American Journal of Applied Sciences 6 (7): 1341-1346, 2009
ISSN 1546-9239
© 2009 Science Publications

Proximate Analysis of Dragon Fruit (Hylecereus polyhizus)

1Ruzainah Ali Jaafar, 1Ahmad Ridhwan Bin Abdul Rahman,
1Nor Zaini Che Mahmod and 2R.Vasudevan
1Department of Bioengineering, Section of Biosystem and Bioprocess Engineering Technology,
University Kuala Lumpur-Malaysian, Institute of Chemical and Bioengineering Technology,
Taboh Naning, Alor Gajah, Melaka, Malaysia
2Molecular Biology Lab, Department of Biomedical Science,
Faculty of Medicine and Health Sciences, University Putra Malaysia, Selangor, Malaysia

Abstract: Problem statement: Dragon fruit (Hylecereus polyhizus) is well known for the rich nutrient
contents and it is commercially available worldwide for improving many health problems. Several
studies show the proximity value of red pitaya fruits but the nutrient composition of the stem has not
been extensively studied. Approach: This study was carried out to measure the proximate analysis of
moisture content, water activity, ash, crude protein, crude fat, crude fiber, glucose and ascorbic acids
content in premature and mature of dragon fruit. The dried powder was produced from the stem of
dragon fruit and the proximate analysis of dragon fruit stem was compared between freeze drying
process and drying oven process. Results: Results of this study showed that 96% moisture; 0.270 g of
?
?
protein; 0.552 g L 1 glucose and 132.95 mg L 1 ascorbic acid of dragon fruit stem found higher than
the fruit flesh of the dragon fruit. Conclusion: The premature stem had higher values than the mature
stem of the dragon fruit which may helpful in preventing the risk factors of certain diseases.

Key words: Red pitaya, proximate analysis, Malaysia

INTRODUCTION
the digestive process, prevent colon cancer and

diabetes, neutralize toxic substances such as heavy

Dragon fruit or red pitaya belongs to the Cactaceae
metal, reduce cholesterol levels and high blood pressure
family from the subfamily Cactoidea of the tribe
and consumed regularly the dragon fruit can help
Cactea[1]. In Malaysia, the red pitaya or dragon fruit is
against asthma and cough. It is also rich with
commonly called as “buah naga”. Among the red pitaya
potassium, protein, fiber, sodium and calcium which
species Hylocereus polyrhizus (Red flesh) fruits are
goods for health than other fruits[5]. There are three
edible and it has a great source of vitamin C and water
techniques for foods drying are commonly used such as
soluble fiber[2]. Hylocereus polyrhizus is a small fruit
sun drying, drying oven and freeze drying. First, the
climbing cactus that has received world-wide
drying process is heated high to force out the moisture
recognition as an ornamental plant for its large, scented,
from food. Secondly, dry air to absorb the released
night-blooming flowers. The red skin fruit weighed up
moisture and finally the air movement to carried out the
to 1kg has translucent dark-red flesh considered as a
moisture away from the food. The freeze dried product
rich source of nutrients and minerals such as vitamin
should be passing through all the three stages which are
B1, vitamin B2, vitamin B3 and vitamin C, protein, fat,
freezing process, primary and secondary drying
carbohydrate, crude fiber, flavonoid, thiamin, niacin,
process. Freeze-drying is a technique that results in
pyridoxine, kobalamin, glucose, phenolic, betacyanins,
high-quality dehydrated products due to the absence of
polyphenol,
carotene,
phosphorus,
iron
and
liquid water and the low temperatures required in the
phytoalbumin[3]. It is also rich in phytoalbumins which
process. The solid state of water during freeze-drying
are highly valued for their antioxidant properties[4].
protects the primary structure and minimizes changes in
Hylocereus polyrhizus is rich in fibers, vitamin C,
the shape of the product, with minimal reduction of
minerals and phytoalbumins which are highly valued
volume[6]. The drying process may alter these
for their antioxidant properties. The dragon fruit helps
properties, resulting in products with modified texture,
Corresponding Author: Ruzainah Ali Jaafar, Department of Bioengineering, Section of Biosystem and Bioprocess Engineering Technology,
University Kuala Lumpur-Malaysian, Institute of Chemical and Bioengineering Technology, Taboh Naning,

