PaPer

320 Ital. J. Food Sci., vol. 27 - 2015

- Keywords: agrobiodiversity, plum, quality, nutraceutical compounds -

Quality of autochthonous sicilian plums 

f. sottilea, V. GirGentib, n.r. GiuGGiolib, 
m.B. Del siGnorea and c. peanob

aDipartimento Scienze Agrarie e Forestali, University of Palermo, 
Viale delle Scienze 11, 90128 Palermo, Italy

bDipartimento di Scienze Agrarie, Forestali e Alimentari, University of Torino, 
Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy

*Corresponding author: Tel. +39 011 6708646, Fax +39 011 6708658,
email: nicole.giuggioli@unito.it

AbstrAct

thirty four plum local varieties and accessions obtained from different growing area of the si-
cilian island were analyzed for their qualitative and nutraceutical properties and three commer-
cial cultivar were used as references. these properties included the fruit fresh weight (g), the pulp 
firmness (FFF), the total soluble solids (tss), the titratable acidity (tA), the total anthocyanins, 
the phenolics content and the antioxidant activity. 

this preliminary study showed significantly differeces among the plums; Zuccarato giallo and 
Prunu Niuru presented tss higher than the commercial cultivars (24.9 and 21.6 °brix respec-
tively) and interesting data obtained on the nutraceutical compounds values suggested these lo-
cal cultivars as sources of polyphenols (Zuccarato giallo with 663 mg GA/100 gFW) and natural 
antioxidants (Pruno regina with 47.46 Fe2+/100 gFW). the characterization of these plums could 
represent also an important resource for the international activity in the genetic improving and 
the collection of the more interesting quality traits could be useful for improving the Prunus da-
tabase actually in use.



Ital. J. Food Sci., vol. 27 - 2015 321

1. INtroductIoN

the varietal diversity is one of the agricultur-
al biodiversity (HeyWood, 1999) and the man-
agement by farmers at the local community level 
is one of the factors involved to preserve it. the 
International treaty on Plant Genetic resources 
for Food and Agriculture approved in 2001 has 
assigned to all joined Nations the duty to take 
specific local actions in terms of preservation of 
genetic resources, particularly those that are di-
rectly related with the food and agriculture, ie. 
agrobiodiversity. since that, many national ini-
tiatives have been set up aiming at the recovery 
and characterization of the genetic autochtho-
nous resources as well as the enhancement in 
both nutritional and nutraceuticals traits.

the need to maintain, to protect and to man-
age agobiodiversity is increasing; the identifica-
tion of the composition of locally cultivated food 
as sources of nutraceutical compounds is essen-
tial to promote a more food-base approach to nu-
trition and health (scooNes, 1992). Plums are 
the most taxonomically diverse of stone fruits 
(dAs et al., 2011) and the varietal diversity is 
strongly related to the high percentage of self-
incompatibility that led over the centuries to 
various cross-pollinations with recombinations 
of characters (sottIle et al., 2010a). the man-
agement in situ is one of the commonly recom-
mended germplasm conservation approaches 
(MAxted et al., 2010) and in sicily plum fruits 
were cultivated since the sixteenth and sevet-
eenth centuries as reported in literature (cuPA-
NI, 1696; NIcosIA, 1735) due the propitious pe-
doclimatic conditions of the territory for their 
development and genetic diversification (IMPAl-
lArI et al., 2010). the most representative areas 
for the diffusion of plum trees are described by 
these authors as the Palermo and trapani Prov-
ince which today have an important rule to im-
prove and to diffuse the cultivation of the specie 
by using its natural and favorable climatic con-
ditions. the characterization and identification 
of plum varieties usually is performed on mor-
phological data (sottIle et al., 2010b), pheno-
totic traits (HorvAtH et al., 2011) and more re-
cently on some molecular markers (GreGor et 
al., 1994; ortIZ et al., 1997; GHArb et al., 2014), 
but the study of the nutraceutical compounds 
(sottIle et al., 2010b), represent today an im-
portant tool to improve the collected data and 
to describe better the varietal diversity (vAsAN-
tHA ruPAsINGHe et al., 2006; díAZ-MulA et al., 
2009). the replacement of local cultivars with 
the new one introduced by genetic improvement 
programs, due to a higher productivity, as well 
as resistance or tolerance to pests and diseas-
es, or to abiotic stress, has caused a strong ge-
netic erosion of the indigenous fruit tree species 
germplasm (IMPAllArI et al., 2010). As a conse-
quence of the globalization process, the homolo-
gation involved the fruit consumption and deep-

ly contributed in the loss of the unique taste of 
these fruits.

