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Yield and Shear Values of Pectoralis Superficialis after Tumbling in Various Solutions1
Yield and Shear Values of Pectoralis Superficialis after Tumbling in Various Solutions 1 J. L. HEATH and S. L. OWENS Department of Poultry Science, University of Maryland, College Park, Maryland 20742 (Received for publication March 24, 1987) ABSTRACT Effects of breast piece weight (thickness) on yield after tumbling in water and aqueous solutions of acetic acid, NaCl, and soybean oil for 10 and 20 min were determined. Thickness of the piece had no affect on yield when the samples were tumbled in water but addition of acetic acid, NaCl, or oil to the tumbling solution resulted in significant (P<.05) correlations in many cases. Increased sample thickness resulted in smaller cooking loss in those samples tumbled in 10% acetic acid, .5 and 1% NaCl, or 5 and 10% soybean oil. This resulted in improved net yield as sample weight increased. Addition of NaCl (.5 or 1.0%), acetic acid (5 or 10%), or soybean oil (5 or 10%) to the tumbling solution did not affect peak values but addition of 5 or 10% soybean oil reduced shear values in the samples after 10 min tumbling. Oil in the solution had no affect after tumbling for 20 min. Increasing the tumbling time from 10 to 20 min produced lower peak values and shear values in samples tumbled in water, NaCl, and oil. Combination of .5% NaCl, 5% acetic acid, and 5% soybean oil to produce various tumbling solutions resulted in no changes in peak values or shear values and when tumbling time was increased from 10 to 20 min, shear parameters were not reduced. Net yield was higher when samples were tumbled in solutions containing acetic acid. Increasing tumbling time from 10 to 20 min also increased net yield in these samples. (Key words: tumbling, marinade, shear values, broiler breast) 1987 Poultry Science 66:1949-1956 INTRODUCTION
Fast food and convenience food portions of the poultry industry have become highly competitive in a relatively short period of time and must increase efficiency to maintain or improve their competitive positions. This industry often uses tumbling in a marinade solution to produce new and unique products. As a result, there is a need for research to determine the effects of tumbling and marination on tenderness and yield of broiler tissue. There has been little research on poultry products in this area. Acetic acid (vinegar), oil, and salt are common ingredients in various marinade recipes (Reitz and Wanderstock, 1965). The use of ace tic acid in marinade solutions has produced conflicting results. Acetic acid increased tenderness and yield of poultry parts when it was used in marinade solutions without tumbling (Pauli, 1979; Post and Heath, 1983). It was reported by deFremery and Pool (1960) and Khan and Nakamura (1970) that a rapid reduction in pH
'Scientific Article Number A-4618 Contribution Number 7614 of the Maryland Agricultural Experiment Station (Department of Poultry Science).
in the tissue decreased tenderness in the muscles tested. Kotula and Heath (1986) found no effect on tenderness when poultry parts were exposed to 5 and 10% acetic acid in a tumbling solution. They reported that addition of acetic acid to the tumbling medium resulted in increased tumbling solution pickup and increased cooking losses in chill-boned broiler parts. Carpenter et al. (1979), Lyon (1980), Babji et al. (1982), Janky et al, (1983), Lyon et al. (1984), and Mathusa and Janky (1984) found that introduction of NaCl increased water binding in chicken tissue and decreased shear. Kotula and Heath (1986) reported that tumbling chillboned broiler breasts in 4% NaCl solutions increased tumbling solution pickup but tumbling in 1 and 2% NaCl reduced tumbling solution gains, Chen (1980) found that marination increased final yields of fried chicken parts when compared with yields of nonmarinated controls. He also determined that the amount of penetration into parts by the solution during 4 h of still marination can be equaled by 10 min of rotating marination. This study was conducted to determine the effects on shear and yield parameters of tumbling for 10 and 20 min in aqueous solutions containing acetic acid, NaCl, or oil.
1949
1950
HEATH AND OWENS MATERIALS AND METHODS
General Procedure. Broiler carcasses slaughtered at the University of Maryland's processing facility were held overnight in plastic bags at 4 C to allow rigor mortis to resolve. The pectoralis superficialis without skin was removed from each side of the breast and samples were cut from the anterior and posterior part of the muscles for Experiment 1 and from the anterior part of the muscle for Experiments 2 and 3, using a 5 x 5-cm template. Each sample was weighed, isolated from other samples in cloth mesh ham socks, and tumbled in 2 L of aqueous solutions containing NaCl (w/v), acetic acid (w/v), and soybean oil (w/v) individually or in combination for 10 or 20 min. These solutions are described later when conditions for each experiment are defined. Tumbling was accomplished in a Lyco model 40 tumbler (Columbus, WI) at 18 rpm and under vacuum (15 in. Hg). Samples were removed from the tumbler, allowed to drip for 10 min while suspended on wire racks at room temperature, removed from the cloth mesh, and weighed. They were placed on ridged aluminum pans, covered with aluminum foil, heated in a forced air oven (Market Forge model 2400HE, Everett, MA) at 175 C to an internal temperature of 85 C.Temperature was measured by insertion of a thermometer into the center of pieces selected for this purpose. Samples were removed from the oven, allowed to cool without uncovering at room temperature, and then weighed. A meat sheer was used to remove two 3-mm thick slices from the external portion (the part normally next to the skin) of each breast piece. A 3 x 3-cm subsample was removed from the center of the second slice. It was positioned in a Kramer shear cell (Instron Corp., Canton, MA) and sheared at a 90° angle to the direction of the muscle fibers. Shear parameters were calculated using the force deformation curves produced at room temperature by an Instron universal Testing Instrument (Instron Corp., Canton, MA) with a 100-kg load cell and a downstroke of 20 cm/min. The force required to compress the sample and initiate shear caused the largest deflection on the chart and the resistance represented by this peak was recorded as the peak value in kilograms per gram. When the blades started to shear the sample the force was recorded on the chart as a decrease from the initial peak; as the blades passed through the sample, a plateau was formed on the chart that was reported as the shear value in kilograms per gram (Bouton et al., 1975).
