JFS:
Food Chemistry and Toxicology
Effect of Double-packaging and
Acid Combination on the Quality
of Irradiated Raw Turkey Patties
K.C. NAM AND D.U. AHN
Food Chemistry and Toxicology
ABSTRACT: Effects of double-packageing (combinational use of vacuum and aerobic packaging conditions) and
acid (citric or ascorbic acid) combinations on color, lipid oxidation and volatiles of irradiated raw turkey breast
were determined. Acid did not affect the a-values but increased the L-values of meat after irradiation. Citric acid
promoted lipid oxidation of irradiated turkey meat, whereas ascorbic acid had an antioxidant effect. The amounts
of total volatile and dimethyl sulfide in doubly packaged turkey meat were 35 to 56% and 58 to 73% lower than
those of the irradiated vacuum-packageed control, respectively, and dimethyl disulfide and dimethyl trisulfide
were not found in double-packageed meat. The combination sequence of aerobic/anaerobic packaging was not
a critical factor in the production of off-odor volatiles of irradiated turkey.
Keywords: acid, aerobic/anaerobic packaging combination, color, volatiles, irradiated turkey
Introduction
T
HE INTENSITIES OF OFF-ODOR AND PINKING IN IRRADIATED MEAT
were significantly influenced by packaging conditions: the
amounts of sulfur volatiles in irradiated meat were higher with
vacuum packaging than aerobic packaging because sulfur compounds formed by irradiation were highly volatile (Ahn and others 2000; Ahn and others 2001; Nam and others 2001). Jo and
Ahn (2000) and Ahn (2002) reported that sulfur compounds derived from the radiolytic degradation of sulfur amino acids were
responsible for the irradiation off-odor.
Irradiation increased the intensity of pink color in turkey
breast meat due to carbon monoxide-myoglobin (CO-Mb) complex formation, and the pink color was stable during storage under vacuum conditions (Luchsinger and others 1996; Nam and
Ahn 2002). Exposing irradiated meats to aerobic conditions, however, increased oxidation-reduction potential of meat and CO
against O2 competition, which reduced the chances for CO-Mb
ligand formation and decreased pink color intensity (Nam and
Ahn 2002). These results indicated that double packaging could
be effective in lowering irradiation off-odor and pinking. Double
packaging is a new packaging concept that we have developed to
tackle quality problems associated with irradiation in meat. Two
double-packageing models can be used: in model 1, meats are
first individually packaged in oxygen-permeable plastic bags. A
few of the aerobically packaged meats are then vacuum-packageed in an oxygen-impermeable bag and irradiated. The outer
vacuum bags can be removed to expose the inner bag to aerobic
conditions for a few d before marketing or consumption. In model 2, fillets are aerobically packaged and irradiated first, and then
vacuum-packageed after a few d of storage under aerobic conditions. The major advantages of this double-packageing concept
are (1) off-odor problems can be completely eliminated, (2) pinking on the surface of the meat can be reduced, and (3) additives
can be avoided. The limitations of using double packaging alone
to control meat quality are that lipid oxidation could be a potential problem, and the color inside of the meat may not be influenced much by the double-packageing methods.
Citric or ascorbic acid is commonly used in meat processing as
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a preservative or an antioxidant (Stivarius and others 2002). Addition of acid to meat lowers the pH and also increases the lightness of meat. Therefore, the overall color impression would be
less pink, and lipid oxidation (by ascorbic acid) during storage
would be decreased.
The objective of this study was to determine the effects of
double-packageing and acid combinations on color, lipid oxidation, and volatile compounds of irradiated raw turkey breast
meat during refrigerated storage.
