Research Note: Expression level of heat shock protein 27 in PSE-like and fast-glycolyzing conditions of chicken pectoralis major muscle.

This study compared the meat quality traits, histochemical characteristics, and heat shock protein (HSP) 27 expression levels of the broiler Pectoralis major (PM) muscles in groups classified by pale, soft, and exudative (PSE)-like and fast-glycolyzing conditions using the lightness and muscle pH change values. Chicken PM muscles showing higher pH change value and paler meat surface (as HP group) could be associated with the PSE-like condition, and exhibited a lower pH value and higher cooking loss compared to PM muscles showing lower pH change value and normal color (as LN group) (P < 0.05). Greater PM muscle weight and fiber area were observed in the HP group compared to the other groups (P < 0.05); meanwhile, the PM muscles showing higher pH change value with normal color (as HN group) and the PM muscles showing lower pH change value with paler color (as LP group) did not differ in the water holding capacity, Warner-Bratzler shear force, and muscle fiber characteristics (P > 0.05). Muscle samples showing a higher pH change value exhibited a greater level of HSP27 compared to muscle samples showing a lower pH change value (P < 0.05). Therefore, the current findings suggested that the expression level of HSP27 can be a useful indicator for explaining variations in the glycolytic rate of chicken breast muscle.