Abstract

Muscle ultimate pH (pHu) is known to influence eating quality, functional properties and safety in beef, lamb and pork. The extent to which muscle pH affects tenderness and the extent to which it can be `aged` out is different for lamb compared to beef and two studies have been carried out with venison in order to determine the implications for venison tenderness. Longissimus thoracis et lumborum (striploin) muscles from nine carcasses which went prematurely into rigor (`stiff` carcasses) had higher mean pH than muscles from nine control carcasses (5.93 vs 5.61, SED = 0.091 at 2 days postmortem (PM); 5.83 vs 5.56, SED = 0.100 at 7 days PM; 5.81 vs 5.54, SED = 0.096 at 21 days PM). A typical quadratic relationship was observed between tenderness and pH which explained non-significant differences in tenderness between the stiff and control muscles. The tenderness-pH relationship for venison striploins assessed at 2 days after slaughter was typical of that reported for unaged beef and lamb in that muscles with pH in the range of 5.8-6.2 were tougher (P< 0.05) than normal (5.5-5.7) and high (>6.2) pH muscles. The tenderness profile change after 7 and 21 days chilled storage at 4°C was similar to that reported for lamb in that all of the striploin samples tenderised to an acceptable level. Ten intermediate pH (5.8-6.2) biceps femoris (BF) muscles were tougher (P< 0.05) than ten normal pH (5.5-5.7) muscles at all times with chilled storage at 0°C for up to 6 weeks. The intermediate pH muscles that were frozen then thawed prior to assessment were significantly more tender than the chilled intermediate pH muscles, but still tended to be tougher than the normal pH muscles. Both the chilled and frozen intermediate pH muscles were significantly more variable in tenderness than the normal pH BFs.

JM, Stevenson-Barry, WJ Carseldine, SJ Duncan, and RP Littlejohn

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 145-147, 1999