Materials and Methods
Sample preparation
A total of 16 turkey carcasses slaughtered by the USDA guidelines (USDA 1982) were chilled in ice water for 2 h and then
drained in a cold room. The carcasses were randomly divided
into 4 groups (4 birds/group) and breast muscles were deboned
from the carcasses 24 h after slaughter. Breast meat from 4 carcasses were pooled, and used as a replication. Skin and visible
fat were removed from the breast, and the meat was ground
twice a 3-mm plate. Six different treatments were prepared using
the ground meat as shown in Table 1. Citric acid and ascorbic
acid were selected because they are commonly used ingredients
in meat processing. Citric acid monohydrate (0.2%) or L-ascorbic
acid (0.5%) was used to drop the pH of meat by approximately
0.4 units, according to the result of a preliminary study. Each acid
was mixed together with the ground meat for 3 min in a bowl mixer (Model KSM90; KitchenAid Inc., St. Joseph, Mich, U.S.A.) and
the mixed samples were ground again through a 3-mm plate to
ensure uniform distribution of the acid. Control meats without
added acid were also treated the same as acid-added samples.
Turkey breast meat patties (about 50 g) were prepared from
each treatment, individually vacuum-packageed with high–oxygen-barrier bags (nylon/polyethylene, 9.3 mL O2/m 2/24 h at
0 °C; Koch, Kansas City, Mo., U.S.A.) or double-packageed and
then stored at 4 °C for 10 d. On the basis of our previous works, 1
double-packageing condition was selected from each doublepackageing model and used in this study: the V7/A3 (vacuum© 2002 Institute of Food Technologists
12/5/2002, 3:33 PM
Acid and packaging on irradiated turkeys . . .
Treatment
Irradiation
Dose
Acid
Packaging
Nonirradiated, vacuum
Irradiated, vacuum
Irradiated, citric, A3/V7
Irradiated, citric, V7/A3
Irradiated, ascorbic, A3/V7
Irradiated, ascorbic, V7/A3
0 kGy
1.5 kGy
1.5 kGy
1.5 kGy
1.5 kGy
1.5 kGy
Not added
Not added
0.2% Citric
0.2% Citric
0.5% Ascorbic
0.5% Ascorbic
Vacuum for 10 d
Vacuum for 10 d
Aerobic for 3 d then vacuum for 7 d
Vacuum for 7 d then aerobic for 3 d
Aerobic for 3 d then vacuum for 7 d
Vacuum for 7 d then aerobic for 3 d
packageed for 7 d then aerobically packaged for 3 d) condition
was selected from double-packageing model 1, and A3/V7 (aerobically packaged for 3 d then vacuum-packageed for 7 d) from
double-packageing model 2. The V7/A3 packaging condition
was the aerobically packaged patties vacuum-packageed in oxygen-impermeable bags (nylon/polyethylene, 9.3 mL O2/m2/24
h at 0 °C; Koch), irradiated, and stored for 7 d under anaerobic
conditions before opening of the outer vacuum bags and storage for 3 more d. The A3/V7 packaging condition involved patties aerobically packaged in oxygen-permeable bags (polyethylene, 4 × 6, 2 mil; Associated Bag Company, Milwaukee, Wis.,
U.S.A.), irradiated, stored for 3 d under aerobic conditions and
then vacuum-packageed and stored for 7 d under anaerobic
conditions. The irradiation doses used were 0 or 1.5 kGy, and a
Linear Accelerator (Circe IIIR; Thomson CSF Linac, Saint-Aubin,
France) with 10 MeV of energy, 10 kW of power level, and 83.0
kGy/min of average dose rate was used. To confirm the target
dose, 2 alanine dosimeters per cart were attached to the top
and bottom surfaces of the sample and were read using a 104
Electron Paramagnetic Resonance instrument (EMS-104; Bruker Instruments Inc., Billerica, Mass., U.S.A.). Color, lipid oxidation, and volatile compounds of meat were determined at 0 and
10 d of storage at 4 °C.
Color
CIE color values were measured on the surface of the sample
using a LabScan colorimeter (Hunter Associated Labs Inc., Reston, Va., U.S.A.) that had been calibrated against black and
white reference tiles covered with the same packaging materials
as used for samples. The CIE L-(lightness), a-(redness), and b(yellowness) values were obtained using an illuminant A. An average value from both top and bottom locations on a sample surface was used for statistical analysis.
