Sodium Metabisulfite is a reducing agent used in dough.

It is used frequently in cookie and cracker production.

It is also used as a preservative for baked goods, wine, dried fruit and jams due to its antioxidant capacity.

Sodium metabisulfite is an antioxidant which serves as a preservative for dried fruit that is used in baked products.

Sodium metabisulfite, Na2S2O5. It is used as a sterilizer and antioxidant / preservative.

Sodium Metabisulfite is a white to slightly yellowish, crystalline powder with an odor of sulfur dioxide.

** Function

As a reducing agent, sodium Metabisulfite makes the dough flexible for better sheeting, and this is the rationale for sodium Metabisulfite’s working as reducing agent.

It reacts with the cysteine amino acids in dough, creating S-sulfocysteine residues within the protein structure, which inhibit the restoration of disulfide bonds.

Essentially, sodium Metabisulfite acts as a cap, covering the reactive thiol group on cysteine, so it is unavailable to reform disulfide bonds.

Lack of adequate disulfide bonds means that dough can’t form a strong gluten network.

** Application

Compared with other reducing agents, like glutathione and L-cysteine, sodium Metabisulfite has the greatest reducing capacity.

It is usually used at 0.03% dry flour weight in cracker production.

It is rarely used in bread dough production.

In the chemical and pharmaceutical industries: as a reducing agent, for purifying and isolating aldehydes and ketones.

For destroying waste bromine. In drinking water treatment to remove excess chlorine and chloramines and protect RO membranes.

In the treatment of wastewater, particularly. from electroplating plants, to neutralize chromic acid; to remove excess chlorine in the neutralization of cyanide.

In special cases to remove oxygen from boiler feed water. For cleaning and bleaching wool, jute, and other vegetable fibers.

In the paper and pulp industry for bleaching ground wood.

Sodium Metabisulfite food grade (E223): For preserving foodstuffs (restricted use in accordance with the additives approval regulations, E 223).

As anti-melanosis additive for sea food (prawns, shrimp).

Sodium Metabisulfite Solution (SMBS) is made by dissolving solid sodium metabisulfite into water and has a pH of 4.6 at 1.0 % (by weight) solution strength.

The SMBS solution is not stable to air and reacts with oxygen as well as chlorine, therefore it is recommended that batches of less than 2 % by weight be used within 3 to 7 days and batch solutions less than 10 % be used within 7 to 14 days.