Effects of power ultrasound treatments on properties of Longissimus beef muscle

1
Effects of power ultrasound treatments on
properties of Longissimus beef muscle G. M.
Gonzalez1, J. C. Cordray1, M. Mina2, J. S.
Dickson1, R. E. Rust1 and M. J. Daniels3 1 Dept.
of Animal Science, 2 Department of Electrical and
Computer Engineering, Iowa State University,
Ames, IA 50011 and 3Dept. of Statistics,
University of Florida, Gainesville, FL 32611
Introduction
Ultrasound is the area of the sound spectrum
that humans cannot hear (above 18kHz). Ultrasound
is divided in three main areas (1) Power
ultrasound (20kHz to 100 kHz), (2) Extended power
ultrasound and (3) High frequency or diagnostic
ultrasound (2MHz to 10 MHz) (Povey and Mason,
1998). Power ultrasound is the area of the sound
spectrum where cavitation is created. Cavitation
can be defined as the formation of cavities in a
liquid environment when a negative pressure is
applied. These cavities allow any gas dissolved
in the liquid to concentrate and form a bubble
(Mason, 1991 Povey and Mason, 1998).

• Important observation When excessive moisture
  was present at the surface of the samples,
  surface cooking took place when the treatments
  were applied (probably due to cavitation).
• In both experiments, the histological samples
  showed an evident separation of the muscle fibers
  (figures 3 and 4). All of the samples were from
  day 1.

Figure 4. High Intensity - Histological
Cross-Sectional Samples of Longissimus Beef
Muscle
Objectives
The objectives of this research are to (1)
determine if the use of a direct application of
ultrasound energy will increase the tenderness of
Longissimus beef muscle (2) determine the effect
of direct application of ultrasound energy on
different characteristics of fresh meat.
Materials and Methods

• The average cooking yields for experiment no. 1
  was 78 for both days (figure 4), with a
  difference between samples of less than 2.
• The difference in cooking yields between samples
  for experiment no. 2 was less than 2 and the
  average yield was 81 for day one and 86 for day
  seven (figure 5).
• In both experiments it is noticeable that
  ultrasonic cavitation does not cause a
  considerable difference in cooking yields between
  the control and the treated samples.

Fig.1 MaXonics 6000 system with TERFENOL-D
probe (ETREMA, Ames, IA)
Figure 5-Low Intensity Treatment Cooking Yields
Figure 6-High Intensity Treatment Cooking Yields
Electrical Power Intensity (W/cm2)
Electrical Power Intensity (W/cm2)

• In the case of the amount of power (Intensity,
  I) entering the samples, the results were
  fascinating.
• In the first experiment the intensity decreased
  as the power applied increased (table 3), which
  is normal. According to Mason (1991), ultrasonic
  cavitation, in the presence of water, creates
  heat (?H383 kJ/mol) and when the power is
  increased, the amount of energy introduced into
  the system will be greater, but also the
  dissipation of energy, in the form of heat, will
  be greater causing a loss of energy entering the
  system (Leighton, 1997).
• The data obtained from the second experiment
  presented a completely different scenario, where
  the best result was at 40 W/cm2 and the lowest
  was at 20 W/cm2. A possible reason for these
  findings is that at 20 W/cm2 the energy was not
  sufficient to produce enough cavitation, and with
  this, induce changes in meat, and at 50 W/cm2
  some sort of barrier is created (e.g. cooking the
  surface of the meat) and the energy is not able
  to enter the sample. Ultrasound transmission in
  muscle depends on factors such as density,
  frequency, intensity, temperature and moisture
  content (Solntseva, Sukhanova, Khlamova,
  Sarvazyan, Lyrchivok Shestimirov 1987 Yevelev,
  1989). It also depends on cavitation, which is
  produced when power ultrasound is applied. This
  cavitation creates high amounts of heat, that in
  turn, raises the temperature and increases the
  loss of energy (Leighton, 1997).

Table 3. Ultrasonic Power Measurements and
Temperature Increase
Results

• For experiment no. 1, no difference in shear
  force was observed for day 1, however, at day 7
  the 5 W/cm2 treatment required a lower force
  (plt0.05) to shear the sample (table 1). SDS PAGE
  did not show any difference between treatments.

Table 1. Low Intensity Treatment Shear Values (Kg)

• For experiment no. 2, shear force values for day
  1 were not significant, but showed a tendency
  toward lower values for the treated samples. At
  day 7, the shear force values were significant
  for the 40 W/cm2 treatment (table 2). Five
  percent gels indicated a possible degradation of
  titin at day 7 (figure 2).

Acknowledgements
The authors thank Tom Adams and the PM
Holdings group for supplying the beef loins,
Scott Eichhorn with ETREMA Products Inc. for his
technical advice and the ETREMA group for
supplying the ultrasonic equipment and technical
support. Tracey Pepper and Dr. Jack Horner for
doing the histology, Laura Rowe and Dr. Steven
Lonergan for their assistance with the SDS PAGE
test. Gretchen Mosher, Marcia King-Brink, Elaine
Larson and Krystal Johnson for their laboratory
assistance and Deb Michel and Ardella Krull for
the clerical work.
Figure 2.Five Percent Gels of Myofibrils Prepared
at Two Different Times Post-Treatment. (1-2)
Control, (3-4) 20 W/cm2, (5-6) 40 W/cm2, and
(7-8) 50 W/cm2. T1Intact Titin. T2 Degraded
Titin
Table 2. High Intensity Treatment Shear Values
(Kg)
References

• Leighton, T.G. (1997). The Acoustic Bubble.
  London, UK Academic Press.
• Mason, T.J. (1991). Practical Sonochemistry.
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• Solntseva, G.L., Sukhanova, S.I., Khlamova, R.I.,
  Sarvazyan, A.P., Lyrchivok, A.G., and
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  characteristics of muscle tissue. Proc. European
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• Yevelev, S.A. (1989). The study of acoustical
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