Identification of different domains of calpain from blood and goat skeletal muscle and their influence on quality during post-mortem ageing of meat during holding at 4 ± 1 °C

• Simple Zymography method for simultaneous identification of calpains and calapastatin is optimized.
• Simple one step DEAE-Sephacel based separation of calpains and calapastatin is developed.
• Influence of calpains and calpastatins in post-mortem ageing of Biceps femoris muscle is determined.

The aim of this study was to determine the activity of different domains of calpains and calpastatin in goat blood and tissue samples to understand their influence on ageing of meat during holding at 4 ± 1 °C. The enzymes were extracted and they were subjected to casein zymography analysis. Both these enzymes were purified and separated using anion exchange column chromatography, and their presence was confirmed by SDS-PAGE analysis. Casein Zymography results indicated the presence of μ- and m-calpains activity in both the sample extracts. However the band intensity kept decreasing with the increase of ageing time indicating the decrease in activity of these enzymes. The pH and Warner-Brazler Shear Force (WBSF) values were also decreased with the increase in ageing time while Lovibond tintometer colour, TBARS values, FFA contents and peroxide values were least affected. Thus, it was concluded that both these enzymes are present in the muscle sample but that were autolyzed with the increase of aging. The μ-calpain induced postmortem ageing time for Biceps femoris muscle of Jamunapari and Jhakrana breeds of goat was optimized at 72 h and 48 h respectively.