TENDERNESS IMPROVEMENT IN FRESH OR FROZEN/THAWED BEEF STEAKS TREATED WITH HYDRODYNAMIC PRESSURE PROCESSING*
ABSTRACT Tenderness improvement in fresh (F) or frozen/thawed (FT) beef steaks treated with hydrodynamic pressure processing (HDP) technology was examined. In Experiment 1, the effect of HDP and meat state at 48 h postmortem (fresh, never frozen compared to frozen at 48 h postmortem followed by thawing at 6 d postmortem) on meat tenderness at both day 1 and day 6 after HDP was evaluated. The effect of HDP was sustained throughout day 6 of aging.FT samples were 1 kg lower at day 1 compared to F samples and 0.8 kg lower at day 6. In Experiment 2, 40 boneless, rib-eye sections (5 d postmortem) were used. One control steak was cooked fresh, while a second was frozen for 60 d. HDP was performed on the 40 F rib-eye sections. Twenty of the HDP-treated rib eyes were frozen after HDP treatment. The remaining 20 F HDP-treated samples were cooked 24 h after treatment for tenderness determination. Sixty days after HDP treatment, the frozen control and HDP-treated samples were thawed and cooked. Control (never frozen) steaks prior to HDP treatment had shear values of 6.5 kg. A 29% reduction in shear force was observed for HDP-treated (F) samples. Freezing accounted for a 14% reduction in shear force. HDP treatment followed by freezing resulted in a 30% reduction in shear force compared to the frozen control samples.PRACTICAL APPLICATIONSPostmortem storage at refrigerated temperatures has been clearly demonstrated to improve meat tenderness. Freezing and then thawing meat has been shown to either improve tenderness, increase toughness or have no effect at all on meat tenderness. The use of hydrodynamic pressure processing (HDP) in conjunction with freezing meat either before or after HDP treatment was evaluated. Use of HDP, whether on fresh or frozen/thawed meat, successfully tenderized meat. Whether one freezes the meat before performing HDP or after HDP treatment, both successfully improve meat tenderness and the improvements are maintained even after frozen storage. Although freezing alone did show signs of improving meat tenderness, the magnitude of improvement was much less than the tenderness improvements found when using HDP technology.