Determining sensory thresholds for juiciness and hardness in chicken breasts using chew-stage protocol and physicochemical validation

Juiciness and hardness are critical attributes of meat quality. In this study, we measured the juiciness and hardness of chicken breasts cooked using the vacuum low-temperature method, the pressure filter paper method, and a rheometer. To improve measurement efficiency and suitability for consumer panels, we employed a chew-stage sensory protocol that collected discrete ratings at three predefined stages (3 chews, 10 chews, and ready for swallowing). In addition, polarized sensory positioning (PSP) was introduced, using chicken breasts cooked at 100 °C for 3 hours as a fixed reference sample. This approach has helped to minimize the perceptual variation among panelists, and it also provided a consistent sensory anchor during evaluation. The results indicated that simultaneously achieving high juiciness and low hardness was challenging because hardness was predominantly influenced by temperature, whereas juiciness was primarily influenced by the cooking duration. Consequently, a perfect balance between juiciness and hardness cannot be achieved at a single temperature or cooking time, requiring tradeoffs based on specific cooking requirements. Sensory evaluation revealed a significant increase in juiciness with increased chewing time (P < 0.05), whereas hardness was not significantly affected. These sensory and physicochemical data suggest that controlling the cooking duration is more crucial than temperature for enhancing the juiciness of chicken breasts. A strong correlation was observed between the sensory ratings of juiciness and hardness and the corresponding physicochemical measurements (juiciness: r = 0.85, P < 0.001; hardness: r = 0.87, P < 0.001), thus confirming the validity of the sensory evaluation method used in this study. This study established a perceived juiciness threshold of 3.5% and a hardness threshold of 16.5 N. Based on the above findings, greater attention should be paid to optimizing the heating time during chicken breast cooking to achieve the desired meat quality and enhance cooking efficiency.