Many studies have showed that the locally 
available cultivars, varieties and wild underu-
tilized ecotypes; JAbloNskA-rys et al., 2009; 
PetruccellI et al., 2013;) are in many cases 
more rich in nutrients than similar commercial-
ly foods, confirming the old ecotypes as genetic 
resources of fruit nutritional traits.

Plums have the potential to contribute great-
ly to human nutrition because of their richness 
in fiber and antioxidants (stAceWIcZ-sAPuNt-
ZAkIs et al., 2001; sottIle et al., 2010b). In 
many cases the genetic resources with a high-
er relevance in terms of nutraceutical facts are 
related to old varieties and reported with a high 
risk of erosion. to limit the loss of biodiversity 
and to adopt collaborative conservation strat-
egies it is necessary to improve the knowledge 
of the genetic resources and their horticultur-
al aspects. the reduction in the genetic varia-
bility is increasing from the past century so as 
established by international approaches to bi-
odiversity preservation protocols, each coun-
try is responsible for its own genetic resources 
(dAs et al., 2011). No detailed study concerning 
physical and nutritional properties of old sicil-
ian plum ecotypes have been performed up to 
now, so the aim of this study was to determine 
some qualitative and nutritional traits of plum 
fruits belonging to some local cultivars identi-
fied in the sicily island.

2. MAterIAls ANd MetHods

2.1 Plant material and collection of data

one hundred forty-three georeferenced plum 
cultivars and accessions were identified in the 
sicilian island from existing bibliography and a 
territorial investigation but in this preliminary 
study only thirty-seven varieties are consid-
ered. In the table 1 the total 37 local cultivars 
and accessions of plums used for the qualita-
tive and nutraceutical analysis on fruits are re-
ported. these included 34 plum trees from dif-
ferent locations in the sicily region and 3 com-
mercial varieties respectively of Prunus domesti-
ca l. (cv. stanley) and Prunus salicina lindl. (cv. 
shiro and cv. Angeleno), as references. the in-
vestigated area is located both in the West and 
in the eastern part of sicily. For each local cul-
tivars and accession 30 fruits randomly collect-
ed from the entire production were used. 

the plants of the sicilian germplasm were 
maintained on site in their natural habitat where 
they are routinely grown by local farmers. In all 
cases minimal cultural techniques have been 
applied, without any fruit thinning. All culti-
vars produce primarily on spurs and pruning 
is not commonly carried out. An integrated pest 
management approach is ordinary adopted by 



322 Ital. J. Food Sci., vol. 27 - 2015

growers by following the regional governmental 
rules for plum.

the fruits were picked by hand at the ripe 
stage (table 2). the fruits damaged were re-
moved, were graded for color and size uniformi-
ty and they were immediately transported to the 
pomological laboratory for analysis.

2.2 Fruit quality traits

the weight was obtained measuring individ-
ually 30 fruits per each local cultivars and ac-
cessions. the data were expressed as the mean 
± se. Fruit weight (g) was performed using an 
electronic balance (se622, Wvr, usA) with an 
accuracy of 0.01 g. 

the fresh fruit firmness (FFF) was measured 
using an effegi hand-held penetrometer (turoni, 
Italy) with a 5-mm-diameter plunger in accor-
dance with standard industry practice. the skin 
of the fruits was partially removed before mea-
suring. two measurements (30 fruits) were made 
on opposite sides of the central zone of the fruits 
and then averaged to yield a mean value for the 
fruit. the measurements were reported in kg 
force (kgf) cm−2. 

After the firmness measurements for the to-
tal soluble solids (tss) and the titratable acidi-
ty (tA) determination, the same fruits were com-
pletely hand-peeled and skin and pulp were cut 
in small pieces to obtain homogeneous samples. 
For tss and tA determination 10 g of pulp sam-
ples were squeezed using a commercial blend-
er and the extracted juice was later sieved and 
centrifuged at 8,000 × g for 20 min (sigma 3-18 
k, osterode and Harz, Germany). An aliquot of 
this supernatant was used to determine tss 
with a digital pocket refractometer Atago PAl-
1 (Atago co. ltd., Japan) calibrated at 20°c to 
0% with distilled water, and expressed as per-

table 1 - list of cultivars and accessions plums collected 
from the local germplasm of sicily and sampling locations.

