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Methanolic extract of Java Plum (Syzygium cumini Linn.) seeds as a natural antioxidant on lipid oxidation of oil-in-water emulsions


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Fish oil is considered as a great nutritional importance due to a high content of essential n-3 polyunsaturated fatty acids (PUFAs) such as linolenic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). However, PUFAs are susceptible to oxidative deterioration. Methanolic extract of Java plum seed was a source of strong antioxidant polyphenols against DPPH as well as strong Ferric (Fe³⁺) reducing agent. The aim of the research was to evaluate the effect of methanolic extract of Java Plum seed (MEJS) on lipid oxidation of fish oil from striped catfish (Pangasius hypothalamus) in oil-in-water emulsions as a food model at 35±2°C during 144 h of storage. The results showed that MEJS has stronger inhibition activity than Grape Seed Extract (GSE) but lower than BHA (p < 0.05) according to conjugated dienes (CD), peroxide values (PoV), and thiobarbituric acid reactive substances (TBARS). Inhibition activity of MEJS on lipid oxidation ranged between 28% and 38% at concentrations of 50-800 mg/L during 144 h of storage.
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International Food Research Journal 24(4): 1636-1643 (August 2017)
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1.2*Rohadi, 2Raharjo, S., 3Falah, I.I. and 2Santoso, U.
1Department of Processing Agricultural Product, Faculty of Agricultural Technology, Semarang
University, Jl. Arteri Soekarno-Hatta, Semarang 50196, Indonesia
2Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology,
Gadjah Mada University, Jl. Flora No. 1, Bulaksumur , Yogyakarta 55281, Indonesia
3Department of Chemistry, Faculty of Mathematics and Natural Science, Gadjah Mada University,
Jl. Sekip Utara, Yogyakarta 55281 Indonesia
Methanolic extract of Java Plum (Syzygium cumini Linn.) seeds as a natural
antioxidant on lipid oxidation of oil-in-water emulsions
Fish oil is considered as a great nutritional importance due to a high content of essential n-3
polyunsaturated fatty acids (PUFAs) such as linolenic acid, docosahexaenoic acid (DHA),
and eicosapentaenoic acid (EPA). However, PUFAs are susceptible to oxidative deterioration.
Methanolic extract of Java plum seed was a source of strong antioxidant polyphenols against
DPPH as well as strong Ferric (Fe3+) reducing agent. The aim of the research was to evaluate
the effect of methanolic extract of Java Plum seed (MEJS) on lipid oxidation of sh oil from
striped catsh (Pangasius hypothalamus) in oil-in-water emulsions as a food model at 35±2ºC
during 144 h of storage. The results showed that MEJS has stronger inhibition activity than
Grape Seed Extract (GSE) but lower than BHA (p<0.05) according to conjugated dienes
(CD), peroxide values (PoV), and thiobarbituric acid reactive substances (TBARS). Inhibition
activity of MEJS on lipid oxidation ranged between 28% and 38% at concentrations of 50-800
mg/L during 144 h of storage.
Fish oil is considered as a great nutritional
importance. This is due to its naturally high content
of essential n-3 polyunsaturated fatty acids (PUFAs),
such as α-linolenic acid (C18:3), eicosapentaenoic
acid (C20:5) and docosahexaenoic acid (C22:6).
These fatty acids have benecial effects for heart’s
health (Simopoulos, 2008). However, PUFAs are
susceptible to oxidation which leads to the production
of short-chain chemical compounds associated with
decreasing food quality attributes such as rancidity as
well as textural and nutritional modication (Hsieh
and Kinsella, 1989; McClements and Decker, 2000;
Maqsood, 2010). The rate oxidation of PUFAs in
bulk oil increases equal to their unsaturated degree.
A high-PUFAs food product has more susceptible
to oxidative deterioation (McClements and Decker,
2000) such as sh oil from farmed freshwater Tra
catsh (Pangasius hypothalamus) (Ho and Paul,
Previous research showed that methanolic extract
of Java Plum (Syzygium cumini Linn.) seed (MEJS)
has a strong antioxidant activity according to RSA-
DPPH (radical scavenging activity 2,2’diphenyl-1-
picrilhydrazil) and FRAP (ferric reducing antioxidant
power) (Rohadi et al., 2016). In addition that a polar
hydrophilic antioxidant is less effective in an oil-in-
water emulsion compared to a non-polar lipophilic
and vice versa. The polar antioxidants such as trolox,
ascorbic acid, rosmarinic acid, and carnosic acid are
more effective in bulk oil due to its accumulation
in the air-oil interphase area while in an emulsion
system, the non-polar ones such as α-tocophorol,
ascorbyl palmitate, and carnosol are more effective
(McClement and Decker, 2000).
Synthetic antioxidants such as BHA (Butylated
Hydroxy Anisole), BHT (Butylated Hydroxy
Toluene) and TBHQ (tert-butylhydroquinone) were
more effective to inhibit food deterioration due to
lipid oxidation during processing and storage (Frankel
1998; Maqsood, 2010). However, application of
those antioxidants raised doubt in terms of toxicity-
related problems of synthetic antioxidants (Madavi
and Salunke, 1995; Buxiang and Fukuhara, 1997;
Baydar et al., 2007; Vayupharp and Laksanalamal,
Java Plum seed
Natural antioxidant
Lipid oxidation
Oil-in-water emulsions
Article history
Received: 27 April 2016
Received in revised form:
15 July 2016
Accepted: 24 July 2016
1637 Rohadi et al./IFRJ 24(4): 1636-1643
2012). In the other hand, consumer’s demand for
environmentally friendly natural antioxidants has
greatly increased in recent years (Perumalla et al.,
2011). The last decades researches have been focused
on the effectiveness of natural antioxidants as a chain-
breaking agent in lipid oxidation, such as tocopherol,
plant extracts (rosemary, blackberries, blueberries,
cherries, grapes, raspberries, strawberries, tea), and
kiam wood extract (Kanner et al., 1994; Frankel,
1996; Maqsood, 2010; Perumalla et al., 2011).
