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PUBLISHED DATE: - 29-11-2024
https://doi.org/10.37547/tajas/Volume06Issue11-04
PAGE NO.: - 17-23
EVALUATION OF COOLING AGENT
DEPENDENCY AND AVERAGE PHYSICAL
PROPERTIES OF APPLES AND APRICOTS
INTENDED FOR EXPORT
Niyazova Sh.A.
Senior teacher of shakhrisabz branch of tashkent chemical-technological
institute, Uzbekistan
Zokirov B.U.
PhD, Shakhrisabz branch of tashkent chemical-technological institute,
Uzbekistan
Khasanov Sh.Sh.
Alfraganus University, associate professor, Uzbekistan
Dodayev Q.O.
Professor, Tashkent Institute of Chemical Technologies, Republic of
Uzbekistan, Tashkent, Uzbekistan
INTRODUCTION
The export of Uzbek apple and apricot varieties to numerous countries reflects the high quality and
efficiency of the country's agricultural sector.
RESEARCH ARTICLE
Open Access
Abstract
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Varieties such as Golden Delicious, Red Delicious,
and Subhoniy are among the most exported fruits,
renowned worldwide for their exceptional taste
and quality. The diverse climatic conditions and
fertile soils of Uzbekistan contribute to high
productivity and enable these fruits to be widely
distributed globally [1-4].
The apricot (Prunus armeniaca) belongs to the rose
family and is a fruit-bearing plant. Its origin is
Central Asia, where 10 species are known. Varieties
such as common apricot, Manchurian apricot,
Siberian apricot, David apricot, and black apricot
are widely cultivated. Apricots are grown in
regions including Northern India, Iran, Turkey,
Italy, Spain, North and South Africa, North America,
Australia, Central Asia, the Caucasus, and southern
parts of European Russia. Apricots were
domesticated over 5,000 years ago in Central Asia
and China and 2,000 years ago in Southern Europe.
There are now more than 500 known varieties [5-
6].
The Subhoniy apricot is one of Uzbekistan's famous
and widely cultivated apricot varieties. This variety
is known for its high-quality fruit and exceptional
productivity. Subhoniy has been grown since
ancient times and is prevalent across various
regions of Uzbekistan. Its fruits are medium-sized,
with a diameter of 4-5 cm and a weight of 30-50
grams, often slightly elongated or round. When
ripe, the fruits are yellow to golden in color, with
occasional red hues on their surface. They are
sweet, flavorful, and juicy, with a unique aromatic
scent. The texture is soft, smooth, and delicate, and
the flesh separates easily from the pit [7].
The apple (Malus domestica) belongs to the
Rosaceae family and is a deciduous tree or shrub
that produces seeded fruits. In Uzbekistan, wild
apple varieties are predominantly found in the
mountainous regions of Tashkent province,
including Bostanlik, Parkent, and Ohangaron
districts. Based on ripening periods, apples are
categorized into summer, autumn, and winter
varieties. Apples are frost-resistant, sun-loving,
and moisture-demanding. They are adaptable to
various soil types but yield the best results in fertile
soils [8].
The Golden Delicious apple is one of the most
popular and globally recognized apple varieties.
This apple variety has a diameter of approximately
6
–
8 cm and weighs between 150
–
200 grams. The
fruit features a golden-yellow skin, sometimes with
a greenish hue. It is sweet with a slight tartness,
predominantly sweet in taste, very juicy,
moderately firm, and has a delicate, pleasant aroma
[9].
The Golden Delicious apple was discovered in 1914
in West Virginia, USA. Initially, it was known as
"Mullins Yellow Seedling" or "Mullins' Yellow
Apple" before being renamed Golden Delicious.
This variety thrives in temperate climates.
Extremely cold or hot conditions can harm its
growth and quality. Golden Delicious apples are
typically harvested in September and October
when fully ripened, as they do not continue to ripen
after being picked. Its naturally sweet flavor makes
it an excellent choice for fresh consumption.
