JFS: Food Chemistry and Toxicology
Antioxidant Properties of Far Infraredtreated Rice Hull Extract in Irradiated
Raw and Cooked Turkey Breast
S.-C. LEE, J.-H. KIM, K.C. NAM, AND D.U. AHN
Food Chemistry and Toxicology
ABSTRACT: The antioxidant effect of far infrared–treated rice hull (FRH) extracts in irradiated turkey breast meat
was compared with that of sesamol and rosemary oleoresin. The FRH extracts significantly decreased thiobarbituric
acid-reactive substances values and volatile aldehydes (hexanal, pentanal, and propanal) and was effective in
reducing the production of dimethyl disulfide responsible for irradiation off-odor in irradiated raw and cooked
turkey meat during aerobic storage. The antioxidant activity of FRH extracts (0.1%, wt/wt) was as effective as that of
rosemary oleoresin (0.1%). However, the addition of FRH extracts increased red and yellow color intensities and
produced an off-odor characteristic to rice hull in raw and cooked meat.
Keywords: far infrared–treated rice hull extracts, volatile, color, irradiation, turkey breast
Introduction
I
RRADIATION PRODUCES HIGHLY REACTIVE HYDROXYL RADICALS
that react with meat components and change color, odor, and
taste of meat (Ahn and others 2001). Thus, the addition of free-radical scavenging or terminating antioxidants can interrupt free-radical chain reactions and is useful in reducing irradiated-dependent
quality changes in meat and meat products. Gray and others
(1996) reported that vitamin E was capable of quenching free radicals in meat during irradiation and storage. Nam and others (2002)
reported that addition of phenolic compounds such as sesamol,
gallic acid, or tocopherol, singly or in combination with turkey meat
or pork, prevented quality changes in the meat by irradiation.
The commercial use of natural antioxidants such as rosemary extracts by the meat industry is growing because of consumer demands
for natural products (Yu and others 2002). Rice hull can be an attractive protective source because it contains many antioxidant compounds, which can be extracted easily (Ramarathnam and others
1989; Wu and others 1994). Our pervious studies indicated that
methanolic extracts of rice hull contained several phenolic compounds such as cinnamic and benzoic acid derivatives (Nam and
others 2003a). Furthermore, radiation of rice hull with far infrared
(FIR) for 2 h increased the content of phenolic compounds in extract
from 0.12 mM to 0.18 mM, the 1,1-diphenyl-2-picrylhydrazyl (DPPH)
radical scavenging activity from 47.74% to 82.98%, and the inhibited
lipid peroxidation from 41.07% to 48.44%, respectively (Lee and others
2003). According to the gas chromatography-mass spectrometry
(GC-MS) analysis, more phenolic compounds (p-coumaric acid, 3vinyl-1-oxybenzene, p-hydroxy benzaldehyde, vanillin, p-hydroxy
benzoic acid, and 4,7-dihydroxy vanillic acid) were detected in FIRtreated rice hull (FRH) extracts. These results indicated that FIR radiation onto rice hull could liberate and activate covalently bound
phenolic compounds that have antioxidant activities.
Although a few natural extracts with antioxidant activities are
currently used as safe antioxidants, they are not as effective as
synthetic antioxidants and the manufacturing costs of those natural extracts are high (Addis and Hassel 1992). Therefore, rice hull
extract treated by FIR can be a good candidate to be used in irradiated meat systems as a natural antioxidant.
1904
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 6, 2003
The objective of this study was to determine the effect of FRH
extracts on lipid oxidation, volatiles, color, and sensory characteristics of irradiated raw and cooked turkey breast meat during aerobically packaged refrigerated storage.
Materials and Methods
Rice hull extract and antioxidants
Rice (Oriza sativa L., Japonica) hulls purchased from a milling
plant (Kimcheon, South Korea) were pulverized and passed
through a 48-mesh sieve. The ground rice hulls were irradiated in
a wooden box using a FIR heater (2 to 14 ␮m wavelength range,
35 × 10 cm, 100 V, max 300 W; Hakko Electric Machine Works Co., Nagano, Japan) for 2 h. Each portion (300 g) of FIR-treated rice hulls
was extracted with 1.5 L methanol overnight at room temperature,
filtered through a Whatman nylon membrane (0.2 ␮m), and evaporated to dryness in a rotary evaporator at 40 °C (Lee and others
2003). FRH extracts were stored at 4 °C under nitrogen atmosphere.
