World Journal of Agricultural Sciences 7 (1): 62-67, 2011
ISSN 1817-3047
IDOSI Publications, 2011
Effects of Boiling Time on Mineral and Vitamin C Content of
Three Varieties of Hibiscus sabdriffa Drink in Nigeria
1
E.I. Bamishaiye, 2F.F. Olayemi and 3O.M. Bamishaiye
Chemistry Unit, Nigerian Stored Products Research Institute, Private Mail Bag 3032, Kano, Nigeria
Engineering Unit, Nigerian Stored Products Research Institute, Private Mail Bag 3032, Kano, Nigeria
3
Department of Pre-National Diploma, Federal College of Agricultural Produce Technology,
Private Mail Bag 3013, Kano, Nigeria
1
Abstracts: The effect of heat treatment on the mineral and vitamin C content of non-alcoholic drink obtained
from three varieties of zobo calyx (Hibiscus sabdariffa); dark red, bright red, wine and subjected to different
time of preparation conditions were investigated. 50g of each of the samples were boiled separately in one litre
of water for 5, 10 and 15mins at 1000.2C to extract the juice. The ash, pH, vitamin C and individual mineral
content were assayed for all varieties. The dark red variety has the highest ash content (16.370.84%) and least
in bright red variety at 10mins (14.050.63). Bright red variety at 15 mins (137.48 mg L 1) was found to have the
highest calcium level while dark red at 5mins and wine at 5 mins recorded the least. Potassium was found to be
high in dark red at 15mins (403.11 mg L 1) and low in bright red at 5mins (324.32 mg L 1). Sodium was high in
wine variety at 10mins (9.98 mg L 1) of boiling while the least was in bright red variety at 10mins (5.53 mg L 1).
Magnesium level was the highest in dark red variety at both 5 and 15mins (78.23 mg L 1) and low in bright red
variety at 5mins (54.67 mg L 1). Dark red variety at 10mins has the highest level of vitamin C (36.24mg/100ml)
while bright red variety at 5 mins has the least (25.66mg/100ml). Dark red variety at 15mins was rated highest
for sensory evaluation, there was no significant difference with wine variety at 15 mins while bright red variety
at 5mins was rated least. It was therefore concluded that heat treatment had no effect on the minerals but had
an effect on vitamin C content. Furthermore, each of the varieties had its peculiar nutritional contents, therefore,
the choice depends on the producer and consumer; however from the sensory evaluation the dark red variety
at 10 and 15mins may be the best variety and time of preparation.
Key word: Dark red
Bright red
Sensory evaluation
INTRODUCTION
Zobo drink is a local, cheaper soft drink made from
Hibiscus sabdariffa calyx which is an herbaceous
medicinal plant grown in the tropics. It has a wide range
of names worldwide depending on the locality which had
earlier been documented by various authors [1]. In
Nigeria, it is known as Isapa pupa in the South Western
part of the country and Zobo in the Northern part [2].
Virtually all parts of the plant can be utilized for food,
drink and medicine. Yadong et al, [3] reported that the
calyx drink is rich in riboflavin, ascorbic acid (AandC),
niacin, carotene, calcium and iron that are nutritionally
important. The juice can be extracted by using either
cold or hot water depending on choice. The drink serves
Wine
as a cheaper alternative to the industrially produced
carbonated soft drinks that is available in all parts of the
country [4]. The demand for zobo drinks due to its low
prices, nutritional and medicinal properties is on the high
side [5, 6]. It is served indoors or at special occasion to
people of various tribes and tradition, in fact the drink has
gained a wide and general acceptance in Nigeria. There
are two main types: H. sabdariffa var. altissima and var.
sadariffa. Altissima is cultivated for its economic
importance in jute-like fiber making while sabdariffa is
exploited for its calyx and fiber [7]. In Nigeria, the
processing method and choice of variety depends on
individuals preference ranging from cold water extraction
to hot water extraction and at different length of time
(even for as long as thirty minutes) as long as the extract
Corresponding Author: Bamishaiye Eunice, Chemistry Unit, Nigerian Stored Products Research Institute,
Private Mail Bag 3032, Kano, Nigeria. Tel: (+234) 8037732371, E-mail: bamishaiyeeunice@yahoo.com
62
World J. Agric. Sci., 7 (1): 62-67, 2011
RESULTS AND DISCUSSION
is out leading to variation in the quality. Many people
process it without considering the effect of heat on the
nutritional parameters imbedded especially the vitamins
which are easily susceptible to destruction. Therefore
this work was done to ascertain the effect of heat on the
mineral and vitamin C Content of three varieties of
Hibiscus sabdariffa drink found in Nigeria.
