Application of food additive sodium metabisulfite

Sodium metabisulfite is a widely used food additive. In addition to its bleaching effect, it also has the following effects:

1) Antiseptic, sulfurous acid can act as an acidic preservative. Undissociated sulfurous acid is considered to inhibit yeast, mold, and bacteria. According to reports, the inhibitory effect of undissociated sulfurous acid on E. coli is 1,000 times stronger than bisulfite. It is 100-500 times stronger for beer yeast and 100 times stronger for mold. When sulfur dioxide is acidic, it has the strongest microbial effect.

2) Anti-oxidation effect. Sulfurous acid has a significant effect on oxidation. Because sulfurous acid is a strong reducing agent, it can consume oxygen in fruit and vegetable tissues and inhibit the activity of oxidase, which is very effective in preventing the oxidative destruction of vitamin C in fruits and vegetables.

3) The role of loosening machine can be used as a component of loosening machine.

4) Anti-browning effect, enzymatic browning often occurs in fruits and potato foods. Sodium metabisulfite is a reducing agent, which has a strong inhibitory effect on the activity of polyphenol oxidase, 0.0001% sulfur dioxide can Reduce enzyme activity by 20%, 0.001% of sulfur dioxide can completely inhibit enzyme activity, can prevent enzymatic browning; In addition, it can consume oxygen in food tissue to play the role of deoxygenation; sulfuric acid can be added with glucose The reaction prevents the glucose and amino acids in the food from undergoing a sugar-ammonia reaction, thereby having the effect of preventing browning. 

Reference standard for sodium metabisulfite:

The hygienic standard for the use of food additives in my country (GB2760-86) stipulates the use standard of sodium metabisulfite: wine and wine. 0.25g/kg; sugar, bamboo shoots, candied fruit, biscuits, canned food, vermicelli, sugar should not exceed 0.05g/kg, and brown sugar and other varieties should not exceed 0.1g/kg.

The mechanism of sodium metabisulfite functioning:

Bleaching agents can be divided into two categories according to their mode of action, oxidizing bleaching agents and reducing bleaching agents. Sodium metabisulfite is a reducing bleach.

Sodium metabisulfite discolors pigments by reduction to achieve bleaching. The color of most organic substances is produced by the chromophore contained in their molecules. The chromophores all contain unsaturated bonds. Reducing the bleach to release hydrogen atoms can turn the unsaturated bonds contained in the chromophore into single bonds, and the organic matter loses its color. The browning of some foods is caused by the presence of ferric iron ions. The addition of reducing bleaching agents can turn ferric iron ions into ferric iron ions to prevent food browning.

Sodium metabisulfite utilizes sulfite addition reaction to discolor to achieve the purpose of bleaching. Addition reaction of anthocyanin and carbohydrates can be bleached to discolor it. This reaction is reversible, and sulfurous acid can be removed by heating or acidification treatment to regenerate anthocyanin and restore the original red color.

Sodium metabisulfite products are classified into industrial grade and food grade, and their quality indicators are different. Industrial grade sodium metabisulfite is widely used. Used for purification of chloroform, phenylpropyl sulfone and benzaldehyde in the pharmaceutical industry; used as a coagulant in the rubber industry; used as a dechlorinating agent for cotton bleaching, cotton cloth smelting aid and mordant for printing and dyeing in the printing and dyeing industry; for the leather industry Used in leather processing, it can make leather soft, plump and tough, with waterproof, flexural, abrasion resistance and other properties; used in the chemical industry for the production of hydroxyvanillin, hydroxylamine hydrochloride, etc.; used in the photosensitive industry as a developer. Food grade sodium metabisulfite can be used as bleaching agent and leavening agent for biscuits and cakes, nutrient retention agent for dehydration of vegetables, preservative for storing fruits, sterilization preservative for brewing and beverages, etc. Below we discuss in detail the two applications of our focusing sodium sulfite. 

