Characterization of Striping in Fresh, Enhanced Pork Loins

1
Characterization of Striping in Fresh, Enhanced
Pork Loins
J.P. Gooding, F.K. McKeith, T.C. Carr, J.
Killefer, and M.S. Brewer
University of Illinois, Urbana
Introduction With the evolution of case-ready
products, visual acceptability of enhanced pork
products has become a greater concern to the pork
packing industry. Color is unquestionably a
significant issue that consumers consider when
developing purchase intent (Brewer and McKeith,
1999), and any difference from the normal
reddish-pink color can impart negative
impressions. Today, approximately 60 of fresh
pork loins are enhanced in some way (Meisinger,
2003). A substantial amount of research has been
conducted over the years involving the
enhancement of fresh pork loins however, very
little research has been done with the striping
phenomenon and characterization of light and
dark stripes in enhanced fresh meat.
Statistical Analysis Data were analyzed using the
GLM procedure of SAS and significance was
determined at the 0.05 level.

• Objective
• Characterize the effects of individual brine
  components.
• Characterize the effects of brine solutions
  containing a variety of
• phosphates to provide a range in brine pH.
• Characterize the effects of brine solutions
  containing different
• concentrations of ingredients.
• Characterize the effects of pumping at different
  pressures.
• Characterize the effects of different meat to
  brine temperature
• differentials.
• Characterize the effects of various pump levels.
• Characterize differences between stripes.

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2
3
4
5

• Methods
• Product - 102 boneless pork loins were collected
  from a commercial processing facility.
  Experiment 1 2 were selected for 3 pH levels,
  lt 5.8, 5.8 - 6.0, gt 6.0, while remaining were
  selected for subjective color score gt 3 (NPPC,
  1999).
• Enhancement - At 48 hr postmortem, six
  experiments were conducted where loins were
  fabricated into sections and pumped with various
  treatments. Product was enhanced to 12 at 2
  bars pressure, unless otherwise specified. At 72
  hr postmortem, a 2.54 cm chop was evaluated and
  given a subjective striping score 1 none, 5
  severe (Figure 1).
• Experiment 1 - Loins were treated with the
  following
• No pump
• Water only
• 0.4 salt
• 0.4 phosphate
• 2.5 sodium lactate
• 0.4 salt, 0.4 phosphate, 2.5 sodium lactate
• Experiment 2 - Loins enhanced with variety of
  phosphates
• Provide a range in brine pH 6.38, 7.25, 7.96
• 0.4 salt, 0.4 phosphate, 2.5 sodium lactate
• Experiment 3 - Loins enhanced with variety of
  concentrations
• 0.4 salt, 0.4 phosphate, 2.5 sodium lactate
• 0.3 salt, 0.3 phosphate, 2.0 sodium lactate
• 0.2 salt, 0.2 phosphate, 1.5 sodium lactate
• Experiment 4 - Loins enhanced at different bar
  pressures
• 0.4 salt, 0.4 phosphate, 2.5 sodium lactate
  brine

• Conclusions
• Striping was observed in all enhancement
  treatments however, no differences in striping
  scores within treatments.
• Striping did not dissipate following continuous
  tumbling for 2 hr.
• Striping coincided with needle injection site
  and was noticed immediately after enhancement,
  indicating the phenomenon is instantaneous.
  Striping originated at the needle injection site
  and proceeded to follow parallel with the muscle
  fibers.
• Darker colored pork is more susceptible to
  striping. Selecting lighter colored pork for
  enhancement may reduce striping severity.

References Brewer, M. S. and McKeith, F.K.
(1999). Consumer-rated quality characteristics as
related to purchase intent of fresh pork. Journal
of Food Science. 64, 171-174. Meisinger, D.
(2003). Personal communication. NPPC. (1999).
Pork composition and quality assessment
procedures. Natl. Pork Prod. Counc., Des Moines,
IA.