Food additives in the air - nitrogen


Air is everywhere, and oxygen, which accounts for 21% of it, is the basic condition for human survival. However, oxygen is the enemy of food. On the one hand, oxygen can allow bacteria, fungi and other putrefactive microorganisms to multiply; on the other hand, it can oxidize oils and produce a "smell", oxidize and discolor natural pigments, and cause some nutrients to oxidize and lose their nutritional value.

In order to fight against oxygen, food companies have thought of vacuuming. Vacuum blister packaging is very common in cooked food, rice, tea and other foods. But not every food is suitable for vacuuming. Fluffy foods such as bread and cakes are afraid of being squeezed. Foods such as bagged potato chips and biscuits may be broken into pieces when consumers get them if they are vacuumed. The opposite processing method to vacuuming is to inflate. Commonly used gases are nitrogen, carbon dioxide, or a mixture of nitrogen, carbon dioxide and oxygen in a certain proportion. Among them, nitrogen is the most used, accounting for about 90% of commonly used inflation gases.

In the food industry, nitrogen is used as a food additive and is classified as a processing aid. Although people often talk about food additives in a negative light, in fact, when we take a breath, they are full of food additives.

Is nitrogen safe?

Nitrogen can eliminate air, create an oxygen-deficient environment, inhibit the growth of bacteria and mold, and extend the shelf life of food. At the same time, it can prevent the oxidation of oils, natural pigments, and micronutrients, maintain the original color and flavor of food, and improve food quality.

In addition, nitrogen is almost insoluble in water and oil, and food has basically no adsorption of nitrogen, so nitrogen-filled packaging will not collapse.

Nitrogen is colorless, odorless, chemically inert and does not easily react with other substances, so it is very safe.

Using nitrogen is more environmentally friendly

Beer is afraid of oxygen. Oxidation will cause the beer to change color and taste, and also affect the taste. When producing cans of beer, nitrogen is first charged and the air is squeezed out. This can maintain the original taste of the beer and make the beer foam softer. In the past, food companies mostly used carbon dioxide, but now nitrogen has been gradually promoted.

Fruit and vegetable packaging is filled with nitrogen to preserve freshness, which can maintain the appearance of fruits and vegetables and extend their shelf life. For foods with a certain amount of moisture, such as barbecued meats, snacks, and pasta, nitrogen-filled packaging can increase the shelf life by more than four times. Some drinks also use nitrogen, not to prevent oxidation, but to pressurize them. For example, plastic beverage bottles and aluminum cans (non-carbonated) are easily deformed during stacking and transportation. Filling them with a little nitrogen (actually dropping a drop of liquid nitrogen and then sealing them) can make the bottles stronger. It is said that this can reduce the use of packaging materials by 1/3, save a lot of plastic and metal every year, and is an environmentally friendly technology.

In addition to nitrogen, its other form, liquid nitrogen, also has many wonderful uses. For example, liquid nitrogen can be used to freeze and grind spices, such as garlic, cinnamon, etc., to avoid loss of flavor due to friction and heat. Liquid nitrogen can also be used for quick freezing of food, such as quick-frozen seafood, so that the taste and nutrition can be maintained to the maximum extent. Liquid nitrogen is widely used in cold chain transportation. It has been practiced internationally for many years and is comparable to traditional refrigeration methods. Liquid nitrogen also plays an important role in biomedical research, food testing, etc.