Research on the correlation between respiration intensity and egg internal quality based on grey relational analysis

The main egg internal quality indicators, such as albumen and yolk quality, are associated with respiration intensity of the egg during storage. In this study, Hy-Line pink eggs were selected as test samples to determine the correlation between respiration intensity and the egg quality indicators: Haugh Unit (HU), albumen height, pH, viscosity, yolk index, yolk proportion and yolk color. Respiration intensity was quantified by measuring the amount of carbon dioxide produced during 20 d of storage at 25°C. We found a significant correlation (P<0.01) between respiration intensity and HU, albumen height and viscosity (r = 0.75, r = 0.92 and r = 0.84, respectively). A negative correlation was observed between respiration intensity and pH (r = -0.82, P < 0.01), whereas the correlation between respiration intensity and both yolk index (r = 0.64, P < 0.01) and yolk color (r = 0.89, P < 0.01) was positive. However, the correlation between respiration intensity and yolk proportion was not statistically significant. The HU, yolk color, viscosity and albumen height have a high impact on the respiration intensity based on grey relational analysis, in which the greatest impact is viscosity. These results suggest that the egg internal quality parameters HU, egg albumen height, pH, viscosity, yolk index and yolk color are correlated with respiration intensity.