Zhang and Lin (2009) reported that Java plum
(Syzygium cumini Linn.) extract has high tannin
content and antioxidant activity toward DPPH and
FRAP test, therefore, it has a high potential as a
natural antioxidant. Among part of the plant, the seed
has the highest polyphenols content (Vasi and Austin,
2009; Rydlewsky, 2013; Saha et al., 2013). Rohadi
et al. (2016) reported that yield of Java Plum seed
extract using 50% methanol (v/v) was 16.29% (db)
and contain 45.99±0.25% total phenolic compound
expressed as g gallic acid equivalents (GAE/100 g
dry extract), 2.28±0.07% total avonoid expressed
as g quercetin equivalents (QE/100 g dry extract),
and 26.9±0.07% total tannin as expressed as g tannic
acid equivalents (TAE/100 g dry extract). This result
showed that extract of Java plum seed has a high
potential as a natural antioxidant. Several studies
have reported the natural polyphenol of plant extracts
were more effective to inhibit lipid oxidation in an
oil-in-water emulsion (Roedig-Penman and Gordon,
1997; Maqsood and Benjakul, 2010; Skowyra
et al., 2014; Azman et al., 2016). However, the
scientic information of Java plum seed as a natural
antioxidant on lipid oxidation of sh oil in an oil-
in-water emulsion is still limited. Therefore, the
aim of this research was to evaluate the effect of
methanolic extract of Java Plum seed (MEJS) on lipid
oxidation of sh oil from striped catsh (Pangasius
hypothalamus) in an oil-in-water emulsion as a food
model during storage.
Materials and Methods
Live striped catsh (Pangasius hypothalamus)
were obtained from “Mina Jaya” farmer group in
Margo Mulyo Village, Seyegan, Sleman, Yogyakarta.
Java plum (Syzygium cumini Linn. var. Genthong) were
collected from Semarang, Central Java, Indonesia
during December 2014. Grape seed extract (GSE)
contained 95% oligoprotoanthocianidin (OPC) (Bulk
powder, UK), 2,2’-diphenyl-1-picrilhydrazil (DPPH)
and 1,1,3,3-tetra methoxypropane (TMP) (Aldrich
Chemical Co.), and butylatedhydroxyanisole (BHA)
(Sigma Chemical Co.) were an analytical grade.
Preparation of methanolic extract of Java plum seed
The seed was separated from the fruit pulp and
then was sliced with stainless steel knife, dried using
cabinet dryer at 47±3º C for 24 h. The dried seed
was ground into powder using a grinder then sieved
through 80 mesh. Twenty ve grams of Java Plum
seed powder were exhaustively three times extracted
with aqueous-methanol 50% (v/v) at a ratio of 1:10
(w/v) using the maceration method for 6 h at ambient
temperature according to (Vasi and Austin, 2009)
with slight modication. The extracts were collected
and concentrated using a rotary vacuum evaporator
(IKA-RV 10 Basic Germany) then the solid crude
extract was freeze-dried for solvent removal and kept
in the refrigerator for further analysis. This extraction
procedure was repeated three times.
Preparation of striped catsh llet and its lipid
Six live striped catsh (Pangasius hypothalamus)
is weighed of approximately 1 kg per head. They were
cleaned and lleted in 2 x 5 cm2 size using stainless
steel knife, stored in polyethylene (PE) bag, and
freezed prior to oil extraction. The lipid content of
striped catsh llet was extracted according to Bligh
and Dyer (1959). Twenty ve grams of thawed llet
cuts were ground using a meat grinder and added with
200 mL of a mixture of chloroform: methanol:distilled
water (1:2:1, v/v) then centrifuged at 3000 rpm and
4oC for 5 min. A-50 mL of chloroform and 25 mL
of distilled water were added into homogenate and
furthermore mixed for 2 min at a similar speed. The
homogenate was centrifuged at 4oC with speed 3000
rpm for 45 min using J-6B Centrifuge (Beckman,
Fullerton, CA, USA). Thereafter, the supernatant
was put into a separating funnel, which chloroform
fraction was drained off into Erlenmeyer glass
previously lled with 25 g of activated anhydrous
sodium sulphate with gentle shaken. The mixture
was ltered using Whatman lter paper No.4. The
solvent was evaporated from ltrate using a vacuum
rotary evaporator at 25ºC, and the remaining solvent
residue was removed using nitrogen gas.
Determination of fatty acid prole
Fatty acid composition of striped catsh oil was
determined as Fatty Acid Methyl Ester (FAME)
according to Latimer (2000). Into 0.5 mL of sh oil,
1.5 mL of methanolic sodium was added then heated
at 70ºC for 5-10 min while vigorously shaken. The
mixture was cooled and added with 2 mL of boron
triuoride methanoate then reheated at 70oC for
Rohadi et al./IFRJ 24(4): 1636-1643 1638
5-10 min and cooled again. Thereafter, the mixture
was extracted using 1 mL of heptane and 1 mL of
saturated NaCl. The top layer was taken and put into
Eppendorf tubes. One µL of sample was injected
into GC-2010 Shimadzu (Shimadzu, Kyoto Japan)
equipped with ame ionization detector (FID) at
260ºC. Capillary column (CP-Sil8-CB 30 m x 0.25
mm) was used. The standard retention time of FAME
was used to identify chromatogram peak of each
sample. Fatty acid content was quantied based on
peak area ratio as g fatty acid /100 g oil (%).
Preparation of sh oil emulsion
Fish oil emulsion was prepared based on Maqsood,
(2010) with slight modication. Twenty ve mL of
striped catsh oil were mixed with 225 mL of 0.1 M
buffer acetate (pH 5.4) and 2.5 mL of Tween 40 then
homogenized in 400 mL plastic jars for making 250
mL of oil-in-water emulsion. The mixture was kept
in an ice-bath (10±2ºC) during homogenization at
6500 rpm (Ultra Turrax T50, IKA Werke, Germany)
for 5 min. The methanolic extract of Java plum seed
(MEJS) powder was mixed into sh oil emulsion at
various concentration (25, 50, 100, 200, 400 and 800
mg/L) using vortex (Velp Scientica Europe) at 3000
rpm for 3 min. The mixture (10 mL) was then kept
at 35±2ºC in the dark room. The control of oil-in-
water emulsion was prepared in the same procedure
but distilled water was added instead of the extract.
BHA and grape seed extract (GSE) were used as the
reference antioxidant. Samples were taken at every
24 h for the determination of conjugated diene (CD)
value, peroxide value (PoV) and the thiobarbituric
acid reactive substances (TBARS).
Determination of lipid oxidative deterioration
The lipid oxidation was determined using
evaluation of conjugated diene (CD), peroxide value
(PoV), and thiobarbituric acid reactive substances
(TBARS) value.
Analysis of conjugated diene (CD)
Determination of conjugated diene was carried
out according to Frankel et al. (1996) in (Maqsood,
2010). Fish oil emulsion (0.1 mL) was dissolved in
5 mL of methanol and the absorbance was measured
at λ=234 nm using spectrophotometer UV-1601
(Shimadzu, Kyoto Japan). The absorbance of λ 234
nm indicated CD value.
