Combination of sensory evaluation with conventional physiochemical analyses to evaluate quality changes during long-term storage and estimate the shelf life of chicken eggs

Abstract

ABSTRACT 1. This study developed a comprehensive sensory evaluation system that consisted of descriptions corresponding to United States Department of Agriculture photos to evaluate overall acceptability, albumen and yolk appearances and odours. It determined physiochemical parameters of eggs stored at 7°C (7W12 and 7U12 for washed and unwashed, respectively) for 12 weeks and stored at 25°C (25W4 and 25U4 for washed and unwashed, respectively) for four weeks. 2. Throughout storage, there was a general downward trend in Haugh units (HU) and yolk index and an upward trend in air cell size, weight loss and S-ovalbumin content were observed (P < 0.05). The 25W4 and 25U4 egg quality rapidly deteriorated from grade AA (HU 81.7) to grade B after two weeks (HU 46.5 and 49.6), whereas 7W12 and 7U12 eggs remained grade A after 12 weeks (HU 67.3 and 66.9). High correlations were observed between the sensory and physiochemical parameters (i.e., R2 = 0.93, 0.93, 0.88 and 0.94 for albumen appearance, yolk appearance, sensorial odour and overall acceptability, respectively, with HU in 25W4 eggs). 3. Eggs stored at 25°C and classified into ‘premium’, ‘class I’, and ‘class II’ on the basis of their HU had estimated shelf life of 0.5, 1.5 and 2.5 weeks, while shelf lives of 4, 9 and 15 weeks were estimated for 7°C-stored premium, class I and II eggs, respectively. 4. In conclusion, distinct HU requirements for eggs of different quality classes under two storage temperatures need to be established. Incorporating sensory evaluation with conventional physiochemical analyses is promising to assess and estimate egg quality changes. Further research work about the influences of different storage temperatures and possible temperature fluctuations during storage on egg quality changes is needed.