Antioxidative effects of glycosyl-ascorbic acids synthesized by maltogenic amylase to reduce lipid oxidation and volatiles production in cooked chicken meat.

Abstract

Glycosylated ascorbic acids were synthesized by using the transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose to show effective antioxidative activity with enhanced oxidative stability. The modified ascorbic acids comprised mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. The antioxidative effects of the glycosyl derivatives of ascorbic acid on the lipid oxidation of cooked chicken breast meat patties were compared, and the synergistic effect when combined with alpha-tocopherol was determined in terms of thiobarbituric acid-reactive substances (TBARS) and volatiles production during storage. The results indicate that the glycosylated ascorbic acids had very effective antioxidative activity in preventing lipid oxidation, and were better in their synergistic effect in comparison to authentic ascorbic acid, with maltosyl-ascorbic acid being the most effective. Volatiles production was highly correlated with the TBARS values in the lipid oxidation of cooked meat. The antioxidative effect preventing the production of volatiles was particularly strong on pentanal, fairly strong on propanal and butanal, and not at all on ethanal. Propanal, pentanal, and the total volatiles thus provided a good representation of the lipid oxidation status of cooked chicken meat.

Full text

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Antioxidative Effects of Glycosyl-ascorbic Acids Synthesized by Maltogenic
Amylase to Reduce Lipid Oxidation and Volatiles
Production in Cooked Chicken Meat
Soo-Bok LEE,1;yKi-chang NAM,2Sung-Joon LEE,3Jong-Ho LEE,1
Kuniyo INOUYE,4and Kwan-Hwa PARK5
1Research Institute of Food and Nutritional Sciences and Department of Food and Nutrition,
Yonsei University, Seoul 120-749, Korea
2Department of Animal Science, Iowa State University, Ames, Iowa 50011-3150, USA
3Palo Alto Medical Foundation Research Institute, Stanford University, Palo Alto, California, USA
4Division of Food Science and Biotechnology, Graduate School of Agriculture,
Kyoto University, Kyoto 606-8502, Japan
5Center for Agricultural Bio-Materials and Department of Food Science and Technology,
School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
Received May 1, 2003; Accepted August 15, 2003
Glycosylated ascorbic acids were synthesized by using
the transglycosylation activity of Bacillus stearothermo-
philus maltogenic amylase with maltotriose to show
effective antioxidative activity with enhanced oxidative
stability. The modified ascorbic acids comprised mono-
and di-glycosyl transfer products with an ?-(1,6)-
glycosidic linkage. The antioxidative effects of the
glycosyl derivatives of ascorbic acid on the lipid
oxidation of cooked chicken breast meat patties were
compared, and the synergistic effect when combined
with ?-tocopherol was determined in terms of thiobar-
bituric acid-reactive substances (TBARS) and volatiles
production during storage. The results indicate that the
glycosylated ascorbic acids had very effective antiox-
idative activity in preventing lipid oxidation, and were
better in their synergistic effect in comparison to
authentic ascorbic acid, with maltosyl-ascorbic acid
being the most effective. Volatiles production was highly
correlated with the TBARS values in the lipid oxidation
of cooked meat. The antioxidative effect preventing the
production of volatiles was particularly strong on
pentanal, fairly strong on propanal and butanal, and
not at all on ethanal. Propanal, pentanal, and the total
volatiles thus provided a good representation of the lipid
oxidation status of cooked chicken meat.
Key words: antioxidant;
maltogenic amylase; glucosyl-ascorbic acid;
maltosyl-ascorbic acid; lipid oxidation
Bacillusstearothermophilus
Ascorbic acid, a well-known natural antioxidant, is
commonly used in many food systems for maintaining
organoleptic quality and protecting against oxidation.1,2)
It functions both as a reducing agent and as a free radical
scavenger by donating either one or two electrons to
more-oxidized neighboring species.3–5)It readily scav-
enges such reactive oxygen and nitrogen species as
superoxide and hydroperoxyl radicals, aqueous peroxyl
radicals, singlet oxygen, peroxynitrite, and nitroxide
radicals. It can also act as a reducer by regenerating ?-
tocopherol from the ?-tocopheroxyl radical that is
produced via the scavenging of lipid-soluble radicals.
Ascorbic acid has two major properties to make it an
effective antioxidant.6)First is the low one-electron
reduction potential of both ascorbate and its one-
electron oxidation product, the ascorbyl radical. This
low reduction potential enables ascorbate and its
ascorbyl radical to reduce basically all physiologically
relevant radicals and oxidants. Second is the stability
and low reactivity of the ascorbyl radical that is formed.
