With the progress and development of human society, food processing technology has also been continuously developed and improved, which has promoted the improvement of human physical strength and intelligence. In essence, enzymes are catalytically active biomolecules, mainly in the form of proteins. Compared with other catalysts, enzymes have multiple advantages, such as strong substrate specificity, mild reaction conditions, high reaction efficiency, and fewer by-products. In recent years, enzyme technology has been widely used in food processing.
Production of starch sugar
Starch is used as raw material, hydrolyzed by α-amylase and glucoamylase to obtain D-glucose, passed through an immobilized D-glucose isomerase column to complete the conversion from D-glucose to D-fructose, and then refined, Concentration and other means, you can get different types of high fructose syrup.
Production of sweeteners
Starch sugar is produced with starch as raw material, and its sweetness increase is limited. Therefore, to fundamentally solve the problem of sugar shortage, sweeteners with high sweetness and not using starch as raw material should be produced. Aspartame (APM), produced in large quantities abroad, is a sweetener with high sweetness. Aspartame (aspartame) is a dipeptide sweetener that is 200 times sweeter than sucrose. In the past, L-aspartic acid and L-phenylalanine were used as raw materials for chemical synthesis. Now Japan adopts a new enzymatic synthesis process, which can use DL-phenylalanine with a lower price as a raw material, and the products are all α-type (β-type has a bitter taste), which reduces the production cost by 30%.
Dairy processing
1) Cheese production
More than 100 million tons of milk are consumed in the production of cheese in the world, accounting for 1/4 of the total milk production. The first step in cheese production is to ferment milk with lactic acid bacteria to make yogurt and then add rennet to hydrolyze K-casein. Under acidic conditions, calcium ions make the casein coagulate, and then it is cut into pieces, heated and pressed to make it mature.
2) Decompose lactose
Milk contains 4.5% lactose. Lactose is a disaccharide that lacks sweetness and has low solubility, making it difficult to digest. Some people often have diarrhea, abdominal pain and other diseases after drinking milk, and this is the reason. Moreover, because lactose is insoluble in water, it often precipitates in the form of sandy crystals in condensed milk and ice cream, thereby affecting the flavor of food. The above problems can be solved by treating the milk with lactase to hydrolyze the lactose in the milk into galactose and glucose.
3) Butter flavoring
The unique aroma of dairy products is mainly caused by volatile substances (such as fatty acids, alcohols, aldehydes, ketones, esters, and amines) produced during processing. Adding an appropriate amount of lipase during dairy processing can increase the aroma of cheese and butter. Using flavored butter for toffee, cakes and other foods can save the amount of butter and improve the flavor.
4) Baby milk powder
One of the differences between human milk and cow’s milk lies in the content of lysozyme. Adding egg white lysozyme to milk powder can prevent intestinal infection in infants.
Meat and Fish Processing
1) Improve tissue and tenderize meat
Enzyme technology can promote meat tenderization. In beef and other meats with poor texture (such as old animal meat), the collagen and elastin proteins in the connective tissue and muscle fibers are high in content and complex in structure. The collagen protein is fibrin, which is connected with secondary bonds to form a composition with strong mechanical strength. This cross-linking bond can be divided into two types: heat-resistant and heat-labile.
In the collagen of young animals, there are many heat-labile cross-link bonds, which will break when heated, and the meat will appear tender; while the meat of old animals will have more heat-resistant bonds, and it will be difficult to soften when cooked, so the meat will appear rough and difficult to cook. The taste is also poor. The use of protease can decompose the collagen in the connective muscle tissue, thereby tenderizing the meat. Proteases used as tenderizers can be divided into two categories: the most commonly used one is plant proteases, and the other is microbial proteases.
