JFS:
Food Chemistry and Toxicology
Effect of Antioxidants on Consumer
Acceptance of Irradiated Turkey Meat
ABSTRACT: Antioxidants had no effect on the production of sulfur compounds, color change, and off-odor
intensity of irradiated turkey breast meat, but addition of sesamol ⫹ tocopherol or gallate ⫹ tocopherol was
effective in reducing thiobarbituric acid-reactive substance values and aldehydes, especially under aerobic conditions. Consumers preferred the color of irradiated raw and cooked meat to nonirradiated meat because the pink
color of irradiated meat looked fresher. The packaging method was more important than the antioxidant treatment in reducing irradiation off-odor because S-compounds produced by irradiation easily volatilized under
aerobic packaging conditions. Therefore, the combined use of aerobic packaging and antioxidants is recommended to improve consumer acceptance of irradiated poultry meat.
Keywords: antioxidants, irradiation, packaging, turkey breast meat, consumer acceptance
Introduction
I
RRADIATION TECHNOLOGY HAS A GREAT PO-
tential to be used by the meat industry as
a tool to control pathogenic microorganisms in raw meat. The use of irradiation
technology by the meat industry, however, is limited because of quality concerns
such as off-odor and off-taste production
and color changes in meat by irradiation
that significantly impact on consumer acceptance. Ionizing radiation is known to
generate hydroxyl radicals that can degrade amino acids and lipids, and also produce various volatile compounds and carbon monoxide (CO) that induce off-odor
and color changes in meat (Ahn 2002; Ahn
and Lee 2002; Nam and Ahn 2002a,
2002b; Lee and Ahn 2003a, 2003b). The
volatiles responsible for off-odor are sulfur
compounds such as carbon disulfide, mercaptomethane, dimethyl sulfide, thioacetate S-methyl ester, and dimethyl disulfide generated by the radiolytic
degradation of sulfur amino acids (Ahn
and others 2001; Ahn 2002). Antioxidants
such as free radical terminators or metal
chelating agents are commonly used in
meat to reduce lipid oxidation and improve sensory quality of cooked meat
(Hsieh and Kinsella 1989; Chen and Ahn
1998). The pigment responsible for pinking in irradiated turkey breast was COmyoglobin (Mb), and the changes of oxidation-reduction potential (ORP) in meat
played an important role in the formation
of CO-Mb (Nam and Ahn 2002a, 2002b).
The major sources of CO in irradiated
meat were meat components such as amino acids and phospholipids (Lee and Ahn
© 2003 Institute of Food Technologists
Further reproduction prohibited without permission
2003b). Our previous studies show that
the addition of ␣-tocopherol ⫹ gallate or
␣-tocopherol ⫹ sesamol was effective in
reducing off-odor volatiles, but had no effect on the redness of irradiated turkey
patties (Nam and Ahn 2002b, 2003; Lee
and Ahn 2003c).
More than 4000 stores are currently marketing irradiated ground beef products, and
the consumption of irradiated meat is increasing very rapidly. However, consumer and industry response to irradiated poultry meat is
lukewarm because of off-odor/off-taste and
color changes in irradiated poultry after cooking (Olson 2003). Several reports indicated that
positive attitudes toward irradiation are increasing (Bruhn 1995; Resurreccion and others 1995), and consumer education is very
important for the acceptance of food irradiation (AMIF 1993). Most consumer studies on
irradiated foods were carried out only using a
questionnaire without presenting real irradiated products, and tests using real products
are needed to determine actual consumer response to irradiated meat.
The objective of this study was to determine consumer acceptance of irradiated
raw and cooked turkey breast meat with antioxidants added. The final consumer acceptance of irradiated meat can be determined by 2 factors: exterior color and odor
characteristics of raw irradiated meat and
the interior color and taste of irradiated
meat after cooking. Therefore, finding consumer reactions to the color and odor characteristics of irradiated raw and cooked turkey meat with different packaging is critical
to the use of irradiation technology by the
poultry industry.
Materials and Methods
Sample preparation
Raw turkey breasts were purchased from
4 local grocery stores. The meats purchased
from each grocery store were ground separately through a 3-mm plate and were
treated as a replication. Gallate (3,4,5-trihydroxybenzoic acid) and sesamol (3,4-methylenedioxyphenol) were purchased from
Sigma Chemical Co. (St. Louis, Mo., U.S.A.)
and ␣-tocopherol from Aldrich Chemical Co.