The ascorbyl radical readily dismutates to form ascor-
bate and dehydroascorbic acid. Dehydroascorbic acid is
rapidly and irreversibly hydrolyzed to 2,3-diketogulonic
acid, which then decomposes to oxalate, threonate, and
many other products. Ascorbic acid has also recently
been considered as a cosmetic ingredient for skin-care
due to its beneficial role against skin aging by promoting
collagen biosynthesis7)and inhibiting melanogenesis.8)
Ascorbic acid can be used as a common antioxidant in
many food systems.9,10)However, it easily undergoes
yTo whom correspondence should be addressed. Tel: +82-2-2123-3124; Fax: +82-2-312-5229; E-mail: soobok@yonsei.ac.kr
Abbreviations: BSMA, Bacillus stearothermophilus maltogenic amylase; AA, ascorbic acid; G-AA, glucosyl-ascorbic acid; M-AA, maltosyl-
ascorbic acid; Tc, ?-tocopherol; TBARS, thiobarbituric acid-reactive substances
Biosci. Biotechnol. Biochem., 68 (1), 36–43, 2004

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oxidation to 2,3-diketo-L-gulonic acid, a biologically
inactive compound, and to 2-hydroxyfurfural under
oxidative conditions such as heat, transition metals,
and oxidases,11,12)and consequently loses its antioxida-
tive activity. This instability against such oxidative
environments is disadvantageous in food and other
applications. To overcome this problem, many studies
have been performed to synthesize more-stable ascorbic
acid derivatives by many physico-chemical and enzy-
matic methods.12–14)Among them, 2-O-?-glucosyl as-
corbic acid has been prepared by ?-glucosidase.15)2-O-
glycosyl ascorbic acid derivatives showed greatly
enhanced stability against oxidative degradation, but
due to no reducibility, they were of no use as anti-
oxidants in food. We have recently found that Bacillus
stearothermophilus maltogenic amylase (BSMA), which
is known to have a high degree of transglycosylation
activity for various sugars and sugar-containing mole-
cules, could transfer mono- or disaccharides to an
acceptor, ascorbic acid, by forming an ?-(1,6)-glyco-
sidic linkage.16–18)The glycosyl-transfer products of
ascorbic acid were structurally analyzed and also
determined to show high oxidative stability against
metal ions and oxidase while retaining active reduc-
ibility.
Oxidative deterioration of unsaturated lipids generally
produces an off-flavor and also decreases the nutritional
quality of many lipid-containing foods. This oxidation
can generate a carcinogenic initiator and mutagen which
is a breakdown product of peroxidized polyunsaturated
fatty acids.19)Hence, in cooked meat products, effective
substances are required to be safe and stable to prevent
lipid oxidation during storage. One of the important
factors in preventing lipid oxidation in cooked meat
during storage is blocking the availability of oxygen and
removing the free radicals. These free radicals can be
generated by oxygen reacting with the labile fatty acyl
group of phospholipids in cooked meat. Ascorbic acid,
even though it is susceptible to oxidative degradation, is
known as a safe scavenger of oxygen and oxygen
radicals; therefore, glycosylated ascorbic acids can be
expected to be very effective for the stable storage of
meat due to their dual properties of enhanced oxidative
stability and antioxidative activity.
In the present study, the antioxidative effects of
glycosyl derivatives of ascorbic acid are described on
the storage stability of cooked chicken breast meat,
measured as TBARS and volatiles produced, and their
synergistic effect in combination with ?-tocopherol is
also reported.
Materials and Methods
Materials. Bacillus stearothermophilus maltogenic
amylase (BSMA) was prepared from recombinant
Esherichia coli DH5? containing plasmid pSG12.16)
This plasmid was constructed by inserting the BSMA
gene into the HindIII site of pUC18. The cultivation of
recombinant E. coli and purification of BSMA has been
previously reported.16)Ascorbic acid and maltotriose
were purchased from Sigma Chemical Co. (St. Louis,
MO, USA). All other chemicals used were of reagent
grade.
Enzyme Assay. The activity of BSMA was assayed
with 1% ?-cyclodextrin in a 50mM sodium citrate buffer
(pH 6.0) at 55?C by using 3,5-dinitrosalicylic acid
(DNS) according to the previously reported method.20)
The absorbance of the mixture was measured at 575nm
with an Ultrospec III spectrophotometer (Pharmacia
LKB, Uppsala, Sweden). One unit of enzyme activity is
defined as the amount of enzyme producing 1?mol of
maltose per minute.
