Total Phenolic, Flavonoid Distribution and Antioxidant Capacity in Skin, Pulp and Fruit Extracts of Plum Cultivars

Abstract

Total phenolic, total flavonoid distribution and antioxidant activity in skin, pulp and fruit extracts of 12 plum cultivars were investigated. The results showed that the levels of total phenolic and flavonoid compounds changed depending on cultivars and fruit parts. The total phenolic content in skin was 4.5 times higher than that in pulp and 3.2 times higher than that in the whole fruit. The total flavonoid content in skin was 18.7 times higher than that in pulp and 9.6 times higher than that in the whole fruit. As the trend observed for antioxidant activity, a positive relationship (correlation coefficient r2 = 0.83–0.92) was presented between total phenolics and total antioxidant capacity. The results confirm that plum is a good source of natural phenolic antioxidants.Practical ApplicationsThe present study indicated that plum can contribute to the dietary intake of antioxidants, depending on cultivars and fruit parts. It is among the few studies investigating the distribution of total phenolic, total flavonoids and total antioxidant capacity in the skin, pulp and fruit of plum cultivars. It was observed that the highest values of total phenolic and flavonoid content were obtained from skin extracts. The study highlighted that phenolics and flavonoids in plums may play an important role as radical-scavenging agents that could be used for a healthy human life. This fact may open new perspectives for plum – besides its traditional uses – to be used in assuring a wholesome diet and a healthy life.

Full text

TOTAL PHENOLIC, FLAVONOID DISTRIBUTION AND
ANTIOXIDANT CAPACITY IN SKIN, PULP AND FRUIT EXTRACTS
OF PLUM CULTIVARS
S. COSMULESCU1,3, I. TRANDAFIR2, V. NOUR1and M. BOTU1
1Department of Horticulture & Food Science, Agriculture & Horticulture Faculty, University of Craiova, A.I. Cuza Street 13, Craiova 200585,
Romania
2Department of Chemistry, Sciences Faculty, University of Craiova, Craiova, Romania
3Corresponding author.
TEL: 0040251414541;
FAX: 0040251414541;
EMAIL: sinacosmulescu@hotmail.com
Received for Publication August 2, 2014
Accepted for Publication November 21, 2014
doi:10.1111/jfbc.12112
ABSTRACT
Total phenolic, total flavonoid distribution and antioxidant activity in skin, pulp
and fruit extracts of 12 plum cultivars were investigated. The results showed that
the levels of total phenolic and flavonoid compounds changed depending on cul-
tivars and fruit parts. The total phenolic content in skin was 4.5 times higher than
that in pulp and 3.2 times higher than that in the whole fruit. The total flavonoid
content in skin was 18.7 times higher than that in pulp and 9.6 times higher than
that in the whole fruit. As the trend observed for antioxidant activity, a positive
relationship (correlation coefficient r2=0.83–0.92) was presented between total
phenolics and total antioxidant capacity. The results confirm that plum is a good
source of natural phenolic antioxidants.
PRACTICAL APPLICATIONS
The present study indicated that plum can contribute to the dietary intake of
antioxidants, depending on cultivars and fruit parts. It is among the few studies
investigating the distribution of total phenolic, total flavonoids and total
antioxidant capacity in the skin, pulp and fruit of plum cultivars. It was
observed that the highest values of total phenolic and flavonoid content were
obtained from skin extracts. The study highlighted that phenolics and flavonoids
in plums may play an important role as radical-scavenging agents that could be
used for a healthy human life. This fact may open new perspectives for plum –
besides its traditional uses – to be used in assuring a wholesome diet and a
healthy life.
INTRODUCTION
Plums (Prunus domestica L.) are stone fruits that offer ben-
eficial nutrients and can be eaten fresh, dried or processed.
Every cultivar has its own typical chemical composition.
Plum fruits contain natural phenolic phytochemicals, which
may function as effective natural antioxidants in our daily
diet (Cevallos-Casals et al. 2006; Družic´ et al. 2007; Kristl
et al. 2011). Phenolic compounds, ubiquitous in plants, are
an essential part of human diet and are of considerable
interest due to their antioxidant properties (Balasundram
et al. 2006). According to Kim et al. (2003a), the total phe-
nolic contents (TPCs) of various cultivars of plums widely
varied from 125.0 to 372.6 mg/100 g expressed as gallic acid
equivalents, and the level of total flavonoids in fresh plums
ranged between 64.8 and 257.5 mg/100 g expressed as cat-
echin equivalents. Gil et al. (2002) found a total phenolic
variation in plum genotypes between 42 and 109 mg/100 g
fresh weight (FW), and Vasantha Rupasinghe et al. (2006)
found between 86 and 413 mg/100 g FW expressed as
gallic acid equivalents. In Stanley cultivar, Miletic´et al.
