short communication

Ital. J. Food Sci., vol. 27 - 2015 1

- Keywords: hydroculture, nutritional elements, nutrient solution, strawberry -

EffEcts of NutritioNal ElEmENts lEvEl
oN NutritioNal charactErs 

aNd PhytochEmistry
of strawbErry iN hydroculturE 

robabEh asghari
Institute of Applied Scientific Higher Education of Jahad-e Agriculture, 

Imam Khomeini agricultural higher education center, Karaj, Iran
*Corresponding author: Tel. 09352394098,

email: fariba2022@yahoo.com

AbstrAct

this study was conducted to evaluate the impacts of nutrient elements on phytochemistry char-
acters and qualities of strawberry in soilless culture system. the experiment was carried out in 
a factorial experiment based on randomized complete design with three replications. treatments 
consisted of 6 groups of strawberry growing on soilless medium made of perlite and coco peat 
that were treated with different ratio of nutrient solutions. According to the results modified nu-
trient improved fruit nutritional characters but it was not unique. tss

s
, tA, vitamin c and pH of-

ten were increased by increasing nutritional elements but anthocyanin was decreased by increas-
ing some nutritional elements. 



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

IntroductIon

strawberry (Fragaria × ananassa duch.) is one 
of the most commonly consumed berries, both 
in fresh and processed forms such as jams, 
yoghurts, desserts or juices. the relevant nu-
tritional value of strawberry fruits has been 
remarkably correlated (HAnnuM 2004) with 
the high level of micronutrients such as min-
erals, vitamin c and folate which are essential 
for health, and, more recently, to the high 
levels and different phytochemical constitu-
ents (tuLIPAnI et al., 2009).

since strawberry is an adaptable plant, and 
its fruit can be obtained almost in all seasons, 
its growing areas are being widely expanded in 
the world. on the other hand since the fruits 
can be obtained early in the season, when there 
are no fresh fruits in the markets, its marketa-
bility is high. Another important aspect is that 
it can bring back the investment in a short pe-
riod; therefore it is suitable for family hobby 
(ILGM, 2006).

because of increased demand for more prod-
ucts with high quality and offseason, green-
house production is increasing. soilless me-
dia are popularly used in greenhouse crop pro-
duction because they are relatively lightweight, 
free from diseases, readily available, more uni-
form and more suitable for growing in contain-
ers than soil (YuAn et al., 1996). the choice of 
the medium should be based on physical char-
acteristics as well as availability and cost (LI-
EtEn et al., 2004; tAbAtAbAEI and MoHAM-
MAdrEZAEI, 2006). 

Hydroponics is a method of growing plants 
using mineral nutrient solutions without soil. 
In this method, growing substrate may be an 
organic material (peat moss, shredded bark, 
foam or other organic materials) or an inor -
ganic material such as sand, perlite, vermic-
ulite and rock wool. to support and anchor 
the root system; plant nutrition is provided 
through a nutrient solution circulating in the 
substrate. 

one of the advantages of plant nutrition in 
soilless culture derives from the possibility of 
precise control of nutrient elements (JoHnston 
et al., 2010) which is not possible with soil sub-
strate (ArZAnI, 2007). coco peat is the best me-
d i u m  for growing summer crops, flowers and 
strawberry because i t  has high porosity, and it 
has a good capacity of holding water and nu-
trients. Porosity in perlite provides good air ex-
changes and soil watering and it improves soil 
aeration promoting the growth of the root sys-
tem (noGuErA et al., 2003). Perlite has rich in-
organic materials such as iron, sodium, calci-
um and rare organic materials, since it is based 
an organic feature (dJEdIdI, 1999; EbrAHIMI 
et al., 2012).

strawberry requires high amounts of potassi-
um because this element is a major component 

of the fruit and has a positive correlation with 
fruits size, color and acidity (bEHnAMIYAn and 
MAsIHA, 2002). 

the research was designed and performed to 
evaluate the effect of different concentrations of 
nutrients elements via nutrient solution in soil-
less system composed of 50% perlite and 50% 
coco peat on phytochemical and quality char-
acters of greenhouse grown strawberries cul-
tivar Gaviata (AMErI et al., 2012).

