Evaluation of Various Mixing Stresses on Storage Stability (TBA) and Color of Mechanically Deboned Turkey Meat1

Evaluation of Various Mixing Stresses on Storage Stability (TBA) and Color of Mechanically Deboned Turkey Meat1 M. A. UEBERSAX, L. E. DAWSON, and K. L. UEBERSAX Department of Food Science and Human Michigan State University, East Lansing, Ml 48824

Nutrition,

(Received for publication November 28, 1977)

INTRODUCTION Mechanically d e b o n e d t u r k e y m e a t (MDTM) p r o d u c t i o n has increased dramatically in recent years. This c o m m o d i t y is physically well suited for i n c o r p o r a t i o n into further processed produ c t s such as loaves and c o m m i n u t e d items; however, n u m e r o u s flavor a n d color p r o b l e m s have been associated with its use. Decreased shelf stability a n d p r o d u c t a c c e p t a n c e are major concerns (Dawson, 1 9 7 5 ) . Many studies have been r e p o r t e d o n t h e stability of MDTM and were reviewed by Froning, 1 9 7 5 . In r e p o r t i n g Gardner color and T B A values for MDTM stored u p t o 1 4 weeks a t t e m p e r a t u r e s ranging from - 3 2 C t o - 1 3 C, J o h n s o n et al. ( 1 9 7 4 ) showed T B A values increased with t i m e a n d t e m p e r a t u r e , b u t color values s h o w e d n o significant differences. Dhillon and Maurer ( 1 9 7 5 ) r e p o r t e d T B A values for MDTM stored at —25 C u p t o six m o n t h s fluctuated with storage time. H u n t e r L values showed n o differences, b u t H u n t e r +aL values decreased significantly after one m o n t h frozen storage. Most a t t e m p t s t o improve stability (e.g., addition of a n t i o x i d a n t s or p o l y p h o s p h a t e s ,

1 Michigan Agricultural Experiment Station Journal Article No. 8339.

1978 Poultry Sci 57:924-929

control of t e m p e r a t u r e ) have involved adjustm e n t s m a d e t o t h e processed m e a t itself (Johnson et al., 1 9 7 4 ) ; however, few have been directly related t o t h e processing and handling conditions t h a t m a y result in accelerated lipid oxidation. T h e p r o c e d u r e s used t o p r o d u c e t h e m e a t and formulate t h e further processed p r o d u c t require a relatively large a m o u n t of mixing and handling, resulting in p r o d u c t aeration. T h e process of t u m b l e mixing m e a t in the presence of NaCl a n d p o l y p h o s p h a t e s t o e x t r a c t salt soluble proteins t o increase p r o d u c t binding is in c o m m o n use. Such t u m b l i n g may increase p r o d u c t aeration a n d c o n t r i b u t e t o decreased storage stability of t h e final p r o d u c t . Carbon dioxide chilling chambers on deboning units require " r i b b o n b l e n d i n g " of a " C 0 2 s n o w " t o facilitate rapid low t e m p e r a t u r e maint e n a n c e . Such t r e a t m e n t s should be desirable from a microbial and oxidative reactive standp o i n t ; however, potential prooxidative effects of t h e p r o c e d u r e have been r e p o r t e d (Uebersax etai, 1977). T h e objective of this s t u d y was t o evaluate t h e effect of several mixing t r e a t m e n t s designed t o vary t h e level of oxidative stress placed o n t h e MDTM. Meat was evaluated for color (Hunter Lab) and storage stability (2-thiobarbituric acid, T B A ) .

