Moisture Loss in Post-Harvest Fruits and Vegetables: Effects of Temperature, Humidity, and Surface Coating

This experiment studies the moisture loss of varied vegetable and fruits with different water content and nutritional values, the effect of dehydration on the skin surface coating of fruits which determines the physiological structure and texture of the commodity, and the effect of temperature and humidity on vegetables with higher and lower moisture content.

Introduction to Food Science
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Abstract
Background: Sustainable usage of food items and agricultural produce is highly crucial to provide and promote food security around the world.
One of the most important ways in which this issue can be addressed is by reducing food wastage, which can mainly be done by preventing post-
harvest loss. Thus, for this, the role of moisture needs to be determined as the loss of moisture can facilitate the speeding up of quality
deterioration, ripening of the fruits and vegetables rendering the produce inedible. Methods: To check the loss of moisture content samples of
varied textures, moisture content and physiological features are kept at room temperature and studied for 10 consecutive days. To understand the
effect of moisture loss on the skin surface of the fruits as well as the overall appearance and texture, the fruits are treated with varied substances
to see the effect it has on moisture retention. To understand the effect of temperature and humidity on vegetables with varied moisture content
they are stored in at both temperatures: 4oC and 20oC. Results: The experiment, studies the moisture loss of varied vegetable and fruits with
different water content and nutritional values, the effect of dehydration on the skin surface coating of fruits which determines the rate of
deterioration of the physiological structure and texture of the commodity, and the effect of temperature and humidity on vegetables with higher
and lower moisture content. It is found that the fruits when subjected to higher environmental temperatures and humidity tend to have a shorter
shelf life, by facilitating loss of moisture, increasing microbial damage, and facilitating biochemical reactions inside the fruit or vegetable and
changing the texture, turgor, colour and smell of the commodities. Discussion: This experiment can help understand the different processes and

techniques which can be used to help decrease the “post-harvest loss”, due to the short shelf life of the fruits and vegetables by helping maintain
the overall moisture content and the turgor of these products.
The experiment measured that the rate of spoilage and degradation of the quality of fruits and vegetables were greatly dependent on the moisture
content of the commodities, turgidity, texture, their respiration rate, environmental humidity and temperature.
Introduction
In the recent years, one of the main global challenges is to ensure the food security of the world’s ever growing population. Growing shift in the
diet and lifestyle patterns of the increasing urban population, climate change, emerging economies creates a strain in the usage of the Earth’s
resources, especially food. To feed the increasing population and provide food security, sustainable production, storage and usage of food
resources is highly crucial. In agriculture, loss of crops and food happens at all stages; however the most occurs during the post-harvest period.
After harvest of the vegetables and fruits, they tend to perish and rapidly lose their nutrition value. This phenomenon is called the “post-harvest
loss”.1 This increases the amount of wastage of nutritive food and crops before human or animal consumption. Post-harvest loss can be mainly
seen in fruits and vegetables having high moisture content. 2Fresh vegetables and fruits contain about 80-90% of water. Thus, the moisture loss
and dehydration of the fruits and vegetables after harvest, when kept for a long time, results in the significant loss in the overall quality of the
product and detrimentally affects the acceptability, nutrient/caloric composition as well as the edibility of the commodity.3 Excessive

dehydration also results in the loss in the quantity and volume of the commodity. Thus, this damage restricts the use of the product and
consumption by humans, and increases the quantity of food wastage. The system of post-harvest consists of many interconnected activities
including crop processing, food preparation, marketing, and consumption. These tend to also act as significant risk factors for expediting the
process of perishing in fruits and vegetables. 4 Processes the fruits and vegetables are subjected to after harvest like handling, storage, external
factors like humidity, suberization, processing, chemical control, curing, preservation as well as packaging. Gentle handling and temperature
control, waxing of the surface, controlled atmosphere storage and high humidity are some of the processes and measures that can be used to
control the dehydration as well as the deterioration of the quality of the commodity. Gentle handling after as well as before harvesting is very
important as the bruising or puncturing of the fruit or vegetable skin stimulates dehydration due to the significant physiological deterioration and
also facilitates the entry of fungi and bacteria that can cause the tissues of the commodity to rot faster and render it inedible, by releasing
myotoxins.5 Temperature control measures like avoiding direct sunlight exposure, cool storage places, as well as high humidity reduces the rate
of physiological deterioration and prevents the growth of the bacteria and fungi present in the environment. This also prevents wilting of the
products and helps keep them fresh and in a proper condition for human consumption. Waxing of the surface reduces the loss of water content
from the fruits and vegetables as well as helps maintain the turgor and thus, this method is one of the most used preservation techniques in the
market.6 The reasons behind spoilage, the rate and degree of the spoilage as well as the actions that are required to reduce the deterioration of the
fruits and vegetables greatly depends on the individual products and their characteristic features like moisture content, respiration rate, texture,
skin, favourable conditions, humidity, heat tolerance determines their shelf life and durability.