Sesamol (3,4-methylenedioxyphenol) was purchased from Sigma
Chemical Co. (St. Louis, Mo., U.S.A.) and rosemary oleoresin from
Ecom Manufacturing Corp. (Scarborough, ON, Canada).
Preparation of turkey breast patties
Turkey breast muscles (Pectoralis major) from 16 birds were divided into 4 groups and separately ground through a 3-mm plate.
Six treatments were prepared using irradiation and antioxidant
combinations: (1) nonirradiated control, (2) irradiated control, (3)
with irradiated sesamol (0.01%, wt/wt) added, (4) with irradiated
rosemary oleoresin (0.1%) added, (5) with irradiated FRH extracts
(0.1%) added, and (6) with irradiated FRH extracts (0.2%) added.
Each antioxidant was added to the ground meat and mixed in a
bowl mixer (Model KSM 90; Kitchen Aid Inc., St. Joseph, Mich.,
U.S.A.) for 1 min. The FRH extracts were dissolved in ethanol at 200
mg/mL level before use. To minimize the effect of solvent used to
dissolve FRH extracts, the same amount of ethanol was used to dissolve rosemary oleoresin or added to sesamol or the control treatment. The mixed meats were ground through a 3-mm plate again
to ensure even distribution of the added antioxidants.
© 2003 Institute of Food Technologists
Further reproduction prohibited without permission
Four sets of turkey breast patties (each 50 g; with 6 treatments,
4 replications, and 4 replications per each set) were made by hand
and individually packaged in oxygen-permeable bags (polyethylene, 4 × 6, 2 mil, Assoc. Bag Co., Milwaukee, Wis., U.S.A.), and irradiated at 2.5 kGy using a Linear Accelerator (Circe IIIR; Thomson
CSF Linac, Saint-Aubin, France) with 10 MeV of energy, a 10.2 kW
power level, and 84.9 kGy/min dose rate. To confirm the target
dose, 2 alanine dosimeters were attached to the top and bottom
sample surfaces and were read using a 104 Electron Paramagnetic Resonance (EMS-104; Bruker Instruments Inc., Billerica, Mass.,
U.S.A.). Samples were stored at 4 °C for 5 d. Two sets of the patties
were used for color, lipid oxidation, and volatile production of raw
meat at 0 and 5 d of storage. After 5 d of storage, the remaining 2
sets of raw meat were cooked in a 90 °C water bath to an internal
temperature of 75 °C, and then the cooked meats were aerobically packaged and stored in a refrigerator for 3 d. Cooked meat samples were analyzed for color, lipid oxidation, and volatile production
at 0 d and 3 d after cooking.
mann) and desorbed for 2 min at 225 °C, focused in a cryofocusing
module (–80 °C), and then thermally desorbed into a column for 60
s at 225 °C. An HP-624 column (7.5 m, 0.25-mm inner dia, 1.4 ␮m
nominal), an HP-1 column (52.5 m, 0.25-mm inner dia, 0.25 ␮m
nominal), and an HP-Wax column (7.5 m, 0.250-mm inner 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 1.5 min. After that, the oven temperature was increased to 15 °C at 2.5 °C per min, increased to
45 °C at 5 °C per min, increased to 110 °C at 20 °C per min, and
then increased to 210 °C at 10 °C per min and held for 2.25 min at
that temperature. Constant column pressure at 22.5 psi was maintained. The ionization potential of MS was 70 eV, and the scan
range was 19.1 to 350 m/z. The identification of volatiles was
achieved by the Wiley Library (Hewlett-Packard Co.). The area of
each peak was integrated using ChemStationTM software (HewlettPackard Co.), and the total peak area (total ion counts × 104) was
reported as an indicator of volatiles generated from the samples.