Yield parameters were calculated using the following formulas: percentage drip loss = (raw weight - post drip weight/raw weight) x 100; percentage cooking loss = (post drip weight cooked weight/post drip weight) x 100; percentage net yield = (cooked weight/raw weight) x 100. Moisture of the cooked samples was determined using procedures found in Association of Official Analytical Chemists (1984). Experiment 1. The effect of differences in breast piece weight (thickness) on drip loss, cooking loss, and net yield was determined using a correlation analysis (Steel and Torrie, 1960). Samples (n = 32) were tumbled for 10 or 20 min in water and aqueous solutions of .5% NaCl, 1% NaCl, 5% acetic acid, 10% acetic acid, 5% soybean oil, or 10% soybean oil. Raw weight was correlated with drip loss, cooking loss, net yield, and moisture; correlation coefficients (r) and coefficients of determination (r2) were calculated. Samples were removed from the pectoralis superficialis as previously described. One sample was taken from the anterior end of the muscle and another from the posterior end. As thickness varied along the length of the muscle, different weights and thicknesses were obtained. Experiment 2. The effect on shear and yield parameters of tumbling breast pieces for 10 or 20 min in water and aqueous solutions containing .5 or 1% NaCl (Study 1); 5 or 10% acetic acid (Study 2); and 5 or 10% soybean oil (Study 3) was determined. Peak values and shear values were measured and shear value as a percentage of peak value was calculated. Yield parameters were drip loss, cooking loss, net yield, and moisture. Each study was repeated four times and because trial results were not significantly different (P>.05), they were combined (n = 64) to simplify presentation in tables. Treatments within each study were compared using analysis of variance and significantly different means (P>.05) were separated using the Student-Newman-Kuels test (Steel and Torrie, 1960; Sokal and Rohlf, 1972). Experiment 3. The effect on shear and yield parameters of mixing several ingredients to make a tumbling solution was determined in four trials. As before, trials were combined (n = 64) after it was determined their results were not significantly different. Solutions consisted of water and aqueous solutions containing 5% acetic acid + .5% NaCl, 5% soybean oil + .5% NaCl, 5% soybean oil + 5% acetic acid, and 5% soybean oil -I- 5% acetic acid + .5% NaCl. Treatments were compared using analysis
TUMBLING BROILER BREASTS
1951
proved (P<.05) in those samples tumbled for 10 or 20 min in .5 or 1% NaCl. The improved yield resulted from smaller cooking losses as raw weight increased. This shows an advantage of adding NaCl to the tumbling solution when thicker breast pieces are tumbled. Adding acetic acid to the tumbling solution as raw piece weight increased resulted in increased drip loss and no improvement in net yield. Adding soybean oil to the tumbling medium resulted in decreased cooking losses as piece weight increased but no improvement in net yield. Raw sample weight accounted for <1 to as much as 42% of the variation in drip loss; from < 1 to 66% of variation for cooking loss; from <1 to 61% of variation for net yield; and from <1 to 31% of variation for moisture content across all treatments. Because sample thickness affected yield parameters and accounted for a substantial amount of the variation in some cases, it must be taken into account in experiments involving tumbling with these solutions. Experiment 2. The addition of NaCl, acetic acid, or soybean oil to aqueous tumbling solutions did not (P>.05) alter peak values when compared with peak values of samples tumbled in water (Table 2). Breast pieces tumbled for 20 min in water, .5 and 1% NaCl, and 5 and 10% oil had smaller (P<.05) peak values than
of variance and significantly different means (P<.05) were separated using the Student-Newman-Kuels test (Steel and Torrie, 1960; Sokal and Rohlf, 1972). RESULTS AND DISCUSSION
Experiment 1. This study was designed to determine if breast pieces of different thicknesses could be used to produce a marinated product without adversely affecting drip loss, cooking loss, net yield, and water content. Since pieces were all cut to the same surface dimensions, weight of samples would indicate differences in thickness. The 5 x 5-cm breast pieces used in this experiment ranged in weight from 18 to 91 g. Tumbling samples in water for 10 and 20 min produced very low correlation coefficients (r) and coefficients of determination (r2) (<1%) for all parameters (Table 1). This indicated that weight (thickness) of the piece had no (P>.05) affect on any of the yield parameters when samples were tumbled in water. Adding NaCl, acetic acid, or soybean oil to tumbling solutions increased (P<.05) (positively or negatively) the correlation between sample weight (thickness) and yield parameters in many cases. As raw weight (thickness) increased, net yield was im-
TABLE 1. Correlation coefficients (r) and coefficients of determination (r2) calculated from comparisons of raw weight of tumbled broiler breasts with drip loss, cooking loss, net yield, and moisture (Experiment 1)' Solutions
Drip loss
Tumbling time
(%)
(min)
Water only
10 20 10 20
-.47*
10 20
-.14 -.26
Cooking loss 2
2
Net yield
Moisture 2
(r)
(r )
.08 .01
<.01 <.01
-.03 -.10
<.01 <.01
.02
<.01 .22
-.81* -.53*
.66 .28
.77* .63*
.59 .40
.48* .35*
.23 .12
.02 .07
-.78* -.60*
.61 .36
.78* .70*
.61 .49
.47* .67*
.22 .45
(r) .01 .09
(r )
(r 2 )
(r )
(r)
<.01 <.01
(r) .02 .07
<.01 <.01
NaCl .5% 1%
Acetic acid 5 10
<.01 <.01
-.26 -.34
-.57* -.28
.32 .08
.04 .05
-.41* -.12
.17 .01
.24
.06
-.04
<.01
.16
-.39* -.39*
.15 .15
.24
.06 .13
10 20
.59* .33
.35 .11
-.02
10 20
.65* .38*
.42 .14
10 20
.21 .22
10 20
.40* -.09
.02
<.01
.07 .12
-.03 -.29
.32
.10
-.11
-.01
.56* -.18
.31 .03
.42 .19
.18 .04
.53* .50*
.28 .25
.08
Soybean oil 5 10
<.01
' n = 32. 'Indicates a significant correlation (P<.05).
.36*
1952
HEATH AND OWENS TABLE 2. Shear parameters for broiler breast pit ces tumbled for 10 or 20 min in aqueous solutions containing either NaCl, acetic at id, or soybean oil (Experiment 2) Peak value
Treatment
10 min
20 min
Shear value 10 min
(kg/g)
(kg/g) Study 1 Water only . 5 % NaCl 1% NaCl Study 2 Water only 5% Acetic acid 10% Acetic acid Study 3 Water only 5% Soybean oil 10% Soybean oil
20 min
Shear value 10 min
20 min
(% peak value)
a 7.6 ± , 7 7.6 ± l . l a a 7.5 ± . 8
5.8 ± , 6 b 5.2 + . 8 b 4.8 ± . 4 b
a 2.3 ± . 2 2.4 ± . 3 a a 2.3 ± . 2
b 1.6 ± . 2 1.5 ± . 2 b 1.4 ± - l b
30.7a 31.3a 31.6a
28.2a 28.9a 28.8a
8.3 ± l . l a 7.1 ± ^ab 6.8 ± 6 a b
6.0 ± .8»> 6.8 + yab ab 6.9 ± . 8
2.1 ± . 2 a 1.8 ± . 2 a 1.8 ± . 2 a
2.0 i . 2 a 1.8 ± . 2 a 1.8 t . 2 a
25.9a 26.0a 25.9a
24.2a 27.5a 26.3a
b 5.6 ± . 7 b 5.9 ± . 7 5.5 ± . 8 b
a 2.3 ± . 2 1.7 ± . l b c 1.8 ± . l b
1.4 ± . I " 1 1.4 ± j c d 1.2 ± . l d
27.5a 23.0b 2 4 1 a b
26.6a 24.4ab 22.3b
8.4 ± 7.3 ± 7.6 ±
.7a .8a .8a
Means ± standard error for each parameter in each study followed by different letters are significantly (P>.05) different. 1
n = 64.