(Milwaukee, Wis., U.S.A.). Gallate and sesamol were dissolved in distilled water and
tocopherol in corn oil before use.
Nonirradiated and irradiated controls
(no antioxidant added) and 2 antioxidant
treatments (tocopherol ⫹ gallate, tocopherol ⫹ sesamol, 0.5 mM each, final concentration), which produced the least offodor volatiles and lipid oxidation in our
previous raw study (Lee and Ahn 2003c),
were prepared. Patties (100 g) were prepared after adding an antioxidant treatment
to ground meat and mixing for 3 min to ensure uniform distribution of antioxidants.
Half of the patties from each treatment
were individually packaged in polyethylene
oxygen-permeable bags (Assoc. Bag Co.,
Milwaukee, Wis., U.S.A.), and the other half
were vacuum-packaged in high-oxygenbarrier bags (nylon/polyethylene, 9.3 mL
O2/m2/24 h at 0 °C; Koch, Kansas City, Mo.,
U.S.A.). All samples were irradiated at an average dose of 0 (control) or 3.0 kGy using a
linear accelerator (Circe IIIR; Thomson CSF
Linac, Saint-Aubin, France). The energy and
power level used were 10 MeV and 10 kW,
respectively, and the average dose rate was
Vol. 68, Nr. 5, 2003—JOURNAL OF FOOD SCIENCE
1659
Food Chemistry and Toxicology
E.J. L EE, J. LOVE, AND D.U. A HN
Consumer acceptance of irradiated meat . . .
Food Chemistry and Toxicology
84.9 kGy/min. To confirm the target dose, 2
alanine dosimeters per cart were attached
to the top surface and bottom surface of a
sample vial. The alanine dosimeter was read
using a 104 Electron Paramagnetic Resonance instrument (Bruker Instruments Inc.,
Billerica, Mass., U.S.A.). The max/min ratio
was 1.21 (avg.). Consumer acceptance and
chemical characteristics (lipid oxidation,
volatile profiles, and color) of raw meat were
determined after 4 d of storage at 4 °C. For
the cooked meat study, vacuum-packaged
or aerobically packaged patties were irradiated and stored at 4 °C for 4 d before cooking. Patties were cooked in an electric oven
at 175 °C to an internal temperature of 78
°C. Internal temperatures of meat during
cooking were monitored with thermocouples connected to digital read-out devices.
All the cooked meat patties were vacuumpackaged immediately after cooking to minimize oxidative changes during storage and
handling before consumer test. The cooked
meats were refrigerated for less than 24 h
before the consumer acceptance test. Volatiles, color, and lipid oxidation of cooked patties were also determined as in raw turkey
meat.
Chemical analyses
A purge-and-trap apparatus (Solatek 72
and Concentrator 3100; 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. The conditions of the purge-and-trap
apparatus and GC-MS were described by
Lee and Ahn (2003c). The area of each peak
was integrated using the ChemStation
(Hewlett-Packard) software, and the total
peak area (pA*s ⫻ 104) was reported as an indicator of volatiles generated from the sample. Lipid oxidation was determined by the
thiobarbituric acid-reactive substance
(TBARS) method described by Ahn and others (1998). The color of meat was measured
on the surface of packaged samples using a
Labscan spectrophotometer (Hunter Assoc.
Labs Inc., Reston, Va., U.S.A.) that had been
calibrated against white and black reference
tiles packaged in the same bags as those
used for meat packaging. CIE L* (lightness),
a* (redness), and b* (yellowness) values
were obtained using an illuminant A. An average value from 2 random locations on each
sample surface was used for statistical analysis.
