Lactose is a disaccharide found in mammalian milk and has low sweetness and solubility. Dietary lactose can improve the body's absorption of Ca, P, Mg and other essential trace elements, but it cannot be directly absorbed in the small intestine, and must be hydrolyzed by the small intestine to be digested and absorbed by the body. β-D-galactosidase, also known as lactase, is a odorless, light brown and non-toxic biological enzyme preparation after dissolution. The enzyme can be used to degrade lactose into galactose and glucose, and also has a galactoside transfer effect.
Lactase can produce oligosaccharides, such as galactooligosaccharides and isolactose. Galacto-oligosaccharides produced by transglycosides are hardly digested by the small intestine and are a low-molecular-weight, non-sticky, water-soluble dietary fiber.
As a proliferation factor of bifidobacteria in the intestine, it can only be used by bifidobacteria, but not by spoilage bacteria in the intestine. Proliferating bifidobacteria competitively antagonize the growth of spoilage bacteria can reduce the production of harmful toxins to prevent constipation and diarrhea. Related effects include anti-cancer, lowering blood pressure, enhancing liver function and promoting Ca2 + absorption. Compared with general dietary fiber, galactooligosaccharide (GOS) is stable to acids and has good moisturizing properties. It does not bind metal ions and is easy to add to foods and beverages. The enzyme sources used to produce oligosaccharides are Aspergillus oryzae, Kluyveromyces lactis, Kluyveromyces fragilis, and Bacillus circulans.
Lactase is used to produce oligosaccharide products in dairy products, and many products have been marketed abroad, such as lactose hydrolyzed milk, low lactose milk, cheese ice cream and so on. The hydrolyzed milk has the following characteristics: increase the taste, obviously improve the milk aroma and improve the taste. It is also used in the production of cheese and milk powder. Frozen dairy products such as ice cream and frozen yogurt contain live lactic acid bacteria, which can be preserved longer than other dairy products. At the same time, live lactic acid bacteria can produce lactase, thereby reducing the symptoms of lactose intolerance.
Application in baked goods
Enzyme can increase the volume of bread, improve the color of bread crust, improve the quality of flour, delay the aging, increase the softness, and extend the shelf life. Tests abroad have shown that adding 0.1% amylase to flour can make the flour perfect and greatly improve the quality of the product. Therefore, the amylase activity in flour is used as one of the flour quality indicators abroad.
Application in fruit and vegetable processing
The most commonly used fruits and vegetables are pectinase, cellulase, hemicellulase, amylase, arabinase, etc. Among them, pectinase has become one of the common enzymes for fruit juice and vegetable juice processing in many countries. The use of pectinase and other enzymes (such as cellulase) can greatly improve the juice yield, simplify the process steps, and significantly improve the clarity of the juice, reduce the relative viscosity of the juice, and improve the filtration effect of the juice.
Application in the fermentation industry
At present, the typical application of enzyme engineering in the fermentation industry is the brewing of soy sauce, that is, the enzyme preparation is used instead of koji. After being cooked, it is then cooked, and then added with yeast, or made with immobilized yeast, or exposed to the sun to make modern brewing soy sauce.
Malt is the main raw material for beer. When the malt quality is not good or the auxiliary materials such as barley and rice are used in large amounts, the activity of amylase, cap-glucanase, and cellulase will be insufficient, resulting in insufficient saccharification and insufficient protein degradation. This in turn affects the flavor of the beer.