Transglycosylation of Ascorbic Acid by BSMA. The
transglycosylation reaction was performed with 10%
(w/v) maltotriose as a donor and 60% (w/v) ascorbic
acid as an acceptor in a 25mM sodium citrate buffer at
pH 6.0. BSMA (1U/mg of maltotriose) was added to the
reaction mixture which was incubated for 48h at 55?C
in the dark. The reaction mixture was then boiled for
5min to stop the reaction. After centrifuging at 6,000 ?
g for 10min, the resulting supernatant was subjected to
ultrafiltration by Ultrafree apparatus (Millipore, Bed-
ford, MA, USA). The filtrate was used for further
purification.
Analysis of the Transglycosylation Products by TLC
and HPLC. The reaction products were analyzed by
TLC on Whatman K6F silica gel plates (Fischer
Scientific, Chicago, IL, USA) with n-butyl alcohol/
acetic acid/water (3:1:1, v/v/v). After irrigating twice,
the TLC plate was dried and visualized either by dipping
in a solution containing 0.3% (w/v) N-(1-naphthyl)-
ethylenediamine and 5% (v/v) H2SO4in methanol and
heating at 110?C for 10min, or by UV detection at
254nm (camag Reprostar 3, Muttenz, Switzerland). An
HPLC analysis of the transfer products was carried out
with a Nova-Pak C18 reverse-phase analytical column
(3.9mm ID ? 150mm), using an isocratic solvent
system at 0.7ml/min of 0.1 M phosphoric acid (pH 2.0)
as a mobile phase with detection at 265nm using an
SLC 200 instrument (Samsung, Seoul, Korea).
Purification of the Transfer Products. The reaction
mixture was applied to a Q-sepharose anion exchange
column (6 ? 30cm; Pharmacia) that had been equili-
brated with a 10mM NaOH solution. Elution was
performed with a linear NaCl gradient of 0–1 M in the
same solution at a flow rate of 2ml/min. The peak
fractions of the transfer products were pooled and
concentrated by Speed Vac SC-110 apparatus (Savant
Instruments, Holbrook, NY, USA). The resulting con-
centrate was loaded into a Bio-Gel P-2 column
(1:6 ? 100cm; Bio-Rad) which was eluted with distilled
water at a flow rate of 0.2ml/min at room temperature.
Glycosyl-ascorbic Acids and Their Antioxidative Effects 37

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The fractions containing the transfer products were
confirmed by TLC, collected and lyophilized.
Liquid Chromatography/Mass Spectrometry (LC/
MS). An LC/MS analysis was performed with a jeol
LC instrument used in the atmospheric pressure chemi-
cal ionization (APCI) mode. A 5-?l amount of the
sample at 100?g/ml was directly injected into the
instrument.
13C-NMR Analysis. The
transfer products were recorded with a JNM LA-400 FT-
NMR spectrometer (Jeol, Tokyo, Japan) run in the
heteronuclear multiple bond connectivity (HMBC)
mode. The sample was dissolved in DMSO-d6 at
24.9?C with tetramethylsilane (TMS) as the internal
reference. Two transfer products synthesized were
analyzed to be ?-(1,6)-linked glucosyl-ascorbic acid
(G-AA) and maltosyl-ascorbic acid (M-AA), as shown
in Fig. 1.
13C-NMR spectra of the
Sample Preparation. Hand-deboned and skinless
breast meat (2kg) pieces were prepared from four
chickens. The deboned breast meat was pooled, ground
twice through a 3-mm plate, and used to make meat
patties (30g/patty) of about 35mm in diameter and
5mm in thickness. The experiment was designed with
seven treatments to determine the antioxidative effects
of ascorbic acid, glycosylated ascorbic acids, and their
combinations with tocopherol on the lipid oxidation of
cooked meat against a control with no added antiox-
idant. Eight sets of patty samples with four replications
were prepared by adding a single antioxidant or
antioxidant combination to the ground meat. The
antioxidants of the glycosyl derivatives of ascorbic acid
were prepared in deionized distilled water (DDW), and
an antioxidant stock of 1% (w/v) tocopherol was
prepared as an emulsion by mixing 200ml of DDW
with 2g of tocopherol in a Waring Blender for 1min at
high speed. The antioxidant solutions were added the
ground meat to make patties (15% per patty, v/w) alone
or in combination. A patty made with only DDW was
used as the control. Each patty was put into an oxygen-
impermeable nylon/polyethylene bag and cooked in a
water bath at 80?C for 15min. Immediately after
cooking, each patty was individually vacuum-packed
in the same type of bag and then stored at 4?C.
