IJERD – International Journal of Environmental and Rural Development (2013) 4-2

Research article
erd

Assessment of the Shelf-life of Cucumber underThree Low Cost Storage Methods
SONGHAK PHAL*
Royal University of Agriculture, Phnom Penh, Cambodia
Email: songhakphal@rocketmail.com

THIDA KEM
Royal University of Agriculture, Phnom Penh, Cambodia

VOUCHSIM KONG
Royal University of Agriculture, Phnom Penh, Cambodia

BORARIN BUNTONGRoyal University of Agriculture, Phnom Penh, Cambodia

THONG KONG
Royal University of Agriculture, Phnom Penh, Cambodia.
Received 16 December 2012

Accepted 10 June 2013(*Corresponding Author)

Abstract Cucumbers, harvested from Saang district, Kandal province, Cambodia werewrapped with low density polyethylene (LDPE) or high density polyethylene (HDPE) orin the open before they were stored in two types of storage conditions (evaporative coolingsystem (ECS)(80 USD), designed in the faculty of Agro-Industry, Royal University ofAgriculture and in ice foam box (2.375 USD) filled with an amount of ice for cooling thecucumbers or in ambient condition (1.5 USD) in order to seek for appropriate and low cost
methods to maintain the quality and enhance shelf-life of cucumbers. The shelf-life ofcucumbers were determined based on weight losses, fruit shriveling, changes in color,
titratable acidity (TA) and total soluble solids (TSS). Of the storage treatments, keeping
fruit in both type of polyethylene film in ice foam box filled with husk-covered ice was themost effective way in reducing weight loss, maintained higher TA, TSS and the color
changes as well as retarding fruit shriveling than that of the other treatments. Fruit stored
in the open at ambient condition had the highest weight losses and shortest shelf-life due
to rapid yellowing and shriveling. Regarding the cost of storage, ice foam box was
significantly reasonable accepted in term of gaining better quality (benefit) comparing to
the higher weight losses and unmarketable quality of other treatments.
Keywords cucumber, shelf-life, quality, evaporating cooling system, ice foam box

INTRODUCTION
Cucumbers (Cucumis sativus) of Cucumbitaceae family are one of the famous vegetable consumed
freshly and as processed food in Cambodia. The fruits were harvested in immature stage based on
the fruit size and skin color. They are used as salad, fresh slicing vegetable and pickling for daily
diet (New Guyana Marketing Corporation, 2004). These fruits normally suffer high moisture losses,rotting, and change color quickly from green to yellow during storage. They are also bruised orinjured under mechanical forces in case of improper handling which cause of short shelf-life andunmarketable quality after harvesting. Improper storage condition of cucumbers both at low
temperature (below 10C) and at ambient temperature rapidly results in water loss, decay, andyellowish color in several days that lead to unacceptable quality in the market (Mikal, 2010).
So far, to improve the storage condition of many vegetables to recast in Cambodia,
evaporating cooling system (ECS) has been set up and introduced to the vegetable grower for© ISERD
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preserving the vegetables quality. The system has shown the effectiveness in many aspects since its
temperature is decreased lower than the ambient at least 3 to 5C while its RH is higher thanambient from 20 to 40%. It is very effective to extend the color changes and decay during storage
time of vegetable such as chili, eggplant and leafy vegetables (Buntong, 2010). However, thecombination treatment with film wrapping or other modified packaging materials were not fully
tested for such kind of cucumber vegetable. It is known whether vegetables stored in low or highdensity polyethylene can maintain the shelf-life and quality of vegetable better than those stored inambient temperature because of polyethylene films that can acts as moisture and oxygen barrier
and delay the respiration of the vegetables (ITDG, 2010). As a result, cucumbers can be stored
longer than those in the ambient condition for a few days (Buntong, 2010).
In this study, in order to seek for appropriate and low cost methods to maintain the quality andenhance shelf-life of cucumbers, cucumbers harvested from Saang district were wrapped witheither low density polyethylene (LDPE) or high density polyethylene (HDPE) or left in the open
before they were stored in two types of storage conditions (evaporative cooling system (ECS),
designed in the faculty of Agro-Industry, Royal University of Agriculture and in ice foam box
filled with an amount of ice for cooling the cucumbers) or in ambient condition.
OBJECTIVE
The objective of this study was to find out the appropriate and low cost methods that effectively
maintain the quality and prolong self-life of cucumbers.
METHODOLOGY
Fruit sampling
Cucumber (Cucumis sativus), for the age about 45 days after planting, were harvested from Saang
district and immediately brought to the postharvest laboratory located in the faculty of AgroIndustry, Royal University of Agriculture, Phnom Penh, Cambodia.
Storage materials and conditions
Initially, they were washed with the 100 ppm concentration of chlorine for eliminating microbial
contaminations and preventing fungal infections; then sorted only for uniform size, maturation,color and non-injured cucumbers (FAPRT, 2011). Before storing the fruits in different containers(evaporating cooling system, ice foam box and the ambient condition), they were wrapped with low
density polyethylene (LDPE) or high density polyethylene (HDPE) or in the open.
Evaporating cooling system (ECS), made from zinc and iron film and covered by wet tissues
along with dropping-water system, to conduct heat that kept the temperature between 24-28 oC
with relative humidity between 76-94%.
Ice foam box designed in faculty Agro-Industry is the low cost materials that can be used asstorage equipment for maintaining cucumber quality. The ice foam box was filled with 21kg of ice
and covered with rice husk to reduce ice melting with the temperature between 17-21 oC andrelative humidity 60-70%. Husk rice is traditionally used for keeping ice from melting and easilyfind in local area. It is a good material to reduce the interaction between heat and cool air of ice inbox that decrease melting and stabilize temperature cold (17 to 21 C) and RH (60 to 70%). The
husk rice have low water and moisture permeability, low value of equilibrium moisture content,
low value of the coefficient of temperature conductivity (below 0.036 W.m-1.k-1), high resistance todamage of fungi (Valche et al, 2009). Ice foam box is the well-organized and effective equipmentused for reducing moisture loss, color changes and decay as polyethylene was used in ECScondition for this study. In addition to storing cucumbers in ECS and ice foam box, fruits were also
stored in ambient condition at (temperature at 28-29oC and relative humidity at 80-86%).