The pH of the three varieties of zoborodo is shown in
Table 1. The value ranges between 2.490.06 to 2.730.02
in all varieties and at 5, 10, 15 minutes of boiling which is
indicating and confirming the high acidity usually noticed
in zobo calyx and drinks. There was no significant
difference among the three varieties. The presence of
hibiscus, malic, oxalic, citric, succinic, tartaric and 3indolyl acetic acids which naturally exist in acidic fruit
is responsible for this high acid concentration [13, 14].
Low acid value of the three varieties zobo drink may
affect people with stomach ulceration and may not be an
ideal drink. High acidity will impact a preservative effect
by inhibiting the growth of some microorganisms that
are not tolerant to it thereby giving it a longer shelf life
soft drink [13].
The ash and mineral contents are shown in Table 2.
Generally, the dark red variety has the highest ash content
of 16.370.84, 16.760.91 and 16.94.1.09%, the bright red
having 14.251.07, 14.050.63 and 14.120.29 while the
wine variety has 14.401.79, 14.713.74 and 14.901.85 for
5,10 and 15 minutes respectively. The dark red variety at
15 mins has the highest while the bright variety at 10 mins
has the lowest ash content. Ash content gives an
indication of minerals present in a particular food sample
and it is very important in many biochemical reactions
which aid physiological functioning of major metabolic
processes in the human body [15]. There was a significant
difference (p>0.05) in the dark red variety as compared to
the bright red and wine variety. There was no significant
difference among the varieties at different time of boiling
indicating that heat treatment had no significant effect on
the ash content. It was observed that as the temperature
increases, the bio-availability of the inorganic matter
increased gradually and caused the slight increase.
Bright red variety at 15 mins (137.48 mg L-1) was
found to have the highest calcium level while dark red at
5mins and wine at 5 mins recorded the least indicating that
at higher temperature the minerals are released as shown
in Table 2. It was recorded to be the second highest level
of mineral found in the beverage making this result to
agree with the work of Okeniyi and Kolawole [16]. Calcium
is vital for healthy teeth, bones, aids muscles growth and
prevent muscles cramps. Consuming zoborodo will
definitely contribute to the Required Daily Allowance
(RDA) of calcium in infants and adults. Potassium content
recorded the highest level of mineral in the drink and was
found to be higher in dark red at 15mins (403.11 mg L 1)
and low in bright red at 5mins (324.32 mg L 1). Potassium
plays a large role in supporting the nervous system and
MATERIALS AND METHODS
Source of Sample: Matured dried dark red, bright red
and wine petals of H. sabdariffa used for this study were
obtained from the open market in Kano, Kano State,
Nigeria.
Processing: The three varieties of zobo were picked to
separate dirts from the calyx. 50g of each were weighed
into a clean sterile five litre beaker and washed lightly to
remove dusts. Each sample was poured into one litre
water boiling at 100C i.e. 1:50g(w:v).The extraction time
was varied (i.e. 5, 10 and 15 min respectively) while the
extraction temperature was kept constant (i.e. 100 2C).
At the end of each hot extraction, the extract was filtered
using a clean muslin cloth after which the extract was
cooled to ambient temperature (30 2C) and stored in a
pre-sterilized wide glass bottles and kept for further
analysis.
Chemical Analyses: Ascorbic acid was determined by
using titrimetric method as described by James [8]. The
concentration of ascorbic acid in the sample was
expressed as mg ascorbic acid /100 ml. The pH of
beverage was measured using a digital pH meter
(model EA513-055, ELE, England) standardized with
buffer solutions of 4.0 and 7.0. The mineral was
determined using the method described by AOAC [9].
