What Is Sodium Metabisulfite and Its Uses?

Sodium metabisulfite, one of the sulfites that can be utilized as a preservative, antioxidant, and bleaching agent in food. It is a decreasing agent that is commonly utilized for the preservation of fresh & dried fruits, veggies, and  wine.

How is Sodium Metabisulfite made?

Sodium metabisulfite can be made from the reaction between sulfur dioxide with sodium carbonate. The following is the response equation: SO2 + Na2SO3 → NA2S2O5.

The manufacturing procedure is: Reaction between sodium carbonate (Na2CO3) and sodium bisulfite (NaHSO3) service to form the combined solution of sodium bisulfite and sodium sulfite (Na2SO3). Response equation: Na2CO3 +2 NaHSO3 = Na2SO3+ H2O+ CO2.

Add excess sulfur dioxide (SO2) to the above solution to transform sodium sulfite to sodium bisulfite and additionally obtain the liquified sulfur dioxide. Reaction equation: Na2SO3+ H2O+ SO2= 2NaHSO3.

Transform the liquified sulfur dioxide to sodium bisulfite by adding an alkali active ingredient, e, g, sodium carbonate, sodium hydroxide, or sodium sulfite, or the blends. Reaction formula: Na2CO3+ H2O+ SO2= 2NaHSO3+ CO2.

Getting sodium metabisulfite (Na2S2O5) through two sodium bisulfite molecules responds by cooling down the above sodium bisulfite solution, and follows purification and drying out processes to create crystals or powder. Reaction formula: 2NaHSO3 = Na2S2O5+ H2O.

What're the Uses of Sodium Metabisulfite?

Sodium metabisulfite is a strong reducing agent that can respond with oxidizing agents as the sulfur atom in it with a positive valence of 4, the optimum valence of which is 6. That is the system why sodium metabisulfite is a multifunctional ingredient that can be used as a chemical, antioxidant, and bleaching agent in agricultural foodstuff, wine, and various other applications.

Preservative

The sodium metabisulfite preservative is a sulfur-containing chemical that prevents the oxidase in the food, and also can obstruct the regular physical oxidation procedure of bacteria and hence prevent the reproduction of microorganisms in food preservation.

Antioxidant

Given that sulfite is a strong reducing agent, it reacts with oxygen from vegetables and fruits and also prevents oxidase task, so it prevents food-wasting triggered by oxidation and secures vitamin C in them.

Bleaching agent

Minimize the tinted material to a bright and fresh shade or prevent/slow oxidative browning.

Bakery

Sodium metabisulfite operates as a reducing agent in biscuit/pastry dough which loosens up the dough, decreases the rest time, and speeds up the kneading process by responding with disulfide bonds.

Refined fruit items

Like other sulfites (e.g. sodium sulfite, sulfur dioxide), sodium metabisulfite can be used as both a preservative and antioxidant in processed fruit items to slow down browning reactions, and hinder the development of certain microbes.