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Effect of Salt and Sodium Tripolyphosphate on Shear, Thiobarbituric Acid, Sodium, and Phosphorus Values of Hot-Stripped Broiler Breast Meat1
Effect of Salt and Sodium Tripolyphosphate on Shear, Thiobarbituric Acid, Sodium, and Phosphorus Values of Hot-Stripped Broiler Breast Meat1 C.Y.W. ANG and D. HAMM Richard B. Russell Agricultural Research Center, USDA, ARS, P.O. Box 5677, Athens, Georgia 30613 (Received for publication October 10, 1985) ABSTRACT The effect of infusion of sodium chloride (NaCl) or sodium tripolyphosphate (STPP) into hot-stripped (HS) broiler breast meat on changes in tenderness and oxidative rancidity level as measured by thiobarbituric acid (TBA) values was investigated. Infusion was effected by first mechanically perforating (mechanical tenderization) the breast pieces, then tumbling for 3 min in selected marinades. Hot-stripped meat first infused with a marinade containing 1% NaCl, 3% STPP, and stored from 1 to 8 days at 2 C had reduced toughness, as measured by force to shear (FS), and TBA values and were comparable to or lower than the FS and TBA values from meat conventionally processed and aged 1 day. The combination of NaCl and STPP was most effective in reducing FS and TBA values followed by STPP, then NaCl, and lastly H 2 0 alone. The TBA values slowly increased and FS values decreased through 8 days of storage. Phosphorus and sodium were continuously absorbed into the meat tissue reaching maximal levels after 2 to 4 days. The combined solution was also effective in reducing TBA and FS values when treatment was performed after 8days of storage of chill-stripped or HS meat. (Key words: thiobarbituric acid, shear, sodium tripolyphosphate, hot-strip, broiler meat) 1986 Poultry Science 65:1532-1538 INTRODUCTION
The conventional method for processing of boneless poultry meat involves chilling the eviscerated carcasses in ice water slush and then aging the chilled poultry a minimum of 6 hr prior to deboning. The chilling and aging periods are important for hygiene and development of tender meat (de Fremery, 1963); however, chilling the entire carcass may not be efficient. Hamm and coworkers studied an unconventional method for rapidly producing boneless chicken meat from noneviscerated warm carcasses (Hamm, 1982; Hamm et al, 1984; Hamm and Thomson, 1983; Lillard et al, 1984). The procedure has potential advantages for reducing processing time and cost. One problem encountered in implementing the hot-stripping technique was the toughness of the cooked breast meat. Subsequent chilling and aging of the deboned meat failed to tenderize the meat as occurs with conventionally processed meat (Hamm, 1983). Klose et al. (1971) also observed that cutting the muscle from warm eviscerated carcasses produced toughening in chicken. The use of polyphosphates in meat has been reported to contribute several beneficial func1 Names of products are included for the benefit of the reader and do not imply endorsement or
preferential treatment by USDA.
tions in emulsification, protein binding, water holding, and cured color development. Examples of some items with added phosphates are frankfurters, sausages, and hams (Furia, 1972). Treatment of conventionally processed poultry with polyphosphate or salt was reported to result in more tender meat than meat from nontreated controls (Spencer and Smith, 1962; Klose, et al, 1963; May et al, 1963; Dawson and Sison, 1973; Peterson, 1977; Hamm, 1983). The application of polyphosphate in chilling, cooking, or cooling water, or by marination or injection was found to be effective for inhibition of oxidative changes or flavor deterioration of several types of cooked meat (Mahon, 1962; Spencer and Smith, 1962; Spencer et al, 1963; Thomson, 1964; Farr and May, 1970; Landes, 1972; Rao et al, 1975). Comparatively few reports have been made on the uptake of phosphorus and sodium in the meat as a result of polyphosphate or salt treatment (Katz and Dawson, 1964; Farr and May, 1970). Human intake of Na is of concern particularly to those individuals predisposed to hypertension (IFT, 1980), while the amount of added phosphate in meat and meat products is limited by regulation to .5% (Federal Register, 1982). Because hot-stripping techniques may be employed by the poultry industry in the near future, it would be of interest to the industry as
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SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
well as to scientists in related fields to study the effects of polyphosphate on the physical and chemical properties of hot-stripped meat. The present study was carried out to determine the effects of sodium chloride (NaCl), sodium tripolyphosphate (STPP), or a combination of the two compounds on the tenderness, oxidative stability, and Na and P content of hot-stripped breast meat stored at 2 C for up to 8 days before or after treatment. MATERIALS AND METHODS
Materials and Deboning Methods Experiment 1. Ten eviscerated, nonchilled whole carcasses without giblets (WOG) and 20 noneviscerated, nonchilled New York-dressed carcasses (NYD) were collected from a local commercial processing plant. Care was taken to ensure that all birds selected were from the same farm flock. All birds were 48 days of age when slaughtered. Carcasses without giblets were packed in crushed ice and NYD were packed in insulated containers and transported to our laboratory within 30 min postmortem. The breast with wings attached was stripped from each of the 10 WOG. After holding in crushed ice for 1 or 8 days, the two Pectoralis major muscles, without skin, were stripped from each breast. Deboned breast meat thus obtained resembled the meat processed by the conventional method. These breast pieces were designated as chill-stripped meat (CS). Forty (40) hot-stripped breasts (HS) were obtained by stripping the Pectoralis major muscles from NYD while they were still warm, using a technique described by Hamm (1984), followed by a single pass through a mechanical tenderizer (Model TC 700M, Ross Industries, Inc., Midland, VA) to facilitate the penetration of water or the marinade solution into the meat. After mechanical tenderization, 20 of the HS pieces were tumbled in water ( H 2 0 ) for 3 min and designated as H S H 2 0 samples. The tumbler was an industrial type cement mixer approximately 45 cm in diameter and rotated at 50 rpm. All the HS and H S H 2 0 pieces were then stored in crushed ice for 1 or 8 days. Experiment 2. Breast meat from 7-week-old broilers processed at a commercial plant as unchilled NYD was hot stripped at our laboratory within 30 min postmortem in the same manner as Experiment 1. Breast pieces were pooled, and then they were randomly selected
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for further treatment. The breast pieces were passed one time through the mechanical tenderizer as described above before tumbling in appropriate solution. Salt and Polyphosphate
Treatments
Experiment 1. On the designated days (Day 1 or Day 8), five pieces each of CS, HS, and HSH 2 0 were tumbled in 1-liter solution of 1% NaCl with 3% STPP (NaP) for 3 min in the same manner as outlined for tumbling in water. All CS pieces were passed through the mechanical tenderizer before further treatment. Another five pieces of each deboned group were cooked without phosphate treatment to serve as controls. Experiment 2. Breast pieces were tumbled in a solution of either 1% NaCl, 3% STPP, or a combination of 1% NaCl plus 3% STPP (NaP). Four pieces of breast meat (approximately 120 g/piece) were tumbled for 3 min in 1 liter of the salt solution. Hot-stripped control meat was tumbled in water in a similar manner. The tumbled pieces were individually placed on folded absorbing paper inside plastic bags and held at 2 C for 0 or 8 days to simulate conventional retail handling. Additional NaPtreated samples were also prepared and evaluated at 1, 2, and 4 days. At least four pieces were prepared for each holding period of each treatment. Chill-stripped reference breast meat (REF) was prepared for comparison purpose by removing the breast with wings (bone-in and skin on) from the NYD and chilling in ice slush for 30 min, followed by holding in crushed ice for 24 hr to simulate conventional aging processes. The Pectoralis major muscle was then stripped from the chilled and aged carcass part and held on ice for 2 hr before cooking. Cooking Procedure and Analyses After treatment or holding, all the breast pieces were cooked in 88 C water for 20 min and then cooled in ice water for 10 min. The objective tenderness of the cooked meat was measured as force to shear (Warner-Bratzler single blade shear press). Three shears were made, one each at the top, middle, and bottom of a 2.5-cm strip as described by Lyon et al. (1985), and the mean of the three values was used as the filet value. The cut up pieces of each breast filet were blended in a food processor for further analyses.