(2012) found that TPC was within the range of 70–214 mg/
100 g FW gallic acid equivalents, at different maturity
stages. Comparing the nutrient content and antioxidant
molecules in yellow plums from conventional and organic
products, Lombardi-Boca et al. (2004) showed that the
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64 Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.

highest phenolic acid content was detected in plums grown
on soil covered with trifolium, and total polyphenolic
content was higher in conventional plums. Neochlorogenic
acid was found to be the most important phenolic acid in
six European plum cultivars grown in Norway (Slimestad
et al. 2009).
Plum is one of the oldest cultivated species with a high
genetic diversity due to the long historic cultivation and
suitable climatic conditions of Romania. There are numer-
ous different plum cultivars available for fresh and process-
ing market (Botu et al. 2010) and with physical and
chemical properties, which make them suitable to be grown
in Romania (Ionica et al. 2013). The combined selection of
optimal cultivars and agricultural practices can optimize
health benefits of plums.
The objective of this study was to determine and compare
the total phenolic compounds, total flavonoid content
(TFC) and antioxidant capacity in skin, pulp and fruit of 12
plum cultivars grown in Romania in integrated production.
Skin, pulp and fruit tissues were studied to estimate the
relative contribution of these tissues to medicinal and nutri-
tional value of plum cultivars.
MATERIAL AND METHODS
Plant Material
Preparation of Samples. In this research, the fruit
composition of 12 plum cultivars from trees grafted on
Mirobolan was analyzed. The material of study (fruits)
comes from the experimental orchard of University of
Craiova (SCDP Valcea), located in Sub-Carpathian area
in Oltenia Region, Romania (45°6′17″N, 24°22′32″E).
Fruits were harvested in August and September, in full
maturity stage. Fruits were harvested during the period of
August–September at commercial maturity. Samples
(approximately 60 fruits) were collected from three trees.
After harvest, the fruits were immediately stored at
−20 ±0.2C until further use. Plums were halved, and skin
and seeds were manually removed. Analyses were per-
formed on fresh plums mashed to pulp, skin and whole
fruit tissue.
Extraction Procedure. Skin (1 g), pulp and whole fruit
tissues (2 g) from each cultivar were finely chopped and
then they were homogenized with 5 mL of 70% MeOH and
kept at 25C in an ultrasonic bath for 30 min. The samples
were filtered and the precipitate was subjected to a stripper
with 5 mL of 70% MeOH in an ultrasonic bath for 30 min.
The supernatant was filtered through a 0.45-μm polyamide
membrane and stored at −20C.
TPC
Chemicals and Reagent. Folin–Ciocalteu reagent (2 N,
Sigma-Aldrich, Germany), gallic acid (Sigma-Aldrich,
Germany) and anhydrous sodium carbonate (Sigma-
Aldrich, Germany) were used in this experiment.
Methods. Both TPC in plum fruit extracts were measured
using an Evolution 600 UV-visible spectrophotometer
(Thermo Scientific, Madison, WI) computer controlled by
VISION Pro-software (Thermo Scientific). TPC assay was
conducted using the Folin–Ciocalteu reaction (Cosmulescu
and Trandafir 2012) with gallic acid as standard. A 1.0 mL
of sample of each fruit extract (1:10 diluted with ultrapure
water) or 1.0 mL of double-distilled water (blank) or
1.0 mL of each standard gallic acid solution was placed in a
25-mL flask, and 5 mL of Folin–Ciocalteu reagent was
added (diluted 1:10 with ultrapure water). After 2 min,
4 mL of 7.5% (w/v) sodium carbonate was added and the
flasks were kept at room temperature (24–26C) for 2 h. The
absorbance was measured at 765 nm. A standard curve was
prepared using 50, 100, 150, 200 or 250 ppm gallic acid.
