 |
| About Bioline | All Journals | Testimonials | Membership | News |
|
||||||
|
||||||
The Journal of Food Technology in Africa, Vol. 6, No. 4, Oct-Dec, 2001 pp. 133-134 Compositional attributes of the calyces of roselle (Hibiscus sabdariffa L.)
Babalola, S.O.1 Babalola, A.01 and Aworh, O.C2.
1National Horticultural Research Institute, P.M.B. 5432, Idi-Ishin,
Ibadan, Nigeria. Code Number: ft01035
Abstract
In this study, chemical and mineral composition of the calyces of green, red
and dark red roselle were evaluated. There was no significant difference in
crude protein of green (17.9%) and red (17.4%) coloured roselle calyces. Crude
fibre (11.2%), ascorbic acid (86.5mg/~OOg) and sodium (9.5mg/lOOg) contents
of green coloured calyx were significantly higher than other calyx samples.
However, dark red calyx was significantly higher in ash (6.8%) and potassium
(2320mg/100g) contents than the other two calyces. Also, there was no significant
differences in calcium, magnesium and zinc contents of red and dark red coloured
roselle calyces at P Roselle calyces appeared to be cheap source of vegetable protein, fat and minerals
therefore its consumption should be encouraged.
Key words: Roselle calyces. chemical analvsis.
Introduction
The per capita consumption of vegetables in sub-saharan Africa is far below
the recommended daily intake of 2OOgms of which two-third should be green leaf~
vegetable (Mnzava, 1997). Traditional African vegetables are extremely important
for nutrition and farm income throughout Africa. For example, they ofien supply
most of the daily requirements of proteins minerals and vitamins of poor rural
people (Okafor 1995)
Nutrient deficiency diseases such as night blindness, scurvy and rickets common
among Africans can be avoided by greater consumption of nutritious vegetables.
African traditional vegetable have been relatively neglected by the scientific
and development communities. Their consumption and utilization is flirther limited
due to lack of information on their nutritive values.
Roselle, (Hibiscus sabdariffa L.) is a tropical subshrub with red or green
inflated edible calyces (Purseglove 1977, Seck, 1997). The types can be distinguished
by three different colour groups: green, red and dark red. (Schippers, 2000).
Calyces of the red and dark red coloured type are extracted and sweetened to
produce a refreshing drink while calyces and leaves of the green type are used
for making vegetable stew (Babalola 2000).
The present study was designed to evaluate the compositional attributes of
the calyces of roselle.
Materials and Methods
Maturel calyces (130 days after planting) of green red and dark red types were
obtained from experimental farm of the National Horticultural Research Institute
- Ibadan, Nigeria. The calyces were picked randomly early in the morning and
transferred immediately to the laboratory. They were then separated, cut into
smaller bits, dried using forced air oven at 600C and milled (AOAC,
1990).
Chemical analysis: Total crude fat (method 920.85), ash (923.03) and
protein (method 920.87) were performed according to the standard methods described
in (AOAC, 1990). Protein was calculated using a nitrogen to protein conversion
factor of 6.25. Ascorbic acid was determined by indophenol method described
by Ruck, (1969). All analysis were done on dry matter basis except moisture
and ascorbic acid determination that were done on fresh weight basis.
Mineral composition: For determination of elements (Na, K, Ca, Mg, Zn and Fe)
samples were digested in HN03IHC104 (9:1) as described
by Harris (1970). They were then measured by atomic absorption specrophotometer
(AAS) using as acetylene air flame. All determinations were carried out in four
replicates.
Statistical analysis: Statistical analysis was conducted by analysis
of variance using completely randomised block design and their means were separated
by Duncan Multiple Range test (Duncan, 1955).
Results and Discussion
Table 1 shows the chemical composition
of roselle calyces. There was no significant difference in crude protein and
ash contents of green and red coloured types, but varied significantly from
dark red type at P<0.05. This may be due to genetic differences. Dc la Asuncion
et al (1995) reported a significant difference in protein content of two varieties
of pejibaye palm (Bactris gasipae). Green coloured calyces was significantly
higher than other types in crude fibre (11.2%) and ascorbic acid (86.Smg/TOOg)
contents. Akinlua and Bamgbose (1998) reported a significant difference in ascorbic
acid content of pepper varieties. The result of ether extract and moisture of
these calyces agree with those of other vegetables reported by Uddoh, (1980),
West et al (1988) and Tomar and Kalda, (1996).
On mineral composition of roselle calyces, calcium, magnesium and zinc contents
of dark red calyx were very high but did not vary significantly from red coloured
type at P<0.05 (Table 2). This
trend indicates that the consumption of the highlighted calyces will take an
active role in good bone and teeth formation. Red coloured calyx was significantly
higher in iron content (37.8mg/lOOg) than other calyces, this type could be
useflil in blood formation. Ladeji et al (1995) reported 12mg/lOOg iron for
a popular vegetable, fluted pumpkin (Te ~ria occidentahs).
Conclusion
In summary, roselle calyces could be good source of nutrients, therefore their
consumption should be encouraged among the disadvantaged groups in developing
countries.
References
Copyright 2001 The Journal of Food Technology in Africa, Nairobi |
| |||||||||
