pectinase is sometimes added to remove the pulp-like surface layer that contains large amounts of pectin. Alkaline pectinases are also used in tea processing to increase phenolics, improve tea quality, and promote tea fermentation.

The researchers pointed out that pectinase can significantly improve the quality of black crushed tea and black tea, in particular, can improve its water leachate rate; can improve the instant tea powder in the brewing process is easy to form a foam condition ( U.S. Patent 3787582); with pectinase treatment of tea leachate, it can break down pectin, reduce instant tea to form a solid film of power.

In addition, pectinase can increase the solubility of tea in cold water, increase the aroma, and improve the color and clarity of the soup.

Oil extraction
In the extraction process of vegetable oil, cell wall degrading enzymes, including alkaline pectinase, play an important role. For example, adding alkaline pectinase to olive oil extraction can destroy the pectin that plays a role in emulsification and improve the oil yield, and the extracted oil is very stable when stored, and the content of polyphenols and vitamin E has increased.

Extraction of natural products
The release of natural products is affected or hindered to varying degrees by pectin substances. Under suitable conditions, plant cells will undergo autolysis, can also produce some decomposition enzymes (such as pectinase), but this will cause structural changes in the products to be separated, and even produce some small molecules that are not conducive to the separation of by-products in most cases.

Therefore, relying on the plant cell’s own enzyme system is not conducive to the extraction of natural products. Generally, the intracellular enzyme system should be inactivated and passivated at high temperature before selective enzyme treatment. Usually, natural pigments such as grape violet, tomato red and radish red can be extracted using enzymatic methods, but the pectinase used must not contain anthocyaninase and other miscellaneous enzymes, in order to avoid affecting the color of certain products.

Moreover, natural bioactive substances extracts are very popular in the international market, the proportion of exports has been more than traditional Chinese medicine, and is on the rise. Extracts that can be produced with pectinase include: Ginkgo biloba extract, garlic oil concentrate, mushroom concentrate, ginseng syrup, angelica extract, licorice liquid and so on.

Animal feed
Pectinase can also be used as an animal feed supplement. Its use in ruminant feed production can reduce feed viscosity, increase nutrient absorption and release nutrients. Researchers have studied the effect of pectinase on the growth performance and carcass traits of broilers, and noted that the addition of pectinase preparation to corn-soybean meal diets can significantly increase the average daily weight gain and feed intake of 21-day-old broilers, and improve the feed conversion rate.

Wastewater treatment
At present, the problem of wastewater treatment in factories still needs to be studied. For example, the wastewater produced in some canned fruit production is difficult to degrade due to pectin and other substances, which hinders the subsequent treatment of wastewater. Selecting pectinase to solve the problem of canned fruit wastewater is undoubtedly a better choice, not only to reduce production costs, but also to protect the environment.

Other aspects
The product of pectinase treatment of pectin substances can be used as a dietary fiber, which can treat and prevent some chronic diseases. If reasonably utilized, it is expected to develop a new type of health food or medicine, which will send a gospel to patients with chronic diseases.

Problems to be noted

As mentioned above, pectinase is widely used in the food industry, but so far, its industrial application is still mainly concentrated in the processing of fruit and vegetable juices, although other aspects are involved, but the relevant technology is still not mature enough, that is to say, pectinase in the application of certain limitations still exist.

In addition, pectinase as a kind of complex protease, its effect is affected by temperature, pH, time, substrate and other factors, and due to the different purposes of the producers, the amount of pectinase in the production of the amount of additives and the way of action is also different, so in the practical application of the need to take into account the various factors, select the optimal temperature, pH and so on, and strive to make the enzyme to play the best utility.

Thoughts and Prospects

In recent years, although the research on pectinase has made some achievements, such as pectinase used in fruit juice clarification and processing technology has been quite mature, but other aspects of the application still has a lot of room for development.

In addition, the research and application of acidic pectinase is more, not knowing that alkaline pectinase in the food industry, textile industry and paper industry have potential application value. More in-depth research on the mechanism, engineering properties and molecular biology of alkaline pectinase degradation of substrates will improve its effect and expand the application of pectinase to meet the needs of various related industries.

With the development and progress of society, the rapid rise of China’s industry, the people’s standard of living continues to improve, the pursuit of products is also more and more unique, so the market for specific pectinase demand is particularly urgent. Committed to the application of pectinase research, considering its synergistic effect with other enzymes, expanding its application areas, and adopting various methods to improve the enzyme activity of pectinase will be the hotspot of pectinase research and application in the future, and also its future development trend.