Introduction Of Several Common External Control Type Preservatives
Sep 18, 2020
In actual production, most bakery products (bread, cakes, pastries, etc.) have a few or even large quantities of mildew and deterioration due to surface contamination. These facts have prompted many bakery food manufacturers, especially those with substandard environmental hygiene or workers with poor hygiene awareness, to pay more attention to and use externally controlled preservatives. I will briefly introduce several common externally controlled food preservation agents. Please choose reasonably according to your own needs and avoid blindly following the trend.
What is an externally controlled food preservative?
It means that calcium oxide, silicon dioxide, etc. are put into composite packaging pouches as the contents, or liners made of polymer materials to absorb edible alcohol, etc., are placed in a closed package and are not added to the raw materials for food production. Only by adjusting the humidity inside the package, slowly releasing antibacterial gas (ethanol gas) or spraying antibacterial substances (blended alcohol) directly on the food surface to achieve the effect of antibacterial preservation.
Common external control food preservatives are divided into the following categories
1. Deoxidizer is also known as oxygen absorbent and deoxidizer.
There are many kinds of deoxidizers at present, but inorganic deoxidizers are widely used by food companies. There are three main types: iron deoxidizers, sulfite deoxidizers, and hydrogenation catalyst type deoxidizers.
Food deoxidizers mainly absorb oxygen in food packaging containers, so that food can be stored in an anaerobic state, mainly to prevent food oxidation caused by discoloration, mold, oxidation, rancidity, insects and other deterioration phenomena, especially suitable for fatty acids. And the preservation of oily foods, such as peanuts, melon seeds, pistachios, ham sausage, moon cakes, etc.
Due to the need to preserve the anaerobic state, the requirements for food packaging materials when using deoxidizers are relatively high. You cannot choose PP and PE films with too high oxygen permeability, otherwise they will not be able to perform deoxidation for a long time. At the same time, they will be exposed to air. It can absorb oxygen and should be used up as soon as possible. Note that the temperature at which it plays a role is generally controlled at 5-40°C. When it is lower than -5°C, the deoxygenation preservation effect will decrease.
The choice of deoxidizer is very knowledgeable. It is not only necessary to take into account the size of the oxygen removal capacity to adapt to the packaging of different volumes, consider its model compatibility (such as type 20, type 30, type 50, type 100, etc.), and functional adaptability (such as double-effect , Multi-effect, absorption and release type, etc.), but also pay attention to the safety of deoxidizer packaging materials, because most foods inevitably need to be in direct contact with the deoxidizer, and the moisture or grease in some foods will be adsorbed by the deoxidizer, causing serious The potential safety hazards and hazards, such as:
(1) The heat-seal seal ensures no air leakage, pay attention to the strength and quality of the seal.
(2) The choice of packaging materials is not good, and the powder and granular materials (especially iron powder and other metals) inside the deoxidizer leak out, contaminating food;
(3) Rust spots, oil stains or watermarks are prone to appear on the surface of the deoxidizer packaging material, which seriously affects the aesthetics of the product;
(4) Moisture, grease, etc. penetrate and corrode and damage the deoxidizer packaging materials, causing delamination, easy peeling, and fracture, and the migration of powder and granular materials, causing heavy metal pollution in food;
(5) After the liquid water or grease penetrates into the inner layer of the packaging material, it is easy to form a water film or an oil film to wrap the deoxidizer powder pellets, blocking the contact reaction of oxygen and iron powder. As a result, the oxygen absorption effect of the deoxidizer is reduced or lost, and the anaerobic atmosphere in the food packaging cannot be maintained, making moldy and other problems impossible to eradicate.
2. Alcohol tablets (alcohol fresh-keeping card, ethanol gas generator)
Alcohol tablets and deoxidizers can be used in moon cakes, breads, and pastries to keep fresh, but alcohol tablets cannot be used to keep nuts and roasted foods. The principles of the two are completely different. Alcohol tablets form a gas phase protective layer with a certain concentration around the food to be kept fresh, and slowly release a kind of ethanol to achieve the purpose of food preservation. It does not absorb oxygen and does not have the function of preventing food oxidation. It is generally used for moon cakes, cakes, and wet food. Noodles, baked bread, steamed cakes, etc.
Alcohol tablets exert the effect of inhibiting mold, and the alcohol concentration needs to be adjusted according to the water activity and moisture in the entire packaging system.
In low water activity foods, ethanol with a mass fraction of 2% to 4% has a certain antibacterial effect. On the contrary, for high water activity foods, the best amount of ethanol is 0.002 to 0.004mL/cm2 or less than 2% of the product mass . Foods such as cakes and breads, if processed with more than 2% ethanol, can properly extend the mold-free shelf life, but it is not enough to prevent the growth of mold, and it will greatly affect the taste and flavor of the product, causing consumer disgust. The carrier inside is also It will absorb the moisture of the product and greatly accelerate the aging of the product. Please choose carefully when using it.
3. Food desiccant
Desiccant refers to a water-removing agent that absorbs moisture from the atmosphere. Its drying principle is to physically adsorb water molecules in its own structure or chemically absorb water molecules and change their chemical structure, by removing food packaging The moisture inside reduces the humidity in the food packaging and achieves the effect of preventing food spoilage.
At present, most desiccants on the market use calcium oxide (quicklime), silica gel, ferric oxide and calcium chloride as the main raw materials. Among them, food desiccants using quicklime and silica gel as raw materials are the most common. In addition, according to the food and drug packaging regulations, the packaging of the desiccant must have a certain tensile strength, and its main ingredients and harmful results should be marked on the outer packaging of the desiccant, and safety instructions should be made.
4. Natamycin
Natamycin is safe, reliable, and does not affect the flavor of the product. It is widely used in cheese, meat products, pastries, juices, jams and other foods. But also because it is a natural product, its activity stability is easily affected by ultraviolet rays, pH, temperature, light intensity, oxidants and heavy metals, and it is very sensitive and difficult to store. Therefore, the product should avoid contact with oxidants and sulfur and hydrogen compounds, otherwise it will easily fail.
According to the relevant regulations of GB2760, in the baking industry, natamycin is suitable for cakes, mayonnaise, salad dressing, Cantonese moon cakes, etc., and can only be sprayed on the surface of the product. The editor of Baiqing would like to remind everyone that the use of natamycin for anti-corrosion on the surface of bread belongs to an over-range addition, and natamycin cannot be used for bread.
Natamycin has a low solubility and can only form a suspension. It is easy to cause sedimentation and stratification or block the nozzle after being placed for a long time. Therefore, the spray nozzle is required to achieve atomization and uniformity to avoid uneven spraying on the product surface. Caused by excessive natamycin. Generally, it can only be sprayed on the surface, the sides and bottom are not sprayed, and it is not easy to spray evenly on long products, and it is not global. It can be seen from the above that natamycin is only a preservative aid, and the choice of internally controlled preservatives (that is, directly added to the product) is the decisive role in the product shelf life.