At present, in the processing and preservation of light-colored vegetables in my country, such as mushrooms, lotus root, horseshoe, white asparagus, yam and other products. Sodium metabisulfite solution is often used for color protection, of course, there are some differences in the processes of various factories. For example, in the processing of canned mushrooms, wet mushrooms are used for the transportation of fresh mushroom raw materials to the processing plant, and wet mushrooms are also used. Dry shipping. Generally, at the time of purchase, the fresh mushrooms are soaked twice in water with 0.03% sodium metabisulfite solution for 1 to 2 minutes each time, then soaked in a covered wooden barrel and transported back to the factory, then 0.07 to 0.1% citron Sour pre-boiled for 5.7 minutes, so the processed mushrooms have good color and flavor. The color and flavor of the canned mushrooms processed by the raw materials after color protection are good, and the residual amount of sulfur dioxide in the finished product after pre-cooking and rinsing will not exceed 10g/kg.

In my country's biscuit industry, sodium metabisulfite is used as a biscuit dough modifier. Before use, it is formulated into a 20% solution. During the dough preparation process, it is added to the unripe dough in portions. Due to the weakening effect of the sulfur dioxide released by sodium metabisulfite during dough preparation on the gluten strength of the dough, adding a small amount to the strength and toughness of the flour gluten can prevent the deformation of the finished biscuit due to excessive gluten strength. Tough dough can be added according to the gluten strength. Generally, it is not used in crunchy dough and sweet crunchy dough with a high proportion of oil and sugar. This is because the addition of oil and sugar has already prevented the gluten protein from swelling and preventing the water from swelling. A large amount of gluten is formed without adding sodium metabisulfite.

Precautions for using sodium metabisulfite:

Pay attention to the following points when using sodium metabisulfite when processing food:

1) Sodium metabisulfite solid reducing bleach, its solution is unstable and volatile, and it is used now to prevent unstable and volatile sulfite.

2) When metal ions are present in the food, the residual sulfurous acid can be oxidized; it can also oxidize and change the reduced pigment, thereby reducing the effectiveness of the bleach. Therefore, metal chelating agents are also used during production.

3) Substances bleached with sulfites are easy to recolor due to the disappearance of sulfur dioxide, so usually excess sulfur dioxide remains in food, but the residual amount should not exceed the standard

4) Sulfurous acid cannot inhibit the activity of pectinase, which will damage the cohesion of pectin. In addition, after sulfurous acid penetrates into the fruit tissue, the fruit can be crushed during processing to remove sulfur dioxide. Therefore, fruits preserved with sulfurous acid are only suitable for making jams, dried fruits, fruit wine, preserves, etc., and cannot be used as raw materials for canning.

5) Sulfite can destroy thiamine, so it is not easy to use in fish food. 6) Sulfite reacts easily with aldehydes, ketones, proteins, etc.

Trends and development:

In the field of modern food processing, foods sometimes produce undesirable colors, or some food raw materials have different colors due to different varieties, transportation, storage methods, and the maturity of the picking period. This may lead to inconsistent colors in the final product. Affect the quality of food. Therefore, as people pay more and more attention to the quality of food today, the development of food bleach is limitless. Of course, as a kind of food bleach, the development of sodium metabisulfite is also great. The development of focus sodium sulfite is analyzed in detail below .

First of all, the safety of food has always been the focus of attention. In order to ensure food safety, it is necessary to strengthen the management measures of additives. First, the government should attach great importance to the management of food additives. Regulations on food hygiene and safety law, management methods, regulations and other regulations should be unified and standardized, and food production and operation units are forced to improve their food additive management model to achieve scientific and standardized production, use and management.

Medical colleges have research on food hygiene and food nutrition, while light industry colleges pay attention to the knowledge of food processing technology and food equipment manufacturing. The two should focus on communication. If food hygiene can be jointly organized, the cultivated food Professional talents will be more comprehensive.

Since the promotion of food additives, many food safety accidents have caused the public's nerves to be tense. This has a direct relationship with food production enterprises. Only with sufficient self-discipline, can the food additive industry in China be healthy. track.

Throughout the food safety accidents in recent years, the source of the accidents was not the food additives themselves, but the fraudulent use of food additives by illegal businessmen, which caused harm to consumers' physical and mental health. We are in a weak position for illegal enterprises or businessmen. We only hope that relevant departments strengthen market management, ensure food safety, and create a safe and secure consumption environment for consumers.

Sodium metabisulfite has a wide range of functions, not only bleaching, but also anti-oxidation, enzymatic browning prevention, antiseptic effect, etc. The production method is also simple and convenient. Therefore, under the condition of ensuring food safety, coke Sodium sulfite has a lot of room for development.