Analysis of peroxide value (PoV)
Determination of peroxide value was done
according to Sakanaka et al. (2004). Fish oil
emulsion (50 μL), 2.35 mL of 75% ethanol, 50 μL
of 30% ammonium thiocyanate, 50 μL of 20 mM
ferrous chloride (FeCl2) in 3.5% HCl were mixed and
shaked using a vortex. After 3 min the absorbance
of the sample was measured using spectrophotometer
UV-1601 (Shimadzu, Kyoto Japan) at λ = 500 nm.
An increase absorbance at λ = 500 nm indicated the
formation of peroxide. The percent inhibition of
peroxidation of sh oil-in water emulsion of MEJS
was calculated as follow:
Analysis of thiobarbituric acid reactive substances
Determination of TBARS was done according
to (Buege and Aust, 1978) in (Maqsood, 2010). Fish
oil emulsion (0.5 mL), 2.5 mL of TBA (0,375%
thiobarbituric acid, 15% trichloroacetic acid-TCA
and 0.25 N HCl) was mixed and shaked using a
vortex. The mixture was heated in boiling water
for 10 min until pink color appeared then cooled in
water ow and mixed using a vortex at 3000 rpm
(25ºC) for 10 min and the absorbance was measured
at λ 532 nm. A standard curve was conducted using (TMP) at various
concentrations ranged 0.61-20.9 μM/L. TBARs value
was expressed as μM–MDA equivalent/L.
Statistical analysis
All data was presented as a mean value±standard
deviation (SD). Analysis of the variance was
determined and the mean comparison was examined
by the Duncan’s Multiple Range Test (DMRT) at
the signicance level of 0.05 using SPSS statistic
software series 22 for Windows (SPSS Inc. Chicago,
USA). Regression analysis was applied to determine
correlation among variables.
Results and Discussion
Lipid content and fatty acid composition of striped
catsh oil
The lipid content of striped catsh llet
(Pangasius hypothalamus) was 9.45%, similar to
previous research reported by (Maqsood, 2010)
which showed lipid content of striped catsh from
Thailand was 9.2%. Meanwhile, (Ho and Paul, 2009)
reported lipid content of Tra catsh from Mekong
River delta in Vietnam was only 2.55%.
In the present study, striped catsh contains 43.57%
saturated fatty acid (SFA), 40.01% monounsaturated
fatty acid (MUFA), and 16.42% polyunsaturated fatty
acid (PUFA) (Table 1). Unsaturated fatty acid content
1639 Rohadi et al./IFRJ 24(4): 1636-1643
(56.43%) was 1.3 times higher than saturated fatty
acid content (43.57%), which indicated that lipid
content of the sh was vulnerable to oxidation. The
high percentage of SFA (43.57%) was similar to the
previous study reported by (Ho and Paul, 2009). The
MUFAs content was 36.71% cis9 oleic acid (C18:1
n-9), 2.54% palmitoleat acid, and 0.43% oleic acid
isomer (trans-9 oleic acid). These values showed that
oleic acid was abundant in striped catsh oil.
The PUFAs content of striped sh oil consisted of
8.28% linoleic acid (C18:2 n-6), 2.42% eicosatrienoic
acid (C20:3 n-6), 2.01% linolenic acid (C18:3 n-3),
1.51% eicosatetraenoic acid (C20:4 n-6), and 1.34%
eicosadienoic acid (C20:2 n-6). Eicosapentaenoic
acid (C20:5 n-3) or EPA content was 0.4%, higher
than reported by Ho and Paul, (2009) and Maqsood,
(2010), i.e. 0.31% and 0.13%, respectively. However,
the striped catsh oil did not contain docosahexaenoic
acid (C22:6 n-3), which was similar to the previous
studies (Ho and Paul, 2009; Maqsood, 2010). The
difference of lipid content and fatty acid composition
of striped catsh could be contributed to a different
method of oil extraction, kind of feed, and type of
sh farmed.
Effect of MEJS on lipid oxidation of sh oil
Methanolic Java plum seed extract (MJES)
was prepared from dry Java plum seed powder
which extrated using methanol 50% (v/v), rather
than ethanol 50% (v/v) and ethyl acetate 85% (v/v).
Among the extracts, methanolic extract of Java
Table 1. Fatty acid prole of lipid extracted from striped catsh
(Pangasius hyphotalamus)
Table 2. The phenolic compounds of Syzygium cumini
seed were extracted using three different solvents.
Different subscript letters within the same kind of phenolic
compound mean signicant differences ( p < 0.05) (n=3).
Rohadi et al./IFRJ 24(4): 1636-1643 1640
Plum seed (MEJS) has stronger antioxidant activity
according to DPPH and Feric (Fe3+) reducing capacity
and a moderate activity for linoleic acid oxidation
inhibition (Rohadi et al., 2016). The high antioxidant
activity of Java Plum seed extract could be associated
with the high content of phenolic compounds (Table
2). The phenolic compound acts both as primary
antioxidants donate hydrogen to scavenge alkoxy and
peroxy radicals to form unreactive antioxidant radical
(chain breaking antioxidants), and also as secondary
antioxidants, such as metal chelating agents, singlet
oxygen quenchers, and oxygen scavengers (Frankel,
1998; Brewer, 2011; Saha et al., 2013).
A model emulsion was used to assess the
deterioration of lipids at two stages of oxidation,
i.e. primary oxidation products (CD and PoV) and
secondary oxidation products (TBARS). Maqsood
and Benjakul, (2010) reported that the effectiveness
of four phenolic compounds to inhibit lipid oxidation
in Menheden sh oil emulsion system during 168 h of
storage. Meanwhile, Azman et al. (2016) investigated
that the potential of bearberry leaf extract as a natural
antioxidant to inhibit lipid oxidation of sunower oil
emulsion during 40 days of storage.
Effect of MEJS on conjugated diene (CD) formation
The effect of MEJS (50 ppm) on lipid oxidation
of striped catsh oil emulsion during storage based
on conjugated diene (CD) and peroxide value (PoV)
is presented in Figure 1(a) and 1(b). The CD values
of samples gradually increased until 144 h (p<0.05),
whereas PoV increased up to 96 h (p<0.05) then
decreased slightly until the end of the storage period
(except control). A similar pattern was also found in
TBARS value (Figure 1c). TBARS value reects the
concentration of lipid oxidation secondary products
such as aldehyde (malondialdehyde, 4-hydroxy
nonenal) equivalent to malonaldehyde (µM-MDA
The addition of MEJS can inhibit CD formation of
an oil-in-water emulsion as well as BHA, moreover,
signicantly higher than grape seed extract (GSE)
(Figure 1a). This result could be associated with the
stronger free radical scavenging activity of BHA and
MEJS during initiation or propagation stage, therefore,
it can inhibit free radical formation in further stages.
