Science and Technology Innovation Center Yue Weifeng January 19, 2024
Probiotics are a group of strictly selected live microorganisms that, if administered in sufficient amounts, can confer health benefits to the host. Many researchers believe that there is a close relationship between probiotics and human health. These microorganisms can activate gastrointestinal effects through the intestines, or directly act on other parts of the mouth, vagina, skin, etc. to regulate host health [1]. With the continuous development of modern biotechnology and the improvement of people's health awareness, the probiotic industry has developed explosively. More and more probiotic products are in the form of dietary supplements, dairy products, enzyme preparations, and other microecological preparations. came out one after another. These probiotic products have been widely used in food, planting, animal husbandry, and medical industries, becoming a powerful tool to improve human health.
1. Application of probiotics in the food industry
At present, common probiotic strains that can be used in food include Bifidobacterium adolescentis, Bifidobacterium breve, Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium longum, etc. belonging to the genus Bifidobacterium; Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus kefir, Lactobacillus sake, Lactobacillus johnsonii , Lactobacillus salivarius, Lactobacillus curvature, Lactobacillus brevis, etc.; belonging to certain Streptococcus genus: Streptococcus acidophilus, Streptococcus lactis, Streptococcus faecalis, Streptococcus faecium, Pediococcus pentosaceus, Pediococcus acidilactici, etc. Bacteria[2]. In addition, certain species of Leuconostoc, Propionibacterium, Bacillus, and some Saccharomyces cerevisiae can also be commonly used as probiotics [3]. From the perspective of the applied ingredients of probiotics, it can be a simple live bacteria preparation, a compound preparation composed of multiple strains, or a compound preparation containing Bifidus factors and other ingredients in addition to probiotics; from the perspective of dosage form There are tablets, capsules, granules, and liquid preparations. As a live bacterial preparation, probiotics can be used as both a good therapeutic agent and a health care product. The following mainly introduces its applications in food.
1.1 Application of probiotics in dairy products
Dairy products are the largest application area of probiotics, and yogurt is the largest application area of probiotics in dairy products. According to reports, the proportion of probiotic products in the dairy field can reach 74.5%, and yogurt accounts for 74.5% of the probiotic products. 74%[4]. Many researchers believe that yogurt is the best food carrier for probiotics, and fermented foods, especially fermented dairy products, have good health effects. Therefore, probiotics as fermented strains can combine fermentation performance with health effects. Yogurt has become a type of healthy food that is well-known and favored by consumers, which will help the further promotion and application of this type of product [5]. In recent years, to meet the needs of consumers, many types and flavors of yogurt have emerged. For example, probiotic yogurt containing fruits is very popular among consumers, so people add a variety of fruits to make stirred fruit yogurt[6] To improve the survival of probiotics, enrich the taste of yogurt, and improve its efficacy, researchers have also studied and discovered products such as "Yakult", "Actimel" and "Kefir".
In addition to yogurt, the application of probiotics in dairy products also involves fermented liquid milk, pure milk (with probiotics added but not fermented), milk drinks, milk powder, cheese, infant milk, and almost all milk products.
1.2 Application of probiotics in functional foods
With the continuous improvement of people's living standards, how to pursue health and wellness has become more and more a hot topic in people's daily lives, and research on probiotics as functional foods has also attracted more and more attention due to their unique health care functions. It is not difficult to find various fermented drinks on the market that are added with different probiotics to promote and regulate human health, such as various functional fermented fruit and vegetable drinks, candy products, ice cream desserts, etc. Take kombucha drinks as an example. Because kombucha drinks are rich in vitamin C, vitamin B, and other nutrients, and contain more than three types of microbial flora that are beneficial to the human body, they can regulate human physiological functions, promote metabolism, help digestion, and prevent arterial disease. It has anti-sclerosis, anti-cancer, and health-preserving properties. It is becoming a popular health-preserving drink all over the world [4]. By using one or several probiotic strains alone or mixed with other yeasts, acetic acid bacteria, etc., to enhance the flavor, physical properties, and production performance of the product, a series of functional food additives have been developed on the market, such as some products Flavored lactic acid bacteria such as Lactobacillus bulgaricus and Streptococcus thermophilus (the characteristic flavor is mainly acetaldehyde), Streptococcus lactis butanedione, Acetobacter aceti, Leuconostoc mesenteroides, and Streptococcus case (produce oxalyl, Flavor substances such as lactic acid, acetic acid, and diacetyl), because they can impart aroma to the product, improve the flavor of the product, and reduce the addition of flavors and spices in the product, thereby making the product more natural and easier to be accepted by consumers [7].
1.3 Application of probiotics in dietary supplements
Probiotics as dietary supplements are usually made into so-called probiotic preparations, which are powders, tablets, or capsules containing live bacteria made by appropriate methods [4]. As a type of food, they can improve intestinal microorganisms. It is a balanced and effective active microbial preparation that affects the host. After being taken, it can regulate the intestines and prevent and treat gastrointestinal diseases. Researchers usually develop such dietary supplements for a specific group of people. For example, such products for children include "Mommy Love", "French Biobiotics", "Hanchen's", and "Only Youtuo" Such as probiotic supplements, these dietary supplements can effectively alleviate problems such as constipation or diarrhea in young children, especially those who have used antibiotics. The number of bacteria in the intestines will decrease. Daily supplements containing lactobacilli and bifidobacteria Yogurt or other probiotic-containing foods can speed up the recovery of a healthy gastrointestinal system [8].