Alor Gajah, Melaka, Malaysia Tel: 06-5512022 Fax: 06-5512005
1341

---

Am. J. Applied Sci., 6 (7): 1341-1346, 2009

optical, thermal and nutritional properties[7]. The
105°C. Then the dried sample was weighed for percent
rehydration ratio can be considered as a measure of the
of dry weight and percent of moisture content in
injuries caused by the processing and drying to the
sample.
material. It is generally accepted that the rehydration

capacity is dependent on the degree of cellular and
Ash: The preparation of ash was same as preparing
structural disruption. According to Jayaraman et al.[8],
crucible in moisture content. Two gram of sample was
during the drying process, irreversible cellular rupture
put into crucible and weight was recorded and placed in
and dislocation, results in loss of integrity and hence, in
muffle oven (Furnace Nabertherm, Germany) at 550°C
a dense structure of collapsed, greatly shrunken
for 8 h.
capillaries with reduced hydrophilic properties, which

are reflected by the inability to imbibe sufficient water
Fat: The fat content was determined directly extracting
to fully rehydrate. Proximate analysis used to determine
the dried ground pitaya fruit with petroleum ether in an
the proximate principles of any substance, as contrasted
intermittent Soxhlet extractor (Soxhlet Extractor
with an ultimate analysis. The proximate analysis of
Darmstadt, Germany) and extracted the sample for 4 h.
food refers to the analysis of the total content of a food
The residue in round bottom flask after solvent removal
component, not taking account of the individual
represents the fat content of the sample. The residue
compounds making up that food component. The macro
was weight and checks the Reflective Index (RI) using
components are generally analyzed for their proximate
reflextrometer (Merck KGaA, 64271 Darmstadt,
amounts[9]. The main objectives of this study was to
Germany).
produce the dragon fruit stem in powder form using

Crude protein: Nitrogen
was
determined
using
freeze drying process and to measure the proximate
micro-Kjeldahl method. About 2 g of dried sample was
analysis parameter such as moisture content, water
transferred into digestion tube by adding 2 tablets of
activity, crude protein, crude fat, crude fiber, ash,
catalyst and 20 mL of sulfuric acid to digestion in
glucose and ascorbic acid between mature stem and
30 min using Kjeldahl digester (Tecator Kjeltec
premature stem and also comparing the proximate
System, Germany) at minimum temperature 400°C.
analysis of dragon fruit stem between freeze drying
After that, 50 mL distilled water was added for
method and drying oven method.
distillation using Kjeldahl distillation. Then, the sample

was titrated with hydrochloric acid (0.20 N) to calculate
MATERIALS AND METHODS
the amount of HCL present in NaOH solution (40%).

The boric acid solution (4%) was used for the catalyst
Sample preparation: The dragon stem was cleaned
reagent. The percentages of nitrogen were converted to
and drained off before used. Nearly 200 g of stem was
protein by multiplying by 6.25.
cut into small pieces using Warring blender (Warring

Commercial, Laboratory Blender) for 2 min and was
Water activity: The powder was placed inside the
homogenized using homogenizer (Heidolph DIAX 900)
plastic placing sample. It was measured using Aw sprint
with ratio 1:3 w/v and filtered using Muslin Cloth. The
(Swiss made NOVASINA TH-500) water activity
filtrate was transferred into freeze dryer bottle in and
equipment.
kept at -18°C for four days or at -80°C for two days in

freezer before freeze-drying at -45°C, pressure
Crude fiber: Two gram of sample was put into 250 mL
?
86×10 3 M bar for 4 days. Then the frozen sample was
conical flask and 1.25% Sulfuric acid solution was
freeze dried using freeze dryer (LABCONCO, Freeze
added. The sample was heated about 30 min and was
Dry System/ FREEZONE 4.5). The freeze dried sample
filtered using vacuum filter (today’s vacuum filtration
was kept into a tight container before further analysis.
VF 100) and washed until traces of acid was undetected
Moisture, ash, fat, protein content, water activity and
using pH paper. The Whatman paper 5B which pore
fiber in the sample were determined using method by
size 125 micrometer was placed in the Buchner flask.
AOAC International[10].
After that the acid extracted was transferred into 250 mL

conical flask and 1.25% NaOH solution was added. The
Moisture content: The crucible was placed inside
sample was heated again for 30 min and was filtered
drying oven for 105°C for 2 h. After that, the crucible
using vacuum filter and washed with water until base
was placed in the desiccators for allowing cooling. The
was undetected. The whole material was transferred
beaker was weighed and 2 g of the powder was placed
into crucible and dried for 12 h at 120°C. After that the
in the beaker. The sample was drying in drying oven
crucible was placed into muffle oven at 550°C for 12 h
(Memmert 600, Germany) for 3 h at temperature
and weight of crucible was recorded.
1342

