Probiotics are a class of active microorganisms used to improve the balance of the host's intestinal microflora. Its health effects were first proposed by Russian scientist Mctchn ikoff. So far, people have found that probiotics have important physiological effects such as improving the structure of the intestinal flora, inhibiting pathogenic bacteria, eliminating carcinogenic factors, improving the body's immunity, and lowering cholesterol.
Probiotics are a class of active microorganisms used to improve the balance of the host's intestinal microflora. Its health effects were first proposed by the Russian scientist Mctchn ikoff. So far, people have found that probiotics have important physiological effects such as improving the structure of the intestinal flora, inhibiting pathogenic bacteria, eliminating carcinogenic factors, improving the body's immunity, and lowering cholesterol. The close relationship between probiotics and human health makes it widely used as a biological additive in food and exerts important biological effects. Foods added with probiotics can improve digestive function and promote gastrointestinal motility, especially for preventing gastrointestinal diseases such as diarrhea and indigestion in infants and the elderly.
With the deepening of research, the definition of probiotics is constantly changing. In 1965, Lilly proposed: “Probiotics are beneficial promoters or microorganisms that are beneficial to the balance of the intestinal flora of raised animals." In 1991, Fuller added the definition of probiotics: "Probiotics are living microorganisms that contain physiologically active substances that can pass through the gastrointestinal or colon or multiply in the intestine, adjust the intestinal flora, and improve the body's immunity.”
Later, it was discovered that the cell components or metabolites of dead bacteria also have the same physiological functions as live bacteria. In 1996, Arameo pointed out: “Probiotics contain physiologically active bacteria or dead cells (including metabolites and cell components), which can be improved after ingestion. The balance of microbial flora or enzymes on the mucosal surface, or a microbial agent that stimulates the body’s specific or non-specific immunity.” Therefore, in a broad sense, probiotics can be a single strain, multiple strains or even their fermentation products. That is, probiotics are a type of microeco logics that are beneficial to the human body. It is generally believed that bacteria as probiotics should have the following conditions: beneficial to the host, non-toxic and non-pathogenic, can survive in the digestive tract, can adapt to gastric acid and bile, and can produce useful enzymes and metabolites.
Types of probiotics
Probiotics are mainly normal physiological bacteria and non-intestinal bacteria in the intestinal tract of animals. In 1989, the U.S. Food and Drug Administration (FDA) and the American Feed Inspection Association (AAFCO) announced 41 safe strains. At present, the commonly used probiotics are Bifidobacterium, Lactobacillus and certain streptococci. Bifidobacterium includes Bifidobacterium adolescentis, Bifidobacterium breve, Bifidobacterium bifidobacterium, Bifidobacterium infantis, etc. Acid bacilli include Lactobacillus acidophilus and Lactobacillus bulgaricus. Streptococci include Streptococcus faecalis, Streptococcus lactis, Streptococcus thermophilus and Streptococcus lactis. In addition, strains of Leuconococcus, Fusarium, Propionibacterium, and Bacillus can also be used as probiotics. They have a wide range of sources. Fresh vegetables and fruits contain a small amount of probiotics, and lactic acid fermentation products are also good sources of probiotics.
The research on the promotion of human health by probiotics needs to be further deepened. The function of probiotics, which has been clinically proven, can slow down lactose intolerance and prevent and treat various diarrhea. It is clinically proven that probiotics can regulate the immune function of the body, fight tumors (gastric, intestinal, genitourinary tract tumors), improve blood viscosity, lower serum cholesterol, reduce the incidence of cardiovascular diseases, anti-hypertension and inhibit urogenital infections. At present, probiotics have been successfully applied to the dairy industry, and the focus of future research is to continue to add probiotics as food ingredients to more varieties of foods to provide more convenient nutrition and health ingredients for different groups of people.
The Naming and Characteristics of Restriction Endonucleases
Restriction enzymes, also known as restriction endonucleases, are enzymes that cut double-stranded DNA. Its cutting method is to cut the bond between the carbohydrate molecule and the phosphoric acid, and then create a nick on each of the two DNA strands without damaging the nucleotides and bases.
Introduction to Classification and Application of Cellulase
The optimum pH of cellulase is generally 4.5 to 6.5, which acts on cellulose and products derived from cellulose. Microbial cellulase is of great significance in converting insoluble cellulose into glucose and destroying cell walls in fruit and vegetable juice to improve the yield of juice.
Which Enzyme Preparations Are Often Used in Fruit and Vegetable Processing?
The so-called fruit and vegetable processing means to maximize the nutrient content of the fruit and vegetable through various processing methods, improve the edible value, and make the color, aroma and taste of the processed product more perfect.