One of the outstanding qualities of the Golden
Delicious apple is its excellent storage capability. It
can be stored for several months in a cool and dry
environment. The ideal storage conditions are a
temperature of 0
–
4°C with 90
–
95% relative
humidity.
The Golden Delicious apple is renowned
worldwide for its sweet taste, juicy texture, and
versatility. It is not only delicious but also a healthy
fruit variety that offers numerous benefits for
overall well-being [10
–
11].
Today, the use of high-quality and energy-efficient
technologies in the export of fruits has become
increasingly important as global demand for
seasonal fruits and vegetables rich in natural
vitamins, micro-, and macroelements grows year
by year. Alongside this, research aimed at
preserving the condition of exported fruits,
delivering them to consumers in high quality, and
maintaining the unique flavor components of the
fruit at optimal levels holds significant relevance.
METHODS
Determining the physical properties of fruits is of
significant importance in the food industry, storage
technologies, and export processes. The quality of
fruits such as apples and apricots is assessed by
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analyzing parameters such as mass, volume,
density, circumference, water content, pH level,
and thermal conductivity. Each parameter is
measured using specialized equipment and
techniques.
The mass of a fruit is measured using an electronic
scale and expressed in grams (g). The volume is
determined by the water displacement method,
where the fruit is submerged in water, and its
volume (cm³) is calculated based on the change in
water level. Density is calculated by dividing the
mass of the fruit by its volume, and it is expressed
in grams per cubic centimeter (g/cm³).
The geometric dimensions, particularly the
circumference (diameter), are measured with a
caliper or measuring tape and recorded in
millimeters (mm). Water content is determined by
calculating the difference between the initial mass
of the fruit and its mass after drying, expressed as
a percentage (%). The pH level is measured using a
pH meter to determine the acidity of the fruit juice.
Thermal conductivity is assessed using a
specialized meter, which measures the rate of heat
transfer through the fruit’s internal structure. This
parameter is expressed in watts per meter-kelvin
(W/m•K).
These analyses provide critical data for evaluating
fruit quality, optimizing storage conditions, and
ensuring that fruits meet the standards required
for export.
In subsequent processes, the methods for studying
the respiration rate and water loss (dehydration)
of fruits were implemented.
Respiration Rate Measurement
To measure the respiration rate, fruits are placed in
a specially designed airtight container with a
known volume and temperature. A gas analyzer or
CO₂ sensor is used to regularly measure the levels
of carbon dioxide (CO₂) and
oxygen (O₂) inside the
container. Based on the amount of CO₂ produced
over a specific time, the respiration rate is
calculated in mg CO₂/kg/hour using the formula:
This method ensures accurate results by factoring
in both the fruit's weight and the time of
measurement.
Water Loss (Dehydration) Measurement
To determine water loss, the initial and post-
storage weights of the fruits are compared.
1.
The initial weight of the fruits is measured
precisely using an electronic scale.
2.
The fruits are stored in a refrigerated or
cooling chamber under controlled conditions (e.g.,
for one week or one month, depending on the type
of fruit).
3.
After storage, the final weight of the fruits is
measured.
The percentage of water loss is calculated using the
following formula:
Here:
•
Initial WeightInitial \ WeightInitial Weight:
The weight of the fruit before storage (g),
•
Final WeightFinal \ WeightFinal Weight: The
weight of the fruit after storage (g).
This method provides a quantitative assessment of
water loss, which is critical for evaluating the
quality and shelf-life of fruits during storage.
RESULTS AND DISCUSSION
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Apples and apricots intended for export are
harvested at optimal ripeness to ensure quality.
Apricots, in particular, are seasonal and highly
perishable, making it essential to establish proper
storage conditions and deliver them to consumers
in good condition.