---

Am. J. Applied Sci., 6 (7): 1341-1346, 2009

Ascorbic acid: Five gram of fresh pitaya stem was cut
cooled in a controlled manner. Water activity plays a
and homogenized using warring blender. The sample
main role where it controls the microbial activity and it
was filtrated using Muslin cloth. The filtrate will used
keeps the key for the shelf life of the dragon fruit
to determine the ascorbic acid content using
product especially in stem. The higher moisture content
reflectometer (Merck KGaA, 64271 Darmstadt,
(high water activity, Aw) will thus decrease the keeping
Germany).
quality and the shelf life also shorter. The result shows

the water activities of the mature stem for freeze drying
Glucose concentration: The glucose concentration was
and drying oven result was in range 0.545-0.563 Aw.
determined using 2 g of fresh pitaya stem. The sample
While, for the pre-mature stem show that the result in
was cut into small particles and homogenized using
range 0.836-0.865 Aw. There is a possibility for the
warring blender. Then, the sample was filtrated using
growth of halophilic organisms and xerophilic
Muslin cloth and centrifuged with speed of 15000 rpm
organisms for minimum temperature at 25°C in the
for 15 min. The emulsion was analyzed using glucose
stem of dragon fruit.
analyzer to measure the glucose concentration.

In this experiment, the percentage of nitrogen was

also calculated using the standard procedure of Kjeldahl
RESULTS
methods and the conversion factor was 6.25. The result

of this analysis showed that 7.18% of mature stem and

In this study, we determined the method of
14.7% of premature stem using freeze drying product.
production of Hylocereus polyrhizus stem powder using
While, the percentage by without using freeze drying
freeze drying method and the proximate analysis
product are 6.3% for mature stem and 11.9% for
parameter was carried out using dried sample from
premature stem. Nitrogen was the most distinguishing
freeze dryer and drying oven. For proximate analysis,
element present in proteins. Figure 1 shows that
we determined the moisture content, water activity, ash,
percentage of crude protein in premature stem was higher
crude protein, crude fiber, crude fat determination,
than the mature stem because, the premature stem has
glucose and ascorbic acid. All the analysis was done
more nitrogen presented rather than mature stem.
through Standard Operation Procedure (SOP) in the

To determine the crude fat, the Soxhlet method was
food analysis lab. Table 1 shows the comparison
applied which involved a direct solvent extraction.
between the operating system of freeze dyer and drying

oven. The data shows that drying oven was used at
Table 1: Comparison of operating system of freeze dryer and drying
50°C to dry the sample rather than freeze dryer system
oven
was used at -45°C. About 184.02 g initial weight of
Measurement
Freeze dryer
Drying oven
sample stem was homogenized using homogenizer with
Temperature
-45°C
50°C
Air condition
vacuum, cold
Fresh air inlet,
water ratio 1:3 w/v and dried using freeze dyer at
?
Pressure
86×10?3 M bar
hot normal air
temperature -45°C and vacuum pressure 89 × 10 3 M bar.
Equipment brand
LABCONCO,
Memmert 600,
The final weight was 5.93 g and the weight of moisture

Freeze dry system
Germany
lost was 178.09 g due to high amount of water
Duration time
4 days
1 day
contained in the pre mature stem.