 Authoctonous cultivars  Location*
 and accession name 

 1 69SUS005P  Messina (ME)
 2 Lazzarino Palermo (PA)
 3 Sanacore Tardivo Palermo (PA)
 4 Zuccarino Rosa  Messina (ME)
 5 Prunu Nucidda Messina (ME)
 6 Cuore di Bue  Catania (CT)
 7 Pruno Regina  Catania (CT)
 8 107SUS009E  Trapani (TP)
 9 107SUS008B  Trapani (TP)
10 107SUS007B  Trapani (TP)
11 Rapparinu Russu  Trapani (TP)
12 Sanacore Palermo (PA)
13 Prunu Niuru  Catania (CT)
14 Ariddo di Core Palermo (PA)
15 Occhio di Bue  Catania (CT)
16 Ranco’ Nero   Catania (CT)
17 Don Ciccino  Catania (CT)
18 Cugghiuni di Mulu Catania (CT)
19 Papale  Catania (CT)
20 71SUS028B  Catania (CT)
21 President  Catania (CT)
22 Pruna di S. Antonio  Messina (ME)
23 Susine Nere  Messina (ME)
24 Nivuru Purmintia  Messina (ME)
25 Nivuru  Messina (ME)
26 Pruna i Sceccu  Messina (ME)
27 Santu Vitu  Messina (ME)
28 66SUS052P Messina (ME)
29 Prunu Ciraseddu  Catania (CT)
30 Prugnolo rosso  Messina (ME)
31 Pruno Rosa Palermo (PA)
32 Primintio Palermo (PA)
33 Prunu Nivuru Codulusu  Trapani (TP)
34 Zuccarato Giallo  Messina (ME)
35 Shiro Palermo (PA)
36 Stanley Palermo (PA)
37 Angeleno Palermo (PA)

*Data on geographical position (latitude and longitude) are available for 
all plums.

Fig. 1 - total anthocyanins of local sicilian plums



Ital. J. Food Sci., vol. 27 - 2015 323

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324 Ital. J. Food Sci., vol. 27 - 2015

table 3 - Fruit quality traits of 37 authochtonous sicilian plums.

