Preservatives are an important food additive that can prevent food spoilage and deterioration, ensure food quality and prolong food shelf life. Since natural preservatives are derived from natural resources and have safe, green and efficient preservative properties, they are more widely used in food than chemically synthesized preservatives, and the importance of natural preservatives is also increasing.
Source and application of natural preservatives
Natural food preservatives have the advantages of strong antibacterial properties, high safety, and good thermal stability. According to their sources, they can be divided into plant preservatives, animal preservatives and microbial preservatives. Due to the different sources of various natural preservatives, their composition and structural characteristics are different, and their applications in food are also different. The following three kinds of natural food preservatives will be introduced respectively.
Plant preservatives
Plant preservatives are mostly derived from plant extracts, such as certain natural herbs and spices and plant essential oils. Because of their unique flavor and bacteriostatic preservative effects, plant extracts and plant essential oils have long been used as food preservatives, seasonings and medical preparations.
Animal preservatives
Animal preservatives refer to biologically active substances with antiseptic effect that are artificially extracted from some animals or their metabolites. They are classified according to their functions: antimicrobial enzymes, antimicrobial peptides and antioxidant peptides, etc.
Preservatives for microorganisms and their metabolites
Many compounds produced by bacteria prevent the growth of spoilage bacteria or pathogenic microorganisms in food. Food-grade microorganisms can form a large number of substances to inhibit the growth of other microorganisms, so as to achieve the natural balance of the microbial ecosystem.
Lactic acid bacteria (LAB) in microorganisms have the ability to inhibit the growth of microorganisms and are considered to be good candidate strains. In the production of fermented food, lactic acid bacteria are used to improve the taste, flavor and texture of food and to prevent the growth of pathogenic microorganisms, and LAB is not harmful when eaten. The antibacterial components of LAB mainly include bacteriocin, organic acid, hydrogen peroxide, carbon dioxide and diacetyl; among them, bacteriocin is a natural preservative or biological preservative synthesized by LAB and other strains, and is effective against Staphylococcus aureus, mononuclear Foodborne pathogens such as Listeria prolifera and Clostridium botulinum have good bactericidal or bacteriostatic effects, and also have good antibacterial activity against Gram-positive bacteria. Bacteriocin has better antibacterial activity at lower pH values. powerful.
In addition, bacteriocins can be used in combination with other antibacterial compounds to enhance the inactivation of bacteria. Bacteriocins can be used in bioactive packaging. In recent years, researchers have focused on adding bacteriocins to food packaging films to control the growth of food pathogens. Antibacterial packaging films prevent the growth of microorganisms on food surfaces by contacting packaging materials with food surfaces.
Food is an important source of nutrients and energy that people absorb from the outside world, and its safety and hygiene are particularly important, and preservatives can prevent food spoilage and prolong food shelf life. Therefore, food preservatives are extremely important in food preservation and storage. effect. Compared with chemically synthesized preservatives, which have disadvantages such as large side effects and carcinogenicity, natural preservatives are not only non-toxic and harmless, but also prolong the shelf life of food, and are beneficial to human health; there is no doubt that in addition to existing natural herbs, animal or In addition to microbial additives, more new natural food preservatives are yet to be discovered.
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