Fungal Pectinases in Food Technology

*Mohamed Bassim Atta and Fernanda Ruiz-Larrea*

### **Abstract**

Pectins contribute to the firmness of plant tissues and confer rigidity to cell walls, protecting the plant from droughts and withering. Fungi have been endowed with an array of extracellular pectolytic enzymes that provide them valuable tools for infecting their host. Pectolytic enzymes are broadly referred to as "pectinases" because they act upon pectin and pectic substances. Pectinases are the most frequently and widely used enzymes in food processing and winemaking. Currently, pectinases are applied in the food industry either to create new products or to improve physicochemical and organoleptic characteristics of conventional products, as well as to increase the yield. This review aims at casting some light on the classification and biochemical aspects of pectinases, especially those of interest in winemaking and food industries. Additionally, it gives a comprehensive summary of current applications of fungal pectinases in the field of food and beverage technology.

**Keywords:** fungal pectinases, pectic substances, polygalacturonase genes, pectin lyase genes, vegetable food processing, winemaking

#### **1. Introduction**

Enzymes are important tools used in the field of food technology, where enzymatic reactions are preferred rather than chemical methods due to the high affinity of enzymes for their substrates, specificity, and that they generate less toxicity. Nowadays, all manufactured food products are prepared using some enzyme at some stage of the production of the food or its ingredients. Different types of enzymes are produced at a commercial scale, which are categorised according to the substrate they act upon. Proteases, lipases, cellulases, and pectinases are the most prevalent of the trade enzymes. Enzymes can also receive different names according to the type of reaction that they catalyse. Thus, lytic enzymes and oxidoreductases are commercialised to be used in the food industry to create new products, or to improve the physicochemical characteristics of conventional products, to enhance their organoleptic properties, and to increase the yield. Among them, pectolytic enzymes, which are broadly referred to as "pectinases", act upon pectin and pectic substances. They are the most frequently and broadly used enzymes in the field of food processing [1] and animal feed. They are also used in paper production and textile industry to degrade the pectic substances that cover


#### **Table 1.**

*Abbreviated list of suppliers of commercial pectinases commonly used in food and beverage industry.*

*Fungal Pectinases in Food Technology DOI: http://dx.doi.org/10.5772/intechopen.100910*

cellulose fibres. Moreover, novel biomedical and drug delivery applications of pectic substances [2] have extended the use of pectinases in the pharmaceutical industry as promising tools to obtain the desired macromolecular product. Commercial enzymes can be obtained from animal tissues, plants, and microorganisms. However, microbial pectolytic enzymes represent about 25% of the total commercial enzymes that are used in food processing [1]. A list of companies that produce commercial pectinases for the food, juice and beverage industries is given in **Table 1**.

There are many attempts to produce pectolytic enzymes on a large scale using different strains of bacteria and fungi. However, *Aspergillus* spp. especially, *Aspergillus niger*, is still the most traditionally used fungus for the production of more than 30 commercial pectolytic enzymes, which are used in the food sector [3] due to its safety status GRAS (Generally Recognized as Safe), according to the USA Food and Drug Administration (FDA) [4].

Although the pectinase market is exposed to fluctuations in the global market the value of industrial pectinase sales in 2019 amounted \$30.04 million [5]. The enzyme market is expected to rise further in the near future. Similarly to food enzymes, feed enzymes are gaining increasing importance as they improve the health and performance of livestock. Consequently, development of enzyme production by optimizing fermentation and technique parameters, generation of new strains with a high production via molecular biology and microbial genetics, are current goals of scientists [1].
