20 Controlled Atmosphere Storage UNIDO（气调储藏20 UNIDO）.pdfVIP

20) CONTROLLED ATMOSPHERE STORAGE Controlled atmosphere storage is a system for holding produce in an atmosphere that differs substantially from normal air in respect to CO and O levels. Controlled atmosphere storage 2 2 refers to the constant monitoring and adjustment of the CO and O levels within gas tight 2 2 stores or containers. The gas mixture will constantly change due to metabolic activity of the respiring fruits and vegetables in the store and leakage of gases through doors and walls. The gases are therefore measured periodically and adjusted to the predetermined level by the introduction of fresh air or nitrogen or passing the store atmosphere through a chemical to remove CO . 2 There are different types of controlled atmosphere storage depending mainly on the method or degree of control of the gases. Some researchers prefer to use the terms ”static controlled atmosphere storage” and “flushed controlled atmosphere storage” to define the two most commonly used systems. “Static” is where the product generates the atmosphere and “flushed” is where the atmosphere is supplied from a flowing gas stream, which purges the store continuously. Systems may be designed which utilize flushing initially to reduce the O 2 content then either injecting CO2 or allowing it to build up through respiration, and then maintenance of this atmosphere by ventilation and scrubbing. IMPORTANCE OF CONTROLLED ATMOSPHERE CA storage has