We used 162 top sirloin butts to determine
the influence of different quality grades, postmortem
aging periods, blade tenderization
passes, and degree of doneness on thawing and
cooking losses and Warner-Bratzler shear force
(WBS, tenderness). Select (SEL), Choice
(CHO), and Certified Angus Beef™ (CAB) top
sirloin butts (n=54 for each) were aged for 7,
14, or 21 days and not tenderized (OX) or
blade tenderized one (1X) or two (2X) times.
Steaks from each top sirloin butt were assigned
randomly to final endpoint cooking temperatures
of 150, 160, and 170°F. Each longer aging
period resulted in lower (P<.05, more tender)
WBS. In addition, steaks blade tenderized 2X
had lower (P<.05) WBS than steaks not tenderized
or blade tenderized 1X. Within each
quality grade, WBS increased (P<.05) as
endpoint cooking temperature increased. When
cooked to 160 or 170°F, CHO and CAB
steaks had lower (P<.05) WBS than SEL
steaks. Increased aging periods and blade
tenderization passes of top sirloin butt steaks
improved tenderness. When cooking to higher
endpoint temperatures, using higher quality
grades will minimize toughness caused by cooking.
