# Effect of a Hypoxia-Controlled Atmosphere Box on Egg Respiration Intensity and Quality
## 4 Discussion  
One of the current challenges faced by the poultry and egg industries is to extend the shelf life of large quantities of eggs at low costs. Currently, controlled atmosphere storage has not been used for egg storage and agricultural products. Atmosphere technology is generally divided into controlled atmosphere (CA) and modified atmosphere (MA). CA is the active adjustment of the composition of O\({}_{2}\), CO\({}_{2}\), N\({}_{2}\), and other gases in the storage environment by using equipment to introduce gas. MA is based on the respiration of the agricultural component and the selective permeability of the fresh-keeping enclosure bag to achieve an optimal ratio of O\({}_{2}\) and CO\({}_{2}\) of the storage environment. The goal of both these technologies is to achieve a microenvironmental atmosphere (high CO\({}_{2}\) and low O\({}_{2}\)) that is conducive to storage. CA can be used to accurately match the concentration of gas, although spontaneous atmosphere adjustment is difficult to achieve. The respiratory intensity of eggs is much lower than that of fruits and vegetables. It is difficult to implement an atmosphere effect by relying on the egg's inherent breathing. Therefore, MA was adopted in this study. In this study, we reduced the O\({}_{2}\) concentration in the storage environment to evaluate the impact of hypoxic conditions on the respiratory intensity and quality of eggs. Further, we determined the possible effect of reduced O\({}_{2}\) concentration of the storage environment on egg quality. The optimal O\({}_{2}\) concentration for storing eggs was selected. Lastly, the cost of O\({}_{2}\) required for these specific settings was determined to better apply it in real-world practice. Some studies have reported that when O\({}_{2}\) concentration in the environment is low, the respiration rate is less dependent on temperature [34]. Therefore, the temperature setting chosen for this study was 25 \({}^{\circ}\)C. The conditions for achieving this temperature were relatively simple. In this study, we found that when O\({}_{2}\) concentration during storage was \(<\)10%, the breathing intensity of eggs was poorly suppressed. Studies have shown that a reduction  
Figure 4: Distribution of oxygen (O\({}_{2}\)): This figure describes the distribution of O\({}_{2}\) at different time points when nitrogen (N\({}_{2}\)) is introduced into the air-conditioning box. The color corresponds to the density bar on the left side of the image. The figure, in turn, corresponds to the O\({}_{2}\) distribution at 0 s, 300 s, 600 s, and 1200 s.  
in the respiratory rate of agricultural products under low O\({}_{2}\) levels is not the result of cytochrome oxidase activity, which has a great affinity for O\({}_{2}\). Rather, the effect is due to a decrease in the activity of other oxidases such as polyphenol oxidase, ascorbate oxidase, and glycolate oxidase. These oxidases have a lower affinity for O\({}_{2}\)[35]. We tested the egg quality and found that the weight loss rate of eggs with lower breathing intensity was reduced. This is because the respiration of an egg entails the consumption of its own substances. Reducing its respiration intensity can slow down the loss of the inherent water. The main reason is that the egg, as a living body with a porous structure, continuously discharges water during respiration. Reducing the respiration intensity of eggs can slow water loss. At the same time, we found that the rate of decline of the Haugh unit of eggs with weaker breathing intensity was also slower. This could be because the protein structure in the egg white changes during storage and the protease is depolymerized by the hydroxyl ions, thereby affecting the structure of ovomucin-lysozyme. Due to insolubility of the ovomucin-lysozyme complex, the ovomucin gel degrades, resulting in the thinning of the egg white, that is, a reduction in the Haugh unit [36; 37].