Thus, the most common primary cause of loss which facilitates other primary causes to occur as associated conditions is the loss of moisture in
fruits and vegetables after harvesting. The associated conditions that can be expedited by the loss of moisture are microbial damage,
modification of chemical constituents causing the commodity to change colour, texture, flavour and nutritional value, as well as biochemical
reactions which can result in wilting and increased ripening and impaired growth of the fruits and vegetables.
Thus, the objective of this research is to demonstrate they moisture loss the fresh fruits and vegetables are subjected to after harvest and evaluate
the effects, surface coating, temperature as well as the humidity has on dehydration.
Methods
The selected commodities for the experiment are 300g of Turgid Cabbage Leaves, 5 Apples, 3 Large Carrots, 3 small carrots and 5 oranges.
Each of these types of fresh produce are kept on paper plates and labelled accordingly. Then, to understand the loss of moisture content in the
selected commodities they were stored on an open bench rack at room temperature
(20oC). They are weighed daily for ten consecutive days and their weight are noted in a spread sheet.
Then, the following treatment processes are carried out on randomly selected oranges and stored in the paper plates for further observation:
 The first group of randomly selected oranges is kept as the control group and labelled.
 The next set of randomly selected oranges are treated and washed with detergent and labelled.

 The third set of oranges is wrapped in tissue paper and labelled accordingly. The fruit is weighed before and after the wrapping is done.
 The fourth set of randomly selected oranges is dipped in a wax suspension and allowed to dry. The excess of the wax is removed to
expose the wax coated skin of the oranges. These oranges are placed on the paper plates and labelled accordingly.
 The fifth set of oranges is punctured five times around the diameter or equatorial region with a sharp pointed object. Then they are placed
on the paper plates and labelled.
All of the four types of treatments as well as the control are stored on an open bench rack at room temperature (20oC). These commodities are
then weighed daily for ten consecutive days and the modification of the surface coatings are studied along with the moisture retention and
content. The results are recorded in an online spread sheet.
The third and final part of the experiment is to determine the effects of temperature and humidity on the selected vegetable samples. The selected
sample consists of 200 g of each small and large carrots as well as two 400g of cabbage leaves.
The carrots and cabbages are divided as per the following division:
 2 x ~100 g Carrots
 2 x ~100 g Carrots
 4 x 100 g Cabbage Leaves
 4 x 100 g Cabbage Leaves

One set of the carrots and cabbage leaves are stored in the fridge with a temperature setting of 4oC and the other set in room temperature at 20oC.
Place both samples of carrots and cabbages in respective Clearly Fresh® Produce Storage Bag and then store one sample in the fridge with a
temperature setting of 4oC and the other set in room temperature at 20oC. These commodities are then weighed daily for ten consecutive days
and the effect of temperature and humidity, are studied along with the moisture retention and content of the vegetables. The results are recorded
in an online spread sheet.
Results
The experiment’s main aim is to determine the effects of moisture loss on post-harvest fruits and vegetable and figure out the methods which
can be used or employed to help in moisture retention and prevent the degradation of the nutritional values and quality of the commodity. The
experiment thus, studies the moisture loss of varied vegetable and fruits with different water content and nutritional values, the effect of
dehydration on the skin surface coating of fruits which determines the physiological structure and texture of the commodity, and the effect of
temperature and humidity on vegetables with higher and lower moisture content.7
Explanation of table 1
In case of 300g of turgid Cabbage Leaves, moisture loss was observed. As the weight of the 300g of turgid cabbage leaves are decreased over
the 11 days, it can be stated that loss of moisture from the turbid cabbage leaves are observed.

In case of 5 apples, moisture loss was observed. As the weight of the 300g of turgid cabbage leaves are decreased over the 11 days, it can be
stated that loss of moisture from the five apples are observed.
In case of 3 large carrots, moisture loss was observed. As the weight of the 300g of turgid cabbage leaves are decreased over the 11 days, it can
be stated that loss of moisture from three large carrots are observed.
In case of 3 small carrots, moisture loss was observed. As the weight of the 300g of turgid cabbage leaves are decreased over the 11 days, it can
be stated that loss of moisture from three small carrot are observed.
In case of 5 apples, moisture loss was observed. As the weight of the 300g of turgid cabbage leaves are decreased over the 11 days, it can be
stated that loss of moisture from five apples are observed.

