Application of enzymes in food industry

Enzyme is an efficient and safe biocatalator, which has been widely used in the food industry such as the development of food raw materials, quality improvement, process transformation, etc., with high efficiency, specificity, mild and other biological characteristics. With the deepening of research, enzymes are replacing traditional chemical reagents with their unique advantages, and are increasingly used in the food industry. Enzyme industry has become one of the most promising emerging industries in China.

1. Research progress of biological enzymes in food industry

Enzymes used in the food industry are diverse due to their roles and capabilities in food production. According to the type of reaction they catalyze, they can be divided into five categories: oxido-reductase (dehydrogenase, reductase or oxidase), transferase, hydrolase, isomerase (racemase, superisomerase, cis-isomerase, isomerase, tautomase, mutase, cyclic isomerase) and ligase (synthetase).

Among them, protease, glycoenzyme, esterase, fat oxidase, polyphenol oxidase, peroxidase and ascorbate oxidase are widely used. Protease is a kind of hydrolase, which can be divided into acidic protease and alkaline protease according to the optimal pH, and has been widely used in food industry. The common sugar enzymes are α-lake powder enzyme, β-amylase, glucose amylase, etc., which are mostly used in sweetener production industry; Esterase is a hydrolytic enzyme, and calcium salt can improve the stability of esterase. Polyphenol oxidase is used to control enzymatic Browning reaction and has great influence on the color value of the product.

The industrial production of enzymes for food processing dates back to 1874, when Danish scientist Christian Hansen extracted chymosin from a calf's stomach for use in cheese making. Chymosin is produced by recombinant deoxyribonucleic acid (rDNA) technology introduced by microorganisms containing the bovine tryptase gene. Chymosin, expressed in E. coli K-12, became a recombinant enzyme approved by the U.S. Food and Drug Administration (FDA) for use in foods. Many of the enzymes currently used in food processing are derived from recombinant microorganisms.

How to maintain the color, aroma, taste and structure of food during food processing is a very important issue, so it is necessary to avoid violent chemical reactions during processing. Enzymes are suitable for food processing due to mild reaction conditions, strong specificity, colorless and odorless itself, and easy to control the reaction, and bring new ideas to the traditional food industry.

The ideal enzymes and their functions in food mainly include: endogenous β-glycosidase, polyphenol oxidase (PPO), peroxidase (POD), esterase affecting ripening and flavor production; Cathepsin can be used for myofibrillar protein hydrolysis fermentation products, protease and transglutaminase can be used for food structure modification. Of these enzymes, endogenous PPO or endogenous lipase and lipoxygenase (LOX) cause rancor, resulting in dark discoloration of fresh fruits, vegetables and raw crustaceans. Enzymes are used as additives for a wide range of applications in food processing, such as coagulation, ripening, baking, brewing, cell cracking, hydrolysis, and molecular structural modification. At present, enzymes are widely used in dairy products, baked goods, beverages, oils, meat and functional foods.

2. Application of biological enzymes in food industry

2.1 Sugar industry and starch processing

Pectinase, α-amylase, glucanase, β-amylase and glucose isomerase are commonly used in sugar and starch processing, among which pectinase, glucanase and α-amylase are more widely used.

Pectinase is a kind of complex enzyme which can decompose pectin and hydrolyze pectin specifically to achieve the effect of clarification. α-amylase is an endonuclease that can indiscriminately break the α-1, 4-glucoside bond, acting on both amylose and amylopectin. α-amylase can effectively degrade the starch in the mixed juice, avoiding the increase of acidic flocculants caused by excessive starch content, and rapidly reducing the viscosity.

α-glucanase is a biological enzyme that can hydrolyze macromolecule glucan to glucose and other small molecules. There are two kinds of endo-dextran and exo-dextran enzymes. The hydrolyzing effect of endo-dexanase is better than exo-dexanase. Glucose isomerase, also known as xylose isomerase, refers to the isomerase that can isomerize aldose into the corresponding ketose, which can carry out the isomerization reaction of glucose to produce high fructose syrup in place of sucrose.

2.2 Dairy product processing

Rennet, lactase, protease, lipase and lactoperoxidase are the most commonly used enzymes in dairy products processing.

Rennet turns liquid milk into near-solid cheese; Lactase can hydrolyze the lactose in milk, which brings good news to lactose intolerant people. Protease and lipase can accelerate cheese ripening and improve cheese properties. Lactoperoxidase can remove hydrogen peroxide and prolong the shelf life, which has a remarkable effect on the preservation of goat milk.

So far, lactoperoxidase preservation method is recognized as the most ideal preservation method. Zhang Cong reviewed the application of lipase, complex flavor protease and glucosidase. Cheese, known as cheese, contains very rich nutrients and will play a major role in improving food structure and strengthening body quality for people in the country.