Table 2 shows the proximity analysis in dragon
fruit stem. For freeze dried product, the percentage of
moisture content in mature stem was 96.04% and for pre-
mature stem was 97.62%. While, for drying oven
method, the percentages of mature stem was 96.11 and
96.42% for premature stem. Water activity analysis relies
on measuring the amount of moisture in the equilibrated
headspace above the sample, which correlates directly
with sample Aw. A sample for water activity was placed
in a small closed chamber at constant temperature and a
relative humidity sensor was used to measure the
Equilibrium Relative Humidity surrounding the product
(ERH) of the sample atmosphere after equilibration. A

simple and accurate variation of this approach is the

chilled mirror technique in which the water vapor in the
Fig. 1: Comparison between mature stem and premature
headspace condenses on the surface of a mirror that was
stem using freeze drying and drying oven
1343

---

Am. J. Applied Sci., 6 (7): 1341-1346, 2009

Table 2: Moisture content analysis of Hylocereus polyrhizus

Freeze drying

Drying oven

------------------------------------------------
------------------------------------------
Sample
Mature stem
Premature stem
Mature stem
Premature stem
Moisture:




Weigh of aluminum dish (g)
54.800
55.160
53.980
54.960
Weigh of aluminum dish with sample before drying (g)
60.350
60.200
58.610
54.960
Weigh of aluminum dish with sample after drying (g)
55.020
55.280
54.160
55.150
Dry Metter (%)
3.960
2.380
3.890
3.580
Moisture content (%)
96.040
97.620
96.110
96.420
Water:




Water Activity (Aw)
0.563
0.836
0.545
0.865
Temperature (T)
25.3°C
25.5°C
25.7°C
25.2°C
Time (t)
11 min 32 sec
5 min
41 sec
16 min 08 sec
5 min 52 sec
Crude protein




Amount of HCL required to titrate (mL)
10.000
18.600
9.000
15.000
Nitrogen (%)
1.480
2.350
1.010
1.900
Weight of protein (g)
0.144
0.294
0.126
0.238
Protein (%)
7.180
14.700
6.300
11.900
Crude fat:




Thimble + dry sample (g)
46.890
47.050
47.420
47.580
Weight of thimble after extraction (g)
46.800
46.880
47.310
47.350
Weight of fat (g)
0.090
0.170
0.110
0.230
Crude fat (%)
4.500
8.500
5.500
11.500
Reflective index (Brix%)
10.800
28.400
12.500
33.100
Crude fiber




Weight of crucible (g)
17.300
17.000
16.870
17.460
Weight of crucible + fiber (g):
17.350
17.030
16.910
17.480
Weight of fiber (g)
0.050
0.030
0.040
0.020
Crude fiber (%)
2.500
1.500
2.000
1.000
Ash:




Weight of crucible (g)
16.910
17.440
17.010
17.920
Weight of crucible + ash (g)
17.000
17.480
17.100
17.950
Total ash (g)
0.090
0.040
0.090
0.030
Total ash (%)
4.500
2.000
4.500
1.500

The free lipid content consists of neutral fats
small amount of minerals left out in the stem. It was
(triglycerides) and free fatty acids was determined by
because the content of starches of the stem contains
extracting the dried and ground material with light
fiber, phosphate and calcium. Crucible selection was
petroleum or diethyl ether in a continuous extraction
critical to accurate results but each type of crucible has
apparatus such as a Soxhlet extractor. The result for the
its limitations. While platinum crucibles are the best,
fat weight in the mature stem and premature stem for
they are prohibitively expensive. In Table 2, majority of
freeze drying method was 0.09 and 0.17 g with
premature stem have higher value than mature stem.
reflective index 8.0 and 28.4% Brix. For without freeze
The higher parameters for premature stem are moisture
drying result, weight of the mature stem and premature
content, water activity, crude protein crude fat, glucose
stem was 0.11 and 0.23 g with reflective index 12.5 and
concentration and ascorbic acid. The higher parameters
33.1% Brix.
for mature stem are crude fiber and total ash because of

Table 2 shows the crude fiber analysis for mature
little fiber in premature stem of dragon fruit. But the
stem and premature stem in dragon fruit. The result
Dragon fruit stem gets more fiber while growing up
shows that the percentage of fiber was low in dragon
into a mature stem. Figure 1 shows that comparison
fruit stem compared to the dietary standard of dragon
between mature stem and premature stem using freeze
fruit flesh. The crude fiber percentage of mature stem
drying process and drying oven process.
and premature stem using freeze drying are 2.5 and