those tumbled for 10 min in the same solutions, indicating a reduction in the resistance to compression due to increased tumbling. Increasing the tumbling time from 10 to 20 min had no affect on peak values when acetic acid was used in the tumbling solution. The change in pH caused by the acetic acid probably changed tissue characteristics and masked any changes caused by tumbling. Shear values of breast sample were not (P>.05) affected by the addition of either NaCl or acetic acid to the tumbling medium (Table 2). Tumbling in solutions containing 5 and 10% oil for 10 min produced samples that had shear values that were .6 and .5 kg/g less, respectively, than samples tumbled in water for the same length of time. The use of oil in the tumbling solution produced no change in shear values when tumbling time was increased to 20 min. Increasing tumbling time from 10 to 20 min reduced shear values for samples tumbled in water, .5% NaCl, 1% NaCl, or 10% oil. Reduction in shear force caused by adding oil could be due to the lubricating action of the oil as the blades passed through the tissue. If the tenderizing effect was due to lubrication, the oil must have penetrated at least 3 mm into the tissue, as the second 3-mm slice was used for analysis. The shear cell and blades were washed after each sample to reduce any lubricating effect as the blades passed through the cell.
Shear values were expressed as a percentage of peak values to determine if the relationship between the two changed as a result of the treatments (Table 2). Tumbling in water or aqueous solutions containing NaCl or acetic acid produced no (P>.05) changes in the relationship between the two parameters. Tumbling in solutions containing 5% soybean oil for 10 min and tumbling in 10% oil for 20 min resulted in significantly lower values (P>.05) of 4.5 and 4.3%, respectively, when compared to samples tumbled in water for the same period of time. This showed a reduction in shear values (resistance to shear) without a reduction in peak values (resistance to compression) for these two comparisons. Tumbling broiler breast pieces for 10 or 20 min in water, and in aqueous solutions containing either .5 or 1% NaCl had no affect (P>.05) on drip loss, cooking loss, net yield, or moisture content (Table 3, Study 1). Apparently, differences in shear parameters due to increased tumbling time in these solutions did not result from changes in yield parameters. Addition of 5 and 10% acetic acid to the tumbling solutions resulted in significant weight gains (P< .05) i.e., negative drip loss after breast samples were allowed to drip (Table 3, Study 2). This result agrees with the findings of Kotula and Heath (1986), where the same levels of acetic acid were used. Those samples tumbled
1
a
3.0 ± , 5 e -14.1 + 2.3b - 1 6 . 9 ± 2.6 a
3.0 ± .6 a 2.9 t . 8 a 3.0 ± . 5 a
2.4 ± . 5 e -3.3 ± .7d - 8 . 6 ± 1.3C
2.8 + . 5 a 2.8 ± . 7 a 2.7 ± .6 a
4.2 ± . 6 4.1 ± , 5 a 2.7 ± . 5 a
20 min
Drip loss
a
3.8 ± . 7 3.7 ± .4 a 3.6 ± .4 a
10 min
a
Cooking loss
25.6 ± . 9 a 25.0 ± . 8 a 24.2 ± l . l a b
22.5 ± 1.0 ab 21.3 ± 1.0 bc 21.0 ± 1.0 bc
26.4 ± l . l 26.7 ± 1.3 a 25.8 ± 1.2a
10 min
a
21.5 ± .8 C 25.5 ± . 7 a 23.4 ± . 8 b
23.3 ± .9 a 20.7 ± 1.3C 18.8 ± 1.0d
26.8 ± 1.4 24.8 ± 1.4a 28.7 ± 1.4a
20 min
('")
Net yie
72.3 ± .6 C 72.9 ± . 4 b c 74.0 ± . 7 b
75.7 ± .6 e 81.9 ± . 8 d 85.7 ± .8 C
70.8 ± . 8 a 70.6 ± . 9 a 71.5 ± . 9 a
10 min
n = 64.
Means ± standard error for each parameter in each study followed by different superscripts are significantly dif
Study 1 Water only .5% NaCl 1% NaCl Study 2 Water only 5% Acetic acid 10% Acetic acid Study 3 Water only 5% Soy oil 10% Soy oil
Treatment
TABLE 3. Drip loss, cooking loss, moisture content, and net yield of broiler breast pieces t in aqueous solutions containing NaCl, acetic acid, or soybean oil (Experim
1954
HEATH AND OWENS
in 10% acetic acid for 10 and 20 min had 5.3 and 2.8% greater weight gain, respectively, after dripping than those tumbled in 5% acetic acid. This was due to higher water-holding capacity of the tissue after penetration of the acidic solutions. The evidence for an increase in waterholding capacity was the elevated moisture content of these samples after cooking. This increase in moisture did not alter shear parameters. Samples tumbled for 20 min had larger increases in weight after drip than those tumbled for 10 min because of the increased length of time they were exposed to the acidic solution. No differences (P>.05) were found in cooking losses for samples tumbled for 10 min in water and acetic solutions (Table 3, Study 2). Samples tumbled for 20 min in acetic acid solutions had smaller cooking losses than those tumbled in water and samples tumbled in 10% acetic acid for 20 min had smaller cooking losses than those resulting from any other treament in Study 2. Net yield showed that higher weights resulting from tumbling in acetic acid were not lost during cooking. Both longer tumbling time in acetic acid solutions and higher acetic acid concentrations produced higher net yields. Greater moisture content resulted from longer tumbling times and not from higher acetic acid concentrations. This showed that the higher net yields were not solely attributable to greater water-binding capacity caused by acetic acid. Other factors such as retention of water and soluble proteins could have been involved. Addition of 5 and 10% oil to the tumbling medium did not (P>.05) affect drip losses (Table 3, Study 3). Tumbling breast pieces in solutions containing 5 and 10% oil for 20 min resulted in cooking losses 4.0 and 1.9% greater respectively, than losses of those tumbled in water for the same length of time. Net yield was 1.7% higher when breast pieces tumbled in 10% oil for 10 min were compared with yields of those tumbled in water for 10 min. This same comparison showed a 1.8% lower yield after tumbling for 20 min. Tumbling for 20 min in 10% oil resulted in greater yields than from tumbling in 5% oil. The use of oil in the tumbling medium produced an unexplained and unexpected situation. Moisture levels in the cooked tissue were higher when 5 and 10% oil were used in tumbling for 10 min but were lower when samples were tumbled for 20 min. Another unexpected result was that tumbling in 10% oil for 20 min produced samples with more moisture