This study aimed to evaluate and analyze fruit
samples selected for export under three different
storage methods: cryogenic freezing, shock
freezing, and traditional cold storage. The frozen
fruit samples were subsequently stored under
uniform conditions for 7 to 120 days. Before
storage and throughout the storage period, the
color, aroma, taste, textural properties (firmness
and elasticity), and nutritional qualities (enzyme
activity and sugar content) of the apple and apricot
samples were quantitatively and qualitatively
analyzed at specific intervals. Changes in color,
organoleptic
characteristics,
and
textural
properties were observed during the storage
period.
The quality of fruits stored in traditional cold
storage chambers was found to differ significantly
compared to those stored using cryogenic freezing
and shock freezing methods, with the samples
stored in cold chambers exhibiting better quality.
The results also revealed substantial differences in
storage durations among the three methods.
Naturally, a comprehensive assessment of the
physical properties of fruits requires laboratory
analysis or detailed research. The specific physical
characteristics of fruits depend on the variety,
cultivation region, growing conditions, and other
factors.
In this study, we successfully identified the key
physical properties of apples and apricots.
Average values of physical properties of apples
Physical indicators
Mass (g)
Volume (cm3)
Density (g/cm3)
Big Circumference
(mm)
Average value
240± 10
264.5 ± 2.0
0,92 ± 0.5
132.5 ± 0.5
Average values of physical characteristics of apricots
Physical
indicators
Mass (g)
Volume (cm3)
Density (g/cm3)
Big Circumference
(mm)
Average value
65 ± 2
74.5 ± 2.9
0,82 ± 0.5
75 ± 0.5
Apples and apricots cultivated for export are
typically large, uniform in shape, and of high
quality. They must be firm, sweet, and have a
pleasantly tangy aroma. Attributes such as color,
skin smoothness, and the condition of the fruit peel
must meet export standards.
These physical characteristics of apples and
apricots are key determinants of their export
potential. Factors such as quality, resistance to
damage, and shelf life also play a crucial role.
In addition to the experiments conducted, several
additional physical parameters of these export-
oriented fruits were analyzed to further assess
their suitability for international markets.
Some physical indicators of apples and apricots
physical indicators
Apple (Golden Delicious)
Apricot (subhani)
Amount of water:
84-86%
85-87%
pH level:
3.3 - 4.0
3.5 - 4.0
Thermal conductivity:
0.5 - 0.6 W/m·K
0.47 - 0.52 W/m·K
The preservation of the structural integrity of exported fruits plays a crucial role in determining
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their appeal to consumers. Maintaining the natural
structure of fruits is considered one of the key
indicators of quality.
Through various studies and research, scientists
have concluded that proper and high-quality
storage of fruits requires special attention to the
following factors:
Water Content: Juicy fruits like apples and apricots
can quickly dehydrate during storage due to water
loss, affecting their firmness and flavor. Managing
humidity levels with cooling agents can minimize
such losses.
pH Levels: The acidity of fruits significantly
impacts their shelf life and resistance to spoilage
caused by bacteria and fungi. Lower pH levels in
apples and apricots enhance their natural
antimicrobial properties.
Thermal
Conductivity:
The
low
thermal
conductivity of apples and apricots aids in
retaining cool temperatures during storage,
helping to maintain fruit quality for extended
periods.
Size and Sweetness: The size and sweetness of
fruits are critical factors for market appeal. Larger
fruits with a higher sweetness level are more
valued by consumers, boosting their commercial
value.
The choice of cooling agents for storing apples and
apricots depends on their physical properties.
Several agents are widely used in fruit
preservation, including:
Ammonia (NH₃): A highly efficient agent for storing
apples, ammonia helps retain high humidity levels
and reduces moisture loss, preserving the fruit's
quality and sweetness over time. However, its use
for apricots requires caution, as ammonia may
damage the delicate skin of the fruit.
Freons: These agents operate effectively at low
temperatures, ensuring even cooling for apples and
apricots. Freons are advantageous for maintaining
fruit sweetness and freshness but are less favored
due to environmental concerns.
Carbon Dioxide (CO₂): Effective for preserving the
natural qualities of apricots, CO₂ helps maintain
their color and sweetness over long periods.