CD values of the sample were higher than earlier
study (Maqsood and Benjakul, 2010) (ranged of 0.8-
2.0 at λ 234 nm). The difference in CD value could
Figure 1(a). Effect of methanolic extract of Java Plum
(Syzygium cumini Linn.) seed (MEJS) on lipid oxidation
products formation, conjugated diene (CD) in striped
catsh (Pangasius hyphotalamus) oil-in-water emulsion
at 35±2oC during 144 h of storage, compared to BHA
and grape seed extract (GSE). For all treatments, a nal
concentration of 50 mg/L was used in the system (n=3).
Figure 1(b). Effect of methanolic extract of Java Plum
(Syzygium cumini Linn.) seed (MEJS) on lipid oxidation
products formation, peroxide value (PoV) in striped
catsh (Pangasius hyphotalamus) oil-in-water emulsion
at 35±2oC during 144 h of storage, compared to BHA
and grape seed extract (GSE). For all treatments, a nal
concentration of 50 mg/L was used in the system (n=3).
Figure 1(c). Effect of methanolic extract of Java
Plum (Syzygium cumini Linn.) seed (MEJS) on
lipid oxidation products formation, thiobarbituric
acid reactive substances (TBARS) in striped catsh
(Pangasius hyphotalamus) oil-in-water emulsion at
35±2oC during 144 h of storage, compared to BHA and
grape seed extract (GSE). For all treatments, a nal
concentration of 50 mg/L was used in the system (n=3).
1641 Rohadi et al./IFRJ 24(4): 1636-1643
be contributed to a different fatty acid composition
of sh oil and phenolic compounds. Maqsood and
Benjakul, (2010) investigated Menheden sh oil and
single phenolic compund (not plant extract).
A strong correlation between RSA-DPPH activity
of MEJS or GSE and CD formation during initial 72
h was 0.98 and 0.84, respectively. Moreover, a strong
correlation was also found between MEJS or GSE
and CD formation using FRAP method, i.e. 0.96 and
0.95, respectively.
Effect of MEJS on peroxide value (PoV) formation
Peroxide value (PoV) reects the development of
primary oxidation products in emulsion food model.
The PoV of emulsion with or without 50 ppm MEJS
during storage was presented in Figure 1(b). PoV
of the samples gradually increased during 72 h then
decreased until the end of storage period. The PoV of
the samples with MEJS, BHA, and GSE were lower
than control (p<0.05). The effectiveness of MEJS
and BHA to inhibit PoV formation during initial
72 h of storage were similar, even higher than GSE
(p<0.05). Previous studies of the effectiveness of
emulsion containing plant extract antioxidant have a
similar pattern. Roedig-Penman and Gordon, (1997)
reported that emulsions containing green tea extract
required 8 days to reach the end of the induction time.
Meanwhile, Maqsood and Benjakul, (2010) found
that an emulsion containing 100 mg/L of the tannic
acid took 96 h to reach more than 4.5 (λ=500 nm). An
emulsion containing 48 µg/mL of Tara extract took
13 days to reach more than 10 meq hydroperoxide/
kg (Skowyra et al., 2014). Furthermore, Azman et al.
(2016) noted that the sample containing bearberry leaf
extract (BL) 1 g/kg reached the end of the induction
time after 20 days, while BHT samples after 36 days
of storage.
Inhibition of lipid oxidation among three
antioxidant agents (i.e. MEJS, GSE, BHA) at all
concentration (50-800 ppm) differed signicantly
(p<0.05). BHA has the highest of oxidation inhibition
(45-55%), followed by MEJS (38-40%), and the lowest
GSE (18-22%) (Figure 2). Phenolic composition of
MEJS which consisted of 45.99±0.25% total phenolic
(g GAE/100g), 2.28±0.07% avonoid (g QE/100g),
and 26.9±0.07% total tannin (g TAE/100g) may be
strongly contributed on inhibition of lipid oxidation
in sh oil emulsion system. Meanwhile, GSE
contained 95% of oligoproto-anthocianidin (OPC)
family (Bulkpowders, 2015).
Maqsood, (2010) reported that tannic acid was
very effective to inhibit CD and PoV in menheden
sh oil emulsion system. Tannic acid can be strongly
inhibited the formation of hydroperoxide and a
conjugated diene, which have a strong correlation
with DPPH and ABTS analysis. MEJS has also rich
in tannin acid and exhibited a strong inhibition of
lipid oxidation according to RSA-DPPH and FRAP
methods (Rohadi et al., 2016). A strong correlation
between RSA-DPPH activity of MEJS or GSE (25-
800 mg/L) and PoV formation during initial 72 h was
found, i.e. y = 5.67x +1.002, R2 = 0.87 for MEJS
and y = 0.296x + 1.89, R2 = 0.966 for GSE. A similar
pattern was also obtained using FRAP methods, i.e.
y = -10.95x + 20.26, R2 = 0.82 for MEJS and y =
-18.52x + 36.75, R2 = 0.875 for GSE. Mielnik et al.
(2006) reported that commercial GSE (Grapines-High
Potency) at 0.4-1.6 g/kg concentration was relatively
effective to prevent lipid oxidation in cooked meat.
The difference in PoV inhibition among samples
could be inuenced by the difference of polarity.
McClement and Decker, (2000) reported that
hydrophilic antioxidant was less effective in oil-in-
water (o/w) emulsion system than the lipophilic and
vice versa.
Effect MEJS on TBARS formation
TBARS (thiobarbituric acid reactive substances)
method is widely used to measure malondialdehyde
(MDA), a secondary product of lipid oxidation, which
is reacted with thiobarbituric acid (TBA), to give a
red color at λ 532 nm. Malondialdehyde (MDA) are
responsible for the formation off avor, rancid odor
and the undesirable taste in the foods. The effect of
MEJS on TBARS formation in the emulsion system
is presented in Figure 1(c). TBARS of the control
sample was greater than 3.0 µM-MDA/L (p<0.05) in
72 h of storage, whereas, the samples treated with
antioxidant were less than 2.5 µM-MDA/L emulsions.
Over 144 h of storage, TBARS of all of the samples
were less than 4.0 µM-MDA/L (approximately 0.25
Figure 2. Effect of methanolic extract of Java Plum
(Syzygium cumini Linn.) seed on inhibition of lipid oxidation
in striped catsh (Pangasius hyphotalamus) oil-in-water
emulsion stored at 35±2ºC for 144 h, compared to BHA and
grape seed extract (GSE). For all of the treatment, a nal
concentration of 200 mg/L was used in the system, (n=3).