Consumer acceptance test
Adults who regularly consume turkey or
chicken products were recruited for consumer acceptance tests for raw (99 partici1660
Table 1—Volatile compounds of raw turkey breast meat patties with different
antioxidants added
Volatiles
C-nonIR
C-IR
S + Toc-IR
G + Toc-IR
SEM
ion counts × 104
Aerobic packaging
Cyclo-compounds
Hydrocarbons
Ketones
Alcohols
Aldehydes
Sulfur compounds
Esters
Total volatiles
270b
3544b
21581
273831a
1278b
0b
21236 a
321739
1148a
5466a
25100
27475 b
5043a
171a
2288b
66691
649b
1730c
22584
18001 b
1291b
0b
2090b
46344
640b
1523c
20511
16425 b
898b
0b
1940b
41938
123
438
1273
5831
730
13
1777
Vacuum packaging
Cyclo-compounds
Hydrocarbons
Ketones
Alcohols
Aldehydes
Sulfur compounds
Esters
Total volatiles
604
25567
13761 b
135441a
741b
998b
760
177874
522
32141
15729ab
15766 b
2288a
25500 a
845
92791
258
21962
17519 a
13300 b
0b
24711 a
631
78381
428
11740
16580 a
13098 b
183b
21285 a
800
64114
102
4867
670
670
278
3834
89
C-nonIR, nonirradiated control; C-IR, irradiated control; S + Toc-IR, irradiated sesamol and /alpha/tocopherol; G + Toc, irradiated gallate and /alpha/-tocopherol; SEM, standard error of the means. n = 4.
Cyclo - compounds : cyclooctene, toluene; Hydrocarbons : 1-heptane, hexane, octane, pentane; Ketones :
2-butanone, 2-heptanone, 2-propanone; Alcohols : 1-hexanol, 1-octen-3-ol, 1-penten-3-ol, 1-propanol, 2butanol, 2-propanol, 3-methyl-1-butanol, ethanol; Aldehydes : nonanal, hexanal, 2-heptenal; Sulfur
compounds : dimethyl disulfide, dimethyl trisulfide; Esters : ethyl ester acetic acid, methyl ester formic
acid.
a–cValues with different letters within a row are different ( P < 0.05).
pants) and cooked (83 participants) meats.
The consumer test was approved by the
university’s Human Subjects Committee
and was conducted in the Sensory Evaluation Unit of the Center for Designing Foods
to Improve Nutrition at Iowa State Univ. Raw
turkey patties (8 treatments) were evaluated for the preference of exterior color and
odor, and cooked turkey patties (7 treatments) were evaluated for the preference of
interior color and flavor. Consumer acceptance was determined by asking the participants to indicate their degree of liking on a
9-point horizontal category scale with “dislike extremely” anchoring the left category
and “like extremely” anchoring the right
category. Demographic information such as
gender, age, and level of education, and
questions of consumption frequency of turkey or chicken products also were included
in the questionnaire.
For the raw meat test, patties equilibrated at room temperature for 1 h were presented in sealed packages to the participants. Equilibration of meat at room
temperature before sensory testing was
done to increase the likelihood of detection
of off-odors. After rating the color by marking a category on a paper ballot, participants
were instructed to cut open the bag, smell
the sample, and indicate their opinion of the
odor. For the cooked meat test, cooked patties were warmed in a microwave oven
(Amana Radarange, Amana, Iowa, U.S.A.).
Meats were cooked the previous day be-
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 5, 2003
cause cooking and consumer testing simultaneously was impossible. Cooked meats
were vacuum-packaged in high-oxygen-barrier bags (nylon/polyethylene, 9.3 mL O2/
m2/24 h at 0 °C; Koch) while the meat was
still hot to minimize oxidative changes in
cooked meat (Ahn and others 1992). Three
patties were warmed on a plate that was rotated at 40-s intervals for a total of 120 s of
heating. Patties were placed in preheated
(77 °C) covered casserole dishes. The heated patties were cut into quarters and each
participant received 1 piece in a covered
polyfoam container labeled with a random
3-digit code. For scoring the cooked samples, a computerized system (Compusense
five, v 4.0; Compusense, Inc., Guelph, Ontario, Canada) was used. Participants were
instructed to rinse their mouths with water
before starting to taste, and also between
samples. Samples were evaluated in partitioned booths under fluorescent lighting
conditions (70 foot-candles at the surface of
the counter). A complete block design was
used for each of the tests. Serving order was
randomized.
Statistical analysis
Data were analyzed using the General
Linear Model procedure of SAS software
(SAS Inst. 1995); Student-Newman-Keul’s
multiple range test was used to compare the
mean values among antioxidant treatments. Mean values and standard error of
the means (SEM) were reported. Signifi-
Consumer acceptance of irradiated meat . . .