 Fruit weight FFF TSS  TA MI
 (g) kgf cm-2 °Brix g malic acid L-1

Plums
69SUS005P 34.20±4.51 G-I 0.88±0.21 D-I 19.6±0.21 B-E 7.76±1.74 G-O 2.5
LAZZARINO 16.77±2.90 O-S 0.58±0.26 L-R 16.5±1.47 F-I 6.28±0.41 I-Q 2.6
SANACORE TARDIVO 28.98±7.13 L-M 0.80±0.22 G-N 15.3±0.06 H-N 7.72±0.26 G-P 2.0
ZUCCARINO ROSA 13.67±1.99 R-U 0.31±0.12 S-U 15.1±0.70 H-N 9.02±0.14 F-L 1.7
PRUNO NUCIDDA 12.06±4.32 S-U 1.14±0.36 D 21.2±0.28 B-C 9.00±0.13 F-L 2.4
CUORE DI BUE 83.79±9.02 A 0.76±0.21 H-O 13.3±0.21 L-P 12.21±1.22 C-E 1.1
PRUNO REGINA 33.62±3.58 H-I 0.76±0.22 H-O 18.4±0.21 C-G 7.95±0.09 G-N 2.3
107SUS009E 21.07±7.06 N-O 0.63±0.20 I-Q 11.5±0.21 O-Q 16.56±0.57 B 0.7
107SUS008B 14.26±2.44 Q-U 0.40±0.12 Q-T 12.8±0.00 M-P 11.97±1.02 C-E 1.1
107SUS007B 14.93±3.43 P-U 0.40±0.11 Q-T 15.5±0.42 G-N 10.56±0.15 E-H 1.5
RAPPARINU ROSSO 13.75±2.25 Q-U 0.58±0.21 L-R 15.7±1.91 G-N 4.27±0.75 M-Q 3.7
SANACORE 19.26±5.86 O-Q 0.93±0.30 D-H 16.0±1.06 F-L 7.98±0.43 G-M 2.0
PRUNU NIURU 26.36±4.44 L-N 0.69±0.15 G-P 21.6±1.49 B 4.93±0.25 M-Q 4.4
ARIDDO DI CORE 16.75±3.19 O-S 1.07±0.35 D-F 20.1±2.03 B-D 6.13±0.76 I-Q 3.3
OCCHIO DI BUE 41.76±8.28 E-F 0.55±0.10 N-S 15.6±0.28 G-N 4.86±0.08 M-Q 3.2
RANCO’ NERO 44.13±5.39 E 0.60±0.10 L-R 16.6±0.07 E-I 7.29±0.09 H-P 2.3
DON CICCINO 37.22±5.92 F-H 0.47±0.06 P-S 19.1±0.28 B-F 10.12±0.21 E-I 1.9
CUGGHIUNI DI MULU 61.53±8.92 C 0.56±0.13 M-S 14.6±0.06 I-O 8.24±0.39 G-M 1.8
PAPALE 45.19±6.46 D-E 0.57±0.17 M-R 15.4±0.10 G-N 9.60±1.17 E-I 1.6
71SUS028B 49.99±8.77 D 0.55±0.07 N-S 16.7±0.15 E-I 7.67±0.24 G-P 2.2
71SUS024C 66.52±12.77 B-C 0.87±0.27 E-I 13.7±0.06 I-P 12.78±0.33 C-E 1.1
66SUS006S 16.16±4.37 O-T 0.65±0.17 I-Q 14.8±0.07 H-N 9.43±0.91 E-I 1.6
SUSINE NERE 9.48±1.69 U 0.52±0.05 O-S 14.2±0.07 I-O 11.83±0.99 C-E 1.2
NIVURU PRIMINTIA 40.70±7.23 E-F 0.82±0.17 F-M 14.5±0.96 I-O 10.84±0.26 E-G 1.3
NIVURU 15.21±2.91 P-T 0.69±0.26 H-P 14.9±0.07 H-N 9.65±1.26 E-I 1.5
PRUNA I SCECCU 39.79±7.30 E-G 0.83±0.31 F-L 11.0±0.28 P-Q 22.62±0.59 A 0.5
SANTU VITU 20.41±2.48 O-P 0.52±0.25 O-S 14.0±3.02 I-P 4.45±0.45 P-Q 3.1
66SUS052P 65.64±10.75 B-C 1.04±0.64 D-G 12.8±0.35 N-Q 14.56±0.47 B-C 0.9
PRUNU CIRASEDDU  14.21±2.05 Q-U 0.35±0.04 R-U 10.1±0.14 Q 3.60±0.18 Q 2.8
PRUGNOLO ROSSO 18.45±2.07 O-R 1.10±0.27 D-E 17.7±0.78 D-H 6.76±0.42 I-P 2.6
PRUNO ROSA 17.90±3.32 O-R 0.55±0.26 N-S 16.2±0.74 F-L 8.66±1.07 G-L 1.9
PRIMINTIO 21.09±5.33 N-O 0.46±0.17 P-S 15.7±1.44 G-N 10.94±2.15 D-G 1.4
PRUNU NIVURU CODULUSU  10.78±1.68 TU 0.12±0.04 U 16.7±0.07 E-I 14.23±0.40 B-D 1.2
ZUCCARATO GIALLO 13.57±2.89 R-U 0.16±0.05 T-U 25.0±0.35 A 5.86±0.27 L-Q 4.3
SHIRO 36.62±5.16 F-H 1.57±0.09 C 15.0±0.40 G-M 10.63±0.81 E-H 1.4
STANLEY 40.10±3.35 E-F 2.46±0.10 B 15.9±0.36 G-M 5.23±0.20 L-Q 3.0
ANGELENO 67.70±9.80 B 4.33±0.39 A 21.2±1.28 B-C 4.64±0.61 P-Q 4.6

Data are means ± SD. Values with the same letter at the column level are not statistically different with the Tukey’s test (0.05).

centage (°brix). tA was determined in 1 ml of 
the above supernatant diluted in 25 ml of dis-
tilled water by titration with 0.1 N NaoH up to 
pH 8.1, using an automatic titration device (484 
titrino plus, Metrohm, switzerland) and results 
expressed as grams of malic acid l−1. three rep-
licates per measurement were used and the data 
reported are the mean ± se.

the tss:tA ratio was calculated for individ-
ual fruit from the tss and tA results and it ex-
pressed the maturity index (MI).

