Carbon dioxide (CO₂) is an integral part of nature’s life cycle; it is released into the environment by living things by triggering the process of chlorophyll photosynthesis in plants, which, in turn, emit oxygen into the atmosphere, unsuring our lives.

The characteristics of this gas also make it useful in industry, especially in the food & beverage sector, where food-grade carbon dioxide (CO₂) aids the efficiency of production processes and improves product quality.

In this section, we will delve into its properties, how carbon dioxide (CO₂) is produced, what it is used for, and specifically how it is used in the food industry.

What is CO_2? the characteristics

CO2, or carbon dioxide, is a colorless, odorless, nonflammable gas. It is naturally present in the atmosphere, hydrosphere and biosphere, with a current atmospheric concentration of about 418 ppm (parts per million).

Carbon dioxide: what it is used for

As mentioned, carbon dioxide has numerous applications in various industries and in various forms: gaseous, liquid and solid. Apart from the food industry, here are the main ones:

• Water treatment
  CO₂ is an excellent neutralizer in industrial wastewater treatment and has been proved to be a safer and more flexible solution than traditional sulfuric acid systems. Carbon dioxide produces better results in terms of process controllability and lead times, plus it circumvents the need to handle hazardous substances.
  
  
• Metal processing
  Where it is used as a protective gas in the electric arc welding process. In this process, CO2 is used along with other gases such as argon or helium to protect the molten metal from atmospheric contamination.
  
  
• Floriculture industry and indoor cultivation
  Carbon dioxide is the element essential for plant life and growth. In greenhouses carbon dioxide growing systems (through the practice of carbonic fertilization) are structured to increase the quantity and quality of produce by optimizing plant growth. The higher concentration of CO₂ in indoor crops promotes and increases the process of photosynthesis.
  
  
• Paper industry
  In this case, CO₂ is crucial at several stages of the manufacturing process and enables the reduction of operating costs and the recovery of various chemicals used in manufacturing. In addition, it is the basis for the production of calcium carbonate precipitate (PCC), the use of which allows less virgin wood fibre to be used.
  
  

Ma non è tutto: per rispondere alla domanda “a cosa serve l’anidride carbonica” è necessario elencare una serie importante di applicazioni industriali. Here is an additional list:

• Refrigerant source: carbon dioxide R744 is a natural refrigerant gas with multiple applications in commercial refrigeration, the food industry, and refrigerated logistics (learn more about the SIAD COOOL R744 line)
• Cleaning and solvent extraction to clean equipment components
• Coffee decaffeination
• Cryogenic cleaning and extraction of fat from food products
• Extinguishing fires, without damaging or polluting materials when water is ineffective, undesirable, or unavailable (discover Wall System 300®, the inert gas firefighting system is the result of the extensive experience in complex plant engineering and in-depth knowledge of gases developed by SIAD).

The uses of carbon dioxide (CO₂) in the food industry

Food-grade CO₂ is classified as the additive E290 and is used in many forms in the food industry. It is a great ally for creating protective atmospheres, as a refrigerant and in beverage carbonation.

Next we focus on the application of carbon dioxide in the food sector, here are the main uses:

• Increases the shelf-life due to its natural bacteriostatic power, preserving taste and cell structure and reducing the need for natural and artificial preservatives
• Performs the function of thermoregulation and the cooling of food, such as in bakery doughs
• It is used in the cryogenic and IQF defrosting of foods.
• It is useful in packaging in a protective atmosphere
• It is used in the transport and cooling of ingredients, as well as refrigerated transport, in fact In solid phase can be used for this purpose as dry ice
• Enables cryopurification of moulds and food production equipment
• In bottle container cooling or in HI-CE-specific trays, it can maintain the constant serving temperature of wine, water or dishes

Below we look at some more specific applications.

Cheese coagulation and shaping

In the cheese-making process, carbon dioxide, already present in milk, can be added during coagulation as an alternative to the enzymatic route. It lowers the PH of the product, thus reducing the coagulation time and the amount of rennet and related enzymes needed.

At the forming stage, inert gas mixtures enable a reduction in the use of isozyme, which is a major cause of common food intolerance to cheese.

Cryomacination

In cryomacination processes, nitrogen and carbon dioxide reduce the heat generated in the processing of food products such as chocolate, chili peppers, mustard seeds, cinnamon, nutmeg, corn, oregano leaves and caffeine.

Storage of rice and grains

Storage of rice and grains with CO2 involves storing foodstuffs with the side effect of eliminating insects and pests (in rice, barley, oats, wheat, corn), spices, dried fruits, medicinal herbs, cocoa and nuts).

Freezing, crusting and frosting

Freezing allows organoleptic and freshness properties to be maintained intact over time through a wide range of freezing equipment: drum freezers, immersion freezer-IQF freezing, cryogenic spiral freezers, cryomechanical freezing, cryogenic freezing tunnels and cryogenic freezing tunnels.

Crusting, or cryogenic crusting, is a process by which the surface freezing of the product is achieved. Glazing is a typical application in fish and seafood processing.

How SIAD carbon dioxide is produced: a sustainable process

A common question related to CO₂ is: Who produces carbon dioxide? More importantly, how is it produced?

The CO2 marketd by the SIAD Group is of biogenic origin or comes from carbon capture processes. The Biogas Upgrading process enables the recovery of CO₂ (so-called biogenic CO₂). Of this, about 70% goes to industries that typically require pure carbon dioxide, such as food & beverage, which must meet very high quality standards to qualify as food-grade carbon dioxide.

This process combines an economic benefit with an environmental one, thanks to the reduction of greenhouse gases released into the atmosphere, which from a waste element becomes a raw material for new production.

The carbon capture source involves carbon dioxide production that occurs through the process of steam reforming, the same method used to produce hydrogen, and is based on the reaction between methane and water vapor at a temperature of 800°C.

In addition to the ability to produce CO₂ at an industrial level, SIAD’s technological innovation also enables the recovery and storage of carbon dioxide, a residue of the manufacturing processes.

In addition to the production of carbon dioxide (CO₂₎ and in particular the production of food-grade carbon dioxide, our Group is also involved in supply of ancillary services, which include:

• Transportation in cylinders, cylinder packs, or tankers
• Design and installation of distribution systems
• Provision of equipment for the secure use of CO₂
• Technical assistance and advice on transportation, distribution, and enforcement.

All this is to ensure maximum performance from the use of this valuable food gas.