Rohadi et al./IFRJ 24(4): 1636-1643 1642
mg MDA/L), and may not change the physical and
visual properties of the emulsion. The addition of
BHA in the emulsion could inhibit lipid oxidation and
exhibited the lowest TBARS value throughout the
storage period. Meanwhile, the addition of MEJS in
the emulsion exhibited the lower of TBARS than the
sample with GSE (p<0.05). In addition, the product
was quantied using standard curve equation of y =
0.1509x + 0.029, R2 = 0.9971 (x-axis = concentration
μM-MDA/L; y-axis = absorbance). Nollet and
Toldra, (2011) reported that the acceptable limits of
TBARS value in fat products was 1.0 mg MDA/kg (1
mg-MDA/kg≈ 13.7055 µM-MDA/kg).
During the initial stage of oxidation, TBARS
concentration was 0.6 µM-MDA/L, then increased up
to the peak at 72 h ranged between 3.1 µM-MDA/L
(GSE and control) and 1.97 µM-MDA/L (BHA and
MEJS). After the peak, TBARS decreased in all of
the samples, except the control. The decreasing of
TBARS could be associated with the inhibition of
secondary product of lipid oxidation, particularly
the volatile short-chain carbon compounds which
easily evaporate. The interaction of thiobarbituric
acid (TBA) with many other carbonyl-containing
compounds such as carbohydrates, pigment, and
amino acid could be also contributing to TBARS
values. Malondialdehyde and the short-chain
compound as a lipid oxidation product were also
labile and easily decomposed into alcohol and
organic acids thus, undetectable using TBA analysis
(Borneo et al., 2009; Maqsood, 2010). Azman et
al. (2016) reported that the addition of lyophilized
bearberry leaf extract (1 g/kg) as an antioxidant in
the emulsion food model signicantly inhibited lipid
oxidation during 20 days of storage.
Methanolic extract of Java Plum seeds (MEJS)
had a great potential as the natural antioxidant to
inhibit the oxidative deterioration of oil-in-water
(o/w) emulsion system. Inhibition activity of lipid
peroxidation of MEJS was 28-38%, lower than BHA
(40-45%) but stronger than grape seed extract (GSE)
18-23%. MEJS could be signicantly able to suppress
the TBARS generation due to lipid oxidation.
The authors would like to thank the Directorate
General of Higher Education Ministry of Research
Technology and Higher Education of Republic of
Indonesia for nancial support.
Azman, N.A.M., Gallego, M.G., Segovia, F., Abdullah,
S., Shaarani, S.M. and Pablos, M.P.A. 2016. Study
of the properties of Bearberry leaf extract as a natural
antioxidant in model food. Antioxidants 5(11):1-11.
Baydar, N.G., Ozkan G. and Yasar S. 2007. Evaluation
of the antiradical and antioxidant potential of grape
extract. Food Control 18: 1131-1136.
Bligh, E.G. and Dyer, W.J. 1959. A rapid method of total
lipid extraction and purication. Canada Journal of
Biochemistry and Physiology 37: 911-917.
Borneo, R., Leon, A.E., Aquirre, A., Ribotta, P. and
Cantero, J.J. 2009. Antioxidant capacity of medicinal
plants from the province of Cordoba (Argentina) and
their in vitro testing in a model food system. Food
Chemistry 112:664-670.
Brewer, M.S. 2011. Natural Antioxidant: Source,
compounds, mechanisms of action, and potential
application. Comprehensive Reviews. Food Science
and Food Safety 10: 221-247.
Buege, J.A. and Aust, S.D. 1978. Microsomal lipid
peroxidation. Methods in Enzymology 52: 302-310.
Bulkpowders. 2015. Grape seed extract contains a
minimum 95% OPC. Retrieved on May 12, 2015
from bulkpowders Website: http://www.bulkpowders.
Buxiang, S. and Fukuhara, M. 1997. Effect of co-
administration of butylated hydroxytoluene, butylated
hydroxyanisole and avonoids on the activation of
mutagens and drugs-metabolizing enzymes in mice.
Journal Toxicology 122 (2-4): 61-72.
Frankel, E.N. 1996. Antioxidants in lipid foods and their
impact on food quality. Food Chemistry 57(1):51-55
Frankel, E.N. 1998. Antioxidant. In Frankel, E.N (Ed.).
Lipid Oxidation, p. 225-303. Dundee: The Oily Press.
Ho, B. T. and Paul, D. R. 2009. Fatty acid prole of Tra
Catsh (Pangasius hypophthalmus) compared to
Atlantic Salmon (Salmo solar) and Asian Seabass
(Lates calcarifer). International Food Research
Journal 16: 501-506.
Hsieh, R.J. and Kinsella, J.E. 1989. Oxidation of
polyunsaturated fatty acid: Mechanisms, products and
inhibition with emphasis on sh. Advances in Food
Nutrition Research 33:233-241.
Kanner, J., Frankel, E., Granit, R., German, B. and Kinsella
J.E.1994. Natural antioxidants in grapes and wines.
Journal of Agricultural and Food Chemistry 42(1):
Latimer, G.W, Jr. 2000. AOAC Ofcial Methods of
Analysis. 18th ed. Maryland: AOAC International.
Madavi, D.L. and Salunkhe, D.K. 1995. Toxicological
aspect of food antioxidant. In Madavi, D.L.,
S.S. Despandhe dan D.K. Salunkhe (Eds.). Food
Antioxidant, p. 267-300. New York: Marcel Decker
Maqsood, S. 2010. Maximized uses of phenolic compound
in retardation of lipid oxidation and shelf-life extension
of sh and sh product. Bangkok, Thailand: Prince of
Songkla University, PhD Thesis.
1643 Rohadi et al./IFRJ 24(4): 1636-1643
Maqsood, S. and Benjakul, S. 2010. Comparatives studies
of four different phenolic compound on in vitro
antioxidative activity and the preventive effect on
lipid oxidation of sh oil emulsion and sh mince.
Food Chemistry 119:123-132.
McClements, D.J. and Decker, E.A. 2000. Lipid oxidation
in oil-in-water emulsions: Impact of molecular
environment on chemical reactions in heterogeneous
food systems. Journal of Food Science 65(8):1270-
Mielnik, M. B., Olsen, E., Vogt, G., Adeline, D. and
Skrede, G. 2006. Grape seed extract as antioxidant in
cooked, cold stored turkey meat. Food Science and
Technology 39:191−198.
Nollet, L.M.L. and Toldra, F. 2011. Handbook of Analysis
of Edible Animal By-Products, p.471. Gent, Belgium:
CRC Press.
Perumalla, A.V.S. and Hettiarachchy, N.S. 2011. Green
tea and grape seed extracts-potential applications in
food safety and quality. Food Research International
Roedig-Penman, A. and Gordon, M.H. 1997. Antioxidant
properties of catechins and green tea extract in model
food emulsions. Journal of Agricultural and Food
Chemistry 45(11):4267-4270.
Rohadi, Raharjo, S., Falah, I.I. and Santoso, U. 2016.