Table 2—TBARS and CIE color values of raw turkey breast meat patties with different antioxidants added
TBARS values
CIE color values
L* value
C-nonIR
C-IR
S + Toc-IR
G + Toc-IR
SEM
Aero.
Vac.
0.89ay
0.41by
2.34ax
0.38z
0.35z
0.06
0.63bx
0.37y
0.35y
0.05
SEM
Aero.
Vac.
0.07
0.09
0.01
0.02
48.79 az
46.88 by
52.53 ax
52.26 ax
50.73 y
0.35
46.99 by
49.29 bx
49.85 x
0.40
a* value
SEM
Aero.
Vac.
0.45
0.40
0.29
0.34
4.39bz
4.90ay
5.75bx
4.93by
6.60bw
0.17
8.73ax
9.13ax
9.08ax
0.19
b* value
SEM
0.15
0.22
0.17
0.18
Aero.
Vac.
SEM
8.23az
6.64by
9.33ay
10.95 ax
10.32 ax
0.26
6.59by
7.45bx
7.38bx
0.22
0.25
0.20
0.24
0.26
Table 3—Demographics for consumer
panelists in raw and cooked meat
study
Raw
Cooked
meat (%) meat (%)
Sex
Male
27.3
Female
72.7
Age
18 to 24
68.7
25 to 34
11.1
35 to 44
6.1
45 to 54
9.1
55 to 64
4.0
>65
1.0
Consumption frequency of
turkey or chicken products
Once a week or more 65.7
At least once a month 23.2
Once or a few times
a year
11.1
Never
0.0
25.3
74.7
63.9
4.8
4.8
16.9
9.6
0.0
74.7
19.3
6.0
0.0
cance was defined at P ⬍ 0.05. For the consumer acceptance test, frequencies of responses for the demographic/product usage questions were tabulated using Statistix
(Statistix v 7.0; Analytical Software, St. Paul,
Minn., U.S.A.), and odor and flavor using
Compusense (Compusense Inc.).
Results and Discussion
Effect of antioxidants on raw
turkey breast meat
Irradiation, antioxidants, and packaging
methods influenced the amounts and profiles of volatiles of raw turkey breast patties
(Table 1). With aerobic packaging, greater
amounts of alcohols and esters were produced in nonirradiated than irradiated
meats. It seems that the growth of microorganisms during the 4-d storage before
chemical analyses affected the increase of
these volatiles in nonirradiated meat (data
not shown). Aldehydes, hydrocarbons, and
cyclo-compounds increased after irradiation, and antioxidants were effective in reducing these volatiles. Small amounts of
Table 4—Consumer acceptance test of raw turkey breast meat patties with
different antioxidants added
Aerobic packaging
Treatment
Control (0 kGy)
Control (3 kGy)
Sesamol + Tocopherol (3 kGy)
Gallate + Tocopherol (3 kGy)
SEM
Vacuum packaging
Exterior color
Odor
Exterior color
Odor
4.78b
6.00a
3.94b
6.64a
3.83c
5.89a
0.23
5.26b
4.64c
5.00bc
0.18
5.71a
5.58a
6.04a
0.21
4.72a
3.68b
3.30b
3.40b
0.18
1 = dislike extremely; 5 = neither like nor dislike; 9 = like extremely. SEM is standard error of the means.
n = 4.
a–d Values with different letters within a column are different ( P < 0.05).
sulfur compounds, which are known to
cause irradiation off-odor (Ahn and others
2000a), were detected only in the irradiated
control after 4 d of storage under aerobic
packaging conditions. With vacuum-packaging, irradiation generated many sulfur
compounds such as dimethyl disulfide and
dimethyl trisulfide in turkey breast meat.
This confirmed our previous results that Scompounds produced by irradiation volatilized rapidly under aerobic packaging conditions (Nam and others 2002; Nam and Ahn
2003). Antioxidants had no effect in reducing the amounts of sulfur compounds in
vacuum-packaged meat, but were effective
in reducing the production of lipid-oxidation-dependent volatiles, especially hexanal.
