Functional Analysis of Turkey Breast Muscle

1
Functional Analysis of Turkey Breast Muscle
M.S. Updike, H. Zerby, J.C. Sawdy, M.
Wick Department of Animal Sciences, The Ohio
State University, Columbus, OH
INTRODUCTION
RESULTS and Discussion Cont

• Genetic selection in turkeys has resulted in
  dramatically increased body weight and breast
  yield (Lilburn and Nestor, 1977).
• An increased occurrence of meat functionality
  problems has been noticed in the commercial
  industry (McKee and Sams. 1997).
• RBC2 line has been randomly mated for 30
  generations and represents commercial turkeys
  from the 1960s (Nestor 1977).
• The F-line was created from a subset of the RBC2
  line and selected for body weight at 16 weeks
  (Nestor, 1977).
• The C-line is a commercially available line of
  turkeys obtained from a turkey breeding company
  in Ohio.

F-line (n7)
C-line (n8)
RBC2 line (n9)
P
NS
41.5 ? 0.36
41.2 ? 0.38
40.8 ? 0.34
5 min temp (?C)
lt0.0001
11.1c ? 0.70
7.8b ? 0.80
5.4a ? 0.70
2 hr temp (?C)
NS
3.8 ? 0.3
4.4 ? 0.3
4.2 ? 0.3
20 hr temp (?C)
NS
5.94 ? 0.11
6.19 ? 0.11
5.84 ? 0.09
2 hr pH
lt0.05
5.73ab ? 0.03
5.66b ? 0.03
5.79a ? 0.03
20 hr pH
Table 2. Combined temperature and pH measurements
on the PM of three genetic lines of tom turkeys
harvested at 16 and 22 weeks shown as mean SEM.
METHODS
Animals and tissue preparation. Toms were raised
during the summer of 2001 and fed a diet that met
all NRC requirements. The toms were
exsanguinated, defeathered, and the pectoralis
majors (PM) were removed and placed in an ice
water bath. After 20 hr, the pectoralis majors
were placed at -20 C and stored for future
use. Temperature and pH. Temperature was
measured at 5 min, 2 hr and 20 hr with a
temperature probe in the center of the PM. A pH
probe was used to measure the pH in the center of
the PM at 2 hr and 24 hr after being placed in
the ice water bath. Water holding capacity.
0.3g of breast pectoralis major was minced. 0.9
mL of brine (1.4 M NaCl, 0.1 M Na
tripolyphosphate, pH 7.6 Li and Wick, 2001)
was added and the homogenate mixed for 1 hr at 4
C. The homogenate was centrifuged at 10,000 x
g for 10 min at 4 C . The mass of the
supernatants, which contains the salt soluble
proteins (SSPs) and the mass of the pellets were
determined. Brine partitioning into either the
pellet of supernatant was calculated. Rheological
Analysis. SSP solutions were obtained on 25g of
PM as described in the WHC procedure. The SSPs
were clarified through cheesecloth and studied
using a controlled stress rheometer. A
temprerature ramp from 40 80 C with a heating
rate of 1 C /min was used. The frequency was 1
hz and the stress was constant at 0.1768 Pa.
Storage modulus was recorded Electrophoretic
Analysis. A second set of supernatants was
prepared for sodium dodecyl sulfate
polyacrylamide gel electrophoretic (SDS-PAGE)
analysis, according to Laemmli (1970). The
supernatants were mixed with an equal volume of
Reducing Buffer (60 mM Tris buffer, pH 6.8,
containing 2 SDS, 15 glycerol, 350 mM DTT, and
0.1 bromophenol blue) and heated for 5 min at
100 oC. Twenty µL of sample were loaded on each
lane of a 3/10 acrylamide gel. Protien loads
were standardized by analysis using PhoretixTM 1D
Advanced for total load and then run on a
subsequent gel. Gels were stained with Coomassie
Brilliant Blue G-250and destained with 10 acetic
acid . Statistical Analysis. Data were analyzed
using the PROC MIXED procedure of SAS v.8.
Figure 1. Relative masses of supernatants and
pellets of brine extracted comminuted PM from
RBC2 line (R) (n 9), F-line (F) (n 7), and
C-line (C) (n 8) toms randomly selected from
all three harvest dates
Figure 3. Representative electrophoretic
migration patterns of supernatants of brine
extracted comminuted PM from RBC2 line (R) (n
5), F-line (F) (n 5), and C-line (C) (n 6)
toms.
Figure 2. Distribution of ultimate storage
modulus of thermally-induced meat gels of RBC2
line (n5), F-line (n5), and C-Line (n5).

• C-line PMs cool more slowly than both RBC2 and
  F-line PMs, even though there is no difference in
  mass or size with F-line PMs.
• RBC2 line PMs have a greater water holding
  capacity than C-line PMs, possibly due to an
  increased ability for myofibrillar swelling in
  the presence of high salt solutions.
• The RBC2 line had an 80C G of 131 42 Pa, the
  F-line had an intermediate ultimate G of 89 39
  Pa and the C-line had an ultimate G of 54 42
  Pa (P 0.09).
• The distribution of ultimate G was plotted as a
  frequency (Figure 2). The RBC2 line had more
  samples with ultimate G greater than 100 Pa than
  either the F-line or the C-line.
• 50 fold differences in ultimate G were observed
  in the SSPs which contained equal quantities of
  myosin and total protein.
• Overall selection pressure RBC2 lt F-line lt C-line
• Overall meat functionality RBC2gt F-line gt C-line

RESULTS and Discussion
LITERATURE CITED

• Li, C., and M. Wick. 2001. Improvement of the
  physicochemical properties of pale soft and
  exudative (PSE) meat products with an extract
  from mechanical deboned turkey meat (MDTM). Meat
  Sci. 58189-195.
• Lilburn, M.S. and K.E. Nestor, 1991. Body weight
  and carcass development in different lines of
  turkeys. Poult. Sci. 702223-2231.
• McKee, S.R. and A.R. Sams. 1997. The effect of
  seasonal heat stress on rigor development and the
  incidence of pale, exudative turkey meat. Poult.
  Sci. 761616-1620.
• Nestor, K.E. 1977. The use of a paired mating
  system for the maintenance of experimental
  populations of turkeys. Poult. Sci. 5660-65.

Table 1. Physical and carcass characteristic
measurements on three genetic lines of 16 week
tom turkeys (n 23) shown as least squares mean
SEM