2.3 Total anthocyanins, phenolic content 
and antioxidant activity

to determine the total anthocyanin content, 
the total phenolic content and the total antiox-
idant capacity, fruit extract was obtained using 
10 g of fruit added to 25 ml of extraction buffer 

(500 ml methanol, 23.8 ml deionized water and 
1.4 ml hydrochloric acid 37%). After 1 h in the 
dark at room temperature, the samples were 
thoroughly homogenized for a few minutes with 
an ultra turrax (IkA, staufen, Germany) and cen-
trifuged for 15 min at 3,000 rpm. the clear su-
pernatant fluid was collected and stored at -20 
°c until analysis.

the total anthocyanin content was quanti-
fied according to the pH differential method of 
cHeNG and breeN (1991). Anthocyanins were 
estimated by their difference of absorbance at 
510 and 700 nm in a buffer at pH 1.0 and pH 
4.5, where A

tot
 = (A

515
 - A

700
) pH 1.0 - (A

515
 - A

700
) 

pH 4.5. the results are expressed as milligrams 
of cyanidin-3-glucoside (c3G) equivalent per 100 
g of fresh weight (fw).

the total phenolics content was measured 
using a Folin-ciocalteu reagent with gallic acid 



Ital. J. Food Sci., vol. 27 - 2015 325

as a standard at 765 nm following the meth-
od of slINkArd and sINGletoN (1977). the re-
sults are expressed as milligrams of gallic acid 
equivalents (GAe) per 100 g of fresh weight (fw).

the antioxidant activity was determined using 
the FrAP (Ferric reducing Antioxidant Power) 
assay, according to beNZIe and strAIN (1996) 
method modified by PelleGrINI et al. (2003). the 
antioxidant capacity of the dilute fruits extract 
was determined by its ability to reduce ferric 
iron to ferrous iron in a solution of 2,4,6-tris(2-
pyridyl)-s-tri-azine (tPtZ) prepared in sodium 
acetate at pH 3.6. the reduction of iron in the 
tPtZ–ferric chloride solution (FrAP reagent) re-
sults in the formation of a blue-coloured prod-
uct (ferrous tripyridyltriazine complex), the ab-
sorbance of which was read spectrophotometri-
cally at 595 nm 4 min after the addition of ap-
propriately diluted fruits extracts or antioxidant 
standards to the FrAP reagent. the results were 
expressed as mmol Fe2+ equivalents per kilogram 
of fresh fruits.

All of these analyses were performed using 
a uv-vis spectrophotometer 1600-vWr. three 
replicates per measurement were used.

2.4 Statistical analysis

the data obtained were treated with one-way 
analysis of variance (ANovA) using sPss for 
Windows version 20.0 and the means were sep-
arated using the tuckey test (P ≤ 0.05).

3. results

3.1. Quality parameters

In the table 3 the qualitative traits studied for 
the different plums are reported.

As already reported, fruit size is an important 
quality parameter to evaluate the economic val-
ue for the consumption of fresh fruits (Petruc-
cellI et al., 2013) and to determine the catego-
ry of the ranges of marketability of many fruits. 
It is affected by a number of variables, includ-
ing source–sink relationship (sNelGAr et al., 
1998), water availability (INtrIGlIolo and cAs-
tel, 2006) as well as temperature and grow-
ing conditions in general. In our study a great 
variability on fruit weight has been reported 
among the different plums suggesting a differ-
ent fruit surface/volume (eIFert et al., 2006), a 
fruit size distribution into different classes and 
a different correlation to physical-chemical pa-
rameters, such tss and tA. Fruits with greater 
weight would have a greater proportion of edi-
ble flesh (FrANco-MorA et al., 2009). the fresh 
weight of all plums analysed revealed a mean 
value of 30.91 g ranging from 83.79 to 9.48 g; 
the maximum value was observed for the cuo-
re di bue cultivar while the lowest was observed 
for the susine Nere plums. less than half of the 

plums (sixteen) showed higher values than the 
mean value. the don ciccino cultivar was the 
only one to show the weight (37.22 g) similar to 
the values of the commercial cv. shiro (36.62 g) 
while Nivuru Primintia and occhio di bue with 
respectively 40.70 and 41.76 g showed similar 
weight to the commercial cv. stanley (40.10 g). 
All plums showed statistically differences from 
the commercial cv. Angeleno which weight was 
of 67.70 g.