Thiobarbituric acid-reactive substances (TBARS) and
volatiles in the cooked meat patties, after their exposure
to air, were determined every 6h for 18h at 15?C.
Lipid Oxidation. Lipid peroxidation was determined
by the method of Buege and Aust21)with a slight
modification. A 1-g meat sample was placed in a 50-ml
test tube and homogenized with 5ml of DDW in a
homogenizer for 15s at speed 7–8. The meat homoge-
nate (1ml) was transferred to a disposable test tube
(13 ? 100mm) containing a butylated hydroxyanisole
(50?l, 7.2%) and thiobarbituric acid/trichloroacetic
acid (TBA/TCA) solution (2ml). The mixture was
vortexed and then incubated in a boiling water bath for
15min to develop color. After the color had developed,
the sample was cooled in cold water for 10min and then
centrifuged for 15min at 2;000 ? g. The absorbance of
the supernatant in each sample was determined at
531nm against a blank containing a mixture of 1ml of
DDW and 2ml of TBA/TCA. The TBARS number is
expressed as milligrams of malondialdehyde (MDA) per
kilogram of meat. The TBARS values were determined
at the same time and under the same temperature
conditions as those used in the volatile analysis.
Analysis of Volatiles. Purge-and-trap apparatus con-
nected to a gas chromatograph (GC) was used to analyze
the volatiles potentially responsible for the off-odor in
meat.22)A Precept II and model 3000 purge-and-trap
concentrator (Tekmar-Dorham, Cincinnati, OH, USA)
were used to purge and trap the volatiles emitted from
the samples. A model 6890 GC (Hewlett Packard Co.,
Wilmington, DE, USA) equipped with an HP 5973 mass
selective detector (Hewlett-Packard) was used to char-
acterize and quantify the volatile compounds influenced
by headspace oxygen during the sample-holding period.
A 1-g sample of cooked meat was placed in a sample
vial (40ml), and the vial was sealed tightly with a
Teflon-lined cap. The sample in the vial was placed in a
refrigerated (15?C) sample tray and purged with helium
gas at 40ml/min for 15min by using the Precept II auto-
sampling unit equipped with a robotic arm. The volatiles
were trapped at 30?C in a Tenax/silica gel/charcoal
column (Tekmar-Dorham) and desorbed for 1min at
220?C. The temperature of the connecting transfer lines,
the 3000 concentrator and the GC inlet was maintained
(A)
(B)
O
HO
OH
HO
O
HO
O
O
HO
O-Na+
OH
O
HO
OH
HO
O
O
O
HO
OH
HO
HO
O
O
HO
O-Na+
OH
Fig. 1.
Ascorbic Acid.
(A) ?-(1,6)-glucosyl-ascorbic acid; (B) ?-(1,6)-maltosyl-ascorbic
acid.
Chemical Structures of the Transglycosylated Products of
38 S.-B. LEE et al.

Page 4

at 135?C. A split inlet (49:1 split ratio) was used to
inject the volatiles into a GC column (HP-5MS
capillary, 0.25mm i.d., 30m, and 0.25?m film thick-
ness, Hewlett-Packard) and subjected to an oven
temperature program (30?C for 2min, increased to
40?C at 2?C/min, increased to 50?C at 5?C/min,
increased to 100?C at 10?C/min, increased to 140?C at
20?C/min, increased to 200?C at 30?C/min, and finally
held for 4.5min). The inlet temperature was 180?C,
helium was used as the carrier gas, and the column flow
was 1.1ml/min. The ionization potential for MS was
70eV with a scan range of m=z 45–450. The volatiles
were identified by comparing their mass spectral data
with those in the Wiley library (Hewlett-Packard). The
area of each peak was integrated by using ChemStation
software (Hewlett-Parkard), and the total ion count
(?103) is reported as an indicator of the volatiles
generated from each meat sample. The TBARS values
and selected volatile components of the cooked meat
were statistically analyzed with SigmaStat software
(SPSS, Illinois, USA), and the Student–Newman–Keuls
test was used to compare the differences in the mean
values of TBARS and volatiles affected by the antiox-
idants.