2-Thiobarbituric acid-reactive substances
Lipid oxidation was determined by measuring 2-thiobarbituric
acid-reactive substances (TBARS) content in meat (Ahn and others
1998). Meat sample (5 g) was placed in a 50-mL test tube and homogenized with 15 mL of deionized distilled water (DDW) and 50
␮L butylated hydroxytoluene (7.2% in ethanol) using a Brinkman
Polytron (Type PT 10/35; Brinkman Instrument Inc., Westbury, N.Y.,
U.S.A.) for 10 s at high speed. The meat homogenate (1 mL) was
transferred to a disposable test tube (13 × 100 mm), and thiobarbituric acid (TBA)/trichloroacetic acid (TCA) (20 mM TBA and 15%
[wt/vol] TCA) solution (2 mL) was added. The sample was mixed using a vortex and then incubated in a 90 °C water bath for 15 min to
develop color. After cooling for 5 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 532 nm against a
blank prepared with 1 mL DDW and 2 mL TBA/TCA solution. The
amounts of TBARS were expressed as milligrams of malondialdehyde (MDA) per kilograms of meat.
Color measurement
Commission Internationale de l’Eclairage (CIE) color values were
measured on the surface of samples using a LabScan colorimeter
(Hunter Assoc. Labs Inc., Reston, Va., U.S.A.) that had been calibrated against a black and a white reference tile covered with the same
packaging materials that were used for samples. The CIE L* (lightness), a* (redness), and b* (yellowness) values were obtained using an illuminant A (light source). Area view and port size were 0.6
and 1.0 cm, respectively. The values from 4 random locations of
upper and bottom surfaces were obtained, averaged, and used as
a mean value.
Analysis of volatile compounds
The volatiles of samples were determined using a Solatek 72
Multimatrix-Vial Autosampler/Sample Concentrator 3100 (TekmarDohrmann, Cincinnati, Ohio, U.S.A.) connected to a GC-MS (Model
6890/5973; Hewlett-Packard Co., Wilmington, Del., U.S.A.) according to the method of Ahn and others (2001). Sample (3 g) was placed
in a 40-mL sample vial, flushed with helium gas (40 psi) for 3 s, and
then capped airtight with a Teflon*fluorocarbon resin/silicone septum (I-Chem Co.; New Castle, Del., U.S.A.). The maximum waiting
time for a sample in a loading tray (4 °C) was less than 2 h to minimize oxidative changes before analysis. The meat sample was
purged with He (40 mL/min) for 14 min at 40 °C. Volatiles were
trapped using a Tenax/charcoal/silica column ( Tekmar-DohrJFS is available in searchable form at www.ift.org
Sensory evaluation
A 12-member sensory panel evaluated the intensity of off-odor.
Training sessions were conducted to familiarize panelists with irradiation odor and rancid odor. Panelists were trained with highdose–irradiated meat samples and specific chemicals known to be
major volatiles in irradiated meats (Ahn and others 2000a). Each
sample (3 g) at 5 d of raw, 0 d, and 3 d of cooked irradiated meat was
placed in a coded 20-mL sample vial and capped with a septum (IChem Co.). Four different irradiated samples with different antioxidants (control, 0.01% sesamol, 0.1% rosemary oleoresin, and 0.1%
FRH extract) were presented to each panelist in isolated booths at
each separate session. Panelists were instructed to smell samples
in random order and record the intensity of irradiation and rancid
off-odor on a 15-cm line scale anchored from “not detectable” to
“highly intense.”
Statistical analysis
The experimental design was to determine the effects of FRH
extracts and antioxidants on lipid oxidation, color, volatiles, and
sensory characteristics of irradiated turkey breast meat using 4replication. Analysis of variance was conducted by the procedure
of General Linear Model using SAS software (SAS Inst. 1995). Student-Newman-Keul’s multiple range tests were used to compare
the significant differences of the means of treatments (P < 0.05).
Mean value and standard error of the means (SEM) were reported.
Results and Discussion
Lipid oxidation
FRH showed significant antioxidant activities in both irradiated
raw and cooked turkey breast (Table 1). Irradiated meat became
more susceptible to lipid oxidation than nonirradiated meat, and the
difference was more significant after storage and cooking. Irradiated raw meat with added sesamol, rosemary oleoresin, and FRH extract had significantly lower TBARS values than the control during
the 5-d aerobic storage, but no differences in antioxidant activities
among antioxidant treatments were detected. When FRH extract was
incorporated at the 0.1% level, the TBARS value of irradiated raw
turkey breast meat was only 17% of irradiated control after 5 d of refrigerated storage.
Cooked meat would be more sensitive to lipid oxidation than raw
meat because of protein denaturation and structural damages in
membrane by heat during cooking (Gray and others 1996). The
Vol. 68, Nr. 6, 2003—JOURNAL OF FOOD SCIENCE
1905
Food Chemistry and Toxicology
Rice hull extract on irradiated turkey meat . . .