Flesh firmness is a key quality parameter, 
since it is directly related to fruit ripeness, and 
is often a good indicator of shelf-life potential 
(vAlero et al., 2007). the highest pulp firm-
ness was observed for all the three commercial 
cultivars, the cv. Angeleno with 4.33 (kgf) cm−2 

was the higher value followed by the cv. stanley 
with 2.46 (kgf) cm−2 and the cv. shiro with 1.57 

(kgf) cm−2. All autochthonous plums (34) showed 
statistically differences from these last and only 
11% of them showed FFF value major than 1(kgf) 
cm−2. the mean value was of 0.82 (kgf) cm−2, the 
lowest value was reached by the Prunu Nivuru 
codulusu probably due to the low weight (10.78 
g), while the highest was observed for the Pruno 
Nucidda (1.14) (kgf) cm−2.

the physical-chemical parameters, such tss 
and tA, strongly influence the consumer pref-
erence for stone fruit quality and the aromatic 
profile for the plums consumption (crIsosto 
et al., 2007).

the Zuccarato giallo and the Prunu Niuru 
showed the highest tss content (25.0 and 21.6 
°brix, respectively) while the lowest tss value 
(10.1 °brix) was scored by the Prunu ciraseddu 
cultivar. observing the table 2 there is a ten-
dency for late season plums to have higher tss 
than early season plums.

less than half of the plums (43%) showed 
the tss content greater than the mean value 
(16.6°brix). the 69sus005P, Pruno Nucidda, 
Pruno regina, Prunu Niuru, Ariddo di core and 
don ciccino authoctonous plums showed simi-
lar values to the commercial cv. Angeleno (21.2 
°brix) and no statistically significant differences 
were observed between these fruits. the 66% of 
the plums showed value not statistically differ-
ent from the commercial cv. shiro and stanley 
which scored 15.0 and 16.0 °brix respectively. 
the tss values measured in the local cultivars 
and accession are quite high when compared to 
the value find in the literature; in fact tss be-
tween 14% and 16% (WestWood, 1978) or 10 
and 15% (díAZ-MulA et al., 2009) could suggest 
edible fruit ready for consumption.

the tA mean value was of 9.10 g malic acid 
l-1 and the 58% of the local plums showed tA 
values inferior to the average. the lowest acidity 
was for the Prunu ciraseddu (3.60 g malic acid 
l-1) while the highest value was for the Pruna i 
sceccu (22.62 g malic acid l-1). 

the variations observed in tss and tA affect-
ed the values of the maturity index (MI). Great 



326 Ital. J. Food Sci., vol. 27 - 2015

differences were observed among values which 
ranged from a minimum of 0.5 in the case of 
the Pruna i sceccu to a maximum of 4.6 for the 
commercial cv. Angeleno. the Prunu Niuru and 
the Zuccarato giallo with the MI of 4.4 and 4.3 
showed tss/tA ratio similar to the cv. Ange-
leno while Primintio (1.4) and santu vitu (3.0) 
were similar to the cv. shiro and the cv. stan-
ley respectively.

3.2 Total anthocyanins, phenolic content, 
and antioxidant activity

the evaluation of the total anthocyanins con-
tent (Fig. 1), in general, has shown that this com-
ponent does not assume, in percentage terms, a 
high importance in the context of polyphenolic 
compounds (Fig. 4). the Primintio accession had 
significantly more total anthocyanins content 
(65.22 mg of cyanidin-3-glucoside /100 g FW) 
than other fruits, although it is only 34.5% of the 
total polyphenols (Fig. 4). the lowest value was 
for Ariddo di core (1.22 mg of cyanidin-3-glu-
coside/100 g FW) which content was similar to 
the commercial cv. shiro and the fraction mea-
sured on the total content of the total polyphe-
nols was of 0.3 %. Although the anthocyanin 
fraction mean value was of the 5.8% of the to-
tal polyphenol content it was observed that the 
absolute values detected in some local cultivars 
and accessions such as Primintio, 107sus007b 
and Pruna di s. Antonio were higher than values 
previously reported for other varieties (toMás-
bArberáN et al., 2001; cevAllos-cAsAls et 
al., 2006; useNIk et al., 2009).

