International Conference on Agriculture, Biology and Environmental Sciences (ICABES'14) Dec. 8-9, 2014 Bali (Indonesia)
Regional Effects on Fruit Physical and Chemical
Characteristics of two Apple Varieties Grown
in Libya
Yosef I. Geddeda, and H. Belal
period after pollination has a strong influence on final fruit
size. Physiological and anatomical evidence showed that
development rate during the cell division, determines final
fruit size [3]. Fruit firmness tends to be influenced greatly by
many preharvest factors, such as genetics, cultural practices,
and the applications of fertilizers or growth regulators [4].
Apple cultivars vary in fruit firmness, for example, Granny
Smith apples are firmer than most other cultivars, whereas
McIntosh apples are among the softest. Apples with a
firmness of less than 4.5 kg are usually rejected by consumers
and, therefore, this is considered the minimum acceptable
firmness level for many soft cultivars [5]. Sugars, organic
acids and phenolic compounds all contribute to the aroma of
apples. Total sugar content varies, according to the cultivar,
between 9.5% and 15.03% [6].
Apple fruits have a wide range of flavor ranging from tar
to sweet one. Titratable acidity is an important factor in
assessing fruit quality, as consumers often have distinct
preferences for acid or sweet tasting apples [6]. Whether for
cider making or for blending fresh juice, the acidity of the
juice has an influence on the perceived acidity in the taste of
the fresh juice and of the finished cider; if the acidity is too
low, the juice or cider will lack freshness. On the other hand,
too much acidity may render the juice or cider too sharp and
unpleasant to drink [7].
In Libya apple orchards exist mainly in the mountainous
regions in the East and West of the country; known as Green
Mountain (GM) and Nafusa Mountain (NM). The two regions
differ somewhat in climate. Green Mountain is wetter and
cooler than NM, while NM is wormer and drier. Golden
Delicious and Red Starking apple varieties were introduced to
the two regions during the past few decades [8].
The objective of this research was to study the regional
effects on several physical and chemical characteristics of the
two apple varieties, Golden Delicious and Red Starking,
widely grown in the two regions of Libya i.e. GM and NM.
Abstract---Physical and chemical characteristics of fruits of two
apple varieties (Malus domestica Borkh.) namely; Golden Delicious
and Red Starking grown in two different regions of Libya ; Green
Mountain (GM) and Nafusa Mountain (NM) were studied. Sets of
ten mature, pest free fruits from each variety from both locations
were randomly taken and were replicated five times in a complete
randomized block design (CRBD). Fruit fresh wt., size, length,
width, % moisture content, and firmness were determined. Fruit juice
was extracted, measured and was analyzed for titratable acidity and
pH. Total soluble solids (TSS) were estimated using hand
refractometer. Data was statistically analyzed. Results showed that
fruits of both varieties grown in GM had higher fresh wt. and juice
content than those grown in NM. While Golden Delicious fruits
grown in GM were beggar and longer than fruits of the same variety
grown in NM, fruits of Red Starking were not different in both
locations in these parameters. On the other hand, fruits of both
varieties grown in NM were firmer than those grown in GM. Other
parameters were also discussed.
Keywords----Mallus domestica, Libya, Apple.
I. INTRODUCTION
Apple tree is adapted to various different climates, but
thrives in temperate and cool regions. Most apple varieties
have a high chilling requirements and grow well in loamy,
deep and well aerated soils with a pH of 6-7, and it blooms
relatively late which makes it suitable to areas of early spring
frost [1]. Apple is a pomaceous fruit known for its high yield
and extended storage life. It is one of the most important
fruits in the World, and it is the third most produced fruit crop
in the World (64.3 million t/year) following bananas (81.3
million t/year) and grapes (66.3 million t/year) [2].
Apples have been one of the human diets since ancient
times and are one of the most commonly consumed fruits
worldwide today. The attractiveness of fruit to consumers is
determined by visual attributes that include appearance, size,
uniformity, color and freshness, as well as non-visual
attributes such as taste, aroma, flavor, firmness. The 4-6 week
II. MATERIALS AND METHODS
Apple fruits of two Libyan varieties (Mallus domestica
Borkh.) namely; Golden Delicious and Red Starking budded
on MM106 rootstock grown in two different region of Libya
were studied.
The regions were Green Mountain (GM)
located in the Eastern part of Libya immediately south of The
Mediterranean Sea, and Nafusa Mountain (NM) located in
North West of Libya about 80 Km south of The
Yosef I. Geddeda, and H. Belal are with the Department of Horticulture,
Faculty of Agriculture, University of Tripoli, P.O. Box 9260, Suq Elgumaa,
Tripoli, Libya (corresponding author’s e-mail: [email protected]).
http://dx.doi.org/10.17758/IAAST.A1214052
35
International Conference on Agriculture, Biology and Environmental Sciences (ICABES'14) Dec. 8-9, 2014 Bali (Indonesia)
Mediterranean Sea. The distance between the two regions
about 1200 km. Mature, pest free fruits were picked from
each variety grown in both regions. Samples consisted of sets
of 10 fruits randomly taken at the commercial maturity stage.
The experiment was carried out in a randomized complete
block design with five replicates. Physical characteristics
studied were Fruit fresh wt., size, length, width and firmness.
Fruit size was estimated by water displacement in cm3, fruit
length and width (at the largest diameter) were measured in
cm. Fruit firmness was determined on two opposite sides of
each fruit using Effe-gi fruit firmness tester. Fruit juice was
extracted, measured and the following chemical characteristic
were studied: fruit titratable acidity (TA %), moisture content
%, pH and total soluble solids percentage (TSS %). TA %
was estimated by titrating fruit juice against (0.1N) Na OH.
