Sodium Metabisulfite is a widely used food additive. In addition to its bleaching effect, it also has the following functions:
1)The effect of Anti Browning
Enzymatic Browning often occurs in fruits, potatoes, Sodium Metabisulfite is a reducing agent, the activity of polyphenol oxidase has a strong inhibitory effect, 0.0001% of sulfur dioxide can reduce 20% of the enzyme activity, 0.001% of sulfur dioxide can completely inhibit the enzyme activity, can prevent enzymatic Browning; In addition, it can consume oxygen in food tissue and play the role of deoxygenation. Sulfite in the addition reaction with glucose, prevent the glucose in food and amino acid glycoammonia reaction, thus has the effect of anti Browning.
Sulfurous acid can play the role of acid preservative, undissociated sulfurous acid is believed to inhibit yeast, mold, bacteria.Undissociated sulfite has been reported to be 1000 times more potent than bisulfite in inhibiting E. coli.It is 100-500 times stronger to beer yeast and 100 times stronger to mold. When sulfur dioxide is acidic, it has the strongest effect on carrying microorganisms.
3）Function of loosening agent
Can be used as the components of the loosening agent.
Sulfite has a remarkable oxidation effect.Because sulfurous acid is a strong reducing agent, can consume the oxygen in fruit and vegetable organization, inhibit the activity of oxidase, the oxidation destruction of vitamin C in preventing fruit and vegetable is very effective.
Mechanism of action of sodium metabisulfite:
Bleach according to its mode of action can be divided into two categories: Oxidation Bleach and Reducing Bleach.Sodium metabisulfite is a reductive bleaching agent.
Sodium metabisulfite can be bleached by reducing pigment.The color of most organic compounds is derived from the chromaticity groups contained in their molecules.Hair color groups contain unsaturated bonds, reducing bleach release hydrogen atoms can make hair color group contained in the unsaturated bond into a single bond, organic matter will lose color. Some food Browning is caused by the presence of ferric ions, adding reducing bleach can make ferric ions into ferric ions, prevent food Browning.
Sodium metabisulfite is bleached by addition of sulfites. Anthocyanin and sugar can be bleached by addition reaction. This reaction is reversible, and sulfurous acid can be removed by heating or acidification, so that anthocyanin can be regenerated and its original red color can be restored.
In the biscuit industry, sodium metabisulfite is used as a biscuit dough improver. Before use, it is prepared into 20% solution, and then added into the immature dough in different times during the dough making process.Due to the sulfur dioxide released by sodium pyrosulphate in the process of dough preparation, the strength and toughness of flour gluten are relatively large, and a small amount of addition can prevent the deformation of biscuit products due to excessive strength.Tough dough can be added according to the strength of flour, and generally in the high proportion of oil and sugar crisp dough and sweet crisp dough as far as possible not to use, this is because the addition of oil and sugar itself has prevented the gluten protein water absorption expansion, prevent the formation of a large number of gluten, no need to add sodium metabisulfite.
Points for attention in the use of sodium metabisulfite:
The following points should be noted when using sodium metabisulfite in processed foods:
1) sodium metabisulfite reductive bleaching agent, its solution is unstable and volatile, is now used, to prevent sulfite instability and volatilization.
2) when there are metal ions in food, the residual sulfite can be oxidized;It can also make the reduced pigment oxidation discoloration, thereby reducing the effectiveness of the bleach.Therefore, metal chelators are also used during production.
3) the use of sulfite bleaching materials, due to the disappearance of sulfur dioxide and easy color, so usually in the food residual excess sulfur dioxide, but the residual amount shall not exceed the standard
4) Sulfuric acid can not inhibit the activity of pectinase, which will damage the cohesion of pectin.In addition, sulfurous acid infiltration into the fruit tissue, the processing of broken fruit, in order to remove all sulfur dioxide, so the fruit preserved with sulfurous acid is only suitable for making jam, dried fruit, fruit wine, candied fruit, can not be used as raw materials for cans.
5) Sulfites can destroy thiamine, so it is not easy to use in fish food.6) Sulfites are easy to react with aldehydes, ketones, proteins, etc.
Trends and Development:
In the modern food processing field, because the food sometimes produces undesirable color, or some food raw materials because of the variety, transportation, storage methods, picking period of maturity, the color is different, which may lead to the final product color is not consistent and affect the quality of food.Therefore, in today’s more and more attention to food quality, the development of food bleaching agent is unlimited, of course, as a kind of food bleaching agent, the development of sodium metabisulfite is also great.Sodium metabisulfite has a wide range of functions, not only the role of bleaching, but also the role of oxidation, the role of preventing enzymatic Browning, the role of antisepsis, its production method is simple and convenient, so in the case of ensuring food safety, sodium metabisulfite development space is very large.
Post time: Feb-02-2021