Why Is Lactic Acid Bacteria Fermented With Antioxidant Properties?

To make a baking product with a long shelf life, not only must its shelf life and organization be ensured, but also the freshness of the product must be maintained, without serious odor, such as oil. Since most synthetic antioxidants (such as BHA, BHT, PG, TBHQ) have various food safety issues, the national standard does not allow them to be used in cakes and bread, so natural, safe, and efficient antioxidants have become the focus of bakery manufacturers. Today, the editor of Baiqing introduced the antioxidant properties of lactic acid bacteria.

　　As a type of bacteria that cannot use oxygen to produce respiratory energy, lactic acid bacteria have to face the stress from oxygen in the long-term evolution process. Therefore, in order to avoid the influence of reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide and hydroxyl radicals on biological macromolecules such as protein, cell membrane and DNA, lactic acid bacteria will produce various antioxidant mechanisms, especially secretion. Antioxidant enzymes, metal ion chelation, intracellular redox state, etc.

1. Produce various antioxidant enzymes

When faced with oxidative stress, lactic acid bacteria produce various antioxidant enzymes during metabolism, such as NADH oxidase, NADH peroxidase, superoxide dismutase, catalase, etc.

　　 NADH oxidase is generally present in Streptococcus, which can make oxygen molecules get 1, 2 and 4 electrons, and use oxygen as a substrate to generate water or hydrogen peroxide to catalyze different reactions.

Lactobacillus and faecalis can also produce NADH peroxidase during fermentation, which can directly reduce hydrogen peroxide to water, but this enzyme has a low efficiency in degrading hydrogen peroxide under oxidative stress, and it is only used as a synergistic Oxidative defense mechanism.

Of course, some Lactobacillus and Streptococcus also produce superoxide dismutase, which is a very important metalloenzyme of organisms, and can be divided into Cu/Zn-SOD, Mn-SOD and Fe- based on the combination of different metal ions. There are three types of SOD, but when the expression of SOD reaches a certain level, it will significantly improve the anti-oxidant ability of Lactobacillus and also have anti-inflammatory effects.

 In Lactobacillus plantarum and Lactobacillus sake, two types of catalase (CAT) are usually expressed, which can improve the ability of lactic acid bacteria fermentation products to tolerate hydrogen peroxide. It is added to noodle products to delay the lipid of the product. Peroxidation, etc., maintain the fresh flavor. When SOD and CAT work together, they can play a complementary role in the active oxygen scavenging pathway and significantly improve the antioxidant capacity of the product.

　　 In Lactobacillus plantarum, there are also enzyme proteins such as pyruvate oxidase. Although these enzymes are not widely distributed, they still have a certain antioxidant effect, which reduces the impact of oxidative stress on cells to a certain extent.

2. Manganese ion

Lactobacillus plantarum has a concentration of manganese ions up to 35 mmol/L. This substance is similar to the action of superoxide dismutase, which can remove intracellular superoxide anions. This removal requires intracellular phosphate groups and With the participation of lactic acid, lactic acid bacteria fermentation products can synergistically play a better antioxidant effect.

3. Maintain the intracellular redox state

Lactic acid bacteria themselves contain many small molecular proteins or peptides with antioxidant capacity, such as glutathione (GSH). These small proteins play an important role in maintaining the intracellular redox state of bacteria, such as receiving electrons to participate in oxidative stress. Reaction and repair of damaged proteins and other biological macromolecules.

4. Adaptive mechanism

　　 Lactic acid bacteria undergo certain environmental stress treatments, such as UV radiation, starvation, high temperature and low pH, which can enhance the defense ability of the bacteria against other stresses.

Oxidative stress is an important factor affecting the growth, fermentation performance and product characteristics of lactic acid bacteria. For many years, Guangzhou Baiqing Company has conducted in-depth research on the above and even other different mechanisms to screen and cultivate lactic acid bacteria strains with antioxidant properties and antibacterial and fresh-keeping properties. Deep fermentation, scientifically extracting ingredients with antibacterial and anti-oxidation effects, applied to the baking industry, solved various preservation problems for customers such as aging, oil oxidation, mold growth, and excessive bacteria.