TPCs were expressed as milligrams of gallic acid equivalents
per 100 g fresh weight (mg GAE/100 g FW).
TFC
Chemicals and Reagent. Methanol (Merck, Germany),
aluminum nitrate (Sigma-Aldrich, Germany) and potas-
sium acetate (Sigma-Aldrich, Germany) were used in this
experiment.
Methods. Total flavonoids were determined using the
spectrophotometric method based on color reaction time
of the class of compounds ion Al (III), by using the
method described by Rahimipanah et al. (2010) and
Mohammadzadeh et al. (2007). Briefly, 0.5 mL of extract was
diluted with methanol (1:10) and they were added to test
tubes and mixed with 0.1 mL of 10% aluminum nitrate,
0.1 mL of 1 M aqueous potassium acetate and 4.3 mL of
methanol. After keeping it for 40 min at room temperature,
the absorbance of the reaction mixture was measured at
415 nm. Quercetin was used for preparing the standard curve
(0–100 mg/L). The results were expressed as milligrams of
quercetin equivalents per 100 g FW (mg QE/100 g FW).
Total Antioxidant Capacity (TAC) Assays
Chemicals and Reagent. Methanol (Merck, Germany),
2,2-diphenyl-1-picrylhydrazyl (DPPH; Merck, Germany),
S. COSMULESCU ET AL.PHENOLIC, FLAVONOIDS, ANTIOXIDANT CAPACITY IN PLUM
65Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.

ascorbic acid(Merck, Germany) and 6-hydroxy-2,5,7,8-
tetramethylchroman-2-carboxylic acid (Trolox; Merck,
Germany) were used in this experiment.
Methods. Scavenging activities of methanolic extracts of
plum samples against DPPH radicals were measured
according to Hatano et al. (1988), with some modifications
(Cosmulescu and Trandafir 2012). The absorbance was
measured at 517 nm. Standards of various concentrations
were used: Trolox (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.5 mM) and
ascorbic acid (25–200 ppm). Each methanolic fruit extract
(50 μL of diluted samples: 1:5 for skin extracts and 1:10 for
pulp and fruit extracts) was mixed with 3 mL of 0.004%
(v/v) DPPH in methanol. Each reaction mixture was incu-
bated in the dark for 30 min at room temperature (24–
26C). Antioxidant capacity was expressed in milligrams of
ascorbic acid equivalent per 100 g (mg AAE/100 g FW) or
in mmol Trolox/100 g FW.
Statistical Analysis
Data were subjected to analysis of variance (ANOVA) using
Statgraphics Centurion XVI software (StatPoint Technolo-
gies, Warrenton, VA). Differences were estimated with a
multiple range test using the least significant difference at
P<0.05.
RESULTS AND DISCUSSION
TPC
The results obtained indicated significant differences in
phenolic contents between the 12 cultivars analyzed
(Table 1). The TPC ranged from 249.91 to 773.31 mg GAE/
100 g FW in skin of fruit, from 61.34 to 180.82 mg GAE/
100 g FW in pulp and from 76.5 to 363.34 mg GAE/100 g
FW in fruit, in methanolic extracts of 12 cultivars tested. All
12 plum cultivars used in this study were grown in the same
location under similar horticultural practices. These differ-
ences may be due to genetic factors and different ability to
synthesize secondary metabolites of cultivars. Differences
between cultivars in terms of TPC in plum were observed
by other authors: between 174 and 375 mg GAE/100 g FW
in six cultivars (Cevallos-Casals et al. 2006), between 86 and
413 mg GAE/100 g FW in 20 genotypes (Vasantha
Rupasinghe et al. 2006) and between 348 and 495 mg GAE/
100 g FW in 12 cultivars (Rop et al. 2009). Of all plum culti-
vars studied, “Alutus” and “Valcean” had the highest and
lowest TPCs in total fruit, respectively. The plum cultivars
ranked in the following decreasing order: Alutus >Flora >
Carpatin >Oltenal >Tuleu timpuriu >Andreea >Minerva
>Tuleu gras >Tuleugrascl14>Centenar >Silvia >
Valcean.