Basically, the result that has been taken from the
1.5% while 2.0 and 1.0% for using drying oven. The
experiment cannot be determined as same as the
standard of high-fiber in food was above 40% or above
standard value of dragon fruit flesh. Half of nutrient in
0.75 g. The percentage of fiber in mature stem and
stem has higher value and another half has lower value.
premature stem are 4.5 and 2.0% respectively using
The higher values for proximate analysis parameter are
freeze drying process and 4.5 and 1.5% respectively for
moisture content and ascorbic acid. The lower values
drying oven process. The result shows that there was a
for proximate analysis parameter are crude protein,
1344

---

Am. J. Applied Sci., 6 (7): 1341-1346, 2009

Table 3: Comparison between stem and flesh of dragon fruit
an effect of proximate analysis parameter such as
Nutritional contents
Flesh
Stem
glucose and ascorbic acid. Based on the result of
Moisture
82.5-83 g
96.0-98.0 g
sample preparation by production of powder, to ensure
Protein
0.159-0.229 g
0.120-0.270 g
the powder process was success, several parameters
Fat
0.21-0.61 g
0.09-0.23 g
Crude fiber
0.7-0.9 g
0.02-0.05 g
must be controlled such as cooling chamber,
Ascorbic acid (vitamin C)
8-9 mg
63.71-132.95 mg L?1
temperature and vacuum pressure. The temperature and
Ash
-
0.03-0.09 g
the vacuum pressure must be in low temperature to get
Water activity (Aw)
-
0.545-0.865 Aw
perfect powder. In the manifold method, flasks, impulse
Glucose
-
0.263-0.552 g L?1
or vials are individually attached to the ports of a

manifold or drying chamber. The product is either frozen
crude fat, crude fiber and analysis. The other parameter
in a freezer, by direct submersion in a low temperature
such as glucose, ash and water activity cannot be
bath, or by shell freezing, depending on the nature of the
determined as a lower or higher because the reference
product and the volume to be freeze dried. The pre-
data cannot find. Table 3 shows comparison between
frozen product was quickly attached to the drying
stem and flesh of dragon fruit. The result shows that a
chamber or manifold to prevent warming. The vacuum
small different value between freeze drying process and
must be created in the product container quickly and the
drying oven process. In this experiment, there are some
operator relies on evaporative cooling to maintain the
different between freeze drying and drying oven. The
low temperature of the product. This procedure can only
differentiation of this process has been shown in Table 3,
be used for relatively small volumes and products with
which was freeze drying process are used at -45oC and
?
high eutectic and collapse temperatures.
vacuum pressure at 86×10 3 M bar. For drying oven

process, it was used at high temperature 50°C and
CONCLUSION
pressure at normal air. In this case, the value of ascorbic

acid has more affected to the others parameter because,

A well rich nutrient content has the possibility to
ascorbic acid has a biological role as a reducing agent
prevent various diseases. This study provides that
in hydroxylation reactions in the body, easily oxidized
premature stem of dragon fruit has more nutritional
by air and easily destroyed by during food processing
value than the mature stem. This selection of nutrients
with high temperature. The results of this study were
from the premature stem has an important nutritional
similar to the study done by Khalili et al.[5].
quality to improve the benefit for health and therapeutic

potential by targeting the compounds present in the
DISCUSSION
premature stem. Red pitaya could be considered as a

valuable economic product.

Pitaya is commercially cultivated in many parts of

Asia[11] and cultivation in Malaysia is more
ACKNOWLEDGEMENT
concerned[12]. The pitaya fruit has medicinal value and

increases the excretion of heavy metal toxins and

The researchers would like to extend their gratitude
lowers cholesterol and blood pressure. The peel of
to Prof. Dr. Abu Talib Bin Othman, Deputy Vice
dragon fruit has a high potential to be used as a natural
Chancellor (student’s affairs and Technopreneur) of
dye[13]. However, ingestion of significant amounts of
University Kuala Lumpur (UKL) for sharing his
red-fleshed
dragon
fruit
may
result
in
knowledge, excellent cooperation and support for the
pseudohematuria[14].
research by providing the samples.