2) Conversion of waste protein
It is an effective measure to increase human protein resources to hydrolyze waste protein, such as miscellaneous fish, animal blood, minced meat, etc., with protease and extract the protein for food or feed. Among them, the utilization of trash fish and fish factory waste is the most eye-catching. Many fish in the ocean are inedible due to reasons such as poor color, appearance or taste, but this type of aquatic product accounts for about 80% of marine aquatic products. Using this new biotechnology achievement, most of the protein is dissolved, concentrated and dried to make a product with high nitrogen content and rich in various water-soluble vitamins. Its nutrition is not lower than milk powder, and it can be mixed into bread and noodles. Its economic benefits are very significant in other foods, or as feed.
3) Other applications
The thawed fish can be deodorized by treating the thawed fish with acid protease under the condition of neutral pH. Nowadays, the development and use of alkaline protease to hydrolyze animal decolorization to produce colorless blood meal as a cheap and safe supplementary protein resource, this technology has been used in industrial production.
Fruit and vegetable processing
1) Canned fruit processing
When making canned oranges, removing the sac of the orange petals is necessary. In the past, alkali treatment was used, which consumed a lot of water and took a lot of time. The mixture of hemicellulase, pectinase and cellulase produced by Aspergillus niger can be used to remove the capsule coating of orange petals well while avoiding the shortcomings mentioned above. Canned oranges are often white and turbid, which is caused by the hesperidin in the orange flesh. Using hesperidinase, hesperidin can be hydrolyzed into water-soluble hesperetin, thereby eliminating the white turbidity of canned oranges. Peach fruit contains red anthocyanins, which react with metal ions to turn purple-brown when stored in a jar. Using anthocyanins to treat peach jam, grape juice, etc., can decolorize and increase economic value. This is because anthocyanins can hydrolyze anthocyanin and turn it into a colorless substance.
2) Debittering of citrus
Debittering of citrus has always been a major problem in fruit processing. Limonin in oranges is the cause of the bitter taste of orange juice, and the bitter taste can be eliminated by treating with citric enzyme of Arthrobacter globose immobilized cells.
3) Juice processing
Fruits contain pectin substances. One of the important properties of pectin is that it can form a gel in the presence of acidity and a high concentration of sugar. This property is the basis for making jelly and jam. However, the processing of fruit juice has caused difficulties in squeezing and clarification. Pectinase is now used to treat broken fruit to speed up juice filtration and facilitate clarification.
4) Preservation of fruits and vegetables
Desugar removal of dehydrated vegetables with glucose oxidase prevents browning during storage. The color and aroma of bottled orange juice will deteriorate due to oxidation during storage, and the original color and aroma of the juice can be maintained by using glucose oxidase and catalase to deoxidize. When the fruit is frozen and stored, it is fermented and deteriorates due to the enzyme action of the fruit itself, and glucose oxidase can also be used to keep it fresh.
Baked goods
Adding α-amylase to flour can regulate the production of maltose and balance the production of carbon dioxide and the gas retention of dough. Adding protease can promote gluten softening, increase extensibility, reduce kneading time and power, and improve the fermentation effect. Protease-fortified flour macaroni pasta with good extensibility and flavor. Fortifying flour with beta-amylase prevents stale pastry. Pastry fillings are often filled with starch, adding β-amylase can improve the filling flavor. Pastry making uses invertase to hydrolyze sucrose to invert sugar, preventing the crystallization of the syrup. Appropriate addition of lipase in bread making can enhance the aroma of bread because lipase can decompose a small number of glycerides of alkyd or ketoacid in milk fat, thereby generating flavor substances such as δ-lactone or ketone.
Brewing
1) beer
Beer is an alcoholic beverage made from malt through saccharification and fermentation. Malt contains various enzymes necessary for fermentation. Enzyme preparations such as microbial amylase, protease, β-amylase, and β-glucoamylase can supplement the lack of enzyme activity.
2) fruit wine
The use of acid protease, amylase and pectinase in fruit wine brewing can eliminate turbidity and improve the juicing operation of broken fruit.
3) Liquor
Using glucoamylase instead of bran yeast in liquor production can increase the yield of liquor by 2% to 7%, which can save food and simplify equipment and save workshops.