Sodium metabisulfite is a kind of widely used food additive that not only has bleaching effect, but also has the following effects:

The effect of anti-browning: enzymatic browning often occurs in fruits and potato food. Sodium metabisulfite is a reducing agent with a strong inhibitory effect on polyphenol oxidase activity. 0.0001% sulfur dioxide can reduce enzyme activity by 20%, and 0.001% sulfur dioxide can completely inhibit enzyme activity, which can prevent enzymatic browning. In addition, it can consume oxygen in food tissues and play a role in deoxygenation; In addition, sulfite can conduct addition reaction with glucose to prevent glucose and amino acids in food from sugar ammonia reaction, thus preventing browning.

Antiseptic effect: sulfite can act as an acidic preservative, while undissociated sulfite is believed to inhibit yeast, mold, and bacteria. It is reported that the inhibition of undissolved sulfite on Escherichia coli is 1000 times stronger than that of hydrogen sulfate. It is 100-500 times stronger than beer yeast and 100 times stronger than mold. When sulfur dioxide is acidic, its ability to anti microorganisms is the strongest.

The function of a loosening: can be used as a component of the loosening.

Antioxidant effects:sulfite has significant antioxidant effects. Because of its strong reducing agent, sulfite can consume oxygen in fruit and vegetable tissues, inhibit oxidase activity, and effectively prevent the oxidative damage of vitamin C in fruits and vegetables.

Application of Food Additive Sodium Metabisulfite

Mechanism of sodium metabisulfite acting

Bleaching agents can be divided into two categories based on their mode of action: oxidizing bleaching agent and reducing bleaching agent. Sodium metabisulfite belongs to the category of reducing bleaching agent.

Sodium metabisulfite utilizes the reduction effect of pigments to fade, achieving the purpose of bleaching. The color of most organic compounds is produced by the chromophores contained in their molecules. The chromophore contains unsaturated bonds, and a reducing bleaching agent releases hydrogen atoms, which can turn the unsaturated bonds contained in the chromophore into single bonds, causing organic matter to lose color. The browning of some foods is caused by the presence of trivalent iron ions. Adding a reducing bleaching agent can turn trivalent iron ions into divalent iron ions, preventing food browning.

Sodium metabisulfite fades through sulfite addition reaction to achieve the purpose of bleaching. The addition reaction of anthocyanins and sugars can be carried out to bleach and fade the anthocyanins. This reaction is reversible. The sulfite can be removed by heating or acidification treatment, so that anthocyanins can regenerate and restore the original red color.