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Experimental design and treatments
Split plot design was applied in this research. The fruits were packed in Open, LDPE and HDPE
and stored in different containers including ambient, ECS and ice foam box. The summary oftreatments is as in table 1.
Table 1 Treatments of experimental cucumbers
Treatments
T1
T2
T3
T4
T5
T6
T7
T8
T9

Packagingmaterials
OpenLDPE

HDPE

Storage conditions

Replications

Ambient
ECS
Ice foam box
Ambient
ECS
Ice foam box
Ambient
ECS
Ice foam box

3

Fruit analysis
Throughout the storage, all treatments were tested and recorded every two days with fourparameters-weight losses (WL); color changes (a* and L value) done by using color reader CR-10;
Titratable Acidity (TA) tested by titrating NaOH concentration with phenophtelenine and Total
Soluble Solids (TSS) were tested by using refractometer. Recorded data were analyzed by using
Microsoft Excel 2010.
Weight losses: Weight losses was determined by weighting and recording every 2 days for alltreatments, calculated as a percent of the initial weight following equation 1.

WL (%)  (Wo  Wi ) / Wo  100(1)

Where Wo is the weight on the first day of storage and Wi is the weight in the tested day(Moalemiyan & Ramaswamy, 2012).
Color changes: Color reader CR-10 was used to assess external color of cucumbers. External color
readings were taken on screen of color reader CR-10 before storing in equipment on the following
day of observation. Individual fruit was measured at three point along the axis of the furit for threefruit in a replication.
Total acidity (TA): TA contents was determined by titrating NaOH concentration 0.1N along withphenophtelenine as indicator and calculated by following euquation 2.

CTotal acidity (g/L)  (VNaOH titration  F  C NaOH  M) / V sample(2)

Where C total acidity is the concentration of acid in cucumber (g/L); V NaOH is volume of sodiumhydroxide; CNaOH is concentration of sodium hydroxide of titration (N), and M is molecular weightof ascobic acid (C6H8O6) (g/mole).
Total soluble solids (TSS): Total soluble solid was determined by using refractometer. The
cucumber was extracted and its juicy part was put on the refractometer prism and read for its valueof total soluble solid in Brix degree.
RESULTS AND DISCUSSION
Weight losses
An evaluation of the postharvest quality of cucumbers was conducted after the fruit had been storedin different conditions. Figures 1, 2 and 3 had shown that moisture losses of opened cucumbers in© ISERD150

IJERD – International Journal of Environmental and Rural Development (2013) 4-2

the three conditions decreased orderly from 0 day to 10 days. Ambient lost 21% more than ice
foam lost 17.75%, while ECS had RH higher than ambient (20-40%) and lost only 3.09% during 8days with fewer changes for wrapped HDPE cucumbers. RH of ambient was lower than ECS, buthigher than RH of ice foam box which caused possible higher weight loss (5.7%) for HDPE
cucumber in ice foam box as ambient lost 0.95% in 10 days. However, water loss of wrapped
LDPE cucumber of ambient condition dramatically rose (6%) as water loss of wrapped LDPE
cucumber of ECS and ice foam box slightly changed when the temperature and RH of them wasprobable in the remaining of moisture contained in cucumber.