Phenolic content is different in different parts of the
plum fruit. The results indicated that plum skin displayed
the highest amount of fruit TPC (mean 484.15 mg GAE/
100g FW) followed by fruit (148.31 mg GAE/100 g FW) and
pulp (105.61 mg GAE/100 g FW). The TPC in skin was 4.5
times higher than that in pulp and 3.2 times higher than
that in the whole fruit. This is due to the anthocyanins
present in the skin. “Alutus” skin color is violet dark, and
“Tuleu gras cl.14” skin color is violet blue (Botu et al. 2010).
In terms of different TPC in skin, pulp and fruit tissues,
these results are in agreement with the literature
(Tomás-Barberán et al. 2001). A direct correlation between
skin color intensity and TPC was observed in plum fruit by
Vasantha Rupasinghe et al. (2006). The highest TPC of
TABLE 1. TOTAL PHENOLIC* DISTRIBUTION IN
THE SKIN, PULP AND FRUIT IN 12 CULTIVARS
OF PLUM
No. Cultivar
Total phenolic content (mg GAE/100 g FW)
Skin Pulp Fruit
1 Tuleu timpuriu 562.14 ±10.39g88.04 ±2.33c160.37 ±7.39f
2 Valcean 482.22 ±6.98d89.23 ±3.11c90.62 ±5.18b
3 Centenar 519.37 ±9.45e66.89 ±1.68a93.82 ±4.75bc
4 Alutus 773.31 ±12.66h180.82 ±5.22g363.34 ±13.46i
5 Oltenal 545.16 ±10.22f149.73 ±4.98f166.21 ±6.61f
6 Minerva 490.18 ±8.87d77.77 ±3.44b114.49 ±6.08d
7 Tuleu gras 432.44 ±6.88c80.43 ±3.77b103.43 ±4.58cd
8 Silvia 443.70 ±7.72c61.34 ±2.42a76.5 ±3.72a
9 Carpatin 383.91 ±8.66b135.94 ±4.88e181.07 ±8.55g
10 Flora 491.89 ±11.32d134.66 ±5.56e195.6 ±10.33h
11 Tuleu gras cl.14 249.91 ±6.85a91.20 ±3.19c96.07 ±6.94bc
12 Andreea 435.61 ±9.56c111.22 ±4.32d138.25 ±6.44e
Mean 484.15 ±119.65 105.61 ±36.06 148.31 ±76.29
Note: Different superscript letters within the same column indicate significant differences
(P≤0.05) among cultivars.
* Each value in the table is represented as mean ±SE (n=3).
GAE, gallic acid equivalent; FW, fresh weight.
PHENOLIC, FLAVONOIDS, ANTIOXIDANT CAPACITY IN PLUM S. COSMULESCU ET AL.
66 Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.

773.31 mg GAE/100 g FW was found in the skin of “Alutus”
followed by the skin of “Tuleu timpuriu” (562.14 mg GAE/
100 g FW) and “Oltenal” (545.16 mg GAE/100 g FW). The
highest TPC for fruit (363.34 mg GAE/100 g FW) was
found in “Alutus.” There were significant statistical differ-
ences between cultivars and different parts of the plum
fruit. Even though skin is a concentrated source of phenolic
compounds, it only represents 3.21–8.38% of fruit weight,
while pulp is 86.17–92.86% of fruit weight.
TFC
The results of flavonoid content, expressed as milligrams of
quercetin equivalents per 100 g, are presented in Table 2. In
methanolic extracts of 12 genotypes tested, TFC ranged
from 33.61 to 160.67 mg QE/100 g FW in skin of fruit, from
2.22 to 12.48 mg QE/100 g FW in pulp and from 5.4 to
20.43 mg QE/100 g FW in fruit. In the research made by
Kim et al. (2003b), the TFC ranged from 118 to 237 mg cat-
echin equivalents (CE)/100 g FW in various cultivars of
plum. Many significant differences in individual phenolic
compounds were observed among cultivars (P<0.05). The
highest TFC of 160.67 mg QE/100 g FW was found in the
skin of “Alutus” followed by the skin of “Flora” (133.03 mg
QE/100 g FW) and “Tuleu timpuriu” (114.35 mg QE/100 g
FW). The highest TFC value for fruit (20.43 mg QE/100 g
FW) was found in “Alutus”.
A similar trend in phenolic contents was observed for
total flavonoids in different parts of the plum fruit. The
TFC in the skin (mean 98.18 mg QE/100 g FW) was consid-
erably higher than those in pulp and fruit. It was 18.7 times
higher than that in pulp and 9.6 times higher than that in
the whole fruit.