MAtErIAL And MEtHod

Plant material and growth conditions

the study was conducted from March to 
August, 2013, in an experimental greenhouse 
of the plant production department, Imam 
Khomeini higher educational center Karaj, 
Iran. strawberry plants cv Gavieta were grown 
in 2 liters pots on a soilless medium made of 
50% perlite and 50% coco peat (v:v) with three 
plants per pot. day/ night temperatures were 
kept at 22/17°c. and were treated with differ-
ent ratios of a nutrient solution. the full nu-
trient solution formula was made up with the 
following stock solutions of the different nutri-
ents: 2.6 KH

2
Po

4
, 1.9 Kno

3
, 2.4 ca(no

3
)
2
 4H

2
o, 

0.65 Mgso
4
 7H

2
o and 0.46 K

2
so

4
. Microele-

ments for the full nutrition solution were pro-
vided in the following amounts: 0.16 H3bo3, 
0.09 Mnso4, 0.07 Znso4, 0.01 cuso

4
 and 

0.002 H
2
Moo

4.
 to provide iron, a stock so-

lution containing 0.1 Fe-EdtA was prepared 
(ArZAnI, 2007).

the following treatments were applied:
Full nutrient solution (G1), a modified nu-

trient solution with either 10% less (G2) or 
more (G3) amount of Fe, Znso

4
, b

2
so

4
, Mgso

4
, 

Kno
3, 

a modified nutrient solution with ei-
ther 10% more (G4) or less (G5) amount of 
Fe, ca(no

3
)2, KHPo4, Mnso

4
, cuso

4
, Moso

4 
and a modified nutrient solution consisting 
of +10% ca (no

3
)2, KHPo4, Mnso4, cuso

4
, 

Moso
4
 (G6).

the hydroponic system was open. nutrient so-
lution formula for the group containing chemi-
cal treatment was prepared according to KErEJ 
et al. (1999) instruction (table 1). the pH and 
Ec of nutrient solution were adjusted to 5.7 and 
from 0.9 to 1.4 ds m-1, respectively. 

the pots were arranged in the glasshouse ac-
cording to a randomized complete design with 
three replications per treatment.

Determination 
of Total Anthocyanin Content (ACY)

the AcY of the hydroalcoholic extract of fruits 
was determined using the pH differential meth-
od previously described by GIustI (2001). AcY 
concentration was calculated from the calibra-



Ital. J. Food Sci., vol. 27 - 2015 3

tion curve using pelargonidin- 3-glucoside (Pg-
3-gluc) as a standard. results are expressed as 
mg of Pg-3-gluc equivalents per 100 g of fresh 
weight (FW) of strawberry. data are reported as 
a mean value (sd for six measurements) (tuLI-
PAnI et al., 2008).

total soluble solids (tsss), total titratable 
acidity (tA), and pH determinations

twenty fruits from each replicate were 
wrapped in cheesecloth and squeezed with a 
hand press, and the juice was analyzed. tsss, 
was determined at 20°c by an Atago dbX-55 
refractometer (Atago co. Ltd, tokyo, Japan). 
pH was measured with a pH meter. tA was de-
termined by titrating to pH 8.2 using 0.1 mol/l 
naoH after appropriate dilution (AoAc, 2000).

Determination of vitamin C

Ascorbic acid was measured by HPLc as de-
scribed by HELsPEr et al. (2003). briefly, vita-
min c was extracted by sonication of 0.5 g of 
wet frozen powder in 2 ml of ice cold water with 
5% metaphosphoric acid and 1 mM dtPA, fol-
lowed by centrifugation at 2500 rpm for 10 min, 
filtering, and immediate analysis on an HPLc 
system. Quantification was made through a 
standard calibration curve prepared by run-
ning standard concentrations of vitamin c pre-
pared similarly and measured in duplicate at 
the beginning and end of the analysis. results 
are expressed as mg of vitamin c per g of FW 
(tuLIPAnI et al., 2008).

Statistical analyses

data were analyzed by the general linear mod-
el AnoVA by Minitab® release 13.2 (Minitab 
Inc.). Following AnoVA, treatment means were 
compared using the Lsd test at P = 0.05. sta-
tistical procedures were performed using the Pc  
sAs software package.

rEsuLts

the results showed under G
1
 nutrient solu-

tion (first group) the fruit regarded indexes that 
affect its aroma and taste are in acceptable lev-
el, however when we used modified nutritional 
solution for the other groups (G

2
-G

6
), increasing 

levels of some of the characters was detectable. 
the highest level of tss and vitamin c observed 
in group four that had higher percentage of Fe, n, 
P, s, Mn, cu and K against the group that treat-
ed with G

1 
nutrient solution (first group). Fruits 

produced under treatment G
3
 (group3) that re-

ceived higher amount of Fe, s, Mg, Zn, n and 
K than the other groups exhibited the highest 
level of tA, whereas levels of tss and vitamin c 
were almost similar to group G

4
. Fruits treated 

with modified nutrient solution number 5 that 
contained lower level of Fe, n, P, s, Mn, cu and 
K against normal nutrient solution, showed the 
highest level of anthocyanin and the highest 
amount of pH was detectable in fruits treated 
with modified nutrient solutions G

6
 and G

2
 that 

received higher level of n,ca,P,K,s,Mn,cu and 
Mo and Fe, Zn, b,s,n,K,Mg respectively (table 2).

table 1 - Analysis of variance for strawberry phytochemical characters under different nutrient solutions. 