Fig. 1 Percentage of weightin Ambient

Fig. 2 Percentage of weightloss in ECS

Fig. 3 Percentage of weightloss in Ice foam box

Fig. 4 a* value of cucumber
stored in Ambient

Fig. 5 a* value of cucumber
stored in ECS

Fig. 6 a* value of cucumber
stored in Ice foam box

Fig 7. L value of cucumber
stored in Ambient

Fig 8. L value of cucumber
stored in ECS

Fig 9. L value of cucumber
stored in Ice foam box

Color changes
Peel color of cucumber originally remained dark green at ambient and in ECS after 6 days ofstorage. Although the previous stages retained original color, its color kept changes very quickly
becoming yellow as shown in the fig. 4 and 5. For ice foam box, cucumber peel color wasrelatively dark green from the initial day to the end of storage period, with a bit changes a*=1.46,
0.81 for LDPE and HDPE respectively on the 6th day of storage. The open cucumber stored in ice
foam box was in yellow (color a*=3.17) on the 10th day while others remained green color.
The L value of color’s of cucumber at Ambient and Ice foam box get result of insignificant
change in color L comparing to original brightness color L= 52, accept for ECS condition. It is
more changed in the L value that reached to L= 48.27, 45.29, 47.12 for Open, LDPE, HDPE
respectively at 4th day storage.

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Total acidity (TA) and total soluble solids (TSS)
Changeable decline of TA value (1.26-0.88 g/L) of opened cucumbers in each condition had no
significant differences (0-6 days). ECS had higher RH (20-40%) and lower temperature (1-2 C)than ambient that leaded to senescence very quickly and its TA declined in 1.31 g/L at 8 days.
HDPE cucumbers in ambient condition and ice foam box had similar TA value (1.26-0.80 g/L) in 4days, then TA of ambient values 1.05 g/L, when TA of ice foam box values 0.73 g/L developed tosenescence in 10 days. TA of HDPE cucumbers in ECS were slightly different in TA value (1.260.83 g/L) in 6 days then it would reach to aging when its TA was 1.18 g/L in 8 days. Low density
polyethylene, which was a good moisture barrier and had high gas permeability resistance,
wrapped cucumbers up. They were remarkably varied in the three conditions. In 6 days, TA of ECS
dropped sharply in 0.94 g/L which was higher than TA of ice foam box (0.66 g/L), when the lowest
TA of ambient values was 0.71 g/L in 4 days.
Total soluble solids interactively changed and slowly increased in all fruit treatments stored inthree equipments (shown in fig. 13, 14 and 15), but fruit stored in ice foam box had the highest TSS
value. TSS value increased higher in ambient-stored fruit as in open and as followed by HEPD.
LEPD showed the minimal increase in TSS value of stored-fruit with ECS and ice foam box.

Fig. 10 Concentration of TAof stored-cucumber inAmbient

Fig. 11 Concentration of TA Fig. 12 Concentration of TAof stored-cucumber inof stored-cucumber
ECSIce foam box

Fig. 13 Concentration of TSS Fig. 14 Concentration of TSS Fig. 15 Concentration of TSS
of stored-cucumberof stored-cucumberof stored-cucumber
in Ambientin ECS
in Ice foam box
CONCLUSION
Wrapped-cucumber with LDPE was effective when used with ice foam box and ECS for reducing
water losses. However, ambient was ineffective in storing fruit which made both moisture losses
and color changes remove high. ECS and ambient could maintain water losses from wrappedcucumber with LDPE, but it could not maintain color changes, TSS increase or TA decrease thatdeveloped to senescence very fast. Water losses, color changes, TA, and TSS of wrappedcucumber of LDPE stored for 10 days in ice foam box was better than the ECS and ambientcondition. According to the result and discussion, ice foam box used in this storage method was© ISERD152

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effectively available to buy, convenient for storing fruit, and cost-saving (only 2.375 USD per set).
ACKNOWLEDGEMENTSGratefully, we would like to give our profound thanks to, Mr. Thong Kong, Dean of Faculty ofAgro-Industry, Royal University of Agriculture, and Mr. Borarin Buntong, Head of Department ofPostharvest Technology, who had kindly offered us very helpful, useful advices, good explanationand friendly encouragement. Last but not least, particular thanks also goes to Ms. Vouchsim Kongfor her constructive comments on our research writing.
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Buntong, B. 2010. Guideline of research and development technology of postharvest tomato and chilly.
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Intermediate Technology Development Group (ITDG) Ltd patron HRH. 2010. Packaging materials for foods.
(Retrieved on October 3, 2011. From; www.practicalaction.org/docs/ technical _ information_service/packaging_ materials.pdf.)
Valche, I., et al. 2009. Silica products from rice hulls. Journal of the university of chemical technology andMetallurgy. 44(3), 257-261.
Mikal, E.S. 2010. Cucumber. Department of vegetable crops, Mamn lab. University of California, California.
(Retrieved on October 2, 2011. From; www.ba.ars.usda.gov/ hb66/057 cucumber.pdf.)
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cucumbers coated with a pectin-based film. Journal of Food Research. 3(1), 159-167.
New Guyana Marketing Corportion (NGMC). 2004. Cucumber postharvest care and Market preparation.
Postharvest handling technical bulletin No. 28. 2-11.

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