The Effect Of Ageing On Palatability of SubPrimal Beef

1
The Effect Of Ageing On Palatability of
Sub-Primal Beef L. L. Gibson, J. L. Aalhus, W.
M. Robertson, M. E. R. Dugan, W. J. Meadus, I.
L. Larsen and S. Landry Agriculture and Agri-Food
Canada, Lacombe Research Centre, 6000 C E
Trail Lacombe, Alberta, Canada, T4L 1W1
Results Sensory evaluation for initial tenderness
and overall tenderness demonstrated that not all
muscles have discernable improvements in
tenderness with ageing. Over the full course of
ageing, initial and overall tenderness ratings
only improved significantly up to 14 d of ageing
in the SL, IR, ER, and BE. There was no
significant improvement in initial or overall
tenderness for the OR and CT muscles during
storage time. Panel ratings for initial
juiciness and sustained juiciness were
significantly lower with increasing time of
ageing in all muscles with the exception of ER
and BE, where there was no significant change.
Over time the appropriate beef flavour intensity
steadily decreased and the inappropriate
off-flavour intensity (sour, lactate flavours)
increased significantly in all six muscles.
Despite the lower scores for flavour and
juiciness over time of ageing, overall
palatability scores increased to 14 d of ageing
in the SL and BE. In contrast the IR, OR, and ER
muscles showed no significant increase in
palatability over ageing time, but demonstrated a
significant decrease in palatability ratings
after 21 d. The CT had no improvement in overall
palatability with ageing, but ratings decreased
significantly after 14 d paralleling the drop in
beef flavour. Changes in overall palatability
were initially much more closely related to
improvements in tenderness, and only later in the
ageing period did lower flavour and increased off
flavours play a role in the overall acceptance of
the meat (Figure 1).
Introduction The most common method utilized to
improve beef tenderness is postmortem ageing.
However, there is little information on ageing of
muscles other than the loin/rib-eye. Some
reports indicate ageing may not be advantageous
in all muscles, particularly in the round.
Despite this, the Canadian cold chain study
indicated the average maximum time for exiting
packing plants, warehouses and retail store
chillers was 24, 51 and 80d, respectively. The
purpose of this study was to examine the
influence of extended ageing on the palatability
of six boxed beef cuts.
Materials Methods Boxes of strip loin, SL
inside round, IR outside round, OR eye of
round, ER blade eye, BE chuck tender, CT were
obtained from a local abattoir. Sub-primals were
cut into steaks, vacuum packaged, and aged in
temperature controlled coolers for up to 42 d.
All steaks were grilled to the internal
temperature of 71oC on an electric Garland Grill.
Cooked steaks were cut into 1.5 cm cubes, placed
in preheated glass jars and served to a 7 member
semi-trained laboratory panel in partitioned
booths under 124 Lux red lighting. Sensory
evaluation of cooked samples included assessments
for initial and overall tenderness, initial and
sustained juiciness, beef flavour intensity, off
flavour intensity on a 9 point descriptive scale
and overall palatability on a 9 point hedonic
scale. The CT and BE were only evaluated until d
28, whereas other muscles were evaluated to d
42.
Figure 1. Sensory evaluation characteristics over
storage time
Implications These results clearly indicate
that ageing is not beneficial to all muscles.
Extension of ageing beyond optimum muscle
specific times results in decreased tenderness
and juiciness, and increased off flavour. These
observations will have practical importance in
the beef industry, where guaranteed ageing
programs are implemented, regardless of the
muscle, and distribution of boxed beef often
results in prolonged ageing times, beyond those
needed for optimum tenderness.
Acknowledgements Financial support for this work
was provided by the Beef Cattle Research Council
and the AAFC Matching Investment Initiative.
Technical assistance provided by F. Costello, G.
Croken, K. Landry and R. Thacker is gratefully
acknowledged.
References American Meat Science Association and
National Live Stock and Meat Board 1995, Research
guidelines for cookery, sensory evaluation, and
instrumental tenderness measurements of fresh
meat. American Meat Science Association, Savoy,
IL. C. O. Gill 2002. Temperatures and ages of
boxed beef packed and distributed in Canada. Meat
Science 60 401-410.