Effects of additional electrical stimulation and pre-rigor conditioning temperature on the ageing potential of hot-boned bovine muscles.

OBJECTIVE: The aim of this study is to characterize the impact of additional electrical stimulation (AES) and various pre-rigor holding temperatures (for 3 h) on the ageing-potential of hot boned bovine M. longissimus lumborum (LL). METHODS: Paired LL loins from 12 bulls were hot-boned within 40 min of slaughter, immediate AES applied and subjected to various holding temperatures (5°C, 15°C, 25°C, and 35°C) for 3 h. RESULTS: AES did not accelerate the rate of rigor attainment, but the 3 h pre-rigor holding temperature did. Shear force values decreased as the pre-rigor holding temperatures increased. AES and holding for 3 h (at 25°C) resulted in higher water-holding capacity. CONCLUSION: Data confirmed that AES did not influence the various meat quality parameters in the present study, but pre-rigor holding temperature (25°C) alone or in combination with AES resulted in superior meat quality.

Effect of fast freezing then thaw-aging on meat quality attributes of lamb M. longissimus lumborum.

The objective of this study was to determine the effect of two different freezing rate then thaw-aging regimens on the quality attributes of lamb loins. The loins were randomly allocated to one of five different freezing/thawing/aging regimes: fast-(FF1A0) and slow-(SF1A0) frozen only; fast-(FF1A2) and slow-(SF1A2) frozen then thaw-aged for 14 days; aged for 14 days never frozen (A2). FF1A2 samples had a significantly higher water-holding capacity compared to the slow frozen regardless of further aging periods. FF1A2 samples had lower (p < 0.05) shear force values than A2 and higher (p < 0.05) water-holding capacity compared to the SF1A2. Fast freezing resulted in more intracellular cryo-damage, whereas slow freezing resulted in extracellular cryo-damage. FF1A0 and SF1A0 samples had lower (p < 0.05) myofibrillar proteins degradation. This study demonstrated that fast freezing then thaw-aging can result in an improved water-holding capacity and tenderness through the minimization of extracellular ice crystal formation, reduction in purge and drip losses, and improved proteolysis in thawed lamb.

Effects of electrical stimulation and pre-rigor conditioning temperature on aging potential of hot-boned beef M. longissimus lumborum.

The objective of this study was to create various pH/temp decline rates in hot-boned bull beef M. longissimus lumborum (LL) through a combination of electrical stimulation (ES) and pre-rigor holding temperature. The relationship between the pre-rigor interventions, the activities of µ-calpain and small heat shock proteins (sHSP), and the impacts on meat product quality were determined. Paired LL loins from 13 bulls were hot-boned within 40 min of slaughter, immediately ES and subjected to various holding temperatures (5, 15, 25, and 35°C) for 3 hr. The rate of muscle pH decline, sarcomere length, shear force, and proteolysis of muscle proteins were measured. ES-25°C had a longer sarcomere length compared to non-electrical stimulation samples. ES-25°C and ES-35°C samples had lower shear force values, higher µ-calpain activity and higher desmin, troponin-T, and sHSP degradation. The above findings suggest that pH/temp decline rates created in hot-boned muscle impacted muscle protein proteolysis by increasing the activity of proteases and degradation of sHSP.