Results and Discussion
Lipid Oxidation
Hydroxyl radicals and other reactive oxygen species
can interact with lipids in meat and form lipid hydro-
peroxides. Lipid hydroperoxides are broken down to
form lipid alkoxyl radicals that can initiate and
propagate the chain reaction of lipid peroxidation.23,24)
Phospholipids are generally considered to be responsible
for about 90% of lipid oxidation in meat.24)Subsequent
breakdown of such hydroperoxides generates volatiles,
which may partially contribute to the off-odor of
oxidized meat. The extent of lipid peroxidation can be
represented by the TBARS number which indicates the
amount of malondialdehyde (mg/kg of lipid) produced
from lipid peroxidation. In the present work, the
antioxidative effects of glycosylated ascorbic acids and
the synergistic effects with ?-tocopherol were evaluated
as TBARS values on lipid oxidation in cooked chicken
breast meat (Table 1). The TBARS values for G-AA and
M-AA with or without Tc were significantly different in
comparison with those of the control with increasing
storage time. Cooked chicken breast meat with no
treatment in the sample vial (control) gave TBARS
values of meat samples held in the autosampler at 15?C
that increased during the first 6h of sample-holding time
by 2.9-fold over those at 0h, and that continued to
increase and give significantly higher TBARS values
throughout the whole storage period of 18h. The
development of lipid oxidation in cooked meat patties
has been reported to be very rapid after exposure to air.
Cooking not only disrupts the membrane structure and
destroys the endogenous antioxidative system, but also
facilitates the release of iron from carrier proteins or
storage proteins in food.24)The increments of TBARS
values per hour were evaluated as follows: 0.248
(correlation coefficient, r2¼0:993) for the control,
0.080 (r2¼0:915) for the AA treatment, 0.104 (r2¼
0:902) for the G-AA treatment, 0.0891 (r2¼0:897) for
the M-AA treatment, 0.0652 (r2¼0:949) for the ?-
tocopherol (Tc) treatment, 0.018 (r2¼0:998) for the
AA+Tc treatment, 0.011 (r2¼0:712) for the G-AA+Tc
treatment, and 0.0082 (r2¼0:7224) for the M-AA+Tc
treatment. These results show that the 6-?-glycosyl
ascorbic acids acted as antioxidants and suppressed the
lipid oxidation in cooked chicken breast meat by up to
around 60% of the oxidation in the control during
storage, similarly to ascorbic acid. This result is in
agreement with the report that ascorbic acid was
effective in preventing lipid peroxidation in plasma
and low-density lipoprotein.5)The antioxidative effects
of the glycosylated ascorbic acids on lipid oxidation in
the cooked meat were very strong in comparison to
ascorbic acid, even though small variations were
observed. When the meat samples were treated by the
combinations with ?-tocopherol, the antioxidative ef-
fects were highly synergistic, the most effective being
the combination of M-AA and ?-tocopherol. The
TBARS values with that combined treatment did not
significantly change, maintaining their level up to 18h.
This is believed to have been due to the regeneration of
Table 1.
Oxidation (TBARS) of Cooked Chicken Breast Meat Patties during Storage
Effects of Ascorbic Acid, Glycosyl Derivatives of Ascorbic Acid, ?-Tocopherol, and Their Combinations with ?-Tocopherol on Lipid
ControlAA1
G-AAM-AATcAA+Tc G-AA+TcM-AA+TcSEM2
Storage time TBARS (mg of MDA/ kg of meat)3
0h
6h
12h
18h
0.973a
2.834a
4.001a
5.542a
0.521c
0.831b
1.122bc
2.021b
0.694b
1.083b
1.444b
2.667b
0.712b
0.986b
1.339b
2.376b
0.61b
0.904b
1.171bc
1.826b
0.445c
0.566c
0.659c
0.774c
0.658b
0.701c
0.688c
0.865c
0.558c
0.64c
0.603c
0.735c
0.0127
0.0127
0.0127
0.0130
1Abbreviations for the treatments: AA, ascorbic acid; G-AA, glucosyl-ascorbic acid; M-AA, maltosyl-ascorbic acid; Tc, ?-tocopherol; AA + Tc,
ascorbic acid + ?-tocopherol; G-AA + Tc, glucosyl-ascorbic acid + ?-tocopherol; M-AA + Tc, maltosyl-ascorbic acid + ?-tocopherol.
2SEM indicates the standard error of the mean.
3TBARS indicate mean values expressed as milligrams of malondialdehyde (MDA) per kilogram of meat.
a{cDifferent letters within a row indicate significant difference (P<0.05).