Sensory Evaluation: A 15-member taste panel (members
were familiar with the beverage) was requested to rate the
sample using a nine- point hedonic scale (i.e 9 = like
extremely; 5=neither like nor dislike; 1= dislike extremely).
The scores from the rating were subsequently subjected
to analysis of variance (ANOVA) and means separated
using Duncan Multiple Range test [10, 11].
Statistical Analyses: All the analyses reported in this
study were carried out in triplicates. In each case, a mean
value and standard deviation were calculated. Analysis of
variance (ANOVA) was also performed and separation of
the mean values was carried out using Duncan Multiple
Range Test at p<0.05 [12].
63
World J. Agric. Sci., 7 (1): 62-67, 2011
Table 1: The pH of dark red, bright red and wine variety of zobo drink prepared at different times Extraction time at 100 C
Variety
5mins
10mins
15mins
Dark red
2.730.02a
2.560.04ab
2.610.04a
Bright red
2.520.07ab
2.530.07a
2.490.06ab
Wine
2.610.03
2.620.08
2.590.07ab
Mean values followed by the same superscripts in each column are not significantly different at P<0.05.
Table 2: The ash (%) and mineral content(mg L
Sample
Ash (%)
) of dark red, bright red and wine variety of zobo drink
Ca
Na (mg L 1)
Fe
Zn
Mg
Pb
Dark red
5mins
16.370.84a
125.21c
396.25a
6.39c
0.67b
1.26a
78.23a
0.02 a
10mins
16.760.91
126.71
402.34
6.86
0.67
1.05
ab
77.89
0.02 a
15mins
16.94.1.09
129.52
403.11
6.87
0.83
ab
1.20
78.01
0.03 a
Bright red
5mins
14.251.07b
133.83ab
324.32c
5.54c
0.58
10mins
14.050.63
136.70
326.68
5.53
1.00ab
54.67c
0.01 a
0.67
0.98
55.56
15mins
14.620.29
137.48
332.24
5.56
0.02 a
0.68
1.12
ab
57.11
0.02a
Wine
5mins
14.401.79b
127.66c
386.36b
9.43a
0.98a
1.13 ab
74.32 b
0.02 a
10mins
14.713.74
125.93
387.49
9.98
0.96
1.00
ab
75.55
0.02 a
15mins
14.901.85
126.06
391.04
9.01
1.00
0.99
75.89
0.02 a
Values are means of triplicate determinations SEM; Means bearing different superscripts on the same column are statistically different (p<0.05)
natural heart rhythm. It stabilizes blood pressure and
helps in electrochemical transmissions and has been
shown to prevent strokes and works with sodium to
maintain a proper water balance in the body [17]. Zobo
drink being highly rich in potassium may be used
therapeutically in the area of medicine and to meet the
RDA in infants and adults. Generally, the bright red
variety is lower in potassium content as compared to dark
red and wine varieties. Sodium level is quite low in all the
samples as seen in Table 2, but the highest was observed
in wine variety at 10mins of boiling while the least was in
bright red variety at 10mins. The trend follows as; wine to
dark red to bright red. In most body cellular function
especially in Na+ /K+ pump. This causes influx of K+ into
intracellular fluids and efflux of Na+ accompanied with Cl and water resulting in diuresis. This could account for the
acclaimed diuretic effect and property of zobo drink as
claimed by Osuntogu and Aboaba, [18] and DelgadoVargas and Paredes-Lpez [19]. Iron content in all the
samples was low, though it is regarded as trace mineral.