Sets of ten fresh fruits were weighed, then dried at 68 C0 in a
forced air draft oven until weight stabilized, then weighed and
moisture content % was calculated. The pH was determined
using a pH meter.
TSS % was determined by hand
refractometer using filtrate of fruit juice. Results were
statistically analyzed using LSD mean separation method [9].
Golden Delicious grown in GM had significantly higher fruit
juice and % moisture content than those grown in NM. On
the, contrary fruits from NM were firmer than those from GM
region. The same results were obtained for Red Starking fruits
(Table 2). These results could also be attributed to the
environmental and other factors which dominate in the two
regions. Fruit firmness was shown to be influenced greatly by
several factors, such as; cultural practices and the applications
of fertilizers [4], and it was reported to vary with cultivar, for
example, Granny Smith apples were found to be firmer than
most other cultivars, whereas McIntosh apples were found to
be the softest [3], [4]. Other factors sited were high
temperature stresses within the growing season, water stress
associated with high temperature, water availability and carryover effects from the previous year [14], [15]. Fruits from
non-irrigated apple trees were found to be firmer than those
from irrigated trees [16]. Maturity at harvest can also affect
apple fruit firmness. Some apple cultivars such as Golden
Delicious and Red Chief Delicious showed decreased fruit
firmness with later harvest dates, whereas other cultivars such
as, Starking Delicious did not seem to be affected by harvest
time [4].
III. RESULTS AND DISCUSSION
TABLE II
AVERAGES OF FRUIT JUICE, % MOISTURE CONTENT AND FIRMNESS OF TWO
APPLE VARIETIES GROWN IN GREEN MOUNTAIN (GM) AND NAFUSA
MOUNTAIN (NM) REGIONS OF LIBYA
Variety
Location
Fruit
Moisture
Firmness
juice
content
(kg/cm²)
(ml)
(%)
G. Delicious
GM
6.75 a
79.9 a
6.9 c
NM
2.95 c
75.5 b
9.3 a
Fresh fruits of Golden Delicious grown in GM were
significantly heavier, bigger, longer and wider than fruits of
the same variety grown in NM region. Fruits of Red Starking
grown in GM were heavier than those grown in NM, but had
similar fruit size, length and width (Table 1). These results
could be attributed to the following several factors which may
have prevailed in the two regions. Fruit growth is highly
sensitive to temperature early in the season, but significantly
less responsive later [10]. Water stress was reported to induce
fruit fresh weight reductions at all crop loads [11]. The final
period of fruit growth, which is very rapid, has been also
reported to be sensitive to water stress in peach, apple and
Asian pear [12]. De Silva et al. [13] indicated that
physiological and anatomical development rate during cell
division, determines final fruit size, and that differ from
location to location, reflecting the importance of weather
variation in determining fruit quality and tree performance.
Others found that during the final apple fruit growth phase,
which consists of approximately one-third of the growth
period, 80% of a fruit’s fresh weight was accumulated [6],
[12].
R.
Starking
GM
NM
87.53 b
71.39 c
92.33 b
93.17 b
4.90 a
4.80 a
4.33 b
2.73 c
78.4 a
74.2 b
5.8 d
7.9 b
Values in a column followed by the same letter, are not significantly
different at 5% LSD level.
The results showed that fruit TA% and pH were not
affected by region in both varieties. However, fruit TSS was
higher in fruits of both varieties when grown in NM region
(Table 3). Differences between cultivars in the contents of
some biochemical compounds were reported. Nour et al. [6]
found that the highest titratable acidity was found in ‘Red
Boskoop’ (0.771%), while in ‘Starkrimson’ the titratable
acidity was only 0.101%. They also indicated that the total
sugar content varied between 9.5% in ‘Cadel’ and 15.03% in
‘Red Boskoop’.
TABLE I
AVERAGES OF FRUIT FRESH WT., SIZE, LENGTH AND WIDTH OF TWO APPLE
VARIETIES GROWN IN GREEN MOUNTAIN (GM) AND NAFUSA MOUNTAIN
(NM) REGIONS OF LIBYA
Variety
Location
Fruit
Fruit Size
Fruit
Fruit
fresh wt.
(cm3)
Length
width
(g)
(cm)
(cm)
G.
GM
112.10 a
137.33 a
5.23 a
6.33 a
Delicious
NM
51.99 d
58.00 c
4.10 b
4.76 b
R.
Starking
GM
NM
TABLE III
AVERAGES OF FRUIT TA%, PH AND TSS% OF TWO APPLE VARIETIES GROWN
GREEN MOUNTAIN (GM) AND NAFUSA MOUNTAIN (NM) REGIONS OF LIBYA
Variety
Location
TA%
pH
TSS%
G.
Delicious
5.73 a
5.16 a
R. Starking
Values in a column followed by the same letter, are not significantly different
at 5% LSD level.
GM
0.39 a
4.0 a
18.4 b
NM
0.40 a
4.2 a
21.1 a
GM
0.26 b
4.1 a
19.2 b
NM
0.30 b
4.5 a
22.1 a
Values in a column followed by the same letter, are not significantly different
at 5% LSD level.
http://dx.doi.org/10.17758/IAAST.A1214052
36
International Conference on Agriculture, Biology and Environmental Sciences (ICABES'14) Dec. 8-9, 2014 Bali (Indonesia)
IV. CONCLUSION
In conclusion, apple fruit physical and chemical
characteristics of the studied varieties differed from region to
region for the same variety. Variations due to regions could
be attributed to environmental and soil factors and the
interaction between these factors and the individual variety.
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