However, its application requires high-pressure
systems.
Propane and Isobutane: These are safe options for
apples and apricots, known for their eco-
friendliness. They help preserve the natural
sweetness and flavor of fruits while being effective
even at higher temperatures.
Each cooling agent has its advantages and
limitations. In our research, we used freon-based
agents as the fruits selected for export did not
require long-term storage. Freons are non-toxic,
user-friendly, and suitable for small-capacity
cooling chambers.
Additionally, to maintain the physical condition of
fruits, preliminary processing methods such as
thermal treatment, cooling, irradiation, and other
techniques should be considered. Moreover,
careful attention should be paid to fruit collection,
sorting, packaging, and storage technologies to
ensure optimal preservation and quality.
Analysis of Respiration Rate and Dehydration
Levels in Stored Fruits
In our subsequent research, we studied the
respiration rates and dehydration levels of apples
and apricots during storage periods ranging from 1
to 3 months in cooling chambers. Generally, the
respiration rates of apples and apricots depend on
temperature
and
storage
duration.
For
comparative analysis, we calculated the average
respiration rate data for apples and apricots (these
data are applicable for cooling chambers with
temperatures around 0-4°C).
Fruit
Breathing rate (mg CO
₂
/kg/
hour
)
Apple
5-15 mg CO
₂
/kg/ hour
Apricot
10-20 mg CO
₂
/kg/ hour
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Calculation Procedure
To accurately calculate the respiration rates of
apples and apricots, it is necessary to measure the
amount of carbon dioxide (CO₂) released over a
specified period. The respiration rate is expressed
in mg CO₂/kg/hour, indicating how much CO₂ is
emitted by 1 kg of fruit in one hour.
Respiration Rate and Dehydration Calculation
Apples: The respiration rate varies between 5-15
mg CO₂/kg/hour, depending on the storage
duration. For our calculations, we selected an
average value of 10 mg CO₂/kg/hour and
computed the respiration over one month (30
days):
10 mg CO₂/kg/hour×24 hours×30 days=7200 mg
CO₂/kg
This value represents the amount of carbon dioxide
(CO₂) released by each kilogram of apples over one
month. If the storage period is extended to 3
months:
7200 mg CO₂/kg×3=21600 mg CO₂/kg
Apricots: We assume an average respiration rate of
15 mg CO₂/kg/hour:
15 mg CO₂/kg/hour×24 hours×30 days=10800 mg
CO₂/kg
Over a 3-month period:
10800 mg CO₂/kg×3=32400 mg CO₂/kg
Dehydration Calculation
When fruits are stored for an extended period in
cooling chambers, the level of dehydration is
observed. The water loss in apples and apricots can
vary monthly depending on storage conditions.
Experiments were conducted using the methods
outlined in Chapter 2. During storage, water loss in
apples was observed to range from 0.5% to 1.5%.
In apricots, the average water loss was found to be
higher, ranging from 1% to 2.5%.
In summary, during storage in cooling chambers
from 1 to 3 months, apples released between 7200
mg CO₂/kg and 21600 mg CO₂/kg and experienced
an average water loss of 1% (10 g) to 3% (30 g).
For apricots, the CO₂ released was 10800 mg
CO₂/kg, with a 2% (20 g) water loss in 1 month,
increasing to 32400 mg CO₂/kg and 6% (60 g)
water loss over 3 months.
These results are particularly important for
accurately monitoring the respiration process and
dehydration levels of fruits prepared for export, as
well as optimizing storage conditions.
CONCLUSION
The quality and shelf life of apples and apricots
intended for export depend on effective storage
methods and their physical properties. Factors
such as water content, pH levels, and thermal
conductivity significantly impact the quality of the
fruits during storage. Additionally, ensuring high-
quality export requires careful harvesting, sorting,
packaging, and the application of advanced cooling
technologies. The findings of this study contribute
to enhancing the competitiveness of Uzbek fruits in
international
markets
and
provide
recommendations for improving fruit storage
technologies.
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