Rice hull extract on irradiated turkey meat . . .
Table 1—Thiobarbituric acid-reactive substances values of
irradiated raw and cooked turkey breast with different
antioxidants during refrigerated storage
Table 2—CIE color values of irradiated raw turkey breast
with different antioxidants during refrigerated storage
Irradiated
Irradiated
Compound
Nonirradiated
Control
Control
Sesamol
Rosemary
0.01%
0.1%
FRHa
0.1%
0.45by
0.57bx
0.03
Food Chemistry and Toxicology
Cooked b
Day 0 1.76by
Day 3 3.53bx
SEM
0.17
0.52ay
1.38ax
0.06
0.24c
0.21c
0.01
0.23c
0.21c
0.01
0.25c
0.23c
0.01
0.28c 0.02
0.30c 0.04
0.01
2.81ay 0.52cdy 0.60cdy 0.76cy 0.37dy 0.08
4.74ax 1.21dx 2.31cx 2.02cx 1.05dx 0.11
0.11
0.03
0.08
0.05
0.03
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
b 0 d and 3 d after cooking
Values with different letters (a–d) within a row are significantly different
( P < 0.05), n = 4.
Values with different letters (x,y) within a column with same meat are
significantly different ( P < 0.05).
TBARS values of cooked meat increased rapidly due to structural
disruption in muscle cells. The irradiated cooked turkey breasts with
added antioxidants incorporated were relatively resistant to lipid
oxidation. The addition of antioxidants reduced the TBARS values of
irradiated raw meat by 70% to 85% at d 5. The TBARS value of turkey
meat was highly dependent on the level of added amounts of FRH
extracts, and the TBARS values of cooked meat with 0.2% FRH extracts
was about half that of 0.1% FRH extracts after 3 d of storage. The
TBARS of irradiated cooked meat after 3 d of storage indicated that
0.1% FRH extracts showed almost the same degree of antioxidant
activity as 0.1% rosemary oleoresin, whereas 0.2% FRH extracts
showed the same antioxidant effect as 0.01% of sesamol.
The antioxidant activity of plant extracts is related to their
polyphenol content and structure (Foti and others 1996). The major
antioxidant compounds in rosemary are phenolic diterpenes, carnosic acid, carnosol, rosmanol, and epi- and isorosmanol (Inatani
and others 1983; Schwarz and Ternes 1992). Although it is difficult
to compare antioxidant activity of FRH extracts with pure antioxidant, sesamol, the significant antioxidant effects of FRH extracts at
low concentrations of phenolic compounds could be coming from
the synergistic effects of various compounds in FRH extracts.
Color changes
FRH extracts had a detrimental effect on the color of irradiated
raw and cooked turkey breast meat. Due to the characteristic brown
color of extracts, the incorporation of FRH extracts and rosemary oleoresin both increased a* and b* values of irradiated raw turkey
breast (Table 2). Therefore, addition of FRH extracts or rosemary
increased the color intensities and deteriorated the color attribute
of irradiated turkey breast meat. In particular, addition of 0.2% FRH
extracts in turkey breast meat significantly increased the b* values
of irradiated raw meat. On the other hand, addition of sesamol had
no effect on the color of irradiated raw meat. Irradiation made poultry breast raw meat redder or pinker because of CO-heme pigment
formation (Nam and Ahn 2002).
In general, consumers expect the color of fully cooked poultry
breast meat to be white (Cornforth and others 1986). In irradiated
cooked turkey breast (Table 3), addition of FRH extracts increased
b* values but lowered L* values. Sesamol or rosemary extract had
1906
Control
0.2% SEM
(Total ion counts × 10 4 )
Raw
Day 0
Day 5
SEM
Compound
Nonirradiated
Control
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 6, 2003
Sesamol
Rosemary
0.01%
0.1%
FRHa
0.1%
0.2% SEM
(Total ion counts × 10 4)
L* value
Day 0
51.4
Day 5 51.2c
SEM
0.4
a* value
Day 0 6.6dx
Day 5 4.3cy
SEM
0.1
b* value
Day 0 11.4dx
Day 5 10.1ey
SEM
0.2
52.2
51.9
52.0abc 51.7bc
0.3
0.3
7.8bx
6.0by
0.2
7.0cx
3.8dy
0.1
52.1
52.9a
0.4
52.0
51.1y 0.4
52.8a 52.4abx 0.3
0.3
0.3
8.4ax
6.1by
0.1
8.3ax
6.4ay
0.1
8.4ax
6.6ay
0.1
0.1
0.1
14.1b
14.2b
0.2
17.1a
17.5a
0.2
0.2
0.2
10.5e 10.9de 12.1cx
10.7d 10.8d 11.7cy
0.2
0.2
0.1
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
Values with different letters (a–d) within a row are significantly different
( P < 0.05), n = 4.