In addition to products for children, there are also products on the market suitable for middle-aged and elderly people, women, office workers, and people with diabetes. They all aim to supplement intestinal probiotics and help balance and maintain intestinal microecology [8-9].
1.4 Application of probiotics in fermented meat products
At present, research on fermented meat products using probiotics at home and abroad mainly focuses on the production of fermented sausages. As early as the early 20th century, the production of fermented sausages was accomplished by adding a small piece of the already fermented product as a fermentation starter or by adding some substances that promote the fermentation of the product and are present in the raw materials. However, this natural fermentation process, which relies on the competition between lactic acid bacteria and miscellaneous bacteria in the microflora of raw meat, has many uncertain factors such as unreliability and uncontrollability. It was not until 1940 that Jensen and Psddock first described the application of lactic acid bacteria in fermented sausages and obtained a patent. This pioneered the use of purely cultured microbial starter cultures to produce fermented sausages [10]. In 1996, Nurmi found in his research that a mixture of lactobacilli and catalase-positive cocci could produce better products than inoculating a single strain of bacteria alone. Since then, the research and application of mixed-strain fermented meat products have developed rapidly [11].
In recent years, the probiotics used in the fermentation of meat products are mainly lactic acid bacteria. The fermentation agents are made by compounding different lactic acid bacteria and other microorganisms such as micrococci, staphylococci, or yeasts. These fermentation agents are used in the fermentation and fermentation of meat products. During the maturation process, each plays its unique role. On the one hand, the protease produced by the inoculated microorganisms can decompose the protein in the meat into peptides and amino acids that are easier for the human body to digest and absorb. The lipase produced can decompose fat into short chains. The volatile fatty acids and esters give the product a unique aroma; on the other hand, inoculation of microorganisms can inhibit the growth of spoilage microorganisms in meat and extend the shelf life of the product. Therefore, fermentation of meat products can not only significantly improve their digestion and absorption rate and nutritional value, giving the product a unique flavor, but also increase the safety and shelf life of the product. At present, the popularity of fermented sausages on the market is becoming more and more widespread. It has become the largest and most representative type of fermented meat products and is a major direction for the development of meat products in the future.
2. Application of probiotics in medical treatment
In the past 30 years, great progress has been made in research on the distribution, nutrition, classification, and characteristics of probiotics. Probiotics play an important role in enhancing anti-tumor and immune functions. In addition, multiple randomized meta-analysis studies and controlled clinical trials have found that probiotics can also play a beneficial role in the treatment of many human diseases.
2.1 Physiological functions of probiotics
2.1.1 The role of probiotics in improving the intestinal tract
Probiotics are resistant to gastric acid and intestinal digestive juices and can enter the human intestine alive. Through their growth and various metabolic effects, they promote the normalization of intestinal bacterial groups, inhibit the production of putrefactive substances in the intestine, and maintain normal intestinal function. Probiotics and yogurt containing probiotics can be used to treat and prevent various digestive tract diseases. It has therapeutic and preventive effects on viral and bacterial acute enteritis and dysentery in infants and young children, enteritis and dysentery caused by antibiotic use, dysentery during travel, and constipation in middle-aged and elderly people.
A researcher randomly divided 80 cases of premature infants into two groups, 40 cases were given oral probiotics after artificial feeding, and the other 40 cases served as a control group and were artificially fed according to routine diagnosis and treatment without the addition of probiotics. The weight gain and occurrence of vomiting, gastric retention, abdominal distension, etc. of the two groups of premature infants were observed. Gastrin and motilin were measured before and every week after feeding. The results show that taking probiotics can reduce the occurrence of vomiting, gastric retention, and abdominal distension in premature infants during feeding. It can promote weight gain and the secretion of gastrin and motilin after 3 weeks of use and affects the gastrointestinal motility of premature infants. Significant promotion effect [12].
2.1.2 The blood pressure lowering effect of probiotics
Some probiotics can specifically break down casein and produce two polypeptides (VPP and LPP) that have the activity to inhibit the enzyme (ACE) that causes blood pressure to rise. Regular consumption of yogurt containing these two physiologically active polypeptides can prevent high blood pressure. Valio, a Finnish company, launches Evolus, the first blood pressure-lowering probiotic dairy product on the European market. It is a yogurt product fermented by a special strain of Lactobacillus helveticus. After strict scientific process control, it obtains a high content of blood pressure-lowering peptides. , thereby lowering blood pressure. After many animal experiments and clinical studies, it was found that the blood pressure-lowering effect of Evolus is significantly better than other control products. Hypertensive patients who consume an appropriate amount of Evolus products every day will see a significant reduction in systolic and diastolic blood pressure after 5 to 7 weeks.
