The beef inside round muscle, especially
the deep portion, has poor color stability, a
troublesome condition for the meat industry.
We examined influences of pre-rigor temperature
and pH decline on chemistry of the
inside (deep) semimembranosus (ISM) and
outside (surface) semimembranosus (OSM)
in relation to initial color and stability.
Cold-boned ISM had a slower chill rate;
faster pH decline; more denatured protein;
less metmyoglobin reducing ability, oxygen
consumption, and water holding capacity;
and a lighter, less stable color than the OSM.
Cold-boned steaks were two-toned in color
and discolored by day 3 of display. Hotboned
ISM and OSM chilled at the same
rate, had similar pH declines, similar chemical
characteristics, and acceptable color traits
up to day 5 of display. Techniques that chill
the entire beef SM faster produced a more
uniform stable color, extended the color life
of the ISM, and minimized rework and
discounting.