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ABSTRACT Mechanically deboned turkey meat (MDTM) was mixed under the following treatment conditions: a) control—not mixed, b) exposed to surface air, c) under a flow of nitrogen gas, and d) under a flow of carbon dioxide gas. Twenty-five hundred grams of MDTM were mixed in replicate in a Hobart K5-A mixer in a 4 C cold room. Treatments were intended to simulate several handling conditions and to provide various oxidative stresses to the product. Treated MDTM was packaged in Mylar pouches without air evacuation and under vacuum and held at 4 C up to six days and stored at —18 C up to six months. Samples were evaluated for surface color (Hunter Lab) and for storage stability (2-thiobarbituric acid, TBA) at regular intervals. Data indicate that mixing contributes to color and oxidative changes which occur during storage. Dramatic TBA increases were only noted for MDTM stored at —18 C up to 6 months. TBA numbers of MDTM held at 4 C up to 6 days did not change appreciably. Generally, meat mixed in air and under C0 2 showed higher TBA numbers and greater changes in surface color than did the control meat and meat mixed under nitrogen. Further work is required to make conclusive statements applicable to commercial procedures.

STABILITY OF MECHANICALLY DEBONED TURKEY MEAT MATERIALS AND METHODS

Meat Handling

Following mixing treatment, 100 g meat were packaged in polyethylene Mylar laminated pouches and smoothed and flattened to a uniform 15 cm X 15 cm square (ca. .5 cm thick) and sealed without air evacuation and under vacuum using a Kenfield Model C-14 vacuum sealer (International Kenfield Distributing Co., Parkridge, IL). Replicate pouches for each lot and time interval were protected from light and held at 4 C and sampled daily up to six days and stored at —18 C and sampled monthly up to 6 months. Analytical

Methods

Composition. Proximate composition, including moisture, fat, protein, and ash was determined on random samples for MDTM lots according to AOAC methods (1975). Calcium was also determined on the lots by an EDTA titrimetric method (Steagall, 1966). pH was determined on meat lots and following each mixing treatment by inserting a pH electrode directly into the meat sample. Color. Frozen samples were thawed at 4 C

prior to analyses. The surface color of MDTM was evaluated using a Hunter Lab D-25 Color and Color Difference Meter. Packaging material was c o m p e n s a t e d for during instrument standardization and measures were taken directly through the surface of the flattened sealed pouch. Lipid Oxidation. After color evaluation, pouches were opened and a representative sample was taken for 2-thiobarbituric acid (TBA) analysis (Tarladgis et al., 1960). Analyses included two distillations per package and TBA numbers (mg malonaldehyde per 1000 g sample) were calculated using a constant of 7.8. Statistical

Analysis

All data were subjected to the analysis of variance and performed on the CDC 6500 computer maintained by Michigan State University. Overall mixing treatments were evaluated as planned comparisons and means separated using letter notations, P<.05. The coefficient of variation (CV%) expressed the standard deviation as a percent of the mean. RESULTS AND DISCUSSION

Proximate composition, calcium, and pH of MDTM used in this study are reported in Table 1. These data are typical and within the ranges reported in numerous reports (Dhillon and Maurer, 1975; Grunden et al, 1972). The pH values of MDTM after different mixing stresses are reported in Table 2. All mixed samples had lower pH values compared to those of the control (no mix). Carbon dioxide mixed MDTM had the lowest pH values of all treatments, presumably due to adsorption of C&2 • Mechanically deboned meat has commonly been reported to have relatively high pH values compared to hand boned muscle portions (Field, 1976). The increase in pH has been attributed t o i n c o r p o r a t i o n of marrow constituents (Anderson and Gillett, 1974). Decreases in pH observed in this study, after mixing treatments, may be due to dispersion of marrow constituents or to C 0 2 adsorption. The analysis of variance (mean squares) of TBA numbers and Hunter Lab color values for MDTM mixed under different conditions and held at 4 C up to six days and stored at —18 C up to 6 months is reported in Table 3. Overall

