SmartStretch™ Technology. II. Improving the tenderness of leg meat from sheep using a meat stretching device

This study evaluated the effect of stretching hot-boned sheep hindlegs from 40 sheep carcases, classified as mutton, using a prototype device (SmartStretch™). Left and right legs were collected pre-rigor and randomly allocated to one of four treatments; 0 days ageing + SmartStretch™, 0 days ageing + no stretch, 5 days ageing + SmartStretch™ and 5 days ageing + no stretch. There was a significant interaction between stretch treatment and ageing (P < 0.05) for shear force of the m. biceps femoris such that stretched and aged samples were the most tender. By contrast stretched m. semimembranosus (SM) had a significantly (P < 0.05) lower shear force only at 0 days of ageing. Stretching produced longer sarcomeres (P < 0.001) for both the SM and m. semitendinosus muscles. Myofibrillar degradation indicated by particle size analysis or histology was not affected by stretching, but there was an ageing effect (P < 0.001). SmartStretch™ provided significant improvements in tenderness of the individual muscles.

► Tenderness of m. biceps femoris was improved by applying SmartStretch™ treatment.
► Tenderness of m. semimembranosus was improved by applying SmartStretch™ treatment.
► SmartStretch™ treatment did not impact on protein degradation.
► Improvements from this treatment partially reflect an increase in sarcomere length.
► SmartStretch™ resulted in more purge.