There was no significant difference in all the samples
and at different time of boiling. All were in the range of
1.00 mg L 1 in wine at 15mins to 0.58 mg L 1 bright red at
5 mins. It was observed that at higher temperature of
15 mins, the Iron content increased indicating that heat
did not deactivate or destroy it. Iron is vital for the
production of haemoglobin, formation of red blood cells
and the oxygenation of red blood cells. It also improves
circulation, digestion, elimination and respiration. Zinc is
also one of the trace elements that is required in small
quantity in the body. The recommended daily intake is
between 8-15 mg L 1 and doses larger than 25 mg may
cause anaemia and copper deficiency [20]. Zinc promotes
a healthy immune system, taste, smell, joint and
connective tissue, cell division, repair and growth and
helps in the proper functioning of insulin [17]. The range
for the three varieties was very low between 1.26-0.98
mg L 1 and there was no significant difference (p>0.05)
among them. Zobo drink can still be used to supply
part of the daily requirement. Magnesium is rated the
third highest among the minerals in zobo drink. The
level is the highest in dark red variety at both 5 and
15 mins and is low in bright red variety at 5mins. This
result agrees with the work of Okeniyi and Kolawole [16],
who discovered that the drink is very rich in Magnesium.
It is reported that magnesium is a co-factor in a number
of enzyme system and is involved in neuro-chemical
transmission and muscular excitability along with calcium
and vitamin C.
Lead level in the drink was very low (0.03-0.01
mg L 1) and quite negligible. The body is exposed to
high level of lead on daily basis due to fumes from
generators and exhaust pipes of cars. Lead is very toxic
when accumulated in the body system and can even
cause lead poisoning or death. The low level makes the
drink safe for consumption.
64
World J. Agric. Sci., 7 (1): 62-67, 2011
Table 3: The vitamin C content(mg/100g) of the three varieties of zobo drink prepared at different times
Sample
5mins
Dark red
Bright red
Wine
10mins
34.322.13ab
25.66 0.62c
27.21 1.21c
15mins
36.241.76a
26.121.62c
29.07 2.70b
33.711.09b
21.330.99d
24.392.01d
Mean values followed by the same superscripts in each column are not significantly different at P<0.05.
Table 4: Physical characteristics of the three varieties of zobo drink prepared at different time
Sample
Appearance/colour
Taste
Dark red
5mins
10mins
15mins
red
dark red
brilliant red
slightly sour
sour
very sour
Bright red
5mins
10mins pink
15mins
moderately pink
slightly
red
slightly sour
sour
slightly sour
Wine
5mins
10mins
15mins
dirty red
red
wine/deep purple
slightly sour
slightly sour
sour
Table 5: Sensory evaluation of dark red, bright red and wine variety of zobo drink after 13% sugar inclusion
Sample
Taste
Aroma
General Acceptance
5.9b
6.6 a
7.8a
7.3a
5.7b
5.6b
6.2b
6.9a
6.7a
6.3b
6.8a
7.1a
Bright red
5mins
10mins
15mins
2.1d
4.1c
5.5b
5.4b
5.1b
5.0b
6.0b
6.2b
6.9a
4.2d
5.3c
6.0b
Wine
5mins
10mins
15mins
4.3c
5.8b
7.1 a
5.9b
5.0b
5.4b
5.9b
6.3b
6.7a
5.5c
6.0b
6.2b
Dark red
5mins
10mins
15mins
Appearance
Means not followed by the same letter in the same column differ at 5% level of significance
[22] and Tee et al. [23] who indicated that H.sabdariffa
calyx and drink contain higher vitamin C than guava,
orange and black currant.
From Table 4, it was observed that the physical
appearance of the beverage especially colour largely
depends on the pigment anthocyanin which is
responsible for the characteristics red colour of most H.
sabdariffa as reported by Hong and Wrostlad, [24] and
Tsai and Huang, [25].
An increase in boiling time seems to favour its
extraction making the colour intensity deeper from red at
5mins in dark red to brownish red at 15mins. Also, from
moderately pink at 5 mins in bright red variety to red and
from dirty red colour in wine variety at 5 mins to wine
at 15 mins. The stability or degradation of the brilliant
red colour of the beverage is dependent on such
factors as pH, light, temperature and oxygen [26].
The ascorbic content of the samples are shown in
Table 3. Dark red variety at 10mins has the highest level
of vitamin C (36.24mg/100ml) while bright red variety at 5
mins has the least (25.66mg/100ml). Generally, the dark red
sample seems to record higher vitamin C level followed by
wine variety and bright red. It was also observed that they
all follow the same trend of action at 10mins in all
varieties; the level was higher than at 5mins and 15mins.
