Natural preservatives in food are compounds that are naturally found in plants, animals, or microorganisms and are used to increase the shelf life of foods, prevent spoilage, and maintain their quality. The functions of these preservatives mainly include the following:
1- Antimicrobial
Natural preservatives can inhibit the growth of bacteria, fungi, and molds. Some natural preservatives reduce growth and reproduction by destroying the cell walls of microbes or disrupting their metabolism. Examples:
Citric acid: Found in citrus fruits, it prevents the growth of microorganisms by lowering the pH of the environment.
Vinegar (acetic acid): A natural antimicrobial used in pickles.
Essential oils (such as thyme or rosemary oil): Have antibacterial and antifungal properties.
2- Anti-oxidation
Oxidation is one of the main causes of food spoilage, especially in fatty foods, which causes unpleasant tastes and odors. Natural preservatives help increase shelf life by neutralizing free radicals and preventing oxidation.
Examples:
Vitamin E: An antioxidant that prevents the oxidation of oils and fats.
Vitamin C: Used to prevent oxidation in fruit juices and processed products.
Rosemary extract: A powerful natural antioxidant.
3- Lowering pH
Some natural preservatives reduce the pH of the food environment, making conditions unfavorable for microbial growth. Examples:
Lactic acid: Found in fermented products such as yogurt and kefir.
Propionic acid: Found naturally in some fermented products and used to control mold growth.
4- Inhibition of degradative enzymes
Natural enzymes in foods can cause them to decompose and spoil. Natural preservatives reduce the activity of these enzymes.
Example:
Honey: Contains enzymes that make the environment unsuitable for bacterial growth.
Advantages of using natural preservatives:
Higher safety and no negative health effects compared to synthetic preservatives.
Consumers’ desire for organic and healthy products.
Compatibility with environmental standards.
Limitations:
Less effectiveness compared to chemical preservatives in some cases.
Higher production cost.
Sensitivity to storage conditions (such as temperature or light).
However, due to the increasing desire to use natural and healthy products, the use of natural preservatives is increasing in the food industry.