Table 1: Moisture loss from produce over time:
Turgid Cabbage Leaves (g)
Class Qty Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11
10:30 NA 300 260 218 198 179 163 156 149 130 113 105 96
12:30 NA 300 263 225 203 176 163 154 142 130 117 110 97
14:30 NA 300 228 201 186 165 144 130 117 96 86 76 63
Mean 300 250.3333 214.6667 195.6667 173.3333 156.6667 146.6667 136 118.6667 105.3333 97 85.33333
SD 0 19.39931 12.34234 8.736895 7.371115 10.96966 14.46836 16.8226 19.62991 16.86219 18.35756 19.3477
Oranges (g)
Qty Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11
10:30 5 1025 1009 999 993 981 972 964 958 951 941 933 926
12:30 5 861 854 841 835 823 815 811 805 798 792 785 778
14:30 5 1042 1030 1018 1010 999 991 983 977 965 959 953 941
Mean 976 964.3333 952.6667 946 934.3333 926 919.3333 913.3333 904.6667 897.3333 890.3333 881.6667
SD 99.95499 96.12665 97.17167 96.50389 96.83663 96.5971 94.29917 94.29917 92.64088 91.66424 91.76782 90.0907
Apples (g)
Qty Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11
10:30 5 934 933 932 930 929 927 926 926 925 924 922 921
12:30 5 936 934 931 932 928 927 927 925 927 924 923 920
14:30 5 955 953 955 953 952 950 950 951 947 948 945 947
Mean 941.67 940.00 939.33 938.33 936.33 934.67 934.33 934.00 933.00 932.00 930.00 929.33
SD 11.59 11.27 13.58 12.74 13.58 13.28 13.58 14.73 12.17 13.86 13.00 15.31
Small Carrots (g)

Qty Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11
10:30 3 162 128 98 84 67 50 43 37 30 26 24 21
12:30 3 133 107 85 74 58 48 41 34 26 22 20 30
14:30 3 79 68 55 47 35 26 19 15 14 12 10 10
Mean 124.67 101.00 79.33 68.33 53.33 41.33 34.33 28.67 23.33 20.00 18.00 20.33
SD 42.12 30.45 22.05 19.14 16.50 13.32 13.32 11.93 8.33 7.21 7.21 10.02
Large Carrots (g)
Qty Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11
10:30 3 283 230 185 163 134 111 98 88 74 66 59 52
12:30 3 293 258 212 191 153 136 121 104 87 76 70 45
14:30 3 219 193 169 152 131 107 88 72 57 48 43 38
Mean 265.00 227.00 188.67 168.67 139.33 118.00 102.33 88.00 72.67 63.33 57.33 45.00
SD 40.15 32.60 21.73 20.11 11.93 15.72 16.92 16.00 15.04 14.19 13.58 7.00

Explanation of table 2
Significant effect of modified surface coatings on oranges was observed. 5 groups of oranges were taken and each were treated with some
chemicals and stored at room temperature and weighed every day for a time period of 11 days. Keeping one batch of oranges as a control, each
of the other sets were treated with detergent, wrapped in tissues, dipped in wax and punctured to understand the different effects each
modification would have on the turgidity, texture, shelf life as well as appearance, that is the overall quality of the oranges. The control was set
to show the normal deterioration of oranges, without any modification. Given , the method chosen to obtain the desired results, it was observed
that the oranges dipped in wax were the most resistant towards any physical as well as biochemical deterioration, showing very less moisture
loss, indicating that the method can be successfully used to preserve the freshness of the fruits for a time period longer than their short shelf
life.8 With respect to the control, the oranges washed in detergent underwent the most deterioration in the short time interval. With respect to
their condition in Day 0 to Day 11, the punctured oranges, lost significant amount of moisture, which resulted in the decline in their overall
quality.