Antioxidant activity of duwet (Syzygium cumini Linn.)
seed extract Genthong varieties on lipid peroxidation
models in vitro. Journal of Agritech 36(1): 30-37.
Rydlewsky, A. A. de Morais, D.R., Rotta, E.M., Clause, T.
and Visentainer, J.V. 2013. Determination of bioactive
compounds, antioxidant activity and physical and
chemical composition of different parts of four
Brazilian fruits. Colombo, Brazil: State University of
Maringa, Postgraduate Program.
Saha, R.K., Zaman, N.M. and Roy, P. 2013. Comparative
evaluation of the medicinal activities of methanolic
extract of seed, fruit pulp and fresh juice of Syzygium
cumini in vitro. Journal of Coastal Medicine 1(4):
Sakanaka, S., Tachibana, Y., Ishihara, N. and Raj Juneja
L. 2004. Antioxidant activity of egg-yolk protein
hydrolysates in a linoleic acid oxidation system. Food
Chemistry 86: 99-103.
Simopoulos, A. P. 2008. The importance of the omega 6/
omega-3 fatty acid ratio in cardiovascular disease and
other chronic diseases. The Society for Experimental
Biology and Medicine 233(6):674-688.
Skowyra, M., Falguera, V., Gallego, G., Peiro, S. and
Almajano, M.P. 2014. Antioxidant properties of
aqueous and ethanolic extracts of Tara (Caesalpinia
spinosa) pods in vitro and in model food emulsions.
Journal of the Science of Food and Agriculture 94:
Vasi, S. and Austin, A. 2009. Antioksidan potential of
Eugenia jambolana Lam. seeds. Journal of Biological
Sciences 9(8): 894-898.
Vayupharap, B. and Laksanalamal, V. 2012. Recovery of
antioxidant from grape seeds and its application in
fried food. Journal Food Process Technology 3(4):1-6.
Zhang, L. L. and Lin, Yi Ming. 2009. Antioxidant tannins
from Syzygium cumini fruit. African Journal of
Biotechnology 8(10): 2301-2309.
... The Java Plum seeds (JS) extract contained a diverse group of phenolic compounds as such as (+)-catechin, gallic acid, ellagic acid, quercetin, (+)-epicatechin, rutin, kaempferol, and galloysl glucose group [3,4], meanwhile the methanolic extract of Java Plum seed (MEJS) containing rutin and (+)-catechin in abundant [5]. Many Java plum phenolic compounds mentioned above have been reported to possess potent antioxidant activity [4,6,7,8,9,10,11]. ...
... The heat treatment is ICSTSI 2020 IOP Conf. Series: Materials Science and Engineering 980 (2020) 012044 IOP Publishing doi: 10.1088/1757-899X/980/1/012044 2 commonly applied to food processing for various purposes including inactivation of enzyme, and improving the color and texture. Its effectiveness is strongly influenced by the intensity of heating, methods, temperature, and long periods [14]. ...
... JSP extraction was done using modified methods as described by Rohadi et al. [10]. Briefly, approximately 30 g of JSP was extracted using aqueous methanol 50% (v/v), at ratio materials: solvent (1:10), macerated on water-bath shaker (40 ±1 o C/6 hrs. 100 rpm), thereafter the mixture filtered using Whatman filter paper. ...
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Butylated hydroxy anisole (BHA) is widely added in lipid and food lipid as a preservative and it is effective for inhibiting lipid peroxidation. However, BHA raised doubt would be the health impact for consumers. The methanolic extract of Java Plum seed (MEJS) contains a diverse group of phenolic compounds, it has potential as a natural antioxidant. The objective of the research was to determine the effect of heating treatment on total phenolics content and antioxidant activity of MEJS. Heating treatment applied on MEJS at 110, 120, 130, 140 and 150°C/10 minutes and heating time (10, 15, 20, 25 and 30 minutes/110°C). The results showed that heating of the extract at the temperature rose to 130°C should decrease the total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC) slightly, coincided with a decrease of the reducing power, but it could increase the free radical scavenging activity. Heating treatment at 110°C for about first ten minutes had a positive impact on increasing of its phenolics content and antioxidant activities. However, heating further at a higher temperature (>130°C) gave a bad influence on the free radicals scavenging activity. The extract heated at the 130°C/10 minutes gave the best EC50 value as 140 ppm.
... This tree bears violet-colored fruits that are edible. The seed extract of this tree is also a natural antioxidant [1]. Aside from its sweet fruits, the leaves of this tree are sometimes used as an alternative to the paper used to roll tobacco. ...
... The second fully connected layer has a dimension of 1x1x3 which equates to the three classes of the Java Plum leaf. For all of the convolution operations and the first fully connected layer, the activation function used is the Rectified linear unit (ReLU) shown in Equation (1). After the first fully connected layer, a dropout layer with 80% retention of units is implemented. ...
... Java plum fruit is a valuable indigenous plant with medicinal applications due to its rich content of carbohydrates, vitamins, and important minerals [38,39]. Furthermore, the seed of Java plum contains various phenolic compounds, including lignans, tannins, coumarins, gallic acid, ferulic acid, phloroglucinol derivatives, and flavonoids [40,41]. Fruit wine production from Java plum has been previously reported, and the presence of ground seeds was found to enhance the phenolic content of the wine. ...
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This study evaluated the ability of a yeast strain isolated from traditional fermented tea leaves (Camellia sinensis var. assamica), Miang from northern Thailand, to grow and produce ethanol in the presence of tannin. Among 43 Miang samples, 25 yeast isolates displayed gas-forming character in the presence of 1% (w/v) tannin, but only ML1-1 and ML1-2 isolates were confirmed as ethanol-producing yeast capable of tannin tolerance. These isolates were further identified to be Pichia occidentalis and Saccharomyces cerevisiae, respectively, based on D1/D2 domain sequence analysis. S. cerevisiae ML1-2 was selected for further studies and exhibited growth at 20–35 °C, pH 4–7, and tolerance to high sugar concentrations of up to 350 g/L. Supplementation of 1% (w/v) tannin had no effect on sugar utilization and ethanol production, while delayed sugar consumption and ethanol production were observed in the reference strain S. cerevisiae TISTR 5088. However, 5 and 10% (w/v) tannin showed inhibitory effects on the growth and ethanol production of the selected yeast isolates. During the fermentation under high tannin conditions derived by mixing Java plum fruit with ground seed, S. cerevisiae ML1-2 showed significant advantages in growth and enhanced the content of ethanol, polyphenols, tannin, and flavonoids compared to S. cerevisiae TISTR 5088. This indicated its potential for high-tannin substrate-based bioconversion for the production of either fuel ethanol or functional alcoholic beverages.