It can be deduced that at 5mins the aggregation of vitamin
C has just begun (being water soluble vitamin) while at
10mins it has reached the peak and any further subjection
to heat tends to destroy it. At 15mins in all varieties, they
are gradually subjected to denaturation, further heating
may tend to bring the level to zero as said by Nagy
and Smoot [21]. The presence of ascorbic acid in the
beverage essentially confirms the nutritional benefit of
the drink to the consumers and agrees with Mat Isa
65
World J. Agric. Sci., 7 (1): 62-67, 2011
Therefore, the variation in the colour intensity of zobo
drink is most probably related to the calyx variety, water
ratios and the extent of boiling time. The sourness in all
variety may be related to the high vitamin C content which
has a pleasant acidic/sour property without the addition
of sweetener [27].
The sensory evaluation rating of zobo drink after
adding 13% sugar and 100mls of strawberry flavour is
presented in Table 5. Dark red variety at 15mins was rated
highest by the panel member in terms of appearance while
there was no significant difference with wine variety at 15
mins while bright red variety at 5mins was rated least. The
variety of H.sabdariffa to a large extent determines the
colour and appearance of the drink. Commercially, colour
and taste are known to play a principal role in the
acceptability of zobo beverage by the consumers [28]. All
the varieties at 5 mins were rated higher than at 10 and
15mins and this could be that the lightness of the drink at
that time favours sugar addition, thereby making it
sweeter than when sour. Although, dark red variety is
rated higher than other varieties, all other varieties
compete favorably. Dark red variety at 15mins has the
highest general acceptability among all.
3.
4.
5.
6.
7.
8.
9.
CONCLUSION
Present research
has
shown
that high
temperature reduces the ascorbic acid content and
had no significant effect on mineral content on the
three zobo varieties. It was therefore concluded that
the three varieties had their peculiar nutritional
benefits, therefore, the choice depends on the producer
and consumer. However, from the sensory evaluation,
the dark red variety at 10mins and 15mins has a higher
vitamin C content and general acceptability respectively,
it can thus be said that dark red variety at 10 and 15mins
may be the best variety and time of preparation,
respectively.
10.
11.
12.
13.
14.
REFERENCES
1.
2.
Schippers, R.R., 2000. African Indigenous
Vegetables. An overview of the Cultivated
Species. Natural Resources Institute, Chatham, UK.
pp: 119-133.
Ajiboso, M.O. and O.I. Adejumo, 2003. Physical
Properties of Neem Seeds. Landzun J. Engineering
and Appropriate Technol., 1: 68-77.
15.
16.
66
Yadong, Q.I., K.L. Chin, F. Malekian, M. Berhane and
J. Gager, 2005. Biological Characteristics, Nutritional
and Medicinal Value of Roselle, Hibiscus Sabdariffa.
Agricultural Research And Extension Center No.604
In www.suagcenter.com
Bolade, M.K., I.B. Oluwalana and O. Ojo, 2009.
Commercial Practice of Roselle (Hibiscus sabdariffa
L.) Beverage Production: Optimization of Hot Water
Extraction and Sweetness Level. World J.
Agricultural Sci., 5: 126-131.
Oboh, G. and C.A. Elusiyan, 2004. Nutrient
composition and antimicrobial activity of sorrel
drinks (soborodo). J. Medicinal Food, 7(3): 340-342.
Osueke, J.C. and F.N. Ehirim, 2004. Chemical,
Nutritional and sensory analysis of zobo drink and
selected soft drinks. Journal of Agriculture and Food
Sci., 2: 21-24.
Abu-Tarboush,
H.M.,
S.A.
Ahmed and
H.A. Al Kahtani, 1997. Some nutritional properties of
karkade (Hibiscus sabdariffa) seed products. Cereal
Chemistry, 74: 352-355.
James, C.S., 1995. Analytical Chemistry of Foods.
Blackie Academic and Professional, London, pp: 138.