than those tumbled in 5% oil. Experiment 3. Tumbling solution recipes use basic ingredients in combination. To investigate possible interactions between these ingredients, tumbling solutions were made using mixtures of water, acetic acid, NaCl, and soybean oil to determine if the combinations would cause differences in shear parameters and yields. Combining the ingredients to produce tumbling solutions did not (P>.05) affect peak values (Table 4). This result agrees with results of studies wherein a combination of individual ingredients and water was used to make tumbling solutions (Table 2). When ingredients were used separately, a reduction in peak values was found when tumbling time was extended from 10 to 20 min. This reduction was not found when ingredients were combined (Table 4). Shear values showed the same results, with no (P> .05) differences attributable to the combined tumbling solutions or longer tumbling times. Shear values as a percentage of peak values showed a difference only when the 5% acetic acid + .5% NaCl solution was used and effects of tumbling for 10 min were compared with effects of tumbling for 20 min. Raising the tumbling time from 10 to 20 min had much more of an effect in studies using tumbling solutions with only one additive. This was also the case when the samples were tumbled in water. The pieces tumbled in water for 10 min in the first studies (Table 2) were tougher than those tumbled in the same manner in the latter study (Table 4). Because pieces were more tender in this latter study, the tumbling action may not have increased tenderness sufficiently to produce significant differences. Solutions that contained acetic acid resulted in larger breast piece weights after they were tumbled and allowed to drip (Table 4). The combination of 5% oil + 5% acetic acid produced the largest weight gain of the three solutions that contained acetic acid.The pieces tumbled in water and 5% oil + .5% NaCl had weight losses after drip. Increased tumbling time from 10 to 20 min produced greater weight gains in pieces tumbled in 5% oil + 5% acetic acid solutions. The gain in weight after drip can be attributed to the penetration of acetic acid into the tissue. Acetic acid and salt did not result in weight gains as large as those from the oil + acetic acid combination and the combination of all three ingredients into a tumbling solution produced no greater weight gains than the acetic
10 20
10 20
10 20
10 20
10 20
10 20
Shear value
Shear value as % peak value
Drip loss, %
C o o k i n g loss, %
Net yield, %
Moisture, %
1
80.4 ± l . l d 71.4 ± .7 f 68.8 + . 4 d 65.5 + ,4 f
67.3 ± 67.3 ±
22.4 + 22.8 ±
2.8 ± 3.2 ±
75.4 ± 74.7 ±
1.7 : 1.4: 24.7;ab 24.6:ab
.2a .2al ia
ja
83.6 ± .1 c 98.8 ± , 2 a 71.3 ± .4 C 75.1 + .4 a
20.6 ± l.i b 16.6+ .i
-11.3 ± . -19.9 ± 1.
6.9 ± 5.5 ±
5% oil + 5% acid
.5a .5a
27.4ab 26.9 :ab 1.8 : 2.6 : .3° 19.8+ , 8 c d e 29.1 ± 1.2a
2.0 ± 1.8 ±
6.8 ± 6.5 ±
5% oil + . 5 % NaCl
27.6ab 26.1 ab
1.7 + . 2 a b
6.8 ± . 4 a 6.5 ± . 4 a 1.9 ± j a b
Water only
Means + standard error for each parameter followed by different superscripts are significantly different (P>.05 n = 64.
a—f
10 20
(min)
Tumbling time
Peak value
Parameters
TABLE 4. Shear and yield parameters for broiler breast pieces tumbled for 10 or 20 min in s of water, acetic acid, NaCl, and soybean oil (Experment 3)
1956
HEATH AND OWENS
acid + NaCl combination. This indicated that NaCl reduced the postdrip weight gain that could be possibly produced by acetic acid alone or in combination with oil. It could be expected that samples with the largest gain in postdrip weight would also have the largest cooking losses. This was not the case. The smallest cooking losses were found when pieces were tumbled in 5% acetic acid + .5% NaCl for 20 min. The largest cooking losses were found after tumbling in 5% oil + .5% NaCl for 20 min. Increasing the tumbling time from 10 to 20 min decreased cooking losses when 5% oil + 5% acetic acid and 5% acetic acid + .5% NaCl were used as tumbling solutions. An increase in tumbling time in 5% oil + .5% NaCl increased cooking losses. Net yield can be used to determine the tumbling solution and tumbling time that will give the largest yield. Net yield was improved by increasing tumbling time from 10 to 20 min in all solutions except the ones containing water only and 5% oil + .5% NaCl. The highest yields were found after tumbling the pieces in solutions containing acetic acid. Percent moisture in the cooked tissue does not explain all of the differences found in yield comparisons. All of the samples tumbled in the solutions had more moisture than those tumbled in water only except those tumbled in 5% oil + .5% NaCl for 20 min (Table 4). Increasing tumbling time from 10 to 20 min increased moisture content of the tissue in those samples tumbled in 5% oil + 5% acetic acid and 5% acetic acid + .5% NaCl and decreased moisture in those tumbled in 5% oil + .5% NaCl. Tumbling can be used to increase yield and reduce resistance to compression and shear when broiler parts are marinated. The amount of change in these two factors will depend on the marinade solution composition. It is recommended that the interaction of marinade ingredients be determined before they are included in the solution. Otherwise product yield could be seriously affected.
REFERENCES Association of Official Analytical Chemists, 1984. Official Methods of Analysis. Assoc. Offic. Anal. Chem., Washington, DC. Babji, A. S., G. W. Froning, and D. A. Ngoka, 1982. The effect of short-term tumbling and salting on the quality of turkey breast muscle. Poultry Sci. 61:300-303. Bouton, P. E., P. V. Harris, and W. R. Shorthose, 1975. Changes in shear parameters of meat associated with structural changes produced by aging, cooking and myofibrillar contraction. J. Food Sci. 40:1122-1126. Carpenter, M. D., D. M. Janky, A. S. Arafa, J. L. Oblinger, and J. A. Koburger, 1979. The effect of salt brine chilling on driploss of ice packed broiler carcasses. Poultry Sci. 58:369-371. Chen, T. C , 1980. Studies on the marinating of chicken parts for deep fat frying. Poultry Sci. 59:1592. (Abstr.) deFremery, D., and M. F. Pool, 1960. Biochemistry of chicken muscle as related to rigor mortis and tenderization. Food Res. 25:73-87. Janky, D. M., M. D. Carpenter, D. L. Fletcher, A. S. Arafa, J. A. Koburger, and R. L. West, 1983. Physical characteristics of pectoralis superficialis from brinechilled broiler carcasses. Poultry Sci. 62:433^36. Khan, A. W., and R. Nakamura, 1970. Effects of pre- and post-mortem glycolysis on poultry tenderness. J. Food Sci. 35:266-267. Kotula, K. L., and J. L. Heath, 1986. Effect of tumbling chill-boned and hot-boned broiler breasts in either acetic acid or sodium chloride solutions on cooked yield, density, and shear values. Poultry Sci. 65:717-725. Lyon, B. G., 1980. Effects of salt and phosphate treatment on spent fowl breasts and thighs. Poultry Sci. 59:1632. (Abstr.) Lyon, C. E., D. Hamm, J. E. Thomson, and J. P. Hudspeth, 1984. The effects of holding time and added salt on pH and functional properties of chicken meat. Poultry Sci. 63:1952-1957. Mathusa, M. S., and D. M. Janky, 1984. Effects of salt brine chilling and hot-boning on tenderness of canned fowl light meat. Poultry Sci. 63:1930-1934. Pauli, E., 1979. Classical Cooking the Modern Way. CBI Publ. Co., Inc., Boston, MA. Post, R. C , and J. L. Heath, 1983. Marinating broiler parts: the use of a viscous type marinade. Poultry Sci. 62:977-984. Reitz, A. C , and J. J. Wanderstock, 1965. A Guide to the Selection, Combination and Cooking of Foods. AVI Publ. Co., Westport, CT. Stokal, R. A.,and F. J. Rohlf, 1972. Introduction to Biostatistics. W. H. Freeman and Co., San Francisco, CA. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, NY.