... Syzygium aromatic was ground to fine powder and the extract was prepared by percolating the powder for 48 h, filtration and concentration using rotary evaporating [12]. ...
Purpose: To evaluate the antifungal potency of Syzygium aromaticum (Dianthus) seed extract against the growth and aflatoxin production of Rhizopus stolonifer, and its immunomodulatory effect. Methods: Disc diffusion method was used for assay of antifungal effect of aqueous extract of Dianthus. Lymphoid cell counts, total and differential peritoneal exudate cell counts (PEC), phagocytic activity of PEC, and plaque-forming activities were determined. In addition, E-rosette-forming cells (RFC), T-cell mitogenesis cells and liver functions were measured. Results: The aqueous extract of Dianthus (50 %) exhibited high inhibition zone against most isolates of R. stolonifera. It produced significant increases in the number of splenocytes, as well as in the absolute number and relative proportion of macrophages (p < 0.05). The extract also produced a gradual increase in the scavenging activity of PEC, and significant reduction in serum ALT, relative to control. Conclusion: These results suggest that Dianthus modifies biological responses by enhancement of the immune system, activation of phagocytosis, boosting of immune response, and prevention of liver damage. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria and 2018 The authors.
Syzygium cumini L. seeds have been documented in traditional medicine in Pakistan. The current research was aimed to assess the physicochemical characteristics, polyphenols and antioxidants of S. cumini seed. The physical characteristics such as the color of S. cumini seed were white to pink, the shapes resembled to oblong and coarse texture. The length, width and weight of fresh S. cumini seed were found to be (18.20±0.81mm, 11.05±0.41mm and 1.80±0.16g), respectively while the color of dried S. cumini seeds were light brown to brown,rhombus in shape with loutish texture. The average length, width and weight of dried S. cumini seeds were 16.47±0.45; 10.14±0.25 mm and 0.75±0.12 g respectively. S. cumini seeds powder were evaluated for their chemical composition e.g. carbohydrate, protein, fat, crude fiber, moisture content and ash (77.27±2.50, 3.62±0.30, 6.25±0.55, 10.30±1.20 and 1.55±0.11 g/100g), respectively. Quantitative analysis of total phenolic content was performed it was found that the methanolic and water extract had 52±1.65 and 40±1.25 mg GAE/g content. Free radical scavenging activity was also evaluated to estimate the antioxidant property of extract. Among tested extracts maximum % inhibition 96.61±1.90% was found in methanol extract and 69.30±1.56% in water extract, while BHT has % inhibition 50.70±1.32% at concentration 100 μg/ml. Similarly in reducing power activity assay the maximum absorbance 1.4704±0.05 was shown by methanol extract and 1.2075±0.03 in water extract of S. cumini seed powder respectively which was compared with BHT (0.9207±0.02). Therefore, it was concluded that these Syzygium Cumini L. seeds traditional medicinal plants provide a good source of nutrients, namely protein, fiber and natural antioxidants.
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p>Ekstrak metanolik biji duwet ( Syzygium cumini Linn.) banyak mengandung senyawa antioksidan seperti jambosine , korilagin, kuersetin, asam galat, asam elagat, 1- galloylglucose , 3- galloylglucose , 3,6-hexahydroxy diphenoylglucose , 4,6hexahydroxy diphenoylglucose dan ß-sitosterol . Proses irradiasi dengan gamma 60 Coblat dengan dosis (0 kGy-12,5 kGy) mampu meningkatkan senyawa fenolik dan tanin total pada ekstrak daun teh hijau. Tujuan penelitian ini adalah menganalisis pengaruh iradiasi gamma pada dosis 0 kGy, 2,5 kGy, 5 kGy, 7,5 kGy, 10 kGy, dan 12,5 kGy terhadap stabilitas antioksidatif ekstrak metanolik biji duwet ( Syzygium cumini Linn . ) Ekstrak metanolik biji duwet dipekatkan dengan Vaccum Evaporator kemudian dikeringbekukan menggunakan Freeze Dryer kemudian di Irradiasi gamma dengan 60 Coblat pada dosis 0 kGy, 2,5 kGy, 5 kGy, 7,5 kGy, 10 kGy, dan 12,5 kGy dan dilakukan pengujian meliputi: uji kualitatif fenol, flavonoid, tanin, uji flavonoid, uji total fenolik, uji total tanin, uji penangkapan radikal bebas DPPH RSA-DPPH konsentrasi (25-400 ppm), dan uji reduksi ion ferri (FRAP) konsentrasi (25-400 ppm). Hasil penelitian menunjukkan adanya perbedaan nyata antar perlakuan ( p <0,05) terhadap uji flavonoid, fenolik, tanin, RSA-DPPH, dan FRAP. Sifat antioksidatif terhadap total fenolik, flavonoid dan total tanin stabil pada dosis irradiasi gamma 7,5 kGy-12,5 kGy dan beragam dosis irradiasi gamma menyebabkan total fenolik tidak stabil, flavonoid mengalami peningkatan, tanin tidak stabil, FRAP menggalami penurunan dan meningkatkan nilai IC 50 ekstrak metanolik biji duwet.</p
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The common bearberry (Arctostaphylos uva-ursi L. Sprengel) is a ubiquitous procumbent evergreen shrub located throughout North America, Asia, and Europe. The fruits are almost tasteless but the plant contains a high concentration of active ingredients. The antioxidant activity of bearberry leaf extract in the 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation assay was 90.42 mmol Trolox equivalents/g dry weight (DW). The scavenging ability of the methanol extract of bearberry leaves against methoxy radicals generated in the Fenton reaction was measured via electron paramagnetic resonance. Lipid oxidation was retarded in an oil-water emulsion by adding 1 g/kg lyophilised bearberry leaf extract. Also, 1 g/kg of lyophilised bearberry leaf extract incorporated into a gelatin-based film displayed high antioxidant activity to retard the degradation of lipids in muscle foods. The present results indicate the potential of bearberry leaf extract for use as a natural food antioxidant.
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Objective: Syzgium cumin is a tropical fruit in Bangladesh. The objective of this study is to establish the health benefits of this plant to discover functional components present in the seeds, fruit pulps and fresh juice of this fruit grown in Bangladesh. Methods: Thin layer chormatogarphy and ultra-violet spectroscopy were used to detect the presence of various types of compound in seeds and juice. Antioxidant effects were measured by DPPH scavenging assay and total reducing assay. Receptor binding activities was performed by hemagglutination inhibition assay. Anti-inflammatory assay and hydrogen peroxide induced hemolysis assay was also investigated. Disc diffusion assay was performed to show the antibacterial effect using gram positive, gram negative starins of bacteria and fungi. Results: Methanolic extract of the seeds showed stronger antioxidant, hydrogen peroxide induced hemolysis activities, hemagglutination inhibition activities and membrane stabilization activities than those of fresh juice. However, fresh juice showed stronger antibacterial and antifungal activities than those of methanolic seed extract. The seed contains higher amount of polyphenols and flavanoids than those of fruit juice. Conclusion: Therefore, fruit juice, fruit pulp and seed of Syzgium cumin contains medicinal active componenets in different ratios.