Values with different letters (x,y) within a column with same meat are
significantly different ( P < 0.05).
Table 3—CIE color values of irradiated cooked a turkey
breast with different antioxidants during refrigerated storage
Irradiated
Compound
Nonirradiated
Control
Control
Sesamol
Rosemary
0.01%
0.1%
FRHb
0.1%
(Total ion counts ×
L* value
Day 0
Day 3
SEM
a* value
Day 0
Day 3
SEM
b* value
Day 0
Day 3
SEM
84.7ab
84.3ab
0.2
84.2bc 84.9a
84.4ab 84.8a
0.2
0.2
5.3b
5.3b
0.1
0.2% SEM
10 4)
84.1bc
84.2ab
0.2
83.6c
83.9b
0.2
82.7d
82.7c
0.2
0.2
0.2
5.2bx
4.9dy
0.1
5.6ax
5.2bcy
0.1
5.7ax
5.0cdy
0.1
5.3bx
4.6ey
0.1
5.7a
5.9a
0.1
0.1
0.1
15.6d
15.3cd
0.1
16.1c 15.1ex 15.9cdx 17.1bx 18.0a
16.0b 14.0ey 15.1dy 15.9bcy 17.6a
0.2
0.1
0.1
0.1
0.2
0.1
0.1
a 0 d and 3 d after cooking.
bFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
Values with different letters (a-d) within a row are significantly different
( P < 0.05), n = 4.
Values with different letters (x, y) within a column with same meat are
significantly different ( P < 0.05).
little effect on a* values of meat, but the 0.2% FRH treatment produced higher a* values than the other treatments. Sesamol or
rosemary oleoresin, however, did not show any negative effect on
the color of irradiated cooked turkey breast. Therefore, to increase
the applicability of FRH extracts as an antioxidant, the color should
be removed from the FRH extracts.
Off-odor volatiles
Irradiation produced many new volatiles but the production of
volatile sulfur compounds was the most critical (Table 4). DimeJFS is available in searchable form at www.ift.org
Rice hull extract on irradiated turkey meat . . .
Table 4—Profile of volatiles irradiated raw turkey breast
meat with different antioxidants at 0 d
Irradiated
Control
0.01%
Irradiated
Rosemary
0.1%
FRHa
0.1%
0.2% SEM
(Total ion counts × 10 4)
Pentane
95b
152a
0c
Dimethyl
sulfide
0b
1455a 1284a
0c
0c
1456a 1008a
0c
1366a 153
681ab 727ab
684ab 663ab
96b
286
2-Propanone
1033
1159
1295
245
1-Pentene
Hexane
2-Butanone
Ethyl
acetate
1209
1250
Compound
0
57
46
0
100
56
33
112b
93b
94b
131b
226a
155b
17
0
68
110
4
36
60
29
106b
166b
233b
97b
308b
618a
58
0.2% SEM
404a
66b
47b
63b
55b
25
46
0
0
0
0
18
Carbon
disulfide
0b
0b
75a
29ab
31ab
47ab
15
Propanal
91b
320a
0b
0b
0b
0b
41
2-Propanone
1360c
3375b
3324b
1-Pentene
44
33
10
0
0
23
107c
207a
132bc
154bc
123bc
164b
13
27
40
81
53
75
18
177c
165c
158c
242c
354b
21
0
0
0
11
0
4
Hexane
63b
228a
17
Ethyl
acetate
S-methyl
125a
0b
0b
0b
0b
6
Ethyl
0
propanate
276
0
0
0
0
112
2461b 1144bc 1324bc 491
0.1%
0
42b
4562a 2583b
0.1%
68b
31b
0
0.01%
FRHa
Dimethyl
sulfide
40b
Toluene
Rosemary
Pentane
Ethyl
0b
propanate
ethanethiate
Sesamol
(Total ion counts × 104 )
2-Butanone 18
0b
Control
7
Carbon
1550a
disulfide
1743
Nonirradiated
Control
521a
3798ab 4237a
3282b 205
21
Toluene
161b
324a
278a
391a
298a
315a
36
Octane
32b
136ab
147ab
141ab
231a
152ab
36
Hexanal
52b
2003a
0b
0b
8b
0b
216
18
Dimethyl
disulfide
0c
Octane
48
54
0
0
0
0
24
Nonanal
0
35
0
27
19
41
2-Octene
0
19
0
0
0
0
4
␣-Pinene
0b
0b
0b
152a
0b
0b
8
Hexanal
0b
91a
0b
0b
0b
0b
9
Camphene
0b
0b
0b
67a
0b
0b
3
Nonane
0
13
12
0
0
16
10
Limonene
0b
0b
4b
96a
17b
34b
14
Nonanal
0
28
0
0
0
0
11
1,8-Cineole
0
0
0
88
0
0
36
2427c
7515a
5154b
4397b
4406b
␣-Pinene
0b
0b
0b
132a
0b
0b
1
Total
Camphene
0b
0b
0b
65a
0b
0b
3
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
Limonene
0b
0b
0b
75a
30b
33b
