Relationships of quality indices with wooden breast myopathy severity in chicken breast meat under refrigerated storage.

1. This study investigated the relationships of quality indices with the severity of wooden breast (WB) myopathy in chicken breast meat under refrigerated storage. The physicochemical properties, water-holding capacity (WHC), microbial quality and fatty acid profiles of normal chicken breast meat samples (NOR samples, n = 63), moderate WB (MWB, n = 63) myopathy and severe WB (SWB, n = 63) myopathy (MWB and SWB samples, respectively) were evaluated immediately after sampling and after 4 and 8 d of refrigerated storage at 4°C.2. Total collagen, fat, saturated and monounsaturated fatty acid contents, redness and pH of the SWB and MWB samples were higher than the NOR samples. The SWB samples that were stored for 8 d had poor WHC, total viable counts (TVC) of higher than 7.0log colony-forming units, total volatile basic nitrogen (TVB-N) content of greater than 15 mg/100 g and a thiobarbituric acid - reactive substance level of higher than 1 mg/kg malondialdehyde.3. No significant difference was observed in the TVB-N content and TVC of the MWB and NOR samples during storage. Polyunsaturated fatty acid content was lower in the SWB and MWB samples than in the NOR samples. The SWB samples were tougher than the MWB and NOR samples after 8 d of refrigeration.4. In conclusion, the quality of chicken breast meat with SWB myopathy degraded considerably over time; thus, such meat should not be subjected to extended refrigeration for storage.

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

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.

Application of principal component analysis with instrumental analysis and sensory evaluation for assessment of chicken breast meat juiciness.

1. The objectives of this study were to use principal component analysis (PCA) to analyse the variability of the three instrumental and 14 descriptive sensory properties of chicken breast meat. The meat was cooked until the internal temperature reached 85°C and further cooked for 0, 20, and 40 min. The second objective was to identify the most critical variables for assessing meat juiciness.2. Cooking loss and moisture content exhibited high correlation with sensorial moisture release and mouth feel.3. The distribution of objects on the axes of the first two principal components (PCs) enabled the identification of three groups undergoing different cooking durations. The four major PCs explained 80.0% of the total variability.4. Cooking loss, moisture content, water-holding capacity, sensorial moisture release and mouth feel were demonstrated as the most effective variables for the first two PCs. PCA with instrumental and sensory analyses proved an effective procedure for systematically and comprehensively judging chicken meat juiciness.