This research was carried out from the production

powder from dragon fruit stem using freeze drying
REFERENCES
method and the proximate analysis parameters such as

moisture content, water activity, crude protein, crude
1. Raveh, E., J. Weiss, A. Nerd and Y. Mizrahi, 1993.
fat, crude fiber, ash, glucose and ascorbic acid was
Pitayas (genus Hylocereus): A New Fruit Crop for
measured using freeze drying product (powder) and
the Negev Desert of Israel, Janick, J. and J.E. Simon
without using freeze drying product (dried with drying
(Eds.). New Crops, New York, pp: 491-495.
oven). Freeze dried products at lower temperatures
2. Mizrahi, Y. and A. Nerd, 1999. Climbing and
extends their shelf life. The shelf life of a freeze dried
Columnar Cacti New Arid Lands Fruit Crops. In:
product can be predicted by measuring the rate of
Perspectives on New Crops and New Uses, Janick, J.
degradation of the product at an elevated temperature.
(Ed.). ASHS Press, Alexandria, VA., ISBN: 0-
The drying oven process is used at 50°C and can make
9615027-0-3, pp: 358-366.
1345

---

Am. J. Applied Sci., 6 (7): 1341-1346, 2009

3. Le Bellec, F., F. Vaillant and E. Imbert, 2006.
9. Owusu-Apenten, R.K., 2005. Introduction to Food
Pitahaya (Hylocereus spp.): A new fruit crop, a
Chemistry. Hardback Publisher, CRC PR INC.,
market with a future. Fruits, 61: 237-250. DOI:
ISBN: 13: 9780849317248. ISBN: 084931724X.
10.1051/fruits:2006021
10. AOAC. International, 1995. Official methods of
4. Mahattanatawee, K., J.A. Manthey, G. Luzio,
analysis. Ternds Food Sci. Technol., 6: 382-383.
S.T. Talcott, K. Goodner and E.A. Baldwin, 2006.
DOI: 10.1016/S0924-2244(00)89213-4
Total antioxidant activity and fiber content of
11. Mizrahi, Nerd, Nobel, Y. Mizrahi, A. Nerd and
select Florida-grown tropical fruits. J. Agric. Food
P.S. Nobel, 1997. Cacti as crops. Hortic. Rev.,
Chem., 54: 7355-7363. DOI: 10.1021/jf060566s
18: 291-319.
5. Khalili, R.M.A., A.H. Norhayati, M.Y. Rokiah,

http://www.pubhort.org/hr/hr18/HR_18_06_00000
R. Asmah, M.T. Mohd Nasir and M. Siti Muskinah,
000.pdf
2006. Proximate composition and selected mineral
12. Hoa, T.T., C.J. Clark, B.C. Waddell and A.B. Woolf,
determination in organically grown red pitaya
2006. Postharvest
quality
of
dragon
fruit
(Hylocereus sp.). J. Trop. Agric. Food Sci.,
(Hylocereus undatus) following disinfesting hot air
34: 269-275. DOI: 10.2202/1556-3758.1519
treatments. Postharvest Biol. Technol., 41: 62-69.
6. Ratti, C., 2001. Hot air and freeze-drying of high-
DOI: 10.1016/j.postharvbio.2006.02.010
values foods: A review. J. Food Eng., 49: 311-319.
13. Harivaindaran, K.V., O.P. Rebecca and S. Chandran,
DOI: 10.1016/S0260-8774(00)00228-4
2008. Study of optimal temperature, pH and
7. Krokida, M.K., Z.B. Maroulis and G.D. Saravacos,
stability of dragon fruit (Hylocereus polyrhizus)
2001. The effect of the method of drying on the
peel for use as potential natural colorant. Pak. J.
colour of dehydrated products. Int. J. Food Sci.
Biol.
Sci.,
15:
11:
2259-2263.
DOI:
Technol.,
36:
53-59.
DOI:
10.1046/j.1365-
10.3923/pjbs.2008.2259.2263
2621.2001.00426.x
14. Malaysian
Medical
Resources,
2008.
8. Jayaraman, K.S., D.K. Das Gupta and N.B. Rao,
Pseudohaematuria due to dragonfruit ingestion.
1990. Effect of pretreatment with salt and sucrose
http://www.medicine.com.my/wp/?p=3152
on the quality and stability of dehydrated
cauliflower. Int. J. Food Sci. Technol., 25: 47-60.
DOI: 10.1111/j.1365-2621.1990.tb01058.x

























1346

---