2-Thiobarbituric acid-reactive substances (TBARS)
Lipid oxidation was determined by a spectrometric TBARS
method (Ahn and others 1998). A sample (5 g) was placed in a 50mL test tube and homogenized with 15 mL deionized distilled
water (DDW) and butylated hydroxytoluene (7.2%, 50 mL) using
a Brinkman Polytron (Type PT 10/35; Brinkman Instrument Inc.,
Westbury, N.Y., U.S.A.) for 15 s at high speed. The meat homogenate (1 mL) was transferred to a disposable test tube (13 × 100
mm), and thiobarbituric acid/trichloroacetic acid [20 mM TBA
and 15% (w/v) TCA] solution (2 mL) was added. The mixture was
vortexed for 10 s and then incubated in a 90 °C water bath for 15
min to develop color. After cooling for 10 min in cold water, the
samples were vortexed and centrifuged at 3000 × g for 15 min at
5 °C. The absorbance of the resulting upper layer was read at 531
nm against a blank prepared with 1 mL DDW and 2 mL TBA/TCA
solution. The amounts of TBARS were calculated from a 1,1,3,3-
tetraethoxypropane standard curve and expressed as mg of malonedialdehyde (MDA) per kg of meat.
Volatile compounds
A purge-and-trap apparatus (Precept II and Purge & Trap
Concentrator 3000; Tekmar-Dohrmann, Cincinnati, Ohio, U.S.A.)
connected to a gas chromatograph/mass spectrometer (GC/MS,
Hewlett-Packard Co., Wilmington, Del., U.S.A.) was used to analyze volatiles produced (Ahn and others 2001). Minced meat
sample (3 g) was placed in a 40-mL sample vial, and the vials
were flushed with helium (40 psi) for 5 s. Samples were held in a
refrigerated (4 °C) sample-holding tray before analysis. The
maximum holding time was less than 6 h to minimize oxidative
changes (Ahn and others 1999). The meat sample was purged
with helium (40 mL/min) for 13 min at 40 °C. Volatiles were
trapped using a Tenax column ( Tekmar-Dohrmann) and desorbed for 2 min at 225 °C, focused in a cryofocusing module
(–90 °C) and then thermally desorbed into a column for 30 s at
225 °C.
An HP-624 column (7.5 m × 0.25 mm internal dia, 1.4 ␮m nominal), an HP-1 column (52.5 m × 0.25 mm internal dia, 0.25 ␮m
nominal; Hewlett-Packard Co.), and an HP-Wax column (7.5 m ×
0.25 mm internal dia, 0.25 ␮m nominal) were connected using
zero dead-volume column connectors ( J &W Scientific, Folsom,
Calif., U.S.A.). Ramped oven temperature was used to improve
volatile separation. The initial oven temperature of 0 °C was held
for 2.50 min. After that, the oven temperature was increased to
15 °C at 2.5 °C/min, increased to 45 °C at 5 °C/min, increased to
110 °C at 20 °C/min, increased to 210 °C at 10°C/min and then
held for 4.5 min at the temperature. Constant column pressure
at 20.5 psi was maintained. The ionization potential of mass-selective detector (Model 5973; Hewlett-Packard Co.) was 70 eV,
and the scan range was 18.1 to 300 m/z. Identification of volatiles
was achieved by comparing mass spectral data of samples with
those of the Wiley library (Hewlett-Packard Co.). Standards,
when available, were used to confirm the identification by the
mass-selective detector. The area of each peak was integrated
using the ChemStation (Hewlett-Packard Co.), and the total ion
counts were reported as an indicator of volatiles generated from
the sample.
Statistics
The experiment was designed to determine the effect of double-packageing/acid combinations on lipid oxidation, color, and
volatiles of the irradiated turkey breast patties. Analysis of variance was conducted by the general linear model procedure of
SAS software (SAS 1995); Student-Newman-Keul’s multiple
range test was used to compare the mean values of the treatments (p ⱕ 0.05). Mean values and r standard error of the means
(SEM) were reported.
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Food Chemistry and Toxicology
Table 1—The 6 different treatments (irradiation, acid, and packaging) used in this study
Acid and packaging on irradiated turkeys . . .