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ANG AND HAMM
Moisture content was determined by vacuum oven drying at 95 C. The dried samples were charred and then ashed at 525 C in a muffle furnace (AOAC, 1980). Phosphorus was determined from the ash by an antimony-molybd a t e s p e c t r o p h o t o m e t r i c procedure (EPA, 1974). sodium content was determined from the ash extract by an atomic absorption method as per manufacturer's (Perkin Elmer Corp.) recommendation. The state of oxidative development was measured as thiobarbituric acid (TBA) numbers using a modified version of the method of Tarladgis et al, (1964). An antioxidant, BHT (butylated hydroxy toluene), was added to the meat samples (.03% by weight) during blending in an effort to reduce sample auto-oxidation during final preparations and distillation (Pikul et al, 1983). The TBA values were calculated as mg malonaldehyde (MA)/1000 g meat. Statistical procedures, analyses of variance and Duncan's multiple range test of the results were performed using a SAS (Statistical Analyses System) program of Barr et al. (1979). Regression analyses were made for prediction of trends of changes.
RESULTS AND DISCUSSION Tenderness Analytical results for Experiment 1 on TBA, shear and moisture values, and Duncan's multiple range test are shown in Table 1. The CS samples had the lowest shear values as compared to HS or H S H 2 0 within either the NaP treatment or the control group. However, the differences among the NaP samples were not as pronounced as among the control samples. The HS and H S H 2 0 control samples of Day 8 had higher (P<.001) shear values than those of Day 1. Once the samples were treated with NaP, the shear values were approximately equivalent to CS, regardless of when the NaP was applied or how tough the meat had already become as measured by force to shear. Shear data for Experiment 2 (Table 2) showed that hot-stripped breast meat control (tumbled in water) was toughest, and that aging for 8 days after deboning did not improve tenderness. Treatments with STPP, either as a single ingredient or as a mixture with NaCl at 0 days, significantly reduced toughness of the meat to a degree comparable to the REF at Day
TABLE 1. Effect of NaP1 treatment of stored broiler breast meat deboned by chill or hot-stripping method on the thiobarbituric acid (TBA), shear, and moisture values of cooked meat (Experiment 1) Debone method 3
CS HS HSH,0 CS HS HSH20
Storage day
Analyses of cooked meat 2 Treatment
1 8 1 8 1 8
Control
1 8 1 8 1 8
With NaP1
Shear
Moisture
TBA no.
(kg)
(%)
(mg malonaldehyde/kg)
4.32 ± 4.34 ± 5.96 ± 8.42 ± 10.06 ± 13.86 ±
1.31 c d .61cd .98 c 2.58 b 3.40 b .99*
68.77 70.65 70.68 67.45 69.13 67.67
± ± ± + ± ±
.72 e .68 d .46 d 1.12f .46 e .48 f
.68 1.93 1.52 1.70 1.12 2.42
+ .04de ± .84 b ± .65 c ± .33b + .09 c d ± .47 a
2.44 ± 2.34 ± 4.02 + 3.36 ± 3.10 ± 3.80 ±
.83d .58 d 1.19 c d .86 d .80 d .96d
75.10 78.76 76.10 77.77 78.78 79.14
± ± ± ± ± +
.68 c 1.19 ab .92 c .49 b 1.13 a b 1.00 a
.12 .29 .11 .29 .11 .69
± .03 f ± .06 e f ± .01f ± .09 e f ± .02 f ± .26de
Means in a column followed by different letters are significantly different (P<.05). A solution with 1% NaCl and 3% STPP (sodium tripolyphosphate). 2 Means ± standard deviations of five breast pieces. 3 CS = Chill-stripped, HS = hot-stripped, HSH2 O = hot-stripped followed by tumbling in water. 1
SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
1535
TABLE 2. Effect, of salt (NaCl) and sodium tripolyphosphate (STPP) treatments followed by holding at 2 C on thiobarbituric acid (TBA), shear, phosphorus (P), sodium (Na), and moisture (H2 O) content of hot-stripped broiler breast meat (Experiment 2)
Treatment
Reference (REF) Control (H,0) 1% NaCl 3% STPP l%NaCl + 3% STPP
Holding time
Analyses of cooked meat, wet weight basis1 Shear
TBA
(days)
(mg malonal- (kg) dehyde/kg)
1
5.97 ± .82 b
0 8 0 8 0 8 0 8
4.55 8.69 1.41 4.28 .11 3.42 .08 2.03
+ .43 c ± .96 a ± .52 e ± .31c ± .02 f ± .48 d ± .02 f ± .68 e
P
Moisture
(%)
(mg/lOOg)
5.45 ± 1.59 b 10.80 10.38 9.35 5.87 5.62 3.03 5.62 2.94
Na
± ± ± + + ± ± ±
1.02 a 1.37 a 1.59 a 2.21b .93b .78 c .94 b .91c
193.8 ± 4.8 b 131.6 94.3 146.3 135.9 199.1 201.0 224.7 219.2
± 4.6 d ± 4.1e ± 2.3 C ± 2.0 d ± 6.9 b ± 7.9 b ± 12.5 a ± 7.2 a
69.9 ± .2 C
52.5 ± 5.0% 37.5 ± 33.3 ± 145.0 ± 87.5 ± 62.5 ± 100.5 ± 200.0 + 285.0 ±
5.0% 3.0g 3.5 C 9.6 d e 9.6 e f 8.4 d 29.4 b 19.1 a
70.2 70.8 72.3 70.6 74.3 72.5 74.0 75.0
± ± ± ± ± ± ± ±
1.4C .9 C .8b l.lc 1.5a .3b 1.0a .6 a
Within each column, values followed by different letters are significantly different (P<.05). 1
Means ± standard deviations of four pieces. Duplicate determinations were made for TBA, P, Na, and moisture values for each piece. Triplicate measurements were made for shear test.