The short courses, University of California-Davis (USA), continues a long tradition of offering basic and practical instructions from leaders in the field to assist participants in understanding lipid oxidation and antioxidants. The stimulating lectures presented at this short course elicited many questions and resultant discussions on the wide variety of multidisciplinary topics affecting food and health, as offered by a very competent faculty. Edwin Frankel lectured on the chemistry of free radical lipid oxidation and methods to determine and control oxidation, oxidative stability, and antioxidants. Kathleen Warner discussed factors in choosing Trans-free frying oils, including cost, availability, stability, functionality, flavor, and nutrition. Norman Cloud lectured on the multifunctional role of antioxidants in animal total nutrition: preventing rancidity, adding nutritional enhancers, and improving palatability.
The fatty acid composition of farmed Tra catfish (Pangasius hypophthalmus) was determined and compared to farmed Atlantic salmon (Salmo solar) and to wild-caught Asian seabass (Lates calcarifer). Saturated fatty acids (SFA) were most abundant in catfish (42.6%) while salmon (37.2%) and seabass (39.0%) were rich in polyunsaturated fatty acids (PUFA). Tra catfish contains Docosahexaenoic acid (DHA), but its percentage was lower (4.7%) than salmon (20.2%) and seabass (18.7%). It is interesting that the absolute content of DHA and eicosapentaenoic acid (EPA) in Tra catfish by fillet wet weight did not differ from Asian seabass. Among the three fish, Tra catfish and seabass had lowest fat content. Regarding to nutritional aspect, Tra catfish fillet is a potential source of omega-3 fatty acids and low-fat food.
The successful replacement of some synthetic food antioxidants by safe natural antioxidants has fostered intensive search for new vegetable sources of antioxidants. In our study the phenol and flavonoid content of extracts of tara pods was determined. The antioxidant activity was also studied by three different analytical assays: the measurement of scavenging capacity against a radical ABTS(+) , the oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). All analyzed samples showed a good antioxidant capacity, but the use of a solution of ethanol 75% in a 1-h ultrasonic process allowed achieving the greatest quantity of phenolics (0,464 mg gallic acid equivalent (GAE)/g dry weight (DW) ) and the best antioxidant activity measured by the ABTS(+) and ORAC methods (10.17 and 4.29 mM Trolox Equivalents (TE)/g DW, respectively). The best method for efficient extraction of flavonoids (3.08 mg catechin equivalent (CE)/g DW) was a 24-h maceration in cold water. Two extracts obtained with ethanol 75% and water were added to a model food system (oil-in-water emulsion) and the oxidative stability was studied during storage at 38°C. Oxidation was monitored by determination of the peroxide value. The addition of 48 µg/mL of ethanol extract to the emulsion delayed oxidation to the same extent as 17.8 µg/mL of Trolox, while water extract was only effective in the early stages of the oxidation process. The results of this study indicate that ethanolic tara extracts may be suitable for use in food, cosmetic and nutraceutical applications.
Hydrolysable and condensed tannins in the fruit of Syzygium cumini were identified using NMR, MALDI- TOF MS and HPLC analyses. Hydrolysable tannins were identified as ellagitannins, consisting of a glucose core surrounded by gallic acid and ellagic acid units. Condensed tannins were identified as B- type oligomers of epiafzelechin (propelargonidin) with a degree of polymerization up to eleven. The antioxidant activity were measured by two vitro models: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing/antioxidant power (FRAP). Tannins extracted from S. cumini fruit showed a very good DPPH radical scavenging activity and ferric reducing/antioxidant power. The results are promising thus indicating the utilization of the fruit of S. cumini as a significant source of natural antioxidants.
Efficiency of four concentrations of grape seed extract (0.0, 0.4, 0.8, and 1.6g/kg) in retarding oxidative rancidity was tested with cooked turkey breast meat. Development in lipid oxidation during 13 days of refrigerated storage was evaluated by means of thiobarbituric acid-reactive substances (TBARS) and volatile compound formation. Hexanal, pentanal, octanal, 2-octenal, 1-octen-3-ol, 2-octen-1-ol, and 1-penten-3-ol showed high correlations (r>0.95) with TBARS values and could, therefore, serve as markers for the oxidation process in the cooked turkey breast meat. Supplementation of grape seed extract prior to cooking significantly improved oxidative stability of minced turkey meat during heat treatment and storage. The ability of grape seed extract to prevent lipid oxidation was concentration-dependent. Vacuum-packaging considerably improved oxidative stability of meat regardless of the low concentration of grape seed extract used. It appears that grape seed extract could be very effective in inhibiting lipid oxidation of cooked turkey meat during chill-storage.
Extraction of green tea with hot water provided an extract that was highly effective as an antioxidant for an oil-in-water emulsion at pH 5.5 during prolonged storage (40 days). Other components besides epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) made important contributions to the antioxidant activity of the extract in an oil-in-water emulsion, since ECG, when pure, had no significant antioxidant activity (p > 0.05) and EGCG was completely oxidized within 15 days. Myricetin had a greater antioxidant effect in this system than EGCG or ECG at a concentration of 10-4 M in the absence of ferric ions, but all three flavonoids exhibited prooxidant effects in the presence of ferric ions. Keywords: Antioxidants; epigallocatechin gallate; epicatechin gallate; green tea; emulsions
The concentrations of phenolics of three grape varieties and two red wines were determined. The red grape variety and the red wines contain phenolics at concentrations of 920 mg/kg and 1800 and 3200 mg/L, respectively. The antioxidative effects of wine phenolics on the catalysis of lipid peroxidation by biological catalysts such as myoglobin, cytochrome c, iron ascorbate, and copper ions were estimated. Lipid peroxidation catalyzed by myoglobin, cytochrome c, and iron ascorbate was inhibited (I-50) by wine phenolics at concentrations of 0.2, 0.35, and 0.9 mu g of phenolics/mL. The antioxidative effects of wine phenolics were determined also in a system containing low-density lipoproteins (LDL) oxidized ex vivo by CU2+ ions. The inhibition of LDL oxidation by wine phenolics was compared with that by alpha-tocopherol. The results show I-50 inhibitions of less than 1 mu M for wine phenolics and 2 mu M for alpha-tocopherol, respectively. The nutritional implications of natural antioxidants at high concentration in grapes, wines, and byproducts, and their utilization in foods, are discussed.