11
0b
0b
349a
0b
0b
56
1,8-cineole
Total
0b
3656c
8921a 6332b
Values with different letters (a-d) within a row are significantly different
( P < 0.05), n = 4.
6036b 4799bc 5217bc 560
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
Values with different letters (a–d) within a row are significantly different
( P < 0.05), n = 4.
thyl disulfide (DMDS) and dimethyl sulfide (DMS) were the predominant volatiles in irradiated raw turkey meat. Ahn and others
(2000a) reported that DMDS was a major sulfur compound responsible for the irradiation off-odor. Addition of antioxidants significantly reduced the amount of off-odor volatiles in irradiated
meat: the production of sulfur volatiles (DMDS and S-methyl
ethanethiate) and lipid oxidation–dependent volatiles such as
aldehydes (hexanal and nonanal) and hydrocarbons (pentane
and octane) in irradiated raw turkey meat were significantly decreased by the addition of sesamol, rosemary oleoresin, or FRH extracts. Huber and others (1953) reported that the use of polyphenols was effective in reducing off-odor in irradiated meat. The
volatile-reducing effect of antioxidant was relatively small, but
rosemary oleoresin (␣-pinene, camphene, limonene, and 1,8-cineole) or FRH extracts (ethyl acetate, ethyl propionate, and liJFS is available in searchable form at www.ift.org
4510b 382
monene) produced a few terpenoids and acids responsible for
their characteristic odors.
After 5 d of aerobic storage, the most prevalent volatile compounds in irradiated raw turkey breast were not sulfur volatiles but
2-propanone and hexanal (Table 5). Most sulfur volatiles disappeared from the raw meat after 5 d of aerobic storage. Nam and
others (2002) also reported that sulfur volatiles were highly volatile
and easily disappeared when meats were exposed to aerobic conditions. Thus, more concern in aerobically stored meat was the production of lipid oxidation products such as aldehydes, which produce a rancid off-odor. Added antioxidants significantly reduced
the development of lipid oxidation, and propanal and hexanal were
not produced in meats with antioxidants added.
The production of warmed-over flavor is the most critical problem
in cooked meat during storage, and thus the role of antioxidants is
important in irradiated cooked meat. A large amount of hexanal was
produced, and a few other aldehydes compounds were newly generated in cooked nonirradiated and irradiated turkey breast meat at
0 d (Table 6). In cooked meat, the amount of hexanal correlated the
best with the degree of lipid oxidation (Shahidi and others 1987; Ahn
and others 2000b). Addition of antioxidants was very effective in reVol. 68, Nr. 6, 2003—JOURNAL OF FOOD SCIENCE
1907
Food Chemistry and Toxicology
Compound
Nonirradiated
Control
Sesamol
Table 5—Profile of volatiles irradiated raw turkey breast
meat with different antioxidants at 5 d of refrigerated storage
Rice hull extract on irradiated turkey meat . . .
ducing aldehydes (propanal, pentanal, hexanal, and nonanal) and
hydrocarbons (pentane and octane) related to lipid oxidation in irradiated cooked turkey breast at 0 d. FRH extract also was effective in
decreasing the amounts of rancid volatiles. The amount of hexanal
produced in FRH-treated cooked meat was only 8% to 15% of irradiated control at 0 d. FRH extracts showed a similar effect on the hexanal in nonirradiated cooked turkey meat (Nam and others 2003b).