TAC Assays
The TAC, against DPPH radicals, is shown as quantities in
mg AAE/100 g FW and mmol Trolox/100 g FW (Table 3).
The TAC was determined for skin, pulp and fruit. Antioxi-
dant capacities varied among different plum genotypes and
in different parts of fruits. For example, from 163.62 to
972.74 mg AAE/100 g FW in skin, from 10.49 to 38.17 mg
AAE/100 g FW in pulp and from 22.17 to 92.65 mg AAE/
100 g FW in fruit. The results showed that removal of
skin from plum fruit results in a significant loss of TAC.
The order of TAC (in fruit) is as follows: Alutus >Andreea
>Carpatin >Flora >Oltenal >Valcean >Tuleu timpuriu >
Centenar >Minerva >Tuleugrasclon14>Tuleu gras >
Silvia. Antioxidant capacity, expressed as vitamin C equiva-
lent found by Kim et al. (2003a), ranged from 204.9 to
567.0 mg/100 g, with an average of 290.9 mg/100 g FW,
and from 266 to 559 mg/100 g FW found by Kim et al.
(2003b). TAC ranged from 105 to 424 mg AAE/100 g FW in
studies made by Vasantha Rupasinghe et al. (2006) among
20 genotypes.
The TAC expressed in mmol Trolox/100 g FW varied
among different plum genotypes and in different parts of
the fruits: from 2.54 to 6 mmol Trolox/100 g FW in skin,
from 0.24 to 0.46 mmol Trolox/100 g FW in pulp and from
0.48 to 1.02 mmol Trolox/100 g FW in fruit. The results are
similar to those found by Slimestad et al. (2009) in six Nor-
wegian plum cultivars (where TAC varied from 0.814 to
0.290 mmol Trolox/100 g of FW).
Total phenolic and flavonoid contents of plums were
highly correlated to the antioxidant capacity of fresh fruit
plums. This suggests that phenolics and flavonoids in plums
may play an important role in scavenging free radicals.
TABLE 2. TOTAL FLAVONOID* DISTRIBUTION
IN THE SKIN, PULP AND FRUIT IN 12
CULTIVARS OF PLUM No. Cultivar
Total flavonoid content (mg QE/100 g FW)
Skin Pulp Fruit
1 Tuleu timpuriu 114.35 ±5.34h5.78 ±0.26f15.48 ±0.88e
2 Valcean 96.97 ±4.56e5.97 ±0.31f11.21 ±0.54d
3 Centenar 106.45 ±5.57fg 4.04 ±0.21de 5.71 ±0.32ab
4 Alutus 160.67 ±5.98j12.48 ±0.48h20.43 ±1.02f
5 Oltenal 109.97 ±3.78gh 3.45 ±0.18c7.74 ±0.41c
6 Minerva 101.16 ±4.21ef 7.62 ±0.39g11.04 ±0.59d
7 Tuleu gras 86.12 ±3.12d5.96 ±0.28f10.41 ±0.63d
8 Silvia 113.01 ±5.14gh 4.49 ±0.22e10.83 ±0.54d
9 Carpatin 70.79 ±3.55c2.22 ±0.11a5.64 ±0.26ab
10 Flora 133.03 ±4.67i4.46 ±0.32e11.23 ±0.66d
11 Tuleu gras cl.14 52.00 ±2.66b3.71 ±0.29cd 6.40 ±0.29b
12 Andreea 33.61 ±2.21a2.87 ±0.23b5.40 ±0.31a
Mean 98.18 ±33.59 5.25 ±2.66 10.13 ±4.37
Note: Different superscript letters within the same column indicate significant differences
(P≤0.05) among cultivars.
* Each value in the table is represented as mean ±SE (n=3).
FW, fresh weight; QE, quercetin equivalent.
S. COSMULESCU ET AL.PHENOLIC, FLAVONOIDS, ANTIOXIDANT CAPACITY IN PLUM
67Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.

A significant linear relationship was observed between TPC
and TAC (r2=0.83–0.92).
A positive relationship (correlation coefficient r2=0.977)
was presented between total phenolics and antioxidant
capacity in skin, suggesting that polyphenolics could play an
important role in free radical scavenging found by Kim
et al. (2003a). Good correlation was observed by Gil et al.
