With the increasingly fierce market competition and the gradual improvement of consumption level, there is a growing trend towards controlling the stability of beverage flavor to improve product quality and thus increase market competitiveness. Oxygen "is the enemy of beverage packaging, so the control of dissolved oxygen is of utmost importance in modern beverage industry quality control. The content of dissolved oxygen is closely related to the partial pressure of oxygen in the air and the temperature of water. Under natural circumstances, the oxygen content in the air does not change much, so water temperature is the main factor. The lower the water temperature, the higher the content of dissolved oxygen in the water. At 20 ℃ and 100kPa, dissolved oxygen in pure water is approximately 9mg/L. Some organic compounds undergo biodegradation under the action of aerobic bacteria, which requires the consumption of dissolved oxygen in water. The harm of dissolved oxygen: 1. Changing the flavor of beverages and affecting their color; 2、 Reduce the flavor stability and non biological stability of beverages; 3、 When the temperature rises, the phenomenon of "bottle collapse" occurs due to the consumption of oxygen. The application of nitrogen, accounting for 78% of the Earth's atmosphere, exists in the air as a single substance, inexhaustible and colorless, non-toxic, and odorless inert gas. The density is 1.2506kg/m, the melting point is -209.86 ℃, and the boiling point is -195.8 ℃. It is slightly soluble in water and ethanol and is not prone to chemical reactions with other substances. Gaseous nitrogen does not leave any chemical residues when used in the preservation process, so it is commonly used for food preservation. The use of nitrogen as a preservative for beer, wine, and fruit juice beverages is currently a common understanding faced by manufacturers of such products. It can make the purification of such products more authentic, with a longer shelf life, and more suitable for the taste of modern consumers. Comparison between nitrogen and carbon dioxide Currently, many domestic beer, wine, and juice beverage manufacturers still use carbon dioxide as a safety gas. After the introduction of nitrogen preservation technology, many advantages are significantly outstanding compared to carbon dioxide. 1、 Low operating cost, priceless raw materials, using air as the raw material and using pressure swing adsorption to separate nitrogen from the air, the relative investment is much less than carbon dioxide; 2、 The gas production speed is fast, and it can be turned on and used at any time. Twenty minutes before use, qualified gas can be produced by turning on the machine; 3、 High degree of automation, using Siemens computer programming, without the need for dedicated personnel to monitor, and occupying a small area; 4、 One time investment, simple maintenance. The stirring of nitrogen in beverages can cause the dissolved oxygen in liquids to precipitate, and the oxygen in these liquids can worsen their taste and shorten their shelf life. In a method called "stirring" (the compressed gas stirs the liquid through a spray), gaseous nitrogen is introduced into the liquid during treatment. These nitrogen bubbles remove oxygen to prevent oxidation, corruption and fading of carbonate free drinks (fruit juice, tea and milk)
