Freezing Temperature and Frequency Influence Purge But Not Tenderness of Beef Semitendinosus

Abstract

Our objective was to test the effects of freezing temperature and frequency on purge loss and tenderness of eye of round steaks. Commercially sourced USDA Choice beef semitendinosus (n=10) were aged 24 d postmortem. Twelve steaks were cut from each muscle and randomly assigned to 1 of 12 treatments in a 4×3 factorial treatment structure(unfrozen control at 2.2°C or initial freezing at −17.8°C, −26.1°C, or −34.4°C followed by secondary freezing at −17.8°C, −26.1°C, or −34.4°C). Steaks were weighed after cutting and after thawing following each freezing treatment to determine purge losses. Tenderness was assessed via Warner-Bratzler shear force (WBSF); all data were analyzed via mixed models. Lower total purge losses (6.27%) were observed for steaks initially unfrozen (P<0.001), whereas those initially frozen at −34.4°C, −26.1°C, and −17.8°C lost 8.04%, 8.80%, and 8.53%, respectively. No difference (P>0.501) in WBSF was detected among the freezing treatments. These results suggest that freezing temperature and thus freezing rate impact purge loss of eye of round steaks, but mechanical tenderness was not influenced.