Table 2—pH values of irradiated raw turkey breast meat treated by different acids and packaging conditions during
refrigerated storage
Nonirradiated
Storage
d0
d 10
SEM
Vacuum
Vacuum
A3/V7 1
Irradiated
Citric
V7/A3 2
Ascorbic
A3/V7 1
V7/A3 2
5.89ay
5.86ay
5.45by
5.44cy
5.39dy
5.40dy
5.93ax
0.01
5.93ax
0.01
5.50cx
0.01
5.53bx
0.01
5.46dx
0.01
5.48cdx
0.01
SEM3
0.01
0.01
1 Aerobically packaged for 3 d then vacuum-packageed for 7 d
2 Vacuum-packageed for 7 d then aerobically packaged for 3 d
3 Standard error of the means
a-d Different letters within a row indicate significant difference ( p
0.05); n = 4.
x, y Different letters within a column indicate significant difference (p
0.05).
#
#
Food Chemistry and Toxicology
Table 3—CIE color values of irradiated raw turkey breast meat treated by different acids and packaging conditions
during refrigerated storage
Nonirradiated
Storage
L-value
d0
d 10
SEM
a-value
d0
d 10
NSEM
b-value
d0
d 10
SEM
Vacuum
Vacuum
Irradiated
Citric
A3/V7 1
V7/A3 2
Ascorbic
A3/V7 1
V7/A3 2
59.1by
60.6ax
0.3
60.1ab
60.4a
0.4
0.4
0.4
60.8a
60.8a
0.3
SEM3
56.5cx
54.8by
0.4
56.9cx
55.5by
0.4
59.9aby
61.8ax
0.4
2.6c
2.5b
0.1
4.9by
5.5ax
0.1
6.0a
5.7a
0.3
5.5ay
5.8ax
0.1
5.5a
5.7a
0.3
4.9by
5.9ax
0.1
0.1
0.3
16.2bx
14.7cy
0.1
15.9b
15.6c
0.2
17.6a
17.5b
0.3
15.7by
18.3abx
0.3
17.4ay
18.8ax
0.3
16.2by
18.0abx
0.2
0.2
0.3
1 Aerobically packaged for 3 d then vacuum-packageed for 7 d
2 Vacuum-packageed for 7 d then aerobically packaged for 3 d
3 Standard error of the means
a-c Different letters within a row indicate significant difference ( p
0.05); n = 4.
x, y Different letters within a column indicate significant difference ( p
0.05)
#
#
Table 4—TBARS values of irradiated raw turkey breast meat treated by different acids and packaging conditions during refrigerated storage. Values are given as (mg MDA/kg meat).
Nonirradiated
Storage
d0
d 10
SEM
Vacuum
Vacuum
0.62b
0.69c
0.07
0.64b
0.63c
0.03
Irradiated
Citric
A3/V7 1
V7/A3 2
0.91ay
1.84ax
0.03
1.02a
1.77bx
0.03
Ascorbic
A3/V7 1
V7/A3 2
0.56b
0.80c
0.09
0.57b
0.59c
0.03
SEM3
0.05
0.23
1 Aerobically packaged for 3 d then vacuum-packageed for 7 d
2 Vacuum-packageed for 7 d then aerobically packaged for 3 d
3 Standard error of the means
a-c Different letters within a row indicate significant difference ( p
0.05); n = 4.
x, y Different letters within a column indicate significant difference ( p
0.05).
#
#
Results and Discussion
pH and Color changes
The addition of citric acid or ascorbic acid lowered the pH values of turkey breast meat by about 0.4 unit (Table 2). Irradiation,
however, had no effect on the pH of vacuum-packageed meat.
The pH of the meat increased slightly during the 10 d of storage
at all treatments.
Irradiation increased the a-value of vacuum-packageed turkey breast patties and the increased redness was more consistent after 10 d of storage (Table 3). The increased redness in irradiated turkey meat was attributed to the formation of CO-Mb
3254
complex (Nam and Ahn 2002). Double packaging and acid combinations have shown effects mainly in L- and b-values rather
than a-value of irradiated turkey meat after 10 d of storage. The
acid-treated, double-packageed irradiated turkey meat had
higher L- and b-values than the irradiated vacuum-packageed
control, regardless of kind of acid or double-packageing method
used. Especially, the drastically increased L-values could be
caused by the added acid, which had light-scattering effect in
lower pH muscle. Swatland (1994) reported that decreasing pH
towards the isoelectric point of muscle proteins increased lightreflecting and scattering phenomena in meat, which resulted in
increased L-values. In terms of a-value, however, acid had little
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Acid and packaging on irradiated turkeys . . .
