The coconut palm is considered the tree of life, since it is one humanity's
principal vegetable resources. Every part of this plant can be utilized: roots,
husk, leaves, inflorescence and fruit.
The fruit of the dwarf coconut palm, particularly the green dwarf coconut palm,
are cultivated for their liquid content, whereas the fruit of the giant coconut
palm and the hybrids are cultivated for their albumin, which can be used au
naturelle or processed into grated dried solids or coconut milk.
Flavor varies depending on the stage of maturation of the fruit.
is the juice of the endosperm found within the cavity of the coconut, which begin
to form around 2 months after the natural opening of the inflorescence. According
to research, coconut water accounts for 25% of the weight of the fruit, and its
basic composition is 95.5% water, 4% carbohydrates, 0.1% fat, 0.02% calcium, 0.01%
phosphorous, 0.5% iron, in addition to amino acids, vitamin C, B complex vitamins
and mineral salts.
In some countries coconut water is used as a solution for oral hydration, as
part of the daily diet and as a protein supplement when nutritional deficits are
intense. During the Second World War, coconut water was even used instead of saline
solution during emergency surgeries.
Some studies suggested that coconut water can be used for intravenous rehydration.
Other studies suggest that coconut water can be used for electrolyte replacement
in a wide range of situations.
Studies have compared the chemical composition of coconut water with teas,
still soft drinks,
carbonated soft drinks,
and oral rehydration solution (ORS).
There are a small number of studies that have related the composition of coconut
water to the stage of maturation of the coconut
or with the region where the coconut palms grow (coastal or inland).
We therefore decided to carry out the current study with the following objectives:
to analyze the biochemical profile of coconut water from dwarf coconut palms planted
in inland areas at different stages of maturation of the coconuts, from the sixth
to the ninth months; to determine the concentrations of sodium, potassium, chloride,
calcium, magnesium, glucose, total proteins and osmolarity of coconut water from
the sixth to the ninth months; to identify the sugars contained in coconut water
from the from the sixth to the ninth months.
was a cross-sectional study analyzing coconut water from coconut palms in inland
regions. Eight of the fifteen coconut palms growing at the Lagoa Azul farm, which
is on the banks of the River Araguaia, in the municipality of Britânia,
(Goiás state, Midwest Region, Brazil) were chosen for the study by lots.
At least one coconut from each palm was to be analyzed at different stages of
maturity from the sixth to the ninth months. As a result of climactic issues in
the Midwest Region of Brazil, the maximum number of coconuts obtained at eight
and nine months was four and five, respectively. The coconuts were air freighted
to the laboratory, arriving a maximum of 24 hours after being harvested. Immediately
upon arrival at the laboratory they were perforated and the fluid collected for
Concentrations of the following electrolytes were assayed: sodium,
potassium, chloride, calcium and magnesium. The concentrations of glucose and
total proteins were also determined, together with the osmolarity of the coconut
water. Sodium and potassium were assayed by flame photometry,
and chloride was determined by the Schales & Schales titrimetric method.
Glucose assays were by enzymatic reaction with glucose oxidase and peroxidase;
calcium was measured by the o-cresolphthalein complexone method;
magnesium, by the magnon-sulphonade method
and total proteins with biuret reagent,
and in all cases analysis was performed by spectrophotometry. Osmolarity was measured
with a freezing point osmometer.
We employed descending paper chromatography
to identify the following sugars: fructose, glucose, sucrose and galactose.
comparison between different months of maturity was made using the Kruskal-Wallis
test, complemented by Dunn's multiple comparison test using Jandel Sigma Stat
was defined at less than 5%. The study was approved by the Research Ethics Committee
at the Universidade Federal de São Paulo - Escola Paulista de Medicina.
Table 1 lists median values (with
25th and 75th percentiles) for the study parameters and also the level of significance
of statistical differences,
broken down by maturity.
Table 1 -
Median values (with 25th and 75th percentiles) for each of the parameters investigated,
broken down by coconut maturity
Increases were observed in the median
volume of coconut water, the weight of the coconut shells and the total weight
of the coconuts, as they matured. Thus, the more mature the coconut, the greater
the volume of coconut water, the heavier the shell and the heavier the total weight.
analysis of electrolytes did not reveal any difference in the median (with 25th
and 75th percentiles) sodium concentration (3 mEq/L; 2 and 3) of the coconut water
as the coconuts matured, and it should also be pointed out that these concentrations
were low throughout the study period. Differences were observed in the median
concentration of potassium (64 mEq/L; 46 and 99), calcium (6.5 mmol/L; 5 and 8.5),
magnesium (8 mmol/L; 3.9 and 9.8) and chloride (38.5 mEq/L; 30 and 48.7) in the
coconut water. The concentration of these electrolytes dropped from the sixth
to the ninth month of maturation, and the elevated concentration of potassium
during all months stood out.
An increase was observed in the median (with
25th and 75th percentiles) glucose concentration of coconut water (0.6 g/L; 0.3
and 17.3) from the sixth to the ninth month of maturation, and there were no differences
between the median concentrations of total proteins (9 g/L; 6 and 12) for the
months studied. The median osmolarity of the coconut water (419 mOsmol/L; 354
and 472) was observed to reduce from the sixth to the ninth month of maturation.
relation to the sugars identified by descending paper chromatography, the presence
of fructose, glucose and sucrose were all detected in the coconut water. An increase
was observed in the median concentration of fructose (68 mg/µL; 44 and 320)
and glucose (299 mg/µL; 262 and 332) as the months passed, while sucrose
concentration (340 mg/µL; 264 and 390) reduced between the sixth and ninth
months of maturation of the coconut.
water is often used as an alternative solution for oral rehydration, particularly
in regions where mothers' knowledge of oral rehydration is lacking, thus avoiding
incorrect preparation of sugar-salt solutions.
majority of studies that analyzed the composition of coconut water did not mention
the location where the trees were planted,
although some did state that they studied coastal coconuts
and a single study analyzed inland coconuts.
median sodium concentration observed in coconut water in this study was very similar
to all of the previously-published research,
varying from 0.4 to 14.8 mEq/L, with the exception of one study that found an
elevated mean sodium concentration (32.5 mEq/L).