1, and t h e effect was m o r e p r o n o u n c e d after holding for 8 days. Regression analysis revealed a significant ( P « . 0 5 ) quadratic t r e n d of change on shear values of t h e meat t r e a t e d with NaP (Fig. 1).
increase of T B A values over t i m e was generally linear ( P < . 0 0 0 1 ) . Nevertheless, samples treated with NaP had lower TBA values at Day 8 t h a n conventionally processed m e a t ( R E F ) at Day 1. Moisture
Oxidative
Development
T h e TBA data in E x p e r i m e n t 1 showed significant differences ( P « . 0 5 ) existed a m o n g t h e d e b o n i n g m e t h o d s (Table 3). T h e H S H 2 0 c o n t r o l samples of Day 8 oxidized t h e m o s t as illustrated b y t h e highest T B A n u m b e r s (Table 1). T h e NaP t r e a t m e n t reduced ( P < . 0 0 1 ) t h e TBA values for all samples regardless of deboning m e t h o d s or storage t i m e before t h e t r e a t m e n t . T h e application of NaP t o 8-daystored raw m e a t changed t h a t m e a t comparable t o 1-day-stored m e a t with respect t o TBA values after cooking. Stored u n t r e a t e d m e a t did n o t have extensive oxidative d e v e l o p m e n t during cooking, if NaP was applied just before t h e cooking. Samples in each t r e a t m e n t in E x p e r i m e n t 2 at Day 8 had higher TBA values t h a n those at Day 0 (Table 2). When t r e a t m e n t s were compared separately for Day 0 and D a y 8, NaCl or STPP alone were significantly effective in inhibiting oxidative d e v e l o p m e n t (lower TBA n u m b e r s ) , b u t t h e NaP t r e a t m e n t was most effective. T h e regression curve for samples t r e a t e d w i t h NaP (Fig. 1) illustrates t h a t t h e
Data for meat in E x p e r i m e n t 1 showed t h a t moisture c o n t e n t of NaP-treated samples after
SHEAR
"V. 0
1
2
3
4
5
6
7
8
DAYS AFTER TREATMENT
FIG. 1. Regression analyses of thiobarbituric acid (TBA) and shear values of hot-stripped broiler breast meat tumbled in a combined solution of 1% NaCl and 3% sodium tripolyphosphate (STPP) and held in crushed ice prior to cooking and evaluation. Each TBA point represents mean of four pieces analyzed in duplicate; each shear value point represents mean of four pieces analyzed in triplicate.
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ANG AND HAMM TABLE 3. Analysis of variance of thiobarbitaric acid (TBA), shear, and moisture content of broiler breast meat (Experiment 1) PR>F
Source of variation TRT 1 DEB2 TRT X DEB Day 3 TRT X Day DEB X Day TRT X DEB X Day
Shear
Moisture
TBA
.0001** .0001** .0001**
.0001** .0414* .0001** .0281* .0001** .0001** .0052**
.0001** .0201* .3512 .0001** .0023** .0051**
.0098**
.0086** .0608
.1990
.0624
1
Treatment (TRT) with NaP (1% NaCl + 3% STPP) or not.
2
Debone (DEB) methods: Chill-stripped, hot-stripped or hot-stripped and tumbled in water.
3
Storage time, 1 or 8 days, in crushed ice before cooking.
'Significant at 5% level. **Significant at 1% level.
cooking was significantly higher than samples not treated with NaP (Table 1). However, the reductions in shear and TBA values were not merely due to the dilution effect of the high moisture content of treated meat because the average difference in moisture content was only approximately 8.55%. Both NaCl and STPP promoted the retention of H 2 0 in cooked meat in Experiment 2 (Table 2), although the effectiveness diminished somewhat when the meat was held for 8 days before cooking. When the two components were used in combination, the H 2 0 content remained high through Day 8, with a maximum level attained at Day 4 (Fig. 2).
highest level of P noted (270 mg/100 g) for Day 2 of NaP was equivalent to approximately .3% of added phosphate, which is below the tolerance limit (.5%) set by the US Department of Agriculture (Federal Register, 1982). Lower levels of Na were observed when meat was tumbled with water as compared to REF. However, the effect was not significant (P> .05). When meat was treated with NaCl, a drastic increase of Na was observed at Day 0, but it
,S
Phosphorus and Sodium
~---
Content
Phosphorus and sodium content were determined only on Experiment 2 meat samples. As shown in Table 2, tumbling of hotstripped meat in water reduced the levels of P in comparison with REF, and there was additional loss of P after 8 days of storage. Meat treated with NaCl retained more P than controls, but the P content of STPP treatedmeat equalled that of the REF meat. When meat was treated with NaP, the levels of P at Day 0 were higher than the REF, and an increase was observed during the holding period with a maximum level at Day 2 (Fig. 2). Thereafter, a decrease was found. The changes followed a quadratic trend (P«.005). The
./
y
DAYS AFTER TREATMENT
FIG. 2. Regression analyses of P, Na, and moisture (HjO) content of hot-stripped broiler breast meat tumbled in a combined solution of 1% NaCl and 3% sodium tripolyphosphate (STPP) and held in crushed ice prior to cooking and evaluation. Each point represents mean of four pieces analyzed in duplicate.
SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
1537
s u b s e q u e n t l y declined at Day 8. Samples treated with either STPP or NaP showed higher Na in m e a t at Day 8 t h a n Day 0, and t h e m a x i m u m r e t e n t i o n of Na was f o u n d at Day 4 after t h e t r e a t m e n t with NaP (Fig. 2 ) . These data indicate t h a t Na was continuously absorbed in t h e form of STPP, b u t n o t in t h e form of NaCl, from t h e surface of t h e meat t o t h e inner tissue during t h e holding period. T h e changes followed a quadratic t r e n d ( P < . 0 0 0 3 ) .
shear values, and elevating t h e P, Na, or H 2 0 c o n t e n t of the meat, t h e changes of all t h e parameters measured did n o t follow t h e same t r e n d . Significant ( P < . 0 0 1 ) correlation coefficients existed between t h e levels of Na and H 2 0 (r = . 8 0 7 4 ) , Na and shear (r = - . 7 5 0 3 ) , and shear and H 2 0 (r = —.7261). Correlations b e t w e e n a n y o t h e r pairs of t h e p a r a m e t e r s were low and nonsignificant. T h e exact m e c h a n i s m concerning t h e chemistry of STPP a n d NaCl in meat merits further investigation.
Analysis Between
T h e functions of NaCl and STPP have been recognized in tenderizing of freshly processed m e a t and in preventing t h e oxidative developm e n t of fresh m e a t . T h e present findings further d e m o n s t r a t e d t h e applicability of these chemicals o n stored and oxidized t o u g h e n e d hot-stripped or chill-stripped m e a t . Due t o t h e increasing p r o d u c t i o n of d e b o n e d m e a t , t h e effectiveness of t h e NaP on stored meat m a y be of great significance t o t h e p o u l t r y industry.
of Variance and Parameters
Interactions
Statistical significances of t h e NaP treatm e n t , storage time, and a m o n g t h e three deboning m e t h o d s in E x p e r i m e n t 1 are indicated in Table 3. Significant interaction b e t w e e n NaP t r e a t m e n t and deboning m e t h o d was observed. T h e STPP has been f o u n d to be effective for prevention of o x i d a t i o n in cooked m e a t during storage w h e n t h e raw m e a t was immediately cooked after t h e t r e a t m e n t ( T h o m s o n , 1964) or w h e n STPP was applied t o cooked m e a t ( R a m sey and Watts, 1 9 6 3 ; Farr and May, 1970). In a s t u d y of raw g r o u n d beef, Green (1969) rep o r t e d t h a t STPP was ineffective as an antioxidant during refrigerated storage and t h o u g h t t h a t t h e p h o s p h a t e groups were hydrolyzed presumably b y p h o s p h a t a s e in t h e muscle. However, t h e present study showed t h a t although t h e effectiveness of STPP as an a n t i o x i d a n t was decreasing during holding period, it was still effective at Day 8. Positive a n t i o x i d a n t effect of STPP in raw t u r k e y m e a t stored for 10 d a y s at 5 C was r e p o r t e d b y Marion and F o r s y t h e ( 1 9 6 2 ) and, in c o o k e d p o u l t r y meat, chilled in a p o l y p h o s p h a t e solution, t h e n stored at 3 t o 4 C for 8 days (Farr and May, 1 9 7 0 ) . T h e discrepancy f o u n d b e t w e e n r e p o r t s could be d u e partly t o t h e possibility t h a t p o u l t r y m e a t has less phosphatase t h a n beef or t h a t t h e application m e t h o d s of STPP were different in different studies. Diminishing tenderizing effectiveness of t h e chemical t r e a t m e n t s during t h e holding time was n o t observed. On t h e c o n t r a r y , t h e shear values of treated m e a t continued t o decrease. A p p a r e n t l y , o n c e t h e m e a t was treated, t h e muscle fibers w e r e m o r e susceptible t o t h e aging process, which led t o an increase in tenderization (lower shear values). A l t h o u g h b o t h STPP a n d NaCl t r e a t m e n t s were effective in suppressing TBA, lowering
REFERENCES AOAC, 1980. Official Methods of Analysis, W. Horwitz, ed. 13th ed. Assoc. Offic. Anal. Chem. Washington, DC. Barr, A. J., J. H. Goodnight, J. P. Sail, W. H. Blair, and D. M. Chilko, 1979. SAS User's Guide. SAS Inst. Raleigh, NC. Dawson, L. E., and E. C. Sison, 1973. Stability and acceptability of phosphate-treated and precooked chicken pieces reheated with microwave energy. J. FoodSci. 38:161-164. de Fremery, D., 1963. Relation between biochemical properties and tenderness of poultry. Proc. Meat Tenderness Symposium. Campbell Soup Co., Camden, NJ. EPA, 1974. Methods for chemical analysis of water and waste. US Environmental Protection Agency, National Environmental Center, Cincinnati, OH 45268. Farr, A. J., and K. N. May, 1970. The effect of polyphosphates and sodium chloride on cooking yields and oxidative stability of chickens. Poultry Sci. 49:268-275. Federal Register, 1982. Meat and poultry products: phosphates and sodium hydroxide. Fed. Reg. (March 12): 10779. Furia, T. E., 1972. Handbook of Food Additives. CRC press. Cleveland, OH. Green, B. E., 1969. Lipid oxidation and pigment changes in raw beef. J. Food Sci. 34:110—113. Hamm, D., 1982. A new look at broiler meat harvesting. Pages 3 8 - 3 9 in Broiler Industry. July 1982. Hamm, D., 1983. Techniques for reducing toughness in hot-stripped broiler meat. Poultry Sci. 62: 1430. (Abstr.) Hamm, D., 1984. Hot-stripping Updates. Southeastern's Poultry Processors Workshop. Atlanta, GA, May 1 7 - 1 8 , 1984. Hamm, D., C. E. Lyon, J. P. Hudspeth, F. H. Benoff,