Table 2: Effect of modified surface coatings on oranges:
Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day
10 Day
11
0
50
100
150
200
250
Control
Detergent Washed
Wrapped in Tissue
Dipped in Wax
Punctured

Explanation of table 3
It was observed that the carrots stored in clear fresh bags at room temperature of about 20oC, showed the least deviation whereas, carrots at 20oC
showed the most moisture loss percentage of 83.62%, alongside cabbages at room temperature with 81.40% moisture loss, whereas the
commodities if kept in 4oC, have significantly lower moisture loss percentages of 31.29% and 55.18% when compared to the ones stored in
20oC. These results depict that temperature plays a crucial role in the moisture loss and degradation process of the fruits and vegetables. It can
be concluded from the results that higher the temperature, faster the deterioration of the fruit and vegetable commodities. this means that
freezing or storing them in cooler places can extend their shelf life.9 The commodities with the fresh bag had a lower range of deviation as shown
in the graph, due to the less amount of moisture loss or exposure to atmospheric humidity. This can mean that fresh bags can be used to help
preserve the turgidity and the freshness of the fruits and vegetables.

Table 3a: Effect of temperature and humidity on produce weight over time:
Class Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Day 11 Moisture
Loss (%)
Cabbage 4°C 92.66667 87.33333 83.66667 79.66667 77.33333 75 72.33333 69.33333 66.66667 65.33333 63.66667 31.2949629
Cabbage + Clearly
Fresh Bag 4°C
99 98.33333 98 98 98 97.66667 97.33333 96.66667 97.33333 96.66667 96.66667 2.35689899
Cabbage 20°C 80.66667 66 58 48 41.66667 37 32.33333 26 22 19.66667 15 81.40495945
Cabbage + Clearly
Fresh Bag 20°C
99.33333 98.33333 98 97 95.66667 94.66667 94 92.33333 92 91 91.33333 8.053691545
Carrots 4°C 90 78.33333 74 67.66667 62.33333 58.33333 54.66667 49.66667 47 44.33333 40.33333 55.18518889
Carrots + Clearly
Fresh Bag 4°C
97.33333 97.33333 97 97 97 97 97 96 96.33333 96.33333 96.33333 1.027397295
Carrots 20°C 77.33333 60.33333 50 39 31.33333 26 21.33333 18.33333 15.66667 14.66667 12.66667 83.62068464
Carrots + Clearly
Fresh Bag 20°C
105 105 105 105 105 105 105 105 105 105 105 0

Table 3b: Effect of temperature and humidity on produce weight over time:
Cabbage 4°C Cabbage + Clearly
Fresh Bag 4°C Cabbage 20°C Cabbage + Clearly
Fresh Bag 20°C Carrots 4°C Carrots + Clearly
Fresh Bag 4°C Carrots 20°C Carrots + Clearly
Fresh Bag 20°C
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00

Discussion
The main aim of this experiment is to help understand the role of moisture loss in the degradation of the overall quality of fruits and
vegetables and the factors which affects this loss of moisture content. This experiment can help understand the different processes and
techniques which can be used to help decrease the “post-harvest loss”, due to the short shelf life of the fruits and vegetables by helping maintain
the overall moisture content and the turgor of these products.
The experiment measured that the rate of spoilage and degradation of the quality of fruits and vegetables were greatly dependent on the
moisture content of the commodities, turgidity, texture, their respiration rate, environmental humidity and temperature. These mentioned factors
determined the durability, freshness as well as the shelf life of the fruits and vegetables. The experiment included several skin modification
techniques to observe which modification yielded to a faster rate of degradation and which kept the commodities fresh and turgid. The
experiment further highlighted that increase in the environmental temperature and humidity can reduce the shelf life of the commodities, by
facilitating loss of moisture, increasing microbial damage, and facilitating biochemical reactions inside the fruit or vegetable and changing the
texture, turgor, colour and smell of the commodities.10 Thus, the objective of this research is to demonstrate they moisture loss the fresh fruits
and vegetables are subjected to after harvest and evaluate the effects, surface coating, temperature as well as the humidity has on dehydration.
Even though the direct method can be used to procure accurate data which could result in increasing the accuracy of the results, these methods
often tend to incorporate human errors especially during weighing, which would result in inaccurate and inconsistent results. Errors in the

readings can also occur due to discrepancies in the machines or equipments used to weigh or moderate temperature of the sample fruits and
vegetables. The collection process of the readings and data is restricted to only the laboratories. Operating the laboratory equipments can be time
consuming and they cannot be readily available everywhere.
Thus, it was concluded that the moisture loss or dehydration of fruits and vegetables determine the rate of deterioration of the physiological
structure and texture of the commodity. It was also found that the fruits when subjected to higher environmental temperatures and humidity had
a shorter shelf life. Fruits can be coated with wax or covered with fresh bags or stored in cooler places in order to prevent such cases of
degradation.

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