2.1.3 The role of probiotics in improving blood lipid metabolism
Probiotics can absorb cholesterol in food and promote the excretion of cholesterol in food from the body. Probiotics can also adsorb bile acids in the intestine. As the bacteria excrete bile acids from the body, the reduction of intestinal bile acids can strengthen the conversion of cholesterol into bile acids in the liver, ultimately reducing the cholesterol content in the serum [13].
2.1.4 The role of probiotics in preventing diarrhea
The intestinal microecosystem is the largest and most important microecosystem in the body. The intestines of healthy people are home to 1014 bacteria, and a large number of intestinal bacteria mainly live in the colon and distal small intestine. Under pathological conditions, such as infection, antibiotic use, or low immunity, the normal intestinal microecological system may become imbalanced, which may manifest clinically as infectious diarrhea or other diseases. Obligate anaerobic bacteria, mainly Bifidobacterium and Lactobacillus, combine with specific receptors on the mucosal epithelial surface to form a bacterial film structure and biological barrier with fairly uniform composition, which constitutes intestinal colonization and can effectively resist passing bacteria. Invasion of the body [14].
2.1.5 The role of probiotics in promoting digestion
In terms of human health and nutrition, probiotics can synthesize a variety of vitamins, promote the body's absorption of proteins, calcium, iron, vitamin D, and other substances, and have the functions of helping digestion and increasing appetite. Lactic acid bacteria can decompose lactose in milk to form lactic acid, making the intestines more acidic and inhibiting putrefactive bacteria that grow and reproduce in neutral or alkaline environments. They can also synthesize nutrients such as folic acid and vitamin E that are necessary for the human body. They are themselves rich in Protein and vitamin A and are very beneficial to the elderly and infirm.
2.2 Treatment of diseases with probiotics
2.2.1 Antibiotic-induced diarrhea
Antibiotics not only inhibit the growth of pathogenic bacteria but also inhibit the growth of non-pathogenic bacteria. The imbalance of the normal flora of the human body can cause loss of appetite, nausea and vomiting, dizziness, etc., and can lead to another infectious disease in severe cases. Active Bifidobacterium longum can rebalance gastrointestinal flora imbalance.
2.2.2 Treatment of liver cirrhosis
The bacterial strains in the human intestine can be divided into two categories: beneficial bacteria and harmful bacteria. The former includes bibacteria, lactobacilli, etc., and the latter includes putrefactive bacteria, etc. In a normal body, the two maintain a balance and maintain normal physiological functions of the intestines. Probiotics can significantly regulate intestinal flora. They can not only inhibit ammonia-producing bacteria to reduce ammonia, but also prevent bacterial translocation, effectively reduce blood ammonia, and improve the symptoms of patients with liver cirrhosis. The researchers gave 38 patients in the treatment group 2 packets of Clostridium butyricum and Bifidobacterium combined live antibiotic powder, orally, 3 times a day. The 30 patients in the control group were given routine liver protection and anti-fibrosis. During the observation period, patients in both groups did not receive special dietary intervention. Blood ammonia levels and digital connectivity test (NCT) were measured after 1 month of treatment. Results: The blood ammonia in the treatment group was significantly reduced after treatment, with a significant difference. NCT can also significantly improve the condition, and there is a significant difference between the two groups of patients. The results show that probiotic preparations are effective, convenient, and safe in treating cirrhosis and hyperammonemia [15].
2.2.3 Treatment of ulcerative colitis
Ulcerative colitis (UC) is a well-circumscribed inflammatory reaction limited to the mucosa or submucosa of the colon and rectum. Clinical studies have found that patients with ulcerative colitis have dysbiosis, and intestinal flora plays an important role in the pathogenesis. Measures to regulate intestinal flora imbalance are new strategies for the treatment of UC.
He Jinsong [16] et al randomly divided 72 patients with ulcerative colitis into a study group of 45 cases and a control group of 27 cases. The research group was given 52-aminosalicylic acid + probiotics, and the control group was given 52-aminosalicylic acid. The efficacy and endotoxin levels before and after treatment were compared between the two groups. Results: The endotoxin levels in both groups decreased significantly. The total effective rate of the research group was 93.3% higher than that of the control group, which was 74.1%. The difference between the two groups was statistically significant (P<0.05). It shows that probiotics can effectively treat ulcerative colitis and reduce endotoxin levels in patients.
2.2.4 Treatment of constipation
The acidic substances such as lactic acid and acetic acid produced by probiotics under the combined effect of the intestinal environment can stimulate the intestines to secrete a large amount of intestinal juice, soften the feces, and facilitate feces excretion [17]. Various probiotic preparations have been widely used to adjust and improve the sub-health state of the human body, but their preventive and health-care effects often require longer-term use to become apparent. In 2007, my country officially launched a public nutrition improvement project to add oligosaccharides, a prebiotic, to food, advocating the use of probiotic preparations, which are not only beneficial to the nutritional health of the whole body but also prevent and treat constipation.