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J. L. Ayres, and L. R. Minear, 1984. Meat yields from hot deboned noneviscerated broilers. Poultry Sci. 6 3 : 4 9 7 - 5 0 1 . Hamm, D., and J. E. Thomson, 1983. Adopting hot-stripping techniques to existing poultry processing facilities. Poultry Sci. 62:1349. IFT, 1980. Dietary salt. A scientific status summary by the Institute of Food Technologists expert panel on food safety and nutrition and the committee on public information. Food Technol. 34:85. Katz, M., and L. D. Dawson, 1964. Water absorption and retention by cut up broiler parts chilled in polyphosphate solutions. Poultry Sci. 43:1541— 1546. Klose, A. A., A. A. Campbell, and H. L. Hansen, 1963. Influence of polyphosphates in chilling water on quality of poultry meat. Poultry Sci. 4 2 : 7 4 3 749. Klose, A. A., R. N. Sayre, and M. F. Pool, 1971. Tenderness changes with cutting up poultry shortly after evisceration. Poultry Sci. 50: 585-591. Landes, D. R., 1972. The effects of polyphosphates on several organoleptic, physical and chemical properties of stored precooked frozen chickens. Poultry Sci. 51:641-646. Lillard, H. S., D. Hamm, and J. E. Thomson, 1984. Effect of spray-washing uneviscerated carcasses on microbiological quality of hot boned poultry meat harvested after reduced processing. Poultry Sci. 6 3 : 6 6 1 - 6 6 3 . Lyon, C. E., D. Hamm, and J. E. Thomson, 1985. pH and tenderness of broiler breast meat deboned various times after chilling. Poultry Sci. 64: 307-310. Mahon, J. H., 1962. Phosphates improve poultry. Food Eng. (NY) 34(11):108-113. Marion, W. W., and R. H. Forsythe, 1962. Protection afforded lipids of turkey meat by butylated hydroxyanisole, egg white solids, gelatin and
tripolyphosphate (Kena). Poultry Sci. 41:1663. (Abstr.) May, K. N., R. L. Helmer, and R. L. Saffle, 1963. Effect of phosphate treatment on carcass-weight changes and organoleptic quality of cut-up chicken. Poultry Sci. 4 2 : 2 4 - 3 2 . Peterson, D. W., 1977. Effect of polyphosphates on tenderness of hot cut chicken breast meat. J. Food Sci. 4 2 : 1 0 0 - 1 0 1 . Pikul, J., D. E. Leszczynski, and F. A. Kummerow, 1983. Elimination of sample autoxidation by butylated hydroxytoluene additions before thiobarbituric acid assay for malonaldehyde in fat from chicken meat. J. Agric. Food Chem. 31: 1338-1342. Ramsey, M. B., and B. M. Watts, 1963. The antioxidant effects of sodium tripolyphosphate and vegetable extracts on cooked meat and fish. Food Technol. 17:1056-1059. Rao, C. S., B. C. Dilworth, E. J. Day, and T. C. Chen, 1975. Effects of polyphosphates on flavor volatiles of poultry meat. J. Food Sci. 40: 847-849. Spencer, J. V., M. H.George, K. N. Hall, and L. D. Raspliska, 1963. Effect of chilling turkey carcasses in polyphosphate solution. Poultry Sci. 42:1313. (Abstr.) Spencer, J. V., and L. E. Smith, 1962. The effect of chilling chicken fryers in a solution of polyphosphates upon moisture uptake, microbial spoilage, tenderness, juiciness and flavor. Poultry Sci. 41:1685. (Abstr.) Tarladgis, B. G., A. M. Pearson, and L. R. Dugan, Jr, 1964. Chemistry of the 2-thiobarbituric acid test for determination of oxidative rancidity in foods. II. Formation of the TBA-malonaldehyde complex without acid-heat treatment. J. Sci. Food Agric. 15:602-607. Thomson, J. E., 1964. Effect of polyphosphates on oxidative deterioration of commercially cooked fryer chickens. Food Technol. 18:147-148.
The conventional method for processing of boneless poultry meat involves chilling the eviscerated carcasses in ice water slush and then aging the chilled poultry a minimum of 6 hr prior to deboning. The chilling and aging periods are important for hygiene and development of tender meat (de Fremery, 1963); however, chilling the entire carcass may not be efficient. Hamm and coworkers studied an unconventional method for rapidly producing boneless chicken meat from noneviscerated warm carcasses (Hamm, 1982; Hamm et al, 1984; Hamm and Thomson, 1983; Lillard et al, 1984). The procedure has potential advantages for reducing processing time and cost. One problem encountered in implementing the hot-stripping technique was the toughness of the cooked breast meat. Subsequent chilling and aging of the deboned meat failed to tenderize the meat as occurs with conventionally processed meat (Hamm, 1983). Klose et al. (1971) also observed that cutting the muscle from warm eviscerated carcasses produced toughening in chicken. The use of polyphosphates in meat has been reported to contribute several beneficial func1 Names of products are included for the benefit of the reader and do not imply endorsement or
preferential treatment by USDA.
tions in emulsification, protein binding, water holding, and cured color development. Examples of some items with added phosphates are frankfurters, sausages, and hams (Furia, 1972). Treatment of conventionally processed poultry with polyphosphate or salt was reported to result in more tender meat than meat from nontreated controls (Spencer and Smith, 1962; Klose, et al, 1963; May et al, 1963; Dawson and Sison, 1973; Peterson, 1977; Hamm, 1983). The application of polyphosphate in chilling, cooking, or cooling water, or by marination or injection was found to be effective for inhibition of oxidative changes or flavor deterioration of several types of cooked meat (Mahon, 1962; Spencer and Smith, 1962; Spencer et al, 1963; Thomson, 1964; Farr and May, 1970; Landes, 1972; Rao et al, 1975). Comparatively few reports have been made on the uptake of phosphorus and sodium in the meat as a result of polyphosphate or salt treatment (Katz and Dawson, 1964; Farr and May, 1970). Human intake of Na is of concern particularly to those individuals predisposed to hypertension (IFT, 1980), while the amount of added phosphate in meat and meat products is limited by regulation to .5% (Federal Register, 1982). Because hot-stripping techniques may be employed by the poultry industry in the near future, it would be of interest to the industry as
1532
SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
well as to scientists in related fields to study the effects of polyphosphate on the physical and chemical properties of hot-stripped meat. The present study was carried out to determine the effects of sodium chloride (NaCl), sodium tripolyphosphate (STPP), or a combination of the two compounds on the tenderness, oxidative stability, and Na and P content of hot-stripped breast meat stored at 2 C for up to 8 days before or after treatment. MATERIALS AND METHODS
