# Effect of a Hypoxia-Controlled Atmosphere Box on Egg Respiration Intensity and Quality
## 3 Results
### Comprehensive Evaluation of the Storage Effect in Different O2 Concentrations  
TOPSIS is a multi-index comprehensive method of evaluation widely used in agricultural production and life [33]. This method was used to evaluate the quality indices of eggs stored for 35 days. The quality indicators of the five groups of eggs were sorted based on the evaluation results and the best storage volume fraction was determined according to the ranking. A comprehensive evaluation was carried out based on the following nine  
Figure 3: Changes in the total number of colonies in egg under different oxygen (O2) concentrations during storage.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Storage Days** & **A (0\% O2)** & **B (5\% O2)** & **C (10\% O2)** & **D (15\% O2)** & **E (20\% O2)** \\ \hline
0 & 8.66 \(\pm\) 0.02 a & 8.65 \(\pm\) 0.03 a & 8.58 \(\pm\) 0.05 a & 8.59 \(\pm\) 0.01 a & 8.64 \(\pm\) 0.03 a \\
5 & 8.73 \(\pm\) 0.03 a & 8.68 \(\pm\) 0.04 a & 8.69 \(\pm\) 0.02 a & 8.65 \(\pm\) 0.02 a & 8.70 \(\pm\) 0.12 a \\
10 & 8.88 \(\pm\) 0.04 a & 8.71 \(\pm\) 0.06 b & 8.73 \(\pm\) 0.09 b & 8.70 \(\pm\) 0.03 b & 8.75 \(\pm\) 0.04 b \\
15 & 9.04 \(\pm\) 0.02 a & 8.94 \(\pm\) 0.02 b & 8.87 \(\pm\) 0.04 b & 8.84 \(\pm\) 0.05 b & 8.88 \(\pm\) 0.01 b \\
20 & 9.13 \(\pm\) 0.04 a & 9.07 \(\pm\) 0.03 a & 9.04 \(\pm\) 0.04 b & 8.90 \(\pm\) 0.02 c & 8.98 \(\pm\) 0.02 b \\
25 & 9.14 \(\pm\) 0.03 a & 9.13 \(\pm\) 0.03 a & 9.10 \(\pm\) 0.06 a & 8.94 \(\pm\) 0.01 c & 9.03 \(\pm\) 0.02 b \\
30 & 9.18 \(\pm\) 0.04 a & 9.16 \(\pm\) 0.02 a & 9.14 \(\pm\) 0.01 a & 8.97 \(\pm\) 0.01 c & 9.09 \(\pm\) 0.07 b \\
35 & 9.23 \(\pm\) 0.05 a & 9.21 \(\pm\) 0.11 a & 9.20 \(\pm\) 0.04 a & 9.09 \(\pm\) 0.03 b & 9.16 \(\pm\) 0.04 a \\ \hline \hline \end{tabular} Note: different letters in the same row indicate significant differences between treatments (\(p<0.05\)).  
\end{table}
Table 3: Changes in the pH of eggs stored at different oxygen (O2) concentrations.  
indicators of eggs: weight, yolk color, yolk height, yolk index, Haugh unit, pH, weight loss rate, yolk diameter, and the number of colonies. Among these, egg weight, egg yolk height, egg yolk index, and Haugh unit are very large indicators. Egg yolk color and pH are interval indicators. The egg yolk color range was 11-13 and the pH range was 9-9.3. The weight loss rate, egg yolk diameter, and the number of colonies are very small indicators. MATLAB software was used to standardize all indicators to eliminate the influence of dimensions among the indicators. Distance calculation, scoring, and sorting according to the score were the next steps. The scoring and ranking are shown in Table 4.  
In the storage environment with different O\({}_{2}\) volume fractions, the order of the score of eggs stored for 35 days was determined to be B > A > C > D > E. Group B with 5% O\({}_{2}\) volume fraction and 95% N\({}_{2}\) ranked the highest, indicating the best storage conditions for eggs at 25 \({}^{\circ}\)C. The storage effect of eggs in Group B was far better than those of Group E, which were stored in an environment of air. The scores of Groups A and C were similar. In terms of economic advantages, the use of 10% O\({}_{2}\) incurs lesser costs. Therefore, in actual production and in a real-life setting, the O\({}_{2}\) volume fraction in the egg storage environment can be controlled within the range of 5-10%.