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Mechanically deboned turkey meat (MDTM) was obtained from a commercial processing plant, packed in insulated boxes, and transported to the laboratory within 2 hr. Meat was processed through a Beehive deboner, Model AU968MF (screen, .45 mm. diameter) from hand boned racks including backs with natural portions of skin. Replicate lots of meat were obtained in 40 lb boxes. MDTM was handled under different mixing conditions to simulate inplant aeration which occurs during formulation of further processed products. A Hobart Kitchen Aid K5-A food mixer equipped with a stainless bowl and cake paddle was operated at speed 6 for 2 min in a 4 C cold room. The bowl was covered with a plexiglass lid fitted with tygon tubing to facilitate mixing under a gas flow atmosphere. Replicate lots of 2500 g MDTM were mixed under the following conditions: a) control, no mixing; b) air mixing, mixed without plexiglass lid; c) nitrogen mixing, mixed under 25 psig back pressure flow of nitrogen; and d) carbon dioxide, mixed under 25 psig back pressure flow of carbon dioxide.

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UEBERSAX ET AL. TABLE 1. Proximate composition ofMDTM obtained for different mixing stresses and packaging conditions experiment

Moisture

Fat

%

69.2

.6

15.21

.88

Protein

Ash

%

%

13.2

.5

mean ± SD 1.14

Ca + + pH

.04

.174

.01

6.14

.02

Mean values and standard deviations (2 lots X 3 replicate samples, n=6).

held at 4 C. Overall TBA numbers of MDTM receiving the mixing treatments were significantly higher than those of the control. No overall significant differences were shown among air, nitrogen, and C 0 2 mixed MDTM; however, C 0 2 mixed and air packaged meat had the highest TBA levels. Vacuum packaging lowered the TBA numbers for meat mixed under all conditions below those values of MDTM packaged in air. Overall Hunter L values (darkness), as reported in Fig. 2, were significantly higher for air and nitrogen mixing treatments than for either the control or C 0 2 mixed. No significant differences between packaging conditions were shown for Hunter L values. Over time, Hunter L values generally decreased (meat became darker) from initial values although these changes were not dramatic or consistent. The mixing treatments resulted in gas incorporation and the formation of a slight foam structure. Lighter color (increased Hunter L) for air and nitrogen mixing treatments could be presumed to be due primarily to the foam structure or pigment oxygenation. C 0 2 mixed meat, although having the same physical foam characteristics of other mixed treatments, showed lower Hunter L values (similar to the control). The lower Hunter L values for C 0 2 mixed meat could possibly be due to hemoglobin conversion to carboxyhemoglobin (Cunningham and

TABLE 2. Initial pH values3-for MDTM after different mixing stresses Control (no mix)

Air mix

6.14

6.08

Nitrogen mix

Carbon dioxide mix

6.10

5.76

mean ± SD pH

.02

.01

Mean values and standard deviations (n=2 direct readings).

.00

.02

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TBA means for mixing and packaging treatments are illustrated in Fig. 1. TBA numbers for MDTM held at 4 C did not show dramatic changes among mixing and packaging treatments, or over holding times. These main effects were, however, significantly different. The response to storage time did not indicate an overall significant increasing trend of TBA numbers, but was primarily due to random fluctuations of the TBA numbers. Overall differences among mixing treatments resulted in significantly higher TBA numbers for meat exposed to air than for meat exposed to the other treatments. Meat mixed under nitrogen was not significantly different from the control; MDTM mixed under C 0 2 was not significantly different from that mixed under nitrogen. The significant mixing by packaging interaction was associated with scattered differences between packaging treatments in which unexpected lower TBA numbers were obtained for air packaged meat than for that vacuum packaged. However, vacuum packaging did reduce TBA numbers of C 0 2 mixed meat to a greater extent than it did to meat of the other treatments. TBA numbers for MDTM mixed under the same conditions but stored at —18 C up to 6 months were significantly higher, and showed greater increases with time, than those for meat

.79

*'Significant difference, P<.01.