Fast food and convenience food portions of the poultry industry have become highly competitive in a relatively short period of time and must increase efficiency to maintain or improve their competitive positions. This industry often uses tumbling in a marinade solution to produce new and unique products. As a result, there is a need for research to determine the effects of tumbling and marination on tenderness and yield of broiler tissue. There has been little research on poultry products in this area. Acetic acid (vinegar), oil, and salt are common ingredients in various marinade recipes (Reitz and Wanderstock, 1965). The use of ace tic acid in marinade solutions has produced conflicting results. Acetic acid increased tenderness and yield of poultry parts when it was used in marinade solutions without tumbling (Pauli, 1979; Post and Heath, 1983). It was reported by deFremery and Pool (1960) and Khan and Nakamura (1970) that a rapid reduction in pH
'Scientific Article Number A-4618 Contribution Number 7614 of the Maryland Agricultural Experiment Station (Department of Poultry Science).
in the tissue decreased tenderness in the muscles tested. Kotula and Heath (1986) found no effect on tenderness when poultry parts were exposed to 5 and 10% acetic acid in a tumbling solution. They reported that addition of acetic acid to the tumbling medium resulted in increased tumbling solution pickup and increased cooking losses in chill-boned broiler parts. Carpenter et al. (1979), Lyon (1980), Babji et al. (1982), Janky et al, (1983), Lyon et al. (1984), and Mathusa and Janky (1984) found that introduction of NaCl increased water binding in chicken tissue and decreased shear. Kotula and Heath (1986) reported that tumbling chillboned broiler breasts in 4% NaCl solutions increased tumbling solution pickup but tumbling in 1 and 2% NaCl reduced tumbling solution gains, Chen (1980) found that marination increased final yields of fried chicken parts when compared with yields of nonmarinated controls. He also determined that the amount of penetration into parts by the solution during 4 h of still marination can be equaled by 10 min of rotating marination. This study was conducted to determine the effects on shear and yield parameters of tumbling for 10 and 20 min in aqueous solutions containing acetic acid, NaCl, or oil.
1949
1950
HEATH AND OWENS MATERIALS AND METHODS
General Procedure. Broiler carcasses slaughtered at the University of Maryland's processing facility were held overnight in plastic bags at 4 C to allow rigor mortis to resolve. The pectoralis superficialis without skin was removed from each side of the breast and samples were cut from the anterior and posterior part of the muscles for Experiment 1 and from the anterior part of the muscle for Experiments 2 and 3, using a 5 x 5-cm template. Each sample was weighed, isolated from other samples in cloth mesh ham socks, and tumbled in 2 L of aqueous solutions containing NaCl (w/v), acetic acid (w/v), and soybean oil (w/v) individually or in combination for 10 or 20 min. These solutions are described later when conditions for each experiment are defined. Tumbling was accomplished in a Lyco model 40 tumbler (Columbus, WI) at 18 rpm and under vacuum (15 in. Hg). Samples were removed from the tumbler, allowed to drip for 10 min while suspended on wire racks at room temperature, removed from the cloth mesh, and weighed. They were placed on ridged aluminum pans, covered with aluminum foil, heated in a forced air oven (Market Forge model 2400HE, Everett, MA) at 175 C to an internal temperature of 85 C.Temperature was measured by insertion of a thermometer into the center of pieces selected for this purpose. Samples were removed from the oven, allowed to cool without uncovering at room temperature, and then weighed. A meat sheer was used to remove two 3-mm thick slices from the external portion (the part normally next to the skin) of each breast piece. A 3 x 3-cm subsample was removed from the center of the second slice. It was positioned in a Kramer shear cell (Instron Corp., Canton, MA) and sheared at a 90° angle to the direction of the muscle fibers. Shear parameters were calculated using the force deformation curves produced at room temperature by an Instron universal Testing Instrument (Instron Corp., Canton, MA) with a 100-kg load cell and a downstroke of 20 cm/min. The force required to compress the sample and initiate shear caused the largest deflection on the chart and the resistance represented by this peak was recorded as the peak value in kilograms per gram. When the blades started to shear the sample the force was recorded on the chart as a decrease from the initial peak; as the blades passed through the sample, a plateau was formed on the chart that was reported as the shear value in kilograms per gram (Bouton et al., 1975).