Treatment df   Phythochemical Characters
  TSS TA Vitamin Total Anthocyanin pH
  (Brix) (mg/100 g F.W.) C(mg/g F.W.) (mg/100 g F.w.)

Nutrient Solution 5 2.957* 0.0024* 0.0306* 7527570.5** 0.045**
Error 15 0.944 0.0008 0.0084 435379.3 0.006
CV  10.1 10.9 8.3 26.6 1.9

**,*, ns and CV, significant at 1, 5% level of probability, non-significant and Coefficient of Variation, respectively.

table 2  Effect of different concentration of nutrient solution on strawberry phytochemical characters.

Treatment   Phythochemical Characters pH
 TSS  TA Vitamin C Total Anthocyanin
 (Brix) (mg/100 gF.W.)  (mg/g F.W.)  (mg/100 g F.W.)

G1 10.33ab 0.28b 1.03ab 3997.3ab 3.77b
G2 9.00b 0.26b 1.10ab 3744.3b 4.02a
G3 9.67ab 0.32a 1.10ab 2343.0c 3.85b
G4 11.00a 0.24b 1.26a 2067.3c 3.81b
G5 9.17b 0.25b 1.13ab 4996.8a 3.85b
G6 9.00b 0.26b 1.20ab 1378.1c 4.06a



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

Analysis of variance showed that interac-
tion between nutritional elements of nutrient 
solution supplied with nutritional characters 
of the fruits was significant; tss, tA and vi-
tamin c in 5% level and anthocyanin and PH 
in 1% level of probability (table 1). nutrient 
solution treatment with different ratio chem-
ical nutritional elements showed significant-
ly influence on total soluble solids (tss), total 
acidity (tA), vitamin c (P>0.05), anthocyanin 
and pH (P<0.001).

dIscussIon

considering the results of the present study 
using a modified nutrient improved fruit nu-
tritional characters but it was not unique; dif-
ferent nutritional formula showed different ef-
fect on each index. However often characters 
increased following enhanced nutritional el-
ements (micro and macro), but anthocyanin 
decreased with increasing some nutritional el-
ements (micro and macro) (table 2). sEYYE-
dI (2005) studied the effect of four kinds of 
nutrient solution in hydroculture system on 
the quantitative and qualitative traits of silva 
strawberry. He showed that by increasing po-
tassium up to 3meq/l in nutrient solution, the 
soluble solid material increases. FArZAnEH et 
al. (2009) studied the effect of different nitro-
gen and potassium levels on yield and densi-
ty of nitrogen and potassium of tomato leaf in 
perlite environment and reported that the most 
yield of fruit was gained with 200 mg/L nitrogen 
consumption, and higher levels of nitrogen re-
duced the yield and different levels of potassium 
did not have any significant effect on the yield. 
HArtZ et al. (1999) studied different levels of 
potassium on the quality of muskmelon. they 
found that 240 mg/L potassium level caused 
a significant increase in total sugar, tss, glu-
tamic acid, aspartic acid and acetate volatile 
components in fruit flesh, which have an effect 
on its taste and flavor. MAsHHAdI-JAFArLoo 
et al. (2009) showed that the most strawberry 
yield was obtained in 100% coconut medium 
and cocopeat + perlite (50% + 50%) placed in 
the next stages (EbrAHIMI et al., 2012; AnIEL 
et al., 2007). According previous studies the re-
sult showed that increasing nutritional element 
until a definite level has positive effect on the 
fruit nutritional characters. 

Whereas fruits treated with nutrient solution 
formula exhibited significant effect on nutrition-
al characters in fruit quality, were not the high-
est level but almost all of them were in limited 
amount. However with using of modified nutrient 
solution, some of the indexes decreased though 
some of them increased, so it seems that under 
a usual condition and using G

1
 nutrient solu-

tion we have strawberries with satisfying aro-
ma and taste. When we used a growing medium 

containing 50% perlit and 50% coco peat treat-
ed with G

1
 nutrient solution formula, produced 

strawberries with more acceptable nutritional 
characters comparing the fruits that produced 
under other nutrient solution. However in these 
conditions some nutritional characters exhibit-
ed to increase but the others decreased. there-
fore based on the experiment results fruits pro-
duced under G

1
 conditions are the best.

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