(2002) and Chun et al. (2003) between total phenolics and
antioxidant capacity in fresh plums. Gil et al. (2002) showed
that contributions of phenolic compounds to antioxidant
activity were much greater than those of vitamin C and
carotenoids, and there was a strong correlation (0.93–0.96)
between total phenolics and antioxidant activity of nectar-
ines, peaches and plums. Vasantha Rupasinghe et al. (2006)
also observed a strong correlation (r2=0.96) between TAC
and TPC. Similar observations were made by Chun et al.
(2003) – good linear relationship between the amount of
total phenolics and TAC (r2=0.9887), and by Rop et al.
(2009) – total content of phenolic substances was highly
correlated with TAC of fruit (r2=0.893).
CONCLUSION
The results showed that the levels of total phenolic and fla-
vonoid compounds changed depending on cultivars and
fruit parts. The highest values of total phenolic and flavo-
noid content were obtained from skin extracts, in all culti-
vars. The whole fruit and pulp of plum have valuable
antioxidant activities, with the largest amounts found in
skin. This study confirms that plum is a source of natural
phenolic antioxidants. Further research will be considered
to determine the fruit content under different ecological
conditions and to identify phenolic compounds.
ACKNOWLEDGMENT
This work was partially supported by Grant No. 11C/2014,
awarded in the internal grant competition of the University
of Craiova.
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No. Cultivar
Total antioxidant capacity mg AAE/100 g FW Total antioxidant capacity mmol Trolox/100 g FW
Skin Pulp Fruit Skin Pulp Fruit
1 Tuleu timpuriu 731.96 ±12.44g10.76 ±0.34ab 34.93 ±1.33ab 4.74 ±0.28de 0.27 ±0.01bc 0.64 ±0.03d
2 Valcean 715.85 ±9.68g14.08 ±0.48c40.61 ±2.24c4.54 ±0.18cd 0.31 ±0.02d0.65 ±0.02d
3 Centenar 809.68 ±15.59h10.38 ±0.28a34.08 ±1.19a5.12 ±0.23ef 0.25 ±0.01ab 0.63 ±0.03cd
4 Alutus 972.74 ±13.36i38.17 ±0.82g92.65 ±3.56g6.0 ±0.32g0.46 ±0.03f1.02 ±0.05g
5 Oltenal 659.38 ±10.66ef 36.25 ±1.23f43.23 ±2.02f4.2 ±0.15c0.44 ±0.02f0.73 ±0.03e
6 Minerva 669.69 ±8.89f14.63 ±0.42c32.86 ±1.66c4.27 ±0.13c0.31 ±0.01d0.64 ±0.02d
7 Tuleu gras 502.38 ±9.98c11.83 ±0.56b22.87 ±0.98b3.25 ±0.09b0.29 ±0.01cd 0.59 ±0.02bc
8 Silvia 573.32 ±11.33d10.49 ±0.52a22.17 ±1.67a3.61 ±0.21b0.28 ±0.01c0.61 ±0.03bcd
9 Carpatin 580.92 ±8.97d30.49 ±1.08e67.42 ±2.01e5.16 ±0.44ef 0.34 ±0.02e0.70 ±0.04e
10 Flora 650.94 ±12.51e23.59 ±0.98d48.67 ±1.55d5.47 ±0.37f0.28 ±0.01c0.58 ±0.02b
11 Tuleu gras cl 14 163.62 ±5.22a13.50 ±0.40c29.75 ±0.95c2.54 ±0.24a0.23 ±0.01a0.48 ±0.01a
12 Andreea 445.03 ±10.32b36.68 ±1.33f80.77 ±2.66f4.2 ±0.28c0.24 ±0.01a0.81 ±0.03f
Mean 622.95 ±195.17 20.90 ±11.08 45.83 ±22.14 4.42 ±0.97 0.31 ±0.07 0.67 ±0.13
Note: Different superscript letters within the same column indicate significant differences (P≤0.05) among cultivars.
* Each value in the table is represented as mean ±SE (n=3).
AAE, ascorbic acid equivalent; FW, fresh weight.
PHENOLIC, FLAVONOIDS, ANTIOXIDANT CAPACITY IN PLUM S. COSMULESCU ET AL.
68 Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.

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69Journal of Food Biochemistry 39 (2015) 64–69 © 2015 Wiley Periodicals, Inc.