Yield parameters were calculated using the following formulas: percentage drip loss = (raw weight - post drip weight/raw weight) x 100; percentage cooking loss = (post drip weight cooked weight/post drip weight) x 100; percentage net yield = (cooked weight/raw weight) x 100. Moisture of the cooked samples was determined using procedures found in Association of Official Analytical Chemists (1984). Experiment 1. The effect of differences in breast piece weight (thickness) on drip loss, cooking loss, and net yield was determined using a correlation analysis (Steel and Torrie, 1960). Samples (n = 32) were tumbled for 10 or 20 min in water and aqueous solutions of .5% NaCl, 1% NaCl, 5% acetic acid, 10% acetic acid, 5% soybean oil, or 10% soybean oil. Raw weight was correlated with drip loss, cooking loss, net yield, and moisture; correlation coefficients (r) and coefficients of determination (r2) were calculated. Samples were removed from the pectoralis superficialis as previously described. One sample was taken from the anterior end of the muscle and another from the posterior end. As thickness varied along the length of the muscle, different weights and thicknesses were obtained. Experiment 2. The effect on shear and yield parameters of tumbling breast pieces for 10 or 20 min in water and aqueous solutions containing .5 or 1% NaCl (Study 1); 5 or 10% acetic acid (Study 2); and 5 or 10% soybean oil (Study 3) was determined. Peak values and shear values were measured and shear value as a percentage of peak value was calculated. Yield parameters were drip loss, cooking loss, net yield, and moisture. Each study was repeated four times and because trial results were not significantly different (P>.05), they were combined (n = 64) to simplify presentation in tables. Treatments within each study were compared using analysis of variance and significantly different means (P>.05) were separated using the Student-Newman-Kuels test (Steel and Torrie, 1960; Sokal and Rohlf, 1972). Experiment 3. The effect on shear and yield parameters of mixing several ingredients to make a tumbling solution was determined in four trials. As before, trials were combined (n = 64) after it was determined their results were not significantly different. Solutions consisted of water and aqueous solutions containing 5% acetic acid + .5% NaCl, 5% soybean oil + .5% NaCl, 5% soybean oil + 5% acetic acid, and 5% soybean oil -I- 5% acetic acid + .5% NaCl. Treatments were compared using analysis
TUMBLING BROILER BREASTS
1951
proved (P<.05) in those samples tumbled for 10 or 20 min in .5 or 1% NaCl. The improved yield resulted from smaller cooking losses as raw weight increased. This shows an advantage of adding NaCl to the tumbling solution when thicker breast pieces are tumbled. Adding acetic acid to the tumbling solution as raw piece weight increased resulted in increased drip loss and no improvement in net yield. Adding soybean oil to the tumbling medium resulted in decreased cooking losses as piece weight increased but no improvement in net yield. Raw sample weight accounted for <1 to as much as 42% of the variation in drip loss; from < 1 to 66% of variation for cooking loss; from <1 to 61% of variation for net yield; and from <1 to 31% of variation for moisture content across all treatments. Because sample thickness affected yield parameters and accounted for a substantial amount of the variation in some cases, it must be taken into account in experiments involving tumbling with these solutions. Experiment 2. The addition of NaCl, acetic acid, or soybean oil to aqueous tumbling solutions did not (P>.05) alter peak values when compared with peak values of samples tumbled in water (Table 2). Breast pieces tumbled for 20 min in water, .5 and 1% NaCl, and 5 and 10% oil had smaller (P<.05) peak values than
of variance and significantly different means (P<.05) were separated using the Student-Newman-Kuels test (Steel and Torrie, 1960; Sokal and Rohlf, 1972). RESULTS AND DISCUSSION
Experiment 1. This study was designed to determine if breast pieces of different thicknesses could be used to produce a marinated product without adversely affecting drip loss, cooking loss, net yield, and water content. Since pieces were all cut to the same surface dimensions, weight of samples would indicate differences in thickness. The 5 x 5-cm breast pieces used in this experiment ranged in weight from 18 to 91 g. Tumbling samples in water for 10 and 20 min produced very low correlation coefficients (r) and coefficients of determination (r2) (<1%) for all parameters (Table 1). This indicated that weight (thickness) of the piece had no (P>.05) affect on any of the yield parameters when samples were tumbled in water. Adding NaCl, acetic acid, or soybean oil to tumbling solutions increased (P<.05) (positively or negatively) the correlation between sample weight (thickness) and yield parameters in many cases. As raw weight (thickness) increased, net yield was im-
TABLE 1. Correlation coefficients (r) and coefficients of determination (r2) calculated from comparisons of raw weight of tumbled broiler breasts with drip loss, cooking loss, net yield, and moisture (Experiment 1)' Solutions
Drip loss
Tumbling time
(%)
(min)
Water only
10 20 10 20
-.47*
10 20
-.14 -.26
Cooking loss 2
2
Net yield
Moisture 2
(r)
(r )
.08 .01
<.01 <.01
-.03 -.10
<.01 <.01
.02
<.01 .22
-.81* -.53*
.66 .28
.77* .63*
.59 .40
.48* .35*
.23 .12
.02 .07
-.78* -.60*
.61 .36
.78* .70*
.61 .49
.47* .67*
.22 .45
(r) .01 .09
(r )
(r 2 )
(r )
(r)
<.01 <.01
(r) .02 .07
<.01 <.01
NaCl .5% 1%
Acetic acid 5 10
<.01 <.01
-.26 -.34
-.57* -.28
.32 .08
.04 .05
-.41* -.12
.17 .01
.24
.06
-.04
<.01
.16
-.39* -.39*
.15 .15
.24
.06 .13
10 20
.59* .33
.35 .11
-.02
10 20
.65* .38*
.42 .14
10 20
.21 .22
10 20
.40* -.09
.02
<.01
.07 .12
-.03 -.29
.32
.10
-.11
-.01
.56* -.18
.31 .03
.42 .19
.18 .04
.53* .50*
.28 .25
.08
Soybean oil 5 10
<.01
' n = 32. 'Indicates a significant correlation (P<.05).
.36*
1952
HEATH AND OWENS TABLE 2. Shear parameters for broiler breast pit ces tumbled for 10 or 20 min in aqueous solutions containing either NaCl, acetic at id, or soybean oil (Experiment 2) Peak value
Treatment
10 min
20 min
Shear value 10 min
(kg/g)
(kg/g) Study 1 Water only . 5 % NaCl 1% NaCl Study 2 Water only 5% Acetic acid 10% Acetic acid Study 3 Water only 5% Soybean oil 10% Soybean oil
20 min
Shear value 10 min
20 min
(% peak value)
a 7.6 ± , 7 7.6 ± l . l a a 7.5 ± . 8
5.8 ± , 6 b 5.2 + . 8 b 4.8 ± . 4 b
a 2.3 ± . 2 2.4 ± . 3 a a 2.3 ± . 2
b 1.6 ± . 2 1.5 ± . 2 b 1.4 ± - l b
30.7a 31.3a 31.6a
28.2a 28.9a 28.8a
8.3 ± l . l a 7.1 ± ^ab 6.8 ± 6 a b
6.0 ± .8»> 6.8 + yab ab 6.9 ± . 8
2.1 ± . 2 a 1.8 ± . 2 a 1.8 ± . 2 a
2.0 i . 2 a 1.8 ± . 2 a 1.8 t . 2 a
25.9a 26.0a 25.9a
24.2a 27.5a 26.3a
b 5.6 ± . 7 b 5.9 ± . 7 5.5 ± . 8 b
a 2.3 ± . 2 1.7 ± . l b c 1.8 ± . l b
1.4 ± . I " 1 1.4 ± j c d 1.2 ± . l d
27.5a 23.0b 2 4 1 a b
26.6a 24.4ab 22.3b
8.4 ± 7.3 ± 7.6 ±
.7a .8a .8a
Means ± standard error for each parameter in each study followed by different letters are significantly (P>.05) different. 1
n = 64.
those tumbled for 10 min in the same solutions, indicating a reduction in the resistance to compression due to increased tumbling. Increasing the tumbling time from 10 to 20 min had no affect on peak values when acetic acid was used in the tumbling solution. The change in pH caused by the acetic acid probably changed tissue characteristics and masked any changes caused by tumbling. Shear values of breast sample were not (P>.05) affected by the addition of either NaCl or acetic acid to the tumbling medium (Table 2). Tumbling in solutions containing 5 and 10% oil for 10 min produced samples that had shear values that were .6 and .5 kg/g less, respectively, than samples tumbled in water for the same length of time. The use of oil in the tumbling solution produced no change in shear values when tumbling time was increased to 20 min. Increasing tumbling time from 10 to 20 min reduced shear values for samples tumbled in water, .5% NaCl, 1% NaCl, or 10% oil. Reduction in shear force caused by adding oil could be due to the lubricating action of the oil as the blades passed through the tissue. If the tenderizing effect was due to lubrication, the oil must have penetrated at least 3 mm into the tissue, as the second 3-mm slice was used for analysis. The shear cell and blades were washed after each sample to reduce any lubricating effect as the blades passed through the cell.