Comparing the composition of the ORS recommended by the World Health Organization
(Table 2) with the results of studies that have analyzed coconut water, it will
be observed that the sodium concentration in the coconut water is far below that
in the ORS and that, in the results from the current study, the figure is practically
30 times lower (Table 2).
Table 2 -
Results for electrolytes and glucose concentrations and osmolarity of coconut
water from coconuts at varying stages of maturity, as observed by this study and
as published by others, together with the composition of the World Health Organization
oral rehydration solution
Since the first study of the chemical composition
of coconut water, the mean observed potassium concentration has always been above
30.0 mEq/L. There was no difference between the potassium concentration of coconut
water from coastal and inland palms, nor between more and less mature coconuts.
No significant difference was observed between the potassium concentration of
the coconut water studied here and the results of other studies, irrespective
of whether they used coastal or inland coconuts. In the results of the current
study, in common with those of the others, potassium concentration was above that
in rehydration oral salts (20 mmol/L) (Table 2).
On the other hand, both
in this study and in other publications, the chloride concentration was below
that recommended by the WHO for ORS, with a decline in observed concentrations
during the present study from the sixth to the ninth month of maturation of the
The glucose concentration of coconut water varies (0.01 to 40.3
g/L) in studies that analyzed coconuts from inland and coastal regions. In the
current study the concentration of glucose was below what is recommended for ORS
by the WHO at all different stages of maturation of the coconuts (Table 2).
found that this study and all the others recorded coconut water osmolarity values
above 280 mOsm/L. Comparing the osmolarity of coconut water and the WHO ORS, we
observe that the majority of studies published figures above the recommended level
- including the current study.
Currently the WHO recommends a reduced ORS,
with lower concentrations of glucose and sodium and, consequently, lower osmolarity
(Table 2). When we compared the coconut water studied here with that solution,
we observed that the potassium concentration is at least twice that of the reduced
ORS, while the sodium concentration is at best 18 times less than the recommended
level. With relation to chloride, concentrations were lower than in the reduced
ORS, in particular from the seventh to the ninth months, at around half that recommended
by the WHO. The concentration of glucose reached levels close to that in the reduced
ORS by the eighth and ninth months of maturation. The osmolarity of the coconut
was almost double that of the reduced ORS, with the exception of the eighth month.
a Brazilian study that analyzed coconut water from a coastal region at different
stages of coconut maturation,
some components of the coconut water varied considerably. Osmolarity in that study
was above 300 mOsm/L throughout (probably because of the high concentrations of
carbohydrates), and this study also observed similar levels. The glucose concentration
in that study passed 200 mmol/L (35 g/L), whereas in this study the maximum level
observed was 79 mmol/L (14 g/L). Sodium concentration was low throughout the maturation
process, also confirmed here. The differences may be the result of the location
of cultivation, in the study by Fagundes Neto the palms were at the coast and
in this study they are planted inland.
Research by Kuberski
identified the sugars contained in coconut water, detecting glucose, sucrose and
fructose in the proportion of approximately 50, 35 and 15%, respectively, but
their study did not relate whether these proportions remained constant during
different months. The current study found that the proportions of these sugars
varied depending on the stage of maturation of the coconuts: glucose, from 34
to 45%; sucrose, from 53 to 18% and; fructose, from 12 to 36%.
of studies did not analyze trace elements such as calcium and magnesium. The concentration
of these trace elements did not exceed 17 mmol/L in the coconut water studied
by many of the authors mentioned,
in common with this study. Taking into account reference daily nutrient intakes,
according to age group and calcium and magnesium concentrations during the seventh
month, it is possible that nutritional deficiencies of these trace elements could
be prevented by the daily ingestion of coconut water.
Before ending, we
emphasize that the results of this study should be analyzed and interpreted with
prudence, taking account of the possible limiting effect of the lower number of
coconuts analyzed at months eight and nine. This was the result of climactic conditions
in the Midwest Region of Brazil, where it did not prove possible to obtain a larger
number of coconut water samples during those two months. On the subject of the
total number of green coconuts analyzed to construct a biochemical profile of
coconut water, four
of the seven
studies that mentioned the number of coconuts analyzed, the median (percentiles
25 and 75 in parenthesis) was eight (5.5-32.5) coconuts. It should be pointed
out that the only study in the literature that employed coconuts from inland areas
used 25 of them, but that study did not analyze them at different stages of maturity.
On the other hand, the present study analyzed a total of 45 coconuts, which were
studied at different stages of the maturation process, and it was factors related
to the climate that barred the investigation of a larger number of coconuts during
the last months of maturation. Further studies should be carried out to better
characterize the biochemical profile of the water in green inland coconuts at
different stages of maturity.
In conclusion, the biochemical profile of
the coconut water from dwarf coconut palms planted in an inland region varied
from the sixth to the ninth month of maturation, with reductions observed in the
concentrations of potassium, calcium, magnesium, chloride and in osmolarity, from
the sixth to the ninth month. The elevated concentration of potassium means that
coconut water could possibly be used to replace that electrolyte. Daily consumption
of coconut water may possibly prevent nutritional deficiencies of calcium and
magnesium. When we compared coconut water with ORS, we observed that neither the
concentrations of glucose, sodium, potassium and chloride, nor the osmolarity
of the coconut water from inland palms met the WHO recommendations for ORS.