Materials and Deboning Methods Experiment 1. Ten eviscerated, nonchilled whole carcasses without giblets (WOG) and 20 noneviscerated, nonchilled New York-dressed carcasses (NYD) were collected from a local commercial processing plant. Care was taken to ensure that all birds selected were from the same farm flock. All birds were 48 days of age when slaughtered. Carcasses without giblets were packed in crushed ice and NYD were packed in insulated containers and transported to our laboratory within 30 min postmortem. The breast with wings attached was stripped from each of the 10 WOG. After holding in crushed ice for 1 or 8 days, the two Pectoralis major muscles, without skin, were stripped from each breast. Deboned breast meat thus obtained resembled the meat processed by the conventional method. These breast pieces were designated as chill-stripped meat (CS). Forty (40) hot-stripped breasts (HS) were obtained by stripping the Pectoralis major muscles from NYD while they were still warm, using a technique described by Hamm (1984), followed by a single pass through a mechanical tenderizer (Model TC 700M, Ross Industries, Inc., Midland, VA) to facilitate the penetration of water or the marinade solution into the meat. After mechanical tenderization, 20 of the HS pieces were tumbled in water ( H 2 0 ) for 3 min and designated as H S H 2 0 samples. The tumbler was an industrial type cement mixer approximately 45 cm in diameter and rotated at 50 rpm. All the HS and H S H 2 0 pieces were then stored in crushed ice for 1 or 8 days. Experiment 2. Breast meat from 7-week-old broilers processed at a commercial plant as unchilled NYD was hot stripped at our laboratory within 30 min postmortem in the same manner as Experiment 1. Breast pieces were pooled, and then they were randomly selected
1533
for further treatment. The breast pieces were passed one time through the mechanical tenderizer as described above before tumbling in appropriate solution. Salt and Polyphosphate
Treatments
Experiment 1. On the designated days (Day 1 or Day 8), five pieces each of CS, HS, and HSH 2 0 were tumbled in 1-liter solution of 1% NaCl with 3% STPP (NaP) for 3 min in the same manner as outlined for tumbling in water. All CS pieces were passed through the mechanical tenderizer before further treatment. Another five pieces of each deboned group were cooked without phosphate treatment to serve as controls. Experiment 2. Breast pieces were tumbled in a solution of either 1% NaCl, 3% STPP, or a combination of 1% NaCl plus 3% STPP (NaP). Four pieces of breast meat (approximately 120 g/piece) were tumbled for 3 min in 1 liter of the salt solution. Hot-stripped control meat was tumbled in water in a similar manner. The tumbled pieces were individually placed on folded absorbing paper inside plastic bags and held at 2 C for 0 or 8 days to simulate conventional retail handling. Additional NaPtreated samples were also prepared and evaluated at 1, 2, and 4 days. At least four pieces were prepared for each holding period of each treatment. Chill-stripped reference breast meat (REF) was prepared for comparison purpose by removing the breast with wings (bone-in and skin on) from the NYD and chilling in ice slush for 30 min, followed by holding in crushed ice for 24 hr to simulate conventional aging processes. The Pectoralis major muscle was then stripped from the chilled and aged carcass part and held on ice for 2 hr before cooking. Cooking Procedure and Analyses After treatment or holding, all the breast pieces were cooked in 88 C water for 20 min and then cooled in ice water for 10 min. The objective tenderness of the cooked meat was measured as force to shear (Warner-Bratzler single blade shear press). Three shears were made, one each at the top, middle, and bottom of a 2.5-cm strip as described by Lyon et al. (1985), and the mean of the three values was used as the filet value. The cut up pieces of each breast filet were blended in a food processor for further analyses.
1534
ANG AND HAMM
Moisture content was determined by vacuum oven drying at 95 C. The dried samples were charred and then ashed at 525 C in a muffle furnace (AOAC, 1980). Phosphorus was determined from the ash by an antimony-molybd a t e s p e c t r o p h o t o m e t r i c procedure (EPA, 1974). sodium content was determined from the ash extract by an atomic absorption method as per manufacturer's (Perkin Elmer Corp.) recommendation. The state of oxidative development was measured as thiobarbituric acid (TBA) numbers using a modified version of the method of Tarladgis et al, (1964). An antioxidant, BHT (butylated hydroxy toluene), was added to the meat samples (.03% by weight) during blending in an effort to reduce sample auto-oxidation during final preparations and distillation (Pikul et al, 1983). The TBA values were calculated as mg malonaldehyde (MA)/1000 g meat. Statistical procedures, analyses of variance and Duncan's multiple range test of the results were performed using a SAS (Statistical Analyses System) program of Barr et al. (1979). Regression analyses were made for prediction of trends of changes.
RESULTS AND DISCUSSION Tenderness Analytical results for Experiment 1 on TBA, shear and moisture values, and Duncan's multiple range test are shown in Table 1. The CS samples had the lowest shear values as compared to HS or H S H 2 0 within either the NaP treatment or the control group. However, the differences among the NaP samples were not as pronounced as among the control samples. The HS and H S H 2 0 control samples of Day 8 had higher (P<.001) shear values than those of Day 1. Once the samples were treated with NaP, the shear values were approximately equivalent to CS, regardless of when the NaP was applied or how tough the meat had already become as measured by force to shear. Shear data for Experiment 2 (Table 2) showed that hot-stripped breast meat control (tumbled in water) was toughest, and that aging for 8 days after deboning did not improve tenderness. Treatments with STPP, either as a single ingredient or as a mixture with NaCl at 0 days, significantly reduced toughness of the meat to a degree comparable to the REF at Day
TABLE 1. Effect of NaP1 treatment of stored broiler breast meat deboned by chill or hot-stripping method on the thiobarbituric acid (TBA), shear, and moisture values of cooked meat (Experiment 1) Debone method 3
CS HS HSH,0 CS HS HSH20
Storage day
Analyses of cooked meat 2 Treatment
1 8 1 8 1 8
Control
1 8 1 8 1 8
With NaP1
Shear
Moisture
TBA no.