Glycosyl-ascorbic Acids and Their Antioxidative Effects39

Page 5

?-tocopherol from the ?-tocopheroxyl radical by the
glycosyl-ascorbic acids. TBARS values of the cooked
meat samples at 0h fluctuated to some extent. This is
presumed to have been due to the initial oxidation status
of the cooked meat samples; this can be influenced by
the degree of lipid oxidation, that is, significant amounts
of primary and secondary lipid oxidation by-products, in
the homogenized raw meat before cooking.
Volatiles
The volatile compounds produced from the cooked
meat during storage were analyzed by gas chromatog-
raphy (GC) with the purge-and-trap apparatus. The
volatiles mainly consisted of hydrocarbons (butane and
pentane) and aldehydes (ethanal, propanal, butanal,
pentanal and hexanal) in the cooked chicken breast
meat with no added antioxidant after oxygen exposure
for 18h. In the cooked chicken breast meat with no
treatment (control) and with the other treatments, the
production of total volatile compounds due to lipid
oxidation gradually increased throughout the sample
holding time of 18h (Table 2). The total volatiles
produced from lipid oxidation in the cooked meat patties
were considerably less after treatment with the glycosyl
derivatives of AA, G-AA and M-AA, being the range of
40-50% lower. The synergistic suppression of total
volatiles by the combination with ?-tocopherol (Tc) was
also clearly apparent, the most effective being the
combination of M-AA and Tc which is in good
agreement with the result for TBARS. This is assumed
to have been due to the better stability of M-AA against
an oxidative environment in comparison with AA and
G-AA. The linear correlation between TBARS and total
volatiles in the cooked meat patties was confirmed
(Fig. 2). The correlation coefficients (r2) were as
follows: 0.902 (control), 0.769 (AA), 0.714 (G-AA),
0.798 (M-AA), 0.701 (Tc), 0.764 (AA+Tc), 0.741 (G-
AA+Tc) and 0.744 (M-AA+Tc). Total volatiles were
highly correlated with lipid oxidation (TBARS values)
of the cooked meat patties for the control and treated
samples. The respective production of aldehydes and
hydrocarbons in the volatiles of the cooked meat patties
throughout the storage period also gradually increased
(Tables 3 and 4). The volatile values for G-AA and M-
AA with or without Tc were significantly different from
those of the control with increasing storage time up to
18h. Aldehydes were the major components (around
Table 2.
Production of Total Volatiles in Cooked Chicken Breast Meat Patties during Storage
Effects of Ascorbic Acid, Glycosyl Derivatives of Ascorbic Acid, ?-Tocopherol, and Their Combinations with ?-Tocopherol on the
ControlAA1
G-AA M-AATc AA+Tc G-AA+TcM-AA+TcSEM2
Storage time Total volatiles (total ion count ? 10?3)3
4082 5618
18298a
8353b
17982b
10162c
23781b
13033c
0h
6h
12h
18h
4290
17090a
30445a
49462a
3378
10568b
18484b
26692b
2681
9948b
15947b
23819b
2554
6784b
11482c
13742c
2912
7041b
8429c
12755c
2441
4020b
7013c
8892c
622
672
707
740
1Abbreviations of the treatments: see the legend to Table 1.
2SEM indicates the standard error of the mean.
3Total volatiles are presented as the mean value expressed as the total ion count of volatiles generated.
a{cDifferent letters within a row indicate significant difference (P<0.05).
Control
AA
G-AA
M-AA
Tc
0
10
20
30
50
60
0
TBARS value (mg of MDA/kg of meat)
2346
Total volatiles (area x 10-3)
(A)
40
Tc
AA+Tc
G-AA+Tc
M-AA+Tc
0
4
8
12
16
(B)
0 2346
TBARS value (mg of MDA/kg of meat)
Total volatiles (area x 10-3)
157
157
Fig. 2.
the Control and Antioxidant-treated Cooked Meat Patties.
(A) Antioxidative effects for the control ( ), AA ( ), G-AA
( ), M-AA () and Tc ( ); (B) synergistic effects of Tc ( ),
AA+Tc ( ), G-AA+Tc ( ) and M-AA+Tc (
volatiles on the ordinate indicates the total ion count (?103) of
volatiles generated. Straight lines were drawn by a linear least-
squares regression.
Relationships between TBARS Values and Total Volatiles in
). The area of
40 S.-B. LEE et al.