TBARS values of turkey breast meat patties were affected by irradiation, antioxidant, and packaging methods (Table 2): irradiation increased TBARS values, and
aerobically packaged control meat had higher TBARS values than vacuum-packaged
control meat. Antioxidant treatments were
effective in controlling lipid oxidation of
both aerobically packaged and vacuumpackaged turkey patties. Ahn and others
(1997) reported that irradiation increased
lipid oxidation in raw turkey breast and
thigh meats that were aerobically packaged.
Chen and others (1999) reported that phenolic antioxidants were effective in reducing
lipid oxidation in aerobically packaged irra-
diated turkey patties at Day 0. No difference
in TBARS values between antioxidant treatments was found (Table 2).
Irradiation increased the redness (a* value) of turkey breast meat, and the a* values
of vacuum-packaged turkey breast meats
were higher than those of aerobically packaged meats (Table 2). Luchsinger and others (1996) reported that increased red color
in irradiated pork was more intense and stable with vacuum-packaging than aerobic
conditions during refrigerated storage. The
lightness (L* value) and yellowness (b* value) of irradiated turkey breast in aerobic
conditions were also higher than those in
vacuum conditions. Antioxidant treatments
had no effect on the color of irradiated raw
turkey breast meat (Table 2).
The results of the consumer acceptance
test of raw turkey breast meat patties with
different antioxidants added are shown in
Table 4. Most panelists were female (73%),
between the ages of 18 and 34 (80%), who
consumed turkey or chicken products once
a week or more (66%) ( Table 3). The percentage of females seemed rather high.
However, FMI (1994) reported that the primary food shopper was female (59%) and
only 13% of the primary shoppers were
male.
Consumers easily distinguished odor differences between nonirradiated and irradiated turkey patties. Ahn and others (2000b)
described the irradiation odor from irradiat-
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Food Chemistry and Toxicology
C-nonIR, nonirradiated control; C-IR, irradiated control; S + Toc-IR, irradiated sesamol and /alpha/-tocopherol; G + Toc, irradiated gallate and /alpha/tocopherol; aero., aerobic package; vac., vacuum package; SEM, standard error of the means. n = 4.
a–b Values with different letters within a row of the same parameter are different ( P < 0.05).
w–z Values with different letters within a column are different ( P < 0.05).
Consumer acceptance of irradiated meat . . .
Table 5—Volatile compounds of cooked turkey breast meat patties with different antioxidants added
C-nonIR-V
Cyclo-compounds1
Hydrocarbons
Ketones
Alcohols
Aldehydes
Sulfur compounds
Total volatiles
1921d
42434 b
19211 b
21393bc
22664 b
927c
108550
C-IR-A
4174bc
59335 b
21253ab
32716 a
77940 a
1555c
196973
C-IR-V
9429a
148512a
24705 a
26318 b
76250 a
12359 a
297572
S + Toc-IR-A
S + Toc-IR-V
G + Toc-IR-A
ion counts × 10 4
2651cd
3212bcd
28622 b
41890 b
16795 b
19898ab
20996bc
18102 c
9801b
6189b
1374c
13308 a
80238
102599
3316bcd
33909 b
4304 c
21257bc
6657b
1075c
70518
G + Toc-IR-V
SEM
4493b
59192 b
20331ab
18124 c
11936 b
6968b
121045
400
8067
1254
1634
6203
611
Food Chemistry and Toxicology
C-nonIR-V, nonirradiated control; C-IR, irradiated control; S + Toc-IR, irradiated sesamol and /alpha/-tocopherol; G + Toc, irradiated gallate and /alpha/tocopherol; V, vacuum package; A, aerobic package; SEM, standard error of the means. n = 4.