(kg)
(%)
(mg malonaldehyde/kg)
4.32 ± 4.34 ± 5.96 ± 8.42 ± 10.06 ± 13.86 ±
1.31 c d .61cd .98 c 2.58 b 3.40 b .99*
68.77 70.65 70.68 67.45 69.13 67.67
± ± ± + ± ±
.72 e .68 d .46 d 1.12f .46 e .48 f
.68 1.93 1.52 1.70 1.12 2.42
+ .04de ± .84 b ± .65 c ± .33b + .09 c d ± .47 a
2.44 ± 2.34 ± 4.02 + 3.36 ± 3.10 ± 3.80 ±
.83d .58 d 1.19 c d .86 d .80 d .96d
75.10 78.76 76.10 77.77 78.78 79.14
± ± ± ± ± +
.68 c 1.19 ab .92 c .49 b 1.13 a b 1.00 a
.12 .29 .11 .29 .11 .69
± .03 f ± .06 e f ± .01f ± .09 e f ± .02 f ± .26de
Means in a column followed by different letters are significantly different (P<.05). A solution with 1% NaCl and 3% STPP (sodium tripolyphosphate). 2 Means ± standard deviations of five breast pieces. 3 CS = Chill-stripped, HS = hot-stripped, HSH2 O = hot-stripped followed by tumbling in water. 1
SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
1535
TABLE 2. Effect, of salt (NaCl) and sodium tripolyphosphate (STPP) treatments followed by holding at 2 C on thiobarbituric acid (TBA), shear, phosphorus (P), sodium (Na), and moisture (H2 O) content of hot-stripped broiler breast meat (Experiment 2)
Treatment
Reference (REF) Control (H,0) 1% NaCl 3% STPP l%NaCl + 3% STPP
Holding time
Analyses of cooked meat, wet weight basis1 Shear
TBA
(days)
(mg malonal- (kg) dehyde/kg)
1
5.97 ± .82 b
0 8 0 8 0 8 0 8
4.55 8.69 1.41 4.28 .11 3.42 .08 2.03
+ .43 c ± .96 a ± .52 e ± .31c ± .02 f ± .48 d ± .02 f ± .68 e
P
Moisture
(%)
(mg/lOOg)
5.45 ± 1.59 b 10.80 10.38 9.35 5.87 5.62 3.03 5.62 2.94
Na
± ± ± + + ± ± ±
1.02 a 1.37 a 1.59 a 2.21b .93b .78 c .94 b .91c
193.8 ± 4.8 b 131.6 94.3 146.3 135.9 199.1 201.0 224.7 219.2
± 4.6 d ± 4.1e ± 2.3 C ± 2.0 d ± 6.9 b ± 7.9 b ± 12.5 a ± 7.2 a
69.9 ± .2 C
52.5 ± 5.0% 37.5 ± 33.3 ± 145.0 ± 87.5 ± 62.5 ± 100.5 ± 200.0 + 285.0 ±
5.0% 3.0g 3.5 C 9.6 d e 9.6 e f 8.4 d 29.4 b 19.1 a
70.2 70.8 72.3 70.6 74.3 72.5 74.0 75.0
± ± ± ± ± ± ± ±
1.4C .9 C .8b l.lc 1.5a .3b 1.0a .6 a
Within each column, values followed by different letters are significantly different (P<.05). 1
Means ± standard deviations of four pieces. Duplicate determinations were made for TBA, P, Na, and moisture values for each piece. Triplicate measurements were made for shear test.
1, and t h e effect was m o r e p r o n o u n c e d after holding for 8 days. Regression analysis revealed a significant ( P « . 0 5 ) quadratic t r e n d of change on shear values of t h e meat t r e a t e d with NaP (Fig. 1).
increase of T B A values over t i m e was generally linear ( P < . 0 0 0 1 ) . Nevertheless, samples treated with NaP had lower TBA values at Day 8 t h a n conventionally processed m e a t ( R E F ) at Day 1. Moisture
Oxidative
Development
T h e TBA data in E x p e r i m e n t 1 showed significant differences ( P « . 0 5 ) existed a m o n g t h e d e b o n i n g m e t h o d s (Table 3). T h e H S H 2 0 c o n t r o l samples of Day 8 oxidized t h e m o s t as illustrated b y t h e highest T B A n u m b e r s (Table 1). T h e NaP t r e a t m e n t reduced ( P < . 0 0 1 ) t h e TBA values for all samples regardless of deboning m e t h o d s or storage t i m e before t h e t r e a t m e n t . T h e application of NaP t o 8-daystored raw m e a t changed t h a t m e a t comparable t o 1-day-stored m e a t with respect t o TBA values after cooking. Stored u n t r e a t e d m e a t did n o t have extensive oxidative d e v e l o p m e n t during cooking, if NaP was applied just before t h e cooking. Samples in each t r e a t m e n t in E x p e r i m e n t 2 at Day 8 had higher TBA values t h a n those at Day 0 (Table 2). When t r e a t m e n t s were compared separately for Day 0 and D a y 8, NaCl or STPP alone were significantly effective in inhibiting oxidative d e v e l o p m e n t (lower TBA n u m b e r s ) , b u t t h e NaP t r e a t m e n t was most effective. T h e regression curve for samples t r e a t e d w i t h NaP (Fig. 1) illustrates t h a t t h e
Data for meat in E x p e r i m e n t 1 showed t h a t moisture c o n t e n t of NaP-treated samples after
SHEAR
"V. 0
1
2
3
4
5
6
7
8
DAYS AFTER TREATMENT
FIG. 1. Regression analyses of thiobarbituric acid (TBA) and shear values of hot-stripped broiler breast meat tumbled in a combined solution of 1% NaCl and 3% sodium tripolyphosphate (STPP) and held in crushed ice prior to cooking and evaluation. Each TBA point represents mean of four pieces analyzed in duplicate; each shear value point represents mean of four pieces analyzed in triplicate.
1536
ANG AND HAMM TABLE 3. Analysis of variance of thiobarbitaric acid (TBA), shear, and moisture content of broiler breast meat (Experiment 1) PR>F
Source of variation TRT 1 DEB2 TRT X DEB Day 3 TRT X Day DEB X Day TRT X DEB X Day
Shear
Moisture
TBA
.0001** .0001** .0001**
.0001** .0414* .0001** .0281* .0001** .0001** .0052**
.0001** .0201* .3512 .0001** .0023** .0051**
.0098**
.0086** .0608
.1990
.0624
1
Treatment (TRT) with NaP (1% NaCl + 3% STPP) or not.
2
Debone (DEB) methods: Chill-stripped, hot-stripped or hot-stripped and tumbled in water.
3
Storage time, 1 or 8 days, in crushed ice before cooking.
'Significant at 5% level. **Significant at 1% level.
cooking was significantly higher than samples not treated with NaP (Table 1). However, the reductions in shear and TBA values were not merely due to the dilution effect of the high moisture content of treated meat because the average difference in moisture content was only approximately 8.55%. Both NaCl and STPP promoted the retention of H 2 0 in cooked meat in Experiment 2 (Table 2), although the effectiveness diminished somewhat when the meat was held for 8 days before cooking. When the two components were used in combination, the H 2 0 content remained high through Day 8, with a maximum level attained at Day 4 (Fig. 2).
highest level of P noted (270 mg/100 g) for Day 2 of NaP was equivalent to approximately .3% of added phosphate, which is below the tolerance limit (.5%) set by the US Department of Agriculture (Federal Register, 1982). Lower levels of Na were observed when meat was tumbled with water as compared to REF. However, the effect was not significant (P> .05). When meat was treated with NaCl, a drastic increase of Na was observed at Day 0, but it
,S
Phosphorus and Sodium
~---
Content
Phosphorus and sodium content were determined only on Experiment 2 meat samples. As shown in Table 2, tumbling of hotstripped meat in water reduced the levels of P in comparison with REF, and there was additional loss of P after 8 days of storage. Meat treated with NaCl retained more P than controls, but the P content of STPP treatedmeat equalled that of the REF meat. When meat was treated with NaP, the levels of P at Day 0 were higher than the REF, and an increase was observed during the holding period with a maximum level at Day 2 (Fig. 2). Thereafter, a decrease was found. The changes followed a quadratic trend (P«.005). The
./
y
DAYS AFTER TREATMENT
FIG. 2. Regression analyses of P, Na, and moisture (HjO) content of hot-stripped broiler breast meat tumbled in a combined solution of 1% NaCl and 3% sodium tripolyphosphate (STPP) and held in crushed ice prior to cooking and evaluation. Each point represents mean of four pieces analyzed in duplicate.