Table 5—Volatile profiles of irradiated raw turkey breast patties treated by different acids and packaging conditions at 0 d
(Total ion counts × 104)
Compound
Vacuum
2-Methyl-1-propene
1-Pentene
Pentane
Propanal
2-Propanone
Dimethyl sulfide
1-Hexene
Hexane
Benzene
1-Heptene
Heptane
Dimethyl disulfide
Toluene
1-Octene
Octane
2-Octene
3-Methyl-2-heptene
Dimethyl trisulfide
Total
0c
0b
229b
0
1813b
1328c
0b
219a
0d
0b
0c
0c
0d
298b
676a
169b
375a
0
5110b
Irradiated
Citric acid
A3/V7 1
V7/A3 2
Vacuum
198a
108b
76a
585a
0
3841a
3014a
68a
176ab
137b
66a
89ab
190bc
285a
433a
0d
609a
418a
0
10090 a
0b
526ab
46
3282ab
1661bc
0b
173ab
100bc
59a
72ab
50 c
205b
0c
63cd
0b
0c
0
6349b
Ascorbic acid
A3/V7 1
V7/A3 2
167a
29 c
72a
636a
0
3317ab
1843bc
66a
186ab
238a
70a
102a
816a
283a
274b
514b
145b
245b
74
10360 a
0b
412ab
0
1769b
1273c
0b
115b
69 c
0b
0c
35 c
157c
0c
60cd
0b
0c
0
3921bc
0c
0b
365ab
0
60 c
783cd
0b
111b
90bc
0b
49b
390b
125c
71 c
184c
0b
0c
0
2231c
SEM3
18
5
75
10
392
235
6
19
15
5
12
86
15
43
37
43
36
30
956
Food Chemistry and Toxicology
Nonirradiated
1 Aerobically packaged for 3 d then vacuum-packageed for 7 d (same as aerobically packaged at 0 d)
2 Vacuum-packageed for 7 d then aerobically packaged for 3 d (same as vacuum-packageed at 0 d)
3 Standard error of the means
a-d Different letters within a row indicate significant difference ( p
0.05); n = 4.
#
effect on the redness of irradiated turkey meat indicating that
lowered pH of muscle did not influence the formation or stability
of CO-Mb complex, which were responsible for the increased redness of irradiated meat. Therefore, the overall color perception of
irradiated turkey breast meat was paler and the intensity of red
or pink color was lower in acid-treated meat than that of acid-free
irradiated meat, by the effect of not decreased a-values but increased L-values. There were little different results between citric acid and ascorbic acid at the color values of irradiated turkey
breast patties at 10 d.
than citric acid would be more effective in reducing color intensity of irradiated meat.
The combination sequence of aerobic/anaerobic packaging
(double-packageing models) influenced lipid oxidation. A3/V7
double-packageed (aerobic for 3 d then vacuum for 7 d) turkey
meat developed a higher degree of lipid oxidation than the V7/
A3 double-packageed (vacuum for 3 d then aerobic for 7 d)
meats. This indicates that meats irradiated under aerobic conditions are more susceptible to lipid oxidation than those irradiated under vacuum conditions.