Shear values were expressed as a percentage of peak values to determine if the relationship between the two changed as a result of the treatments (Table 2). Tumbling in water or aqueous solutions containing NaCl or acetic acid produced no (P>.05) changes in the relationship between the two parameters. Tumbling in solutions containing 5% soybean oil for 10 min and tumbling in 10% oil for 20 min resulted in significantly lower values (P>.05) of 4.5 and 4.3%, respectively, when compared to samples tumbled in water for the same period of time. This showed a reduction in shear values (resistance to shear) without a reduction in peak values (resistance to compression) for these two comparisons. Tumbling broiler breast pieces for 10 or 20 min in water, and in aqueous solutions containing either .5 or 1% NaCl had no affect (P>.05) on drip loss, cooking loss, net yield, or moisture content (Table 3, Study 1). Apparently, differences in shear parameters due to increased tumbling time in these solutions did not result from changes in yield parameters. Addition of 5 and 10% acetic acid to the tumbling solutions resulted in significant weight gains (P< .05) i.e., negative drip loss after breast samples were allowed to drip (Table 3, Study 2). This result agrees with the findings of Kotula and Heath (1986), where the same levels of acetic acid were used. Those samples tumbled
1
a
3.0 ± , 5 e -14.1 + 2.3b - 1 6 . 9 ± 2.6 a
3.0 ± .6 a 2.9 t . 8 a 3.0 ± . 5 a
2.4 ± . 5 e -3.3 ± .7d - 8 . 6 ± 1.3C
2.8 + . 5 a 2.8 ± . 7 a 2.7 ± .6 a
4.2 ± . 6 4.1 ± , 5 a 2.7 ± . 5 a
20 min
Drip loss
a
3.8 ± . 7 3.7 ± .4 a 3.6 ± .4 a
10 min
a
Cooking loss
25.6 ± . 9 a 25.0 ± . 8 a 24.2 ± l . l a b
22.5 ± 1.0 ab 21.3 ± 1.0 bc 21.0 ± 1.0 bc
26.4 ± l . l 26.7 ± 1.3 a 25.8 ± 1.2a
10 min
a
21.5 ± .8 C 25.5 ± . 7 a 23.4 ± . 8 b
23.3 ± .9 a 20.7 ± 1.3C 18.8 ± 1.0d
26.8 ± 1.4 24.8 ± 1.4a 28.7 ± 1.4a
20 min
('")
Net yie
72.3 ± .6 C 72.9 ± . 4 b c 74.0 ± . 7 b
75.7 ± .6 e 81.9 ± . 8 d 85.7 ± .8 C
70.8 ± . 8 a 70.6 ± . 9 a 71.5 ± . 9 a
10 min
n = 64.
Means ± standard error for each parameter in each study followed by different superscripts are significantly dif
Study 1 Water only .5% NaCl 1% NaCl Study 2 Water only 5% Acetic acid 10% Acetic acid Study 3 Water only 5% Soy oil 10% Soy oil
Treatment
TABLE 3. Drip loss, cooking loss, moisture content, and net yield of broiler breast pieces t in aqueous solutions containing NaCl, acetic acid, or soybean oil (Experim
1954
HEATH AND OWENS
in 10% acetic acid for 10 and 20 min had 5.3 and 2.8% greater weight gain, respectively, after dripping than those tumbled in 5% acetic acid. This was due to higher water-holding capacity of the tissue after penetration of the acidic solutions. The evidence for an increase in waterholding capacity was the elevated moisture content of these samples after cooking. This increase in moisture did not alter shear parameters. Samples tumbled for 20 min had larger increases in weight after drip than those tumbled for 10 min because of the increased length of time they were exposed to the acidic solution. No differences (P>.05) were found in cooking losses for samples tumbled for 10 min in water and acetic solutions (Table 3, Study 2). Samples tumbled for 20 min in acetic acid solutions had smaller cooking losses than those tumbled in water and samples tumbled in 10% acetic acid for 20 min had smaller cooking losses than those resulting from any other treament in Study 2. Net yield showed that higher weights resulting from tumbling in acetic acid were not lost during cooking. Both longer tumbling time in acetic acid solutions and higher acetic acid concentrations produced higher net yields. Greater moisture content resulted from longer tumbling times and not from higher acetic acid concentrations. This showed that the higher net yields were not solely attributable to greater water-binding capacity caused by acetic acid. Other factors such as retention of water and soluble proteins could have been involved. Addition of 5 and 10% oil to the tumbling medium did not (P>.05) affect drip losses (Table 3, Study 3). Tumbling breast pieces in solutions containing 5 and 10% oil for 20 min resulted in cooking losses 4.0 and 1.9% greater respectively, than losses of those tumbled in water for the same length of time. Net yield was 1.7% higher when breast pieces tumbled in 10% oil for 10 min were compared with yields of those tumbled in water for 10 min. This same comparison showed a 1.8% lower yield after tumbling for 20 min. Tumbling for 20 min in 10% oil resulted in greater yields than from tumbling in 5% oil. The use of oil in the tumbling medium produced an unexplained and unexpected situation. Moisture levels in the cooked tissue were higher when 5 and 10% oil were used in tumbling for 10 min but were lower when samples were tumbled for 20 min. Another unexpected result was that tumbling in 10% oil for 20 min produced samples with more moisture
than those tumbled in 5% oil. Experiment 3. Tumbling solution recipes use basic ingredients in combination. To investigate possible interactions between these ingredients, tumbling solutions were made using mixtures of water, acetic acid, NaCl, and soybean oil to determine if the combinations would cause differences in shear parameters and yields. Combining the ingredients to produce tumbling solutions did not (P>.05) affect peak values (Table 4). This result agrees with results of studies wherein a combination of individual ingredients and water was used to make tumbling solutions (Table 2). When ingredients were used separately, a reduction in peak values was found when tumbling time was extended from 10 to 20 min. This reduction was not found when ingredients were combined (Table 4). Shear values showed the same results, with no (P> .05) differences attributable to the combined tumbling solutions or longer tumbling times. Shear values as a percentage of peak values showed a difference only when the 5% acetic acid + .5% NaCl solution was used and effects of tumbling for 10 min were compared with effects of tumbling for 20 min. Raising the tumbling time from 10 to 20 min had much more of an effect in studies using tumbling solutions with only one additive. This was also the case when the samples were tumbled in water. The pieces tumbled in water for 10 min in the first studies (Table 2) were tougher than those tumbled in the same manner in the latter study (Table 4). Because pieces were more tender in this latter study, the tumbling action may not have increased tenderness sufficiently to produce significant differences. Solutions that contained acetic acid resulted in larger breast piece weights after they were tumbled and allowed to drip (Table 4). The combination of 5% oil + 5% acetic acid produced the largest weight gain of the three solutions that contained acetic acid.The pieces tumbled in water and 5% oil + .5% NaCl had weight losses after drip. Increased tumbling time from 10 to 20 min produced greater weight gains in pieces tumbled in 5% oil + 5% acetic acid solutions. The gain in weight after drip can be attributed to the penetration of acetic acid into the tissue. Acetic acid and salt did not result in weight gains as large as those from the oil + acetic acid combination and the combination of all three ingredients into a tumbling solution produced no greater weight gains than the acetic
10 20
10 20
10 20
10 20
10 20
10 20
Shear value
Shear value as % peak value
Drip loss, %
C o o k i n g loss, %
Net yield, %
Moisture, %
1
80.4 ± l . l d 71.4 ± .7 f 68.8 + . 4 d 65.5 + ,4 f
67.3 ± 67.3 ±
22.4 + 22.8 ±
2.8 ± 3.2 ±
75.4 ± 74.7 ±
1.7 : 1.4: 24.7;ab 24.6:ab
.2a .2al ia
ja
83.6 ± .1 c 98.8 ± , 2 a 71.3 ± .4 C 75.1 + .4 a
20.6 ± l.i b 16.6+ .i
-11.3 ± . -19.9 ± 1.
