Sodium Metabisulfite For Food
Sodium metabisulfite is a strong reducing agent that can react with oxidants because its sulfur atom has a normal valence of 4 and a maximum valence of 6. Sodium metabisulfite is a multifunctional ingredient that can be used as a preservative, antioxidant, and bleach in agricultural products, wine, and other foods.
Preservative
Sodium metabisulfite is a sulfur-containing preservative that can inhibit oxidase in food, block the normal physiological oxidation process of microorganisms, and thus inhibit the reproduction of microorganisms in food preservation.
Antioxidant
Sodium metabisulfite, due to its strong reducing agent, reacts with oxygen in fruits and vegetables to inhibit oxidase activity, thereby preventing food spoilage caused by oxidation and protecting vitamin C.
Bleaching agents
Restore bright and fresh colors to colored materials, or prevent/slow down oxidative browning.
Main uses of sodium metabisulfite in food
Wine
There is sulfur dioxide in the ingredient list of wine, but it is not directly added to the wine. It is formed by adding sodium or potassium metabisulfite. The reaction equation for Na2S2O5 in wine is as follows:
Na2S2O5+H2O<===>2Na++2（HSO3）-
HSO3+H+<===>H2O+SO2
Sulfur dioxide plays an important role in almost every manufacturing process of winemaking, from grape picking to bottling. It mainly inhibits the growth of yeast and bacteria, thereby maintaining the freshness of wine and extending its shelf life.
Sodium metabisulfite or potassium metabisulfite is commonly added as an antioxidant, preservative, and stabilizer to wine, apple cider, or beer. In addition, it can also be used for cleaning and disinfecting wine equipment and bottles.
Bread
Like L-cysteine, sodium metabisulfite acts as a reducing agent in cookie/pastry dough. It reacts with disulfide bonds and hydrolyzes in water to form bisulfite (HSO3-), which produces thiosulfate esters in gluten proteins, making the dough loose, reducing rest time, and accelerating the kneading process.
Processing fruit products
Like other sulfites such as sodium sulfite and sulfur dioxide, sodium metabisulfite can be used as a preservative and antioxidant in processed fruit products to slow down browning reactions and inhibit the growth of certain microorganisms.
Sodium Metabisulfite For Water Treatment
Sodium metabisulfite is the typical chlorine reducing agent of choice for larger RO systems. A dosing rate of 2.0 to 3.0 ppm SMBS per 1.0 ppm chlorine so as to include an industrial safety factor for brackish water RO systems with at least 20 seconds of reaction time.
SMBS is preferred to be used for larger water treatment systems than other chemical reducing agents such as carbon filters and sulphur dioxide due to its advantage of reducing the chance of bacteria growth than produces biological fouling.
When dissolved in water, sodium bisulfite is formed from sodium metabisulfite:
Na2 S2 O5 + H2 O → 2 NaHSO3
sodium bisulfite is then reducing hypochlorous acid according to:
NaHSO3 + HOCl → HCl + NaHSO4
The most critical role of SBS is dechlorination. As the TFC/TFN membranes are less tolerable to chlorine, the residual chlorine must be removed prior to entering the RO unit. The next key application is a use for an RO element preservative for shipping elements and during plant shutdown. Several other SBS applications include deoxygenation, shock treatment as a biostatic agent, and CIP chemical, etc. Thus, SBS can be considered an essential chemical for RO processes.
Sodium metabisulfite is commonly used for removal of free chlorine and as a biostatic. Other chemical reducing agents exist (e.g., sulfur dioxide), but they are not as cost-effective as sodium metabisulfite. In theory, 1.34 mg of sodium metabisulfite will remove 1.0 mg of free chlorine.
Sodium Metabisulfite For Mining
Sodium metabisulfite is a compound commonly used in various industries. It is a white crystalline powder that is soluble in water and has sulfur dioxide odor. It is widely used as a flotation agent for copper and gold mines.
In the copper mine, sodium metabisulfite is added to the slurry to form foam to separate copper minerals from unwanted minerals. The foam is then collected and further processed to extract copper. In gold mines, it is used in a similar way to separate gold minerals from other minerals. It reacts with the surface of gold minerals to form a hydrophobic layer, causing them to float on the surface of the slurry.
Sodium metabisulfite is also used as a reducing agent for copper and gold mines. It helps to reduce the impurity content in ore and prevent the oxidation of certain minerals. This helps to improve the quality of the final product and increase its value.
Sodium Metabisulfite For Cosmetics
Sodium metabisulfite is a widely used additive with many applications in the fields of personal care and cosmetics. It exists in many products, such as hair dye, shampoo, sunscreen, concealer, etc.
Skin care: Sodium metabisulfite can improve the appearance of hyperpigmentation and dark spots. It also has anti-aging and anti damage effects caused by free radicals. The antibacterial properties of sodium metabisulfite can further inhibit the growth of bacteria that cause acne on the skin.
Hair care: Sodium metabisulfite has conditioning properties that help improve the overall health of hair. It helps to strengthen hair and prevent damage caused by environmental stress. Sodium metabisulfite is also used for straight hair treatment to break down protein bonds in hair, allowing it to reshape and straighten.
Cosmetics: Sodium metabisulfite can prevent oxidation of cosmetic ingredients such as oils and fats, which may cause rancidity, odor, and color changes. This preservative is particularly used in water-based formulations to prevent microbial growth that may damage the product.
Sodium Metabisulfite For Wine
Sodium metabisulfite is a kind of common food additive used to preserve and stabilize wine, apple cider, and occasionally used for beer. Sodium metabisulfite can prevent the growth and oxidation of wild yeast and bacteria in wine. When added to wine or grape juice, it forms sulfur dioxide gas (SO2). This can prevent the growth of most wild microorganisms and act as a powerful antioxidant, protecting the color and subtle taste of wine. Sodium metabisulfite solution is also used as a disinfectant flushing solution for brewing equipment.
The function of sodium metabisulfite is the same as that of potassium metabisulfite. Potassium metabisulfite is usually the preferred additive as it does not provide any dietary sodium, but sodium metabisulfite is more popular as a disinfectant rinse.
Recommended usage method
The dosage may vary when sodium metabisulfite is used to kill wild bacteria in grape juice, stop fermentation, or protect finished wine from oxidation. Adding ¼ teaspoon of sodium metabisulfite to 5 gallons can produce approximately 50ppm of free SO2.
To disinfect and rinse the equipment, dissolve 8 teaspoons of sodium metabisulfite in 1 gallon of water. High concentration sulfur dioxide gas is irritating and toxic, so please use it in a well ventilated area. After applying the solution to the equipment, it must be rinsed with clean cold water.