22.2

.01

48

12.6

1.17

.01

.41

1.52 2.16

1.76 2.16

7.24

.31

.34

4.83**

.69

1.37 1.56

2.44**

.01 .01

.29

+»L

Hunter Lab

10.44** 22.71** 8.22** 3.52** 3.26**

4C

.80

.77

.91

04**

.92

305.06** 822.68** 5.18 54.47** 4.75** 1.71 5.83** 3.31

274.84** 813.15** 3.12 6.12** 1.33

41.42** 20.72** 16.02** 58.91** 1.91**

.09** .13** .09** .06**

.01

-18 C

4C

-18 C

L

4C

15

9 3 1 5 23 3 15 5

df

•Significant difference, P<.05.

3-way MXPXT Residual CV(%)

MXP MXT PXT

Main effects Mixing Packaging Time 2-way

variation

TBA

9.32

.68

.79

2.61** 1.36

.15

32.51** 14.44** 9.82** 47.90** 2.02**

-18 C

5.20

.28

.13

.10

.83**

.01

.56*

.32

8.24** 21.49** 8.05**

4C

TABLE 3. Analysis of variance of TBA numbers and Hunter Lab color values for MDTM held at 4 C and stored at - -18 C after different mixing stresses and packaging treatments

://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 11, 2015 +b'L

4.46

.25

.44

.32

1.25**

.37

9.14** 20.96** 2.07** 3.47** 94**

-18 C

H

ts)

2 m >

•<

m

H C

D

zm

O

U3

O w

> r r <

x > Z n

pi

S

"S

O

<

CO

>

928

UEBERSAX ET AL. • Air Packaged lO.OrCj'Vacuum Packaged

M

6.0

•

Air Packaged

1 1 Vacuum Packaged

50

4.0

•

2.0

1.0

tiiiiiti 1

Control

Control

Air

4°C.

Air 4°C.

-I8°C.

FIG. 1. Mean TBA numbers 3 over time for MDTM mixed and packaged under various conditions and held at 4 C up to six days and stored at —18 C up to six months. a Overall mean values: 2 samples/treatment X 2 distillations/sample X 2 reactions/distillation X 6 sampling periods.

-I8°C.

FIG. 3. Mean Hunter +aL values 3 over time for MDTM mixed and packaged under various conditions and held at 4 C up to six days and stored at —18 C up to six months. a See footnote Fig. 1.

at both temperatures had lowest +a.-^ values due to the lack of pigment oxygenation. CO2 mixMugler, 1974) or, to a lesser extent, to the ing resulted in the highest values, possibly due lowering pH effect of C 0 2 incorporation. to the conversion of hemoglobin to carboxyFroning (1975) reported on earlier work of hemoglobin. The significant interaction of mixJanky (1971) that pH adjustment of MDTM ing by time was primarily associated with air resulted in decreased Gardener L and increased mixing. For meat mixed in air, initial high +aL +aL values with decreasing pH. values decreased rapidly to relatively low Overall Hunter +a.]^ values (redness) (Fig. 3) values. This interaction involving air mixing was were significantly different among mixing treat- presumably a result of greater oxygen incorpoments. Meat mixed under nitrogen and stored ration during mixing which thus resulted in a

•

Air Packaged

•

Vocoum Packaged

• Air Packoged D vacuum Packaged

n _TI Hunter L 6 0

co2

1

FIG. 2. Mean Hunter L values2 over time for MDTM and packaged under various conditions and held at 4 C up to six days and stored at —18 C up to six months. a See footnote Fig. 1.

1

FIG. 4. Mean Hunter +h>L values 3 over time for MDTM mixed and packaged under various conditions and held at 4 C up to six days and stored at —18 C up to six months. 3 See footnote Fig. 1.