A.O.A.C., 1995. Official methods of Food
analysis. Association of Official Analytical Chemist
(16th edition), Washington D.C.
IFT., 1981. Sensory evaluation guide for testing food
and beverage products. Food Technol., 35: 50-59.
Meilgaard, M.C., T.B. Carr and G.V. Civille, 1991.
Sensory Evaluation Technique, 2nd Edn., CRC Press,
Boca Raton, FL., pp: 76-88.
Duncan, D.B., 1955. Multiple range and Multiple
F-tests. Biometric, 11: 1-5.
Odebumi, E.O. and O.O. Dosumu, 2007. Fermentation
studies and nutritional analysis of drinks made from
water extract hibiscus sabdariffa calyx (sobo), Juices
of citrus sinensis (orange) and Ananas comosus
(pineapple). J. food Technol., 5: 198-204.
Wong, P., Y.H.M. Salmah and Y.B. Cheman, 2002.
Physico-chemical characteristics of roselle (Hibiscus
sabdariffa l.). Nutrition and Food Sci., 32: 68-73.
Ashaye, O.A. and T.O. Adeleke, 2009 Quality
attributes of stored Roselle jam. International Food
Research J., 16: 363-371.
Okeniyi, S.O. and J.A. Kolawole, 2007. Quantitative
mineral ion content of a Nigerian local refreshing
drink zobo (Water extract of hisbiscus sabdariffa
calyx). Research J. Pharmacol., 1: 23-26.
World J. Agric. Sci., 7 (1): 62-67, 2011
17. Jennifer, K., 2009. The Vital Importance Of Minerals
For Our Health In www selfgrowth.com
18. Osuntogun, B. and O.O. Aboaba, 2004.
Microbiological and physico-chemical evaluation
of some non-alcoholic beverages. Pakistan Journal of
Nutrition, 3: 188-192.
19. Delgado-Vargas, F. and O. Paredes-Lpez, 2003.
Natural Colourants for Food and Nutraceutical Uses.
CRC Press, LLC: Boca Raton, FL.
20. Lenntech Water treatment and B.V. Purification
Holding 2005. Recommended daily intake of vitamins
and minerals In http:// www.lenntech.com/
recommended-daily-intake.
21. Nagy, S. and J.M. Smoot, 1977. Temperature and
storage effects on percent retention and percent U.S.
recommended dietary allowance of vitamin C in
canned single-strength orange juice. J. Agriculture
and Food Chemistry, 25: 135-138.
22. Mat Isa, A., P.M. Isa and A.R. Abd Aziz, 1985.
Analisis kmia dan pemprosesan roselle (Hidiscus
sabdariffa). Mardi Research Bulletin, 13: 68-74.
23. Tee, E.S., M.I. Noor, M.N. Azurin and K. Idris, 1997.
Nutrient composition of Malaysians foods, institute
for medical research, Kuala Lumpur, Malaysiao,
pp: 299.
24. Hong, V. and O. Wrostlad, 1990. Use of HPLC
seperation/photodiode
array
detection
for
characterization of anthocyanin. J. Agriculture Food
and Chemistry, 38: 708-715.
25. Tsai, P. and H. Huang, 2004. Effect of polymerization
on the antioxidant capacity of anthocyannis in
Roselle. Food Res. Int., 37: 313-318.
26. Bridle, P. and C.F. Timberlake, 1997. Anthocyanins as
natural food colours-selected aspects. Food
Chemistry,58: 103-109.
27. Bamgboye A.I. and O.I. Adejumo, 2009. Physical
Properties of Roselle (Hibiscus sabdariffa L.) Seed.
Agricultural Engineering International: the CIGR
Ejournal. Manuscript, 1154: XI.
28. Mounigan, P. and N. Badrie, 2006. Roselle/sorrel
(Hibiscus subdariffa L.) wines with varying calyx
puree and total soluble solids: Sensory acceptance,
quantitative descriptive and physicochemical
analysis. J. Foodservice, 17: 102- 110.
29. Anon, 1984. Toxic effects of vitamin overdose.
Medical Letter and Drugs Therapy, 26: 73-74.
67