1 Cyclo-compounds : 4-1,1-dimethylethyl cyclohexanol, cycloheptene, cyclopentane, toluene; Hydrocarbons : 1-heptane, 1-heptene, 1-pentene, 2,2,5-trimethyl
hexane, 2,2,7,7-tetramethyl octane, 2,4,6-trimethyl octane, 2,5,6-trimethyl octane, 2,6,10-trimethyl dodecane, 2,6,10-trimethyl dodecane, 2,6,7-trimethyl
decane, 2,7,10-trimethyl dodecane, 2-methyl butane, 2-methyl decane, 2-methyl undecane, 2-octene, 3,3,7-trimethyl decane, 3,5-dimethyl octane, 3,7dimethyl nonane, 3-methyl decane, 3-methyl dodecane, 3-methyl nonane, 3-methyl undecane, 4,8-dimethyl undecane, 4-methyl decane, 5,6-dimethyl decane,
5-methyl undecane, butane, decane, dodecane, heptane, hexane, nonane, octacosane, octadecane, octane, pentane, undecane; Ketones : 2-butanone, 2propanone; Alcohols : ethanol, 1-octen-3-ol, 1-pentanol, 1-penten-3-ol, 1-propanol, 2-butanol, 2-propanol; Aldehydes : 2-methyl butanal, 2-methyl propanal, 3methyl butanal, acetaldehyde, heptanal, hexanal, nonanal, pentanal, propanal; Sulfur compounds : carbon disulfide, dimethyl disulfide, methanethiol.
a–dValues with different letters within a row are different ( P < 0.05).
ed turkey as “barbecued corn–like.” For consumer preference of meat odor, nonirradiated turkey meat patties were higher than irradiated meat, and aerobically packaged
meats were superior to vacuum-packaged
meats. This result agrees with the data for
volatiles, in which irradiation increased sulfur compounds but the sulfur volatiles disappeared rapidly under aerobic packaging
conditions (Table 1). Antioxidants had no
significant effect on the off-odor intensity of
irradiated turkey meat in the consumer acceptance test, even though previous data
showed that antioxidants reduced the
amounts of off-odor volatiles significantly
(Lee and Ahn 2003c). Consumers preferred
the color of irradiated control breast patties
to nonirradiated control patties. We believe
that consumers preferred the pink color of
raw meat after irradiation because it looked
fresher than nonirradiated meat. No difference in color preference was observed between irradiated control and antioxidanttreated irradiated meats. This indicated
that antioxidant had little effect on the redness of irradiated meat. The aerobically
packaged, irradiated raw turkey breast
meats with added sesamol ⫹ tocopherols
showed the lowest consumer preference
because the addition of sesamol made the
color dull red. However, consumer liked the
color of irradiated turkey breast meat with
added sesamol ⫹ tocopherols when they
were vacuum-packaged. This agrees with
the result of the CIE color analysis (Table 2).
Effect of antioxidants on cooked
turkey breast meat
Irradiation increased aldehydes, but antioxidants were effective in reducing aldehydes in both aerobically packaged and
vacuum packaged cooked turkey breast
meat (Table 5). Aldehydes contribute to the
1662
Table 6—TBARS, CIE color values, and consumer acceptance test of cooked
turkey breast meat patties with different antioxidants added
Consumer acceptance
TBARS
C-nonIR-V
C-IR-A
C-IR-V
S + Toc-IR-A
S + Toc-IR-V
G + Toc-IR-A
G + Toc-IR-V
SEM
0.60c
1.36a
0.96b
0.35d
0.35d
0.46cd
0.41d
0.05
L* value
CIE color
a* value
b* value
82.93 a
81.87ab
83.01 a
81.99ab
82.65ab
80.16c
81.63 b
0.32
8.35b
10.02 a
10.10 a
8.63b
10.25 a
8.06b
8.67b
0.23
15.60ab
16.14 a
15.34bc
15.97ab
15.71ab
15.32bc
14.88c
0.17
Interior
color
4.94ab
4.55b
4.64ab
5.13ab
5.54a
4.81ab
4.86bc
0.23
Flavor
5.55
5.45
4.99
5.04
5.04
4.71
5.00
0.24
1 = dislike extremely; 5 = neither like nor dislike; 9 = like extremely.
C-nonIR, nonirradiated control; C-IR, irradiated control; S + Toc-IR, irradiated sesamol and /alpha/tocopherol; G + Toc, irradiated gallate and /alpha/-tocopherol; V, vacuum package; A, aerobic package;
SEM, standard error of the means. n = 4.
a–dValues with different letters within a column are different ( P < 0.05).
oxidation flavor (rancidity) of cooked meat
the most, and hexanal is the predominant
aldehyde in cooked meat (Shahidi and Pegg
1994). Under vacuum conditions, many cyclo-compounds, hydrocarbons, and sulfur
compounds were produced by irradiation.
