Abstract: In order to systematically investigate the relationship between changes in egg freshness and S-ovalbumin content and to clarify the effect of various egg quality parameters on the increase in S-ovalbumin content during storage, fresh eggs from Hyline Brown laying hens were tested for Haugh unit (HU), egg yolk index and pH and their correlation with S-ovalbumin content, and the gray correlation degree of egg quality parameters and S-ovalbumin content was analyzed. In addition, the prediction model of equivalent egg age was established with S-ovalbumin content as independent variable. The results showed that there was a strong negative correlation between HU and S-ovalbumin content (R = ?0.913, P < 0.01), and that S-ovalbumin content had a strong negative correlation with egg mas (R = ?0.367, P < 0.01) and a strong negative correlation with concentrated protein height (R = ?0.905, P < 0.01). A strong negative correlation existed between egg yolk index and S-ovalbumin content (R = ?0.900, P < 0.01), and the correlation between pH and S-ovalbumin content was positive (R = 0.648, P < 0.01). In addition, the comprehensive gray correlation degree between each quality factor and S-ovalbumin content was more than 0.6, and pH was the dominant factor affecting the change of S-ovalbumin content (gray correlation degree was 0.742). The decision coefficient (R2) of the established polynomial regression model for equivalent age prediction was 0.986 81 (P < 0.01).

Key words: egg freshness index, S-ovalbumin, storage, gray correlation degree, equivalent egg age