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L t

3.0

STABILITY OF MECHANICALLY DEBONED TURKEY MEAT

product quality are significant and important; however, these data are insufficient to propose changes in commercial handling techniques. The study indicates the need for further research (such as in-plant experiments) on mixing treatments. REFERENCES Anderson, J. R., and T. A. Gillett, 1974. Extractableemulsifying capacity of hand and mechanicallydeboned mutton. J. Food Sci. 39:1147-1149. Association of Official Agricultural Chemists, 1975. Official methods of analysis. 12th ed. Ass. Offic. Agr. Chem., Washington, DC. Cunningham, F. E., and D. J. Mugler, 1974. Deboned fowl meat offers opportunities. Poultry Meat 25:46-50. Dawson, L. E., 1975. Utilization of mechanically d e b o n e d m e a t from turkeys. In Proc. 2nd European Symp. on Poultry Meat Quality. Oosterbeek, The Netherlands, May 1 2 - 1 5 . 5 3 : 1 - 8 . Dhillon, A. S., and A. J. Maurer, 1975. Stability study of comminuted poultry meats in frozen storage. Poultry Sci. 54:1407-1414. Field, R. A., 1976. Mechanically-deboned red meat. FoodTechnol. 30(9): 3 8 - 4 8 . Froning, G. W., 1975. Color and flavor stability of mechanically deboned poultry meat. In Proc. 2nd European Symp. on Poultry Meat Quality. Oosterbeek, The Netherlands, May 1 2 - 1 5 . 5 1 : 1 - 8 . Grunden, L. P., J. H. MacNeil, and P. S. Dimick, 1972. Poultry product quality: chemical and physical characteristics of mechanically deboned poultry meat. J. Food Sci. 37:247-249. Janky, D. M., 1971. The effect of pH and certain additives on turkey meat pigments in model and meat systems. M. S. Thesis, University of Nebraska, Lincoln. Johnson, P. G., F. E. Cunningham, and J. A. Bowers, 1974. Quality of mechanically deboned turkey meat: effect of storage time and temperature. Poultry Sci. 53:732-736. Steagall, E. F., 1966. EDTA titration of calcium and m a g n e s i u m . J. Assoc. Offic. Agr. Chem. 49:287-291. Tarladgis, B. G., B. M. Watts, M. T. Younathan, and L. Dugan, Jr., 1960. A distillation method for the quantitative determination of malonaldehyde in rancid foods. J. Amer. Oil Chem. Soc. 37:44—48. Uebersax, K. L., L. E. Dawson, and M. A. Uebersax, 1977. Influence of " C 0 2 snow" chilling on TBA values in mechanically deboned chicken meat. Poultry Sci. 56:707-709.

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highly oxygenated pigment and increased pigment oxidation with subsequent time. Vacuum packaging resulted in significantly lower Hunter +a L values for all mixing treatments, due to removal of residual oxygen. Hunter +bL values (yellowness) (Fig. 4) were significantly different among mixing and packaging conditions for both temperatures and over time for —18 C storage. Changes over storage time were not great and the mixing by time interaction was associated with scattered values. No significant trend was detected. All mixed samples had higher values than the control. Vacuum packaging significantly lowered the +bL values below those of air packaged MDTM. In summary, mixing MDTM under these conditions generally resulted in increased TBA numbers compared to control meat which was not mixed. MDTM held at 4 C for up to 6 days did not undergo rapid and dramatic changes in TBA numbers among mixing treatments or over holding times. Mixed MDTM stored at —18 C up to 6 months showed greater differences due to the mixing stresses themselves, as well as showing more pronounced increases with storage time. MDTM air mixed had higher TBA numbers than did control samples and showed marked increases in Hunter +a L (redness) values which decreased rapidly during storage. MDTM mixed under nitrogen had TBA numbers slightly less than air mixed MDTM; however, no pigment oxygenation was noted by relatively low Hunter +aL values. Generally, vacuum packaging resulted in lower TBA numbers than did air packaging. Of all treatments, MDTM mixed under C 0 2 developed the highest TBA numbers during storage and showed a darker, redder color. This study indicates potential detrimental effects of the mixing operation which contribute to color changes and reduced storage stability of MDTM. Results of mixing treatments and subsequent aeration effects on

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