Antioxidant treatments reduced the
amount of cyclo-compounds and hydrocarbons in vacuum packaged, cooked turkey
breast meat. The amounts of sulfur compounds in irradiated, cooked turkey breast
meats, which were stored in aerobic conditions before cooking, were much lower than
those stored in vacuum conditions. This indicated that packaging conditions were
more important than antioxidant treatments in reducing irradiation off-odor. Although many sulfur compounds were detected in vacuum-packaged cooked turkey
meat, the amounts of S-compounds in
cooked meat were lower than those in raw
meat, indicating that large proportions of Scompounds were volatilized during cooking
and subsequent handling. Gallate ⫹ toco-
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 5, 2003
pherol treatment was the best in reducing
the amount of S-compounds of cooked turkey breast meat under vacuum conditions.
Huber and others (1953) reported that the
use of antioxidants such as ascorbate, citrate, tocopherol, gallate esters, and
polyphenols was effective in reducing offodor of irradiated meat.
Irradiation increased TBARS values, but
all antioxidant treatments were effective in
reducing lipid oxidation of cooked turkey
breast patties, both with aerobic and vacuum packaging (Table 6). This result agrees
with that of the effect of antioxidants, which
reduced the amounts of aldehydes in
cooked turkey meat patties (Table 5). Ahn
and others (1997, 1998) reported that preventing oxygen exposure after cooking was
more important for cooked meat quality than
irradiation or storage time of raw meat. The
redness (a* value) of irradiated meat was
still high after cooking. Cooking increased the
lightness (L* value) and yellowness (b* value) of meat, and antioxidant treatments were
effective in reducing the a* value of irradiated cooked turkey breast meat except for vacuum-packaged meat with sesamol + tocopherol treatment (Table 6).
The demographics of consumer panelists
for cooked turkey breast meat were similar
to those of the raw meat study: 75% of consumer panelists were female, 90% were between 18 and 54 y old, and 75% consumed
turkey or chicken products once a week or
more often (Table 3). Consumers could not
distinguish odor differences between nonirradiated and irradiated cooked turkey
meat because a relatively large number of
sulfur compounds were volatilized during
cooking (Table 6). No differences in off-flavor were observed between the irradiated
control and antioxidant-added irradiated
meats. Consumers liked the interior color of
vacuum-packaged cooked turkey breast
meat with added sesamol ⫹ tocopherol,
which produced the most red meat samples
among all treatments. We have not specifically asked consumers why they liked certain meat better than others, but we believe
that consumer liked the vacuum-packaged
cooked turkey breast meat with added sesamol ⫹ tocopherol because this meat
showed fresh-looking color.
Conclusions
T
HE USE OF FREE RADICAL SCAVENGERS
reduced the amounts of aldehydes but
had no effect on sulfur compounds in irradiated turkey meat. Packaging method was
more important than antioxidant treatment
in reducing irradiation off-odor in raw samples because S-compounds produced by irradiation easily volatilized under aerobic
packaging conditions. Antioxidants were effective in controlling oxidative change in irradiated turkey breast meat. The combined
use of aerobic packaging and antioxidants
was effective in reducing sulfur volatiles
and lipid oxidation of raw meat, which improved consumer acceptance of irradiated
raw poultry meat. However, the combined
effect of packaging and antioxidants on the
flavor and color of cooked turkey breast
meat was not clear as in raw meat.
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MS20030045 Submitted 1/26/03, Revised 3/24/03,
Accepted 3/25/03, Received 4/3/03
The work was supported by a Natl. Research Initiative Competitive Grant/USDA, Washington, D.C. The NASA FTCSC
has funded the purchase of Solartek72 Multimatrix vial
Autosampler used for the volatile analysis. Authors appreciate the technical help of Ms. Cynthia Shriver for consumer
study.
Authors Lee and Ahn are with the Dept. of Animal
Science, Iowa State Univ., Ames, IA 50011-3150.
Author Love is with the Dept. of Food Science and
Human Nutrition, Iowa State Univ., Ames, Iowa.
Direct inquiries to author Ahn (E-mail:
duahn@iastate.edu).
Vol. 68, Nr. 5, 2003—JOURNAL OF FOOD SCIENCE
1663
Food Chemistry and Toxicology
Consumer acceptance of irradiated meat . . .