The cooked irradiated turkey breast stored for 3 d produced
greater amounts of volatile aldehydes than the meat stored for 0 d
(P < 0.05) (Tables 6 and 7). Added antioxidants played an important role in preventing lipid oxidation products at 3 d, but the effect
was weaker than that at 0 d. The amount of hexanal from FRH-treat-
ed cooked meat was about 27% to 58% of the irradiated control.
More positive antioxidant effect was produced by 0.01% sesamol or
0.2% FRH treatment than 0.1% FRH extracts or 0.02% rosemary
treatment. Lower amounts of propanal, pentanal, and hexanal
Table 7—Volatiles profile of irradiated cooked turkey breast
meat after 3 d of storage
Irradiated
Food Chemistry and Toxicology
Nonirradiated
Control
Compound
Control
Sesamol
Rosemary
0.01%
0.1%
FRHa
0.1%
(Total ion counts ×
Table 6—Profile of volatiles irradiated cooked turkey breast
meat after 0 d storage
Irradiated
Compound
Nonirradiated
Control
Control
Sesamol
Rosemary
0.01%
0.1%
FRHa
0.1%
0.2% SEM
1631b
5032a
647c
0b
0b
445c 263
2-Pentene
0b
1328a
Propanal
398b
1101a
154b
167b
148b
2-Propanone
1486
2432
2171
2370
2150
1-Pentene
0
110
19
32
28
0
263b
606a
277b
665a
273b
321b
Hexane
0b
1013bc 575c
2981a
2-Pentene
0b
64
0b
153
0
708c
78
0
0
997c
0
194
0
18
1617cd 2841b 2156c
1094d
192
2-Propa- 2317b
none
3522a
2498b
2574b
227
1-Pentene
2694b 2364b
0b
0b
72a
0b
0b
93a
13
620b
519c
301d
768a
516c
558bc
23
2-Butanone 92c
194a
193a
155b
152b
150b
7
Ethyl
430a
acetate
172c
178c
137c
269b
332b
25
3-Methyl
butanal
0c
87b
91b
76b
93b
123a
6
2-Methyl
butanal
0b
93a
92a
90a
104a
116a
7
32
56
1-Heptene
35
61
32
74
67
46
12
102ab
122ab
80b
133a
105ab
77b
11
1120d
170
2194 410
2-Butanone 0c
149ab
128b
122b
114b
183a
11
Ethyl
acetate
382a
221bc
137c
186bc
245b
457a
26
Pentanal 1848
3-Methyl
butanal
0d
116ab
99bc
73c
80c
136a
7
2-Methyl
butanal
0c
140a
133a
90b
96b
163a
11
1-Heptene
0c
84a
14bc
30abc
62ab
Heptane
48
143
93
173
77
Toluene
1-Octene
Octane
2-Octene
28abc 14
4008a
1279d
2656b 1999c
0
190
0
0
0
0
77
67c
148b
43c
220a
131b
83c
12
2140bc 2339b
1808c
4019a 2274b
2290b
116
351d
53
576c
1048b
227d
1542a
592c
Hexanal 35172b 48736a 17717c 35630b 28095b 13633c 2253
39
Nonane
0
0
58
175b 186
Nonanal
129ab
159a
136ab
81
2569a 1608b
4455a
Heptane
552ab 503ab
3250a
Propanal 2956b
Hexane
(Total ion counts × 10 4 )
Pentane
Pentane
0.2% SEM
10 4)
30
19
137ab 131ab
53
14
72b
16
Pentanal
766ab
1217a
339b
Toluene
0
184
354
689
163
0
310
Total
Dimethyl
disulfide
0
537
752
0
527
0
295
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
1-Octene
0d
154a
105b
114b
51c
76bc
10
Octane
973b
5772a
1280b
5701a 1699b 1898b 291
2-Octene
277b
693a
187b
582a
218b
311b
82
49471b 69187a 27139d 53775b 40679c 23771d 2249
Values with different letters (a–d) within a row are significantly different
( P < 0.05), n = 4.
