Definition of Thaw Rigor

When pre-rigor meat is frozen, a severe type of rigor mortis occurs during thawing and 60–80% muscle shortening takes place, this is known as:

Correct Answer: Thaw Rigor

Thaw rigor is the phenomenon where pre-rigor meat is frozen and then thawed, resulting in a sudden, severe rigor mortis with 60–80% muscle shortening — the most extreme form of muscle toughening in meat technology.

Why Thaw Rigor is More Severe Than Cold Shortening?

• Freezing halts all enzymatic and metabolic activity — including the slow continuation of glycolysis that normally allows gradual rigor development.
• The sarcoplasmic reticulum is disrupted by ice crystal damage during freezing.
• On thawing: all accumulated Ca²⁺ is suddenly released simultaneously → massive, uncontrolled, instantaneous actomyosin contraction → 60–80% shortening.
• Simultaneously, large amounts of drip (exudate) are lost — further reducing quality.

Cold Shortening vs Thaw Rigor — Quick Comparison