SALT AND TRIPOLYPHOSPHATE ON TENDERNESS
1537
s u b s e q u e n t l y declined at Day 8. Samples treated with either STPP or NaP showed higher Na in m e a t at Day 8 t h a n Day 0, and t h e m a x i m u m r e t e n t i o n of Na was f o u n d at Day 4 after t h e t r e a t m e n t with NaP (Fig. 2 ) . These data indicate t h a t Na was continuously absorbed in t h e form of STPP, b u t n o t in t h e form of NaCl, from t h e surface of t h e meat t o t h e inner tissue during t h e holding period. T h e changes followed a quadratic t r e n d ( P < . 0 0 0 3 ) .
shear values, and elevating t h e P, Na, or H 2 0 c o n t e n t of the meat, t h e changes of all t h e parameters measured did n o t follow t h e same t r e n d . Significant ( P < . 0 0 1 ) correlation coefficients existed between t h e levels of Na and H 2 0 (r = . 8 0 7 4 ) , Na and shear (r = - . 7 5 0 3 ) , and shear and H 2 0 (r = —.7261). Correlations b e t w e e n a n y o t h e r pairs of t h e p a r a m e t e r s were low and nonsignificant. T h e exact m e c h a n i s m concerning t h e chemistry of STPP a n d NaCl in meat merits further investigation.
Analysis Between
T h e functions of NaCl and STPP have been recognized in tenderizing of freshly processed m e a t and in preventing t h e oxidative developm e n t of fresh m e a t . T h e present findings further d e m o n s t r a t e d t h e applicability of these chemicals o n stored and oxidized t o u g h e n e d hot-stripped or chill-stripped m e a t . Due t o t h e increasing p r o d u c t i o n of d e b o n e d m e a t , t h e effectiveness of t h e NaP on stored meat m a y be of great significance t o t h e p o u l t r y industry.
of Variance and Parameters
Interactions
Statistical significances of t h e NaP treatm e n t , storage time, and a m o n g t h e three deboning m e t h o d s in E x p e r i m e n t 1 are indicated in Table 3. Significant interaction b e t w e e n NaP t r e a t m e n t and deboning m e t h o d was observed. T h e STPP has been f o u n d to be effective for prevention of o x i d a t i o n in cooked m e a t during storage w h e n t h e raw m e a t was immediately cooked after t h e t r e a t m e n t ( T h o m s o n , 1964) or w h e n STPP was applied t o cooked m e a t ( R a m sey and Watts, 1 9 6 3 ; Farr and May, 1970). In a s t u d y of raw g r o u n d beef, Green (1969) rep o r t e d t h a t STPP was ineffective as an antioxidant during refrigerated storage and t h o u g h t t h a t t h e p h o s p h a t e groups were hydrolyzed presumably b y p h o s p h a t a s e in t h e muscle. However, t h e present study showed t h a t although t h e effectiveness of STPP as an a n t i o x i d a n t was decreasing during holding period, it was still effective at Day 8. Positive a n t i o x i d a n t effect of STPP in raw t u r k e y m e a t stored for 10 d a y s at 5 C was r e p o r t e d b y Marion and F o r s y t h e ( 1 9 6 2 ) and, in c o o k e d p o u l t r y meat, chilled in a p o l y p h o s p h a t e solution, t h e n stored at 3 t o 4 C for 8 days (Farr and May, 1 9 7 0 ) . T h e discrepancy f o u n d b e t w e e n r e p o r t s could be d u e partly t o t h e possibility t h a t p o u l t r y m e a t has less phosphatase t h a n beef or t h a t t h e application m e t h o d s of STPP were different in different studies. Diminishing tenderizing effectiveness of t h e chemical t r e a t m e n t s during t h e holding time was n o t observed. On t h e c o n t r a r y , t h e shear values of treated m e a t continued t o decrease. A p p a r e n t l y , o n c e t h e m e a t was treated, t h e muscle fibers w e r e m o r e susceptible t o t h e aging process, which led t o an increase in tenderization (lower shear values). A l t h o u g h b o t h STPP a n d NaCl t r e a t m e n t s were effective in suppressing TBA, lowering
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tripolyphosphate (Kena). Poultry Sci. 41:1663. (Abstr.) May, K. N., R. L. Helmer, and R. L. Saffle, 1963. Effect of phosphate treatment on carcass-weight changes and organoleptic quality of cut-up chicken. Poultry Sci. 4 2 : 2 4 - 3 2 . Peterson, D. W., 1977. Effect of polyphosphates on tenderness of hot cut chicken breast meat. J. Food Sci. 4 2 : 1 0 0 - 1 0 1 . Pikul, J., D. E. Leszczynski, and F. A. Kummerow, 1983. Elimination of sample autoxidation by butylated hydroxytoluene additions before thiobarbituric acid assay for malonaldehyde in fat from chicken meat. J. Agric. Food Chem. 31: 1338-1342. Ramsey, M. B., and B. M. Watts, 1963. The antioxidant effects of sodium tripolyphosphate and vegetable extracts on cooked meat and fish. Food Technol. 17:1056-1059. Rao, C. S., B. C. Dilworth, E. J. Day, and T. C. Chen, 1975. Effects of polyphosphates on flavor volatiles of poultry meat. J. Food Sci. 40: 847-849. Spencer, J. V., M. H.George, K. N. Hall, and L. D. Raspliska, 1963. Effect of chilling turkey carcasses in polyphosphate solution. Poultry Sci. 42:1313. (Abstr.) Spencer, J. V., and L. E. Smith, 1962. The effect of chilling chicken fryers in a solution of polyphosphates upon moisture uptake, microbial spoilage, tenderness, juiciness and flavor. Poultry Sci. 41:1685. (Abstr.) Tarladgis, B. G., A. M. Pearson, and L. R. Dugan, Jr, 1964. Chemistry of the 2-thiobarbituric acid test for determination of oxidative rancidity in foods. II. Formation of the TBA-malonaldehyde complex without acid-heat treatment. J. Sci. Food Agric. 15:602-607. Thomson, J. E., 1964. Effect of polyphosphates on oxidative deterioration of commercially cooked fryer chickens. Food Technol. 18:147-148.