Lipid oxidation
Off-odor volatiles
Under vacuum conditions, lipid oxidation of irradiated turkey breast meat did not increase during storage ( Table 4). The
free radicals generated by irradiation accelerated lipid oxidation only when irradiated meat samples were aerobically
stored, because the presence of oxygen is the most critical factor influencing lipid oxidation in meat. (Katusin-Razem and
others 1992; Ahn and others 2000). Citric acid-treated turkey
breast had higher TBARS values than ascorbic acid-treated
meat, and the difference became highly distinct after 10 d of
storage. We speculate that in citric acid-added turkey meat,
the loosened muscle structure caused by lowering pH was
more susceptible to the attacks of free radicals generated by
irradiation, and lipid oxidation was accelerated during the
limited aerobic period. In general, there was a negative correlation between pH post mortem and the TBARS value ( Judge
and Aberle 1980). On the other hand, despite aerobic exposure, irradiated ascorbic acid-treated turkey meat had similar
levels of TBARS compared with the irradiated vacuum-packageed meat. This result indicates that ascorbic acid showed an
antioxidant effect during aerobic storage. Ascorbic acid is capable of inhibiting lipid oxidation by inactivating free radicals
and by regenerating ␣-tocopherol, and the antioxidant effect
in muscle food was very dependent on its concentration
(Decker and Mei 1996). Therefore, using ascorbic acid rather
Irradiation not only increased the amounts of some volatiles
found in nonirradiated turkey breast meat, but also generated
many new volatile compounds (Table 5). In the vacuum-packageed nonirradiated turkey meat, dimethyl sulfide and 2-propanone were the 2 predominant volatiles. The amounts of these
2 volatiles significantly increased after irradiation as well. Irradiation induced drastic changes in the production of alkenes, benzene, toluene, and sulfur compounds. Among the sulfur volatiles, the amount of dimethyl sulfide increased, and dimethyl
disulfide was newly generated in turkey meat after irradiation.
These sulfur compounds have been regarded as the major volatiles responsible for the characteristic irradiation off-odor, and
they have very low thresholds (Ahn and others 2000; Ahn and
others 2001).
In citric acid-treated and irradiated turkey meat samples,
packaging conditions were critical factors influencing the volatile
profiles and their amounts at 0 d (Table 5). A3/V7 double-packageed irradiated turkey meats at 0 d (the same as aerobic conditions at 0 d) had less total and less sulfur volatiles than V7/A3
double-packageed irradiated meat at 0 d (the same as vacuum
conditions at 0 d). This result shows that most volatiles, including sulfur compounds, were evaporated rapidly during irradiation and sample preparation before analysis under aerobic conditions. The production of total and sulfur volatiles from ascorbic
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Acid and packaging on irradiated turkeys . . .
Table 6—Volatile profiles of irradiated raw turkey breast patties treated by different acids and packaging conditions
after 10 d of refrigerated storage (Total ion counts × 104 )
Nonirradiated
Compound
Food Chemistry and Toxicology
2–Methyl–1–propene
1–Pentene
Pentane
2–Pentene
Propanal
2–Propanone
Dimethyl sulfide
1–Hexene
Hexane
Benzene
1–Heptene
Heptane
Dimethyl disulfide
Toluene
1–Octene
Octane
2–Octene
3–Methyl–2–heptene
Dimethyl trisulfide
Total
Vacuum
Vacuum
Irradiated
Citric acid
A3/V7 1
V7/A3 2
0b
76a
129a
0b
379c
0b
0b
3552a
4776a
0b
77 c
0b
0b
0d
0b
0d
509a
1162a
225a
456a
0b
11138 b
0b
553c
0b
0b
1827b
4492a
79a
232b
211a
67a
80 c
6206a
346a
348b
654b
189a
318b
205a
15886 a
128a
4370a
57a
164a
2825a
1200c
0b
429a
170a
100a
346a
0b
255b
0c
251c
54b
0c
0b
10229 b
1 Aerobically packaged for 3 d then vacuum-packageed for 7 d
2 Vacuum-packageed for 7 d then aerobically packaged for 3 d
3 Standard error of the means
a-d Different letters within a row indicate significant difference ( p
Conclusions
OR SHORT-TERM STORAGE (< 3 D) OF IRRADIATED TURKEY BREAST
3256
0b
873c
0b
87b
3077a
1865b
0b
169bc
164a
0b
80 c
0b
170c
127c
248c
71b
108c
0b
7270c
77a
92a
0b
1667b
0b
0b
2871a
1287c
0b
229b
61b
93a
177b
134b
209c
0c
167c
0c
0c
0b
6977c
0b
674c
0b
0b
3481a
1715b
0b
255b
47b
64a
79 c
80b
182c
0c
271c
63b
73 c
0b
7082c
meat in which lipid oxidation is not a great problem, aerobic
3256
14
6
187
3
14
256
123
4
35
18
13
19
262
12
12
60
17
44
12
413
packaging will be more beneficial than vacuum-packageing, because sulfur volatile compounds responsible for the irradiation
off-odor can be significantly reduced under aerobic conditions.