Table 8—Sensory characteristics of irradiated raw and
cooked turkey breast with different antioxidants
Hexanal 13487bc 25855a 3622cd 5012c 3954cd 2067d 698
Nonane
0b
149a
149a
151a
65ab
45ab
32
Off-odor b
Nonanal
241b
883a
581ab
421ab
98b
93b
156
␣-Pinene
0
0
0
511
0
0
128
Irradiation odor
Raw at 5 d
5.3
Cooked at 0 d 3.2
Cooked at 3 d 4.4
Rancid odor
Raw at 5 d
11.5a
Cooked at 0 d 11.9a
Cooked at 3 d 12.9a
Camphene
0
0
0
392
0
0
89
Limonene
0
0
0
360
0
0
93
1,8-cineole
0b
0b
0b
308a
0b
0b
52
Total
19956b
47211a 11248c 18150b 11132c 8675c 1295
Control
Sesamol Rosemary
0.01%
0.1%
FRHa
0.1%
SEM
3.3
6.7
4.7
1.3
2.4
6.3
1.4
3.1
3.9
1.2
1.2
2.0
3.4b
4.8b
3.0b
2.3b
3.9b
4.9b
4.8b
5.3b
3.0b
1.0
1.2
0.7
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
aFRH = far infrared–treated rice hull extracts; SEM = standard error of the means
b 0.0 = not detectable; 15.0 = highly intense.
Values with different letters (a-d) within a row are significantly different
(P < 0.05), n = 4.
Values with different letters (a–d) within a row are significantly different
( P < 0.05), n = 12.
1908
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 6, 2003
JFS is available in searchable form at www.ift.org
were detected in 0.01% sesamol or 0.2% FRH extracts than 0.02%
rosemary oleoresin or 0.1% FRH treatments. The volatile aldehydereducing activities of antioxidants were consistent with the results
of TBARS values in Table 1.
Sensory evaluation
In raw meat, sensory panelists could not detect a significant difference in the intensities of irradiation odor (Table 8). According to
volatiles analysis, almost all sulfur volatiles responsible for irradiation off-odor disappeared after 5 d of raw-meat storage and the
remaining amounts were below threshold levels. Thus, irradiation
odor was not much of a problem in aerobically stored irradiated raw
meat. On the other hand, panelists could easily distinguish rancid
odor in irradiated raw and cooked turkey breast meat. The intensities of rancid odor were much lower in samples with antioxidant
added than in control. The difference among antioxidant treatments, however, was not found even in cooked meat at 3 d.
Conclusions
F
AR INFRARED – TREATED RICE HULL EXTRACTS ADDED IN IR -
radiated turkey meat at 0.1% showed a similar level of antioxidant activities to sesamol (pure phenolic) at 0.01% or commercial
rosemary oleoresin at the 0.1% level. FRH extracts effectively reduced the production of TBARS, volatile aldehydes, and volatile sulfur compounds in irradiated raw and cooked turkey meat. However,
turkey breast with FRH extracts incorporated, had increased color
intensity and produced a characteristic off-odor. Therefore, color
and off-odor compounds should be removed from FRH extract if it
is going to be used in meat as an antioxidant.
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MS 20030111 Submitted 2/26/03, Revised 4/1/03, Accepted 4/25/03, Received
4/25/03
This collaborative research was supported by the Ministry of Science and Technology (MOST)
and the Korea Science and Engineering Foundation (KOSEF) through the Coastal Resource
and Environmental Research Center (CRERC) at Kyungnam Univ., Korea, and State of Iowa
funds. Author Lee thanks Kyungnam Univ. for supporting his visit to Iowa State Univ.
Authors Lee and Kim are with the Dept. of Food Science and Biotechnology,
Kyungnam Univ., Masan 631-701, Korea. Authors Nam and Ahn are with
the Dept. of Animal Science, Iowa State Univ., Ames, Iowa. Direct inquiries
to author Lee (E-mail: sclee@kyungnam.ac.kr).
Vol. 68, Nr. 6, 2003—JOURNAL OF FOOD SCIENCE
1909
Food Chemistry and Toxicology
Rice hull extract on irradiated turkey meat . . .