High and low rigor temperature effects on sheep meat tenderness and ageing

Area of Science:

• Meat Science
• Food Technology
• Animal Science

Background:

• Meat quality is influenced by post-mortem conditions, including temperature during rigor mortis development.
• Understanding the effects of different rigor mortis temperatures on meat tenderness is crucial for the meat industry.

Purpose of the Study:

• To investigate the impact of two different rigor mortis temperatures (18°C and 35°C) on the tenderness and quality of sheep meat (m. longissimus thoracis et lumborum).
• To determine if differences in tenderness are attributable to muscle shortening or aging processes at different temperatures.

Main Methods:

• Sheep longissimus thoracis et lவைக்umborum muscles were subjected to rigor mortis at either 18°C or 35°C after electrical stimulation.
• Meat was aged for varying durations (0, 8, 26, 72 hours) at 15°C before freezing and cooking.
• Shear force, sarcomere length, cook loss, and color (Hunter L, a, b values) were measured.

Main Results:

• Meat reaching rigor at 18°C became significantly more tender with aging compared to meat at 35°C (P<0.001).
• Sarcomere length was significantly shorter in meat at 35°C rigor (P<0.001), but toughness at 35°C was not solely due to shortening.
• Higher cook loss (30.5% vs 28.4%) and higher Hunter L values were observed at 35°C rigor (P<0.01).

Conclusions:

• Lower rigor mortis temperatures (18°C) promote greater meat tenderization during aging than higher temperatures (35°C).
• Meat toughness at higher rigor temperatures is influenced by both a faster aging rate and a greater extent of tenderization at lower temperatures.
• Rigor temperature affects cook loss and meat color, with higher temperatures leading to increased loss and lightness.