For longer-term storage (> 5 d), double packaging of irradiated
turkey meat (exposing irradiated meat under aerobic conditions
for a limited time either at the beginning or at the end of storage)
will be needed to eliminate sulfur volatiles. After exposure to aerobic conditions for 3 d, the irradiated meat should be kept in vacuum conditions to minimize lipid oxidation. The combination of
acid with double packaging did not lower a-value but increased
L-value, and thus lowered the visual pink color intensity. The
combination sequence of aerobic/anaerobic packaging (double
packaging) can be selected depending on the process, labor, and
cost.
References
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Ahn DU, Jo C, Du M, Olson DG, Nam KC. 2000. Quality characteristics of pork
patties irradiated and stored in different packaging and storage conditions.
Meat Sci 56(2):203-209.
Ahn DU, Jo C, Olson DG. 1999. Volatile profiles of raw and cooked turkey thigh as
affected by urge temperature and holding time before purge. J Food Sci 64
(2):230-233.
Ahn DU, Nam KC, Du M, Jo C. 2001. Volatile production in irradiated normal, pale
soft exudative (PSE), and dark firm dry (DFD) pork under different packaging
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JOURNAL OF FOOD SCIENCE—Vol. 67, Nr. 9, 2002
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# 0.05); n = 4.
acid-treated meats was lower than that of citric acid-treated
meats. Ascorbic acid acted as a powerful antioxidant and an inhibitor of radiolytic degradation of protein side chains in meat.
Therefore, if irradiated meat is going to be stored for a short
term, ascorbic acid and aerobic packaging combinations would
be desirable, because off-odor volatiles could be eliminated.
Vacuum-packageed irradiated turkey breast had still greater
amounts of volatile compounds than nonirradiated vacuumpackageed one at 10 d (Table 6). A large amount of dimethyl disulfide was found in vacuum-packageed irradiated turkey meat
both at 0 d and 10 d, and dimethyl trisulfide was newly detected
at 10 d. The ratios among sulfur volatiles in meat were also
changed during the storage, which should have significant impact on overall odor characteristics of irradiated meat, because
each sulfur compound has its own characteristic odor notes (Girard and Durance 2000).
The combination of aerobic/anaerobic packaging (doublepackageing) was highly effective in reducing total and sulfur volatiles of irradiated turkey breast meat during storage (Table 6).
Regardless of acid treatments, exposing the irradiated turkey
meat to aerobic condition for 3 d during the 10 d storage was
enough to eliminate almost all sulfur volatiles. The amounts of
total volatiles and dimethyl sulfide were reduced by 35 to 56%
and 58 to 73% of the vacuum-packageed irradiated control, respectively. Almost all dimethyl disulfide was evaporated, and
dimethyl trisulfide was not found in doubly packaged irradiated
turkey breast meat exposed to aerobic conditions for 3 d. The
combination sequence of aerobic/anaerobic packaging (doublepackageing models) was not a critical factor in the production of
off-odor volatiles of irradiated turkey meat.
F
76a
Ascorbic acid
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Acid and packaging on irradiated turkeys . . .
ments, pros and cons. Meat Sci 36(2):251-259.
USDA 1982. Guidelines for establishing and operating poultry processing plants.
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MS 20020085 Submitted 2/8/02, Revised 3/12/02, Accepted 3/24/02, Received
3/28/02
Journal Paper nr J–19731 of the Iowa Agriculture and Home Economics Experiment Station,
Ames, IA. 50011. Project No. 6523, supported by the National Research Initiative Competitive Grant/USDA.
The authors are with the Dept. of Animal Science, Iowa State Univ., Ames,
Iowa 50011-3150. Direct inquiries to author Ahn (E-mail: duahn@
iastate.edu).
Food Chemistry and Toxicology
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