Polyphenols represent the largest group of 
water-soluble phytochemicals. they have been 

known to be chemotaxonomic markers for clas-
sification purposes in plum fruits (treutter 
et al., 2012) and their content could contrib-
ute strongly to the antioxidant activity in fresh 
fruits. Generally the polyphenol composition is 
related to the cultural practices and abiotic fac-
tors such as the outside air temperature and the 
rainfall rate (sAlGAdo et al., 2008; MIletIc et 
al., 2012). strong variations in the total poly-
phenol content were observed among the plums 
of the study (Fig. 2) whose mean value was of 
301.67 mg GA/100 g FW. the minimum value 
of 104.87 mg GA/100 g FW was observed for 
the sanacore tardivo while the maximum val-
ue of 663.99 mg GA/100 g FW was observed for 
the Zuccarato giallo. the total phenolic content 
in the commercial cultivars used as references 
was lower than that reported by cevAllos-cAv-
Als et al., 2006 (298 to 563 mg/100 g FW) for 
Prunus salicina cv. shiro (191.17 mg GA/100 g 
FW) and cv. Angeleno (242.01 mg GA/100 g FW) 
while according to los et al., (2000) it was in the 
range for Prunus domestica (160-300 mg/100 g) 
(cv. stanley 211.23 mg GA/100 g FW). the 58% 
of the local plums included a total polyphenol 
content major than cv. Angeleno. Previous stud-
ies showed as the averages of the total phenolic 
content of plums were significantly higher than 
the content in other fruits such as apples (lee 
ANd sMItH, 2000; ProteGGeNte et al., 2002) 
and our data confirmed that.

the total antioxidant capacity of fresh fruits 
(Fig. 3), expressed as mmol Fe2+ per kg of fresh 
fruits ranged from a maximum value of 47.46 
measured for Pruno regina and a minimum val-
ue of 4.14 for the rapparinu russu accessions. 
No statistically significantly differences were ob-

Fig. 2 - total phenolics content of local sicilian plums



Ital. J. Food Sci., vol. 27 - 2015 327

served among the cv. shiro, stanley and Angele-
no which values ranged between 4.86 and 9.59 
mmol Fe2+/100 g FW and the 20% of the fruits 
showed values major than the average (13.45 
mmol Fe2+/100 g FW). As described by FrAN-
kel and MAyer (2000), the measure of fruit an-
tioxidant capacity is influenced by the analyti-
cal method used and this could represent a lim-
it for the evaluation. According to MIletIc et al., 
(2012), fruits containing the highest total phenols 
do not necessarily exhibit the highest antioxi-
dant capacity. In fact the highest value observed 

Fig. 3 - total antioxidant activity of local sicilian plums

for the Pruno regina accession is related to the 
relative high phenolic content but the same cor-
relation wasn’t observed for the Zuccarato giallo 
which corresponded the highest phenolic content 
(663.99 mg GA/100 g FW) but the low total an-
tioxidant activity of 11.86 mmol Fe2+/100 g FW. 

comparing the total antioxidant activity of the 
studied plums to the total FrAP of other fruits 
reported in previous work (Guo et al., 2003) it 
is interesting to observe the high values find 
that could suggest interesting uptake of plums 
for the human diet.

Fig. 4 - total anthocyanins and phenolics distribution (%) in authochtonous sicilian plums.



328 Ital. J. Food Sci., vol. 27 - 2015

4. coNclusIoNs

this study provides important data for quali-
tative and nutraceutical properties of the fruits. 

the results obtained by this preliminary 
study reveals that the authocthonous sicilan 
plums contains important amounts of anthocy-
anins and phenols; often their concentrations is 
higher than found not only in the commercial 
cultivars but also in fruits that are reported in 
literature to have high content of nutraceuti-
cal compounds. considerable and significantly 
different among the plums were observed and 
the environmental conditions and the activity 
of propagation and exchange of genetic mate-
rial results of the local farmers could be both 
responsible for the differentiation of the germ-
plasm collected in the investigated areas of the 
sicilian territory.

the maintaining of local genetic materials is 
important for the biodiversity and the action of 
localization and characterization of old fruits cul-
tivar and accessions is fundamental to improve 
the management of the european Prunus data-
base for Plum (ePdP) making them available for 
research and genetic improvement.

the knowledge of the qualitative traits of fruits 
represent a good opportunity not only for the 
health advantages but also for the general con-
sumption; in fact the enhancement and the safe-
guarding of these fruits can be thought as an 
opportunity of new marketing channel but more 
studies need to be undertaken about the evo-
lution of the qualitative and nutraceutical com-
pounds during storage to answer the consum-
er’s demands and expectations.

AckNoWledGeMeNts

this work is part of the activity funded by the sicilian re-
gional Government with the project “risorse Genetiche veg-
etali sicilia’ – scientific coordinator Francesco sottile, uni-
versity of Palermo.

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