6.9 ± 5.5 ±
5% oil + 5% acid
.5a .5a
27.4ab 26.9 :ab 1.8 : 2.6 : .3° 19.8+ , 8 c d e 29.1 ± 1.2a
2.0 ± 1.8 ±
6.8 ± 6.5 ±
5% oil + . 5 % NaCl
27.6ab 26.1 ab
1.7 + . 2 a b
6.8 ± . 4 a 6.5 ± . 4 a 1.9 ± j a b
Water only
Means + standard error for each parameter followed by different superscripts are significantly different (P>.05 n = 64.
a—f
10 20
(min)
Tumbling time
Peak value
Parameters
TABLE 4. Shear and yield parameters for broiler breast pieces tumbled for 10 or 20 min in s of water, acetic acid, NaCl, and soybean oil (Experment 3)
1956
HEATH AND OWENS
acid + NaCl combination. This indicated that NaCl reduced the postdrip weight gain that could be possibly produced by acetic acid alone or in combination with oil. It could be expected that samples with the largest gain in postdrip weight would also have the largest cooking losses. This was not the case. The smallest cooking losses were found when pieces were tumbled in 5% acetic acid + .5% NaCl for 20 min. The largest cooking losses were found after tumbling in 5% oil + .5% NaCl for 20 min. Increasing the tumbling time from 10 to 20 min decreased cooking losses when 5% oil + 5% acetic acid and 5% acetic acid + .5% NaCl were used as tumbling solutions. An increase in tumbling time in 5% oil + .5% NaCl increased cooking losses. Net yield can be used to determine the tumbling solution and tumbling time that will give the largest yield. Net yield was improved by increasing tumbling time from 10 to 20 min in all solutions except the ones containing water only and 5% oil + .5% NaCl. The highest yields were found after tumbling the pieces in solutions containing acetic acid. Percent moisture in the cooked tissue does not explain all of the differences found in yield comparisons. All of the samples tumbled in the solutions had more moisture than those tumbled in water only except those tumbled in 5% oil + .5% NaCl for 20 min (Table 4). Increasing tumbling time from 10 to 20 min increased moisture content of the tissue in those samples tumbled in 5% oil + 5% acetic acid and 5% acetic acid + .5% NaCl and decreased moisture in those tumbled in 5% oil + .5% NaCl. Tumbling can be used to increase yield and reduce resistance to compression and shear when broiler parts are marinated. The amount of change in these two factors will depend on the marinade solution composition. It is recommended that the interaction of marinade ingredients be determined before they are included in the solution. Otherwise product yield could be seriously affected.
REFERENCES Association of Official Analytical Chemists, 1984. Official Methods of Analysis. Assoc. Offic. Anal. Chem., Washington, DC. Babji, A. S., G. W. Froning, and D. A. Ngoka, 1982. The effect of short-term tumbling and salting on the quality of turkey breast muscle. Poultry Sci. 61:300-303. Bouton, P. E., P. V. Harris, and W. R. Shorthose, 1975. Changes in shear parameters of meat associated with structural changes produced by aging, cooking and myofibrillar contraction. J. Food Sci. 40:1122-1126. Carpenter, M. D., D. M. Janky, A. S. Arafa, J. L. Oblinger, and J. A. Koburger, 1979. The effect of salt brine chilling on driploss of ice packed broiler carcasses. Poultry Sci. 58:369-371. Chen, T. C , 1980. Studies on the marinating of chicken parts for deep fat frying. Poultry Sci. 59:1592. (Abstr.) deFremery, D., and M. F. Pool, 1960. Biochemistry of chicken muscle as related to rigor mortis and tenderization. Food Res. 25:73-87. Janky, D. M., M. D. Carpenter, D. L. Fletcher, A. S. Arafa, J. A. Koburger, and R. L. West, 1983. Physical characteristics of pectoralis superficialis from brinechilled broiler carcasses. Poultry Sci. 62:433^36. Khan, A. W., and R. Nakamura, 1970. Effects of pre- and post-mortem glycolysis on poultry tenderness. J. Food Sci. 35:266-267. Kotula, K. L., and J. L. Heath, 1986. Effect of tumbling chill-boned and hot-boned broiler breasts in either acetic acid or sodium chloride solutions on cooked yield, density, and shear values. Poultry Sci. 65:717-725. Lyon, B. G., 1980. Effects of salt and phosphate treatment on spent fowl breasts and thighs. Poultry Sci. 59:1632. (Abstr.) Lyon, C. E., D. Hamm, J. E. Thomson, and J. P. Hudspeth, 1984. The effects of holding time and added salt on pH and functional properties of chicken meat. Poultry Sci. 63:1952-1957. Mathusa, M. S., and D. M. Janky, 1984. Effects of salt brine chilling and hot-boning on tenderness of canned fowl light meat. Poultry Sci. 63:1930-1934. Pauli, E., 1979. Classical Cooking the Modern Way. CBI Publ. Co., Inc., Boston, MA. Post, R. C , and J. L. Heath, 1983. Marinating broiler parts: the use of a viscous type marinade. Poultry Sci. 62:977-984. Reitz, A. C , and J. J. Wanderstock, 1965. A Guide to the Selection, Combination and Cooking of Foods. AVI Publ. Co., Westport, CT. Stokal, R. A.,and F. J. Rohlf, 1972. Introduction to Biostatistics. W. H. Freeman and Co., San Francisco, CA. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, NY.