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(
Chemical constituents )
A normal yielding coconut palm produces
inflorescence at approximately monthly intervals. A
period of 12 months elapses between the emergences
of the inflorescence and complete maturity of the
fruit. The cavity inside the nut differentiates
itself in the second month. The meat starts forming
as a thin and soft layer in the 6th month and
increases its hardness and quantity to the very end
though the rate of increase declines as the nuts
ripen. With the increase in thickness of kernal the
internal cavity gets reduced in size. There is also
a progressive decrease in the quantity of nut water
as the nuts ripen. The chemical composition and
volume of the nut water change during maturation.
Ediriweera (1996) has reported that the water
from the nuts at the Kurumba Stage ( about
220 days old is best suited for drinking as a
beverage since glucose is highest during this stage
besides maximum volume of water. The water of tender
coconut , technically the liquid endosperm, is the
most nutritious wholesome beverage that the nature
has provided for the people of the tropics to fight
the sultry heat. It has calorific value of 17.4 per
100gm.The normal pH of the tender coconut water
varies between 4.9 and 5.2
Chemical Constituents:-
The composition of coconut water varies depending on
the variety , maturity of the nut, condition of the
soil and climatic condition. The major chemical
constituents of coconut water are sugars and
minerals and the minor ones are fat, proteins and
other nitrogenous substances.
Sugars:-
Sugars form an important constituent of the tender
nut water. The concentration of sugars in the nut
water steadily increases from about 1.5% to about
5-5.5% in the early months of maturation and then
slowly falls reaching about 2% at the stage of the
full maturity of the nut.
In the early stages of maturity sugars are in the
forms of glucose and fructose (reducing sugar) and
sucrose (non-reducing sugar) appears only in later
stages ,which increases with the maturity while the
reducing sugars fall. In the fully mature nut
approximately 50% of the total sugars is sucrose.
The quantity of total sugars, reducing sugars and
non-reducing sugars in tender coconut water is found
to vary from variety to variety and from place o
place even at same maturity.
The two major changes in the profile of sugars
during maturation were the steep fall of total
sugars per nut by more than 90% and the
disappearance of reducing sugar.
Minerals:-
The tender coconut water contains most of the
minerals such as potassium, sodium ,calcium, phosphorous ,iron ,copper , sulphur and Magnesium
Among the minerals more than half is potassium the
concentration of which is markedly by influenced by
potash manuring tender coconut water being rich in
potassium and other minerals plays a major role in
increasing the urinary output. The benefical effect
of diets high in potassium and magnesium contents in
reducing stroke especially in individuals with high
blood pressure. Potassium decreases on maturation
and sodium shows an increase. Calcium , magnesium ,
chloride,iron and copper content in coconut water
did not exhibit any particular trend on maturation.
Sulphur showed a sight increase and phosphorus a
decrease.
Proteins:-
Coconut water contains small amounts of protein .
The nitrogen and total protein content of coconut
water increased gradually with maturation. The
percentages of arginine , alanine , cystine and
serene in the protein of tender coconut water are
reported to be higher than those in cow’s milk.
Since it does not contain any complex protein ,the
danger of producing shock to the patient is
minimized . The protein content of nut water
increases from 0.13% to 0.29% while it decreases in
the Kernel from 8.3% at the 8th month to 6.2% at
maturity . In the immature nut water, about 70% of
the free amino acids are made of glutamine ,
arginine ,aspargine , alanine and aspartic acid
while alanine, aminobutyric acid and glutamic acid
constitute about 75% of free amino acids of mature
nut water. Amino acid composition in coconut water
reported by pradera et.al(1942) is given in
Vitamins:-
Tender coconut water contains both ascorbic acid and
vitamins of B group
The concentration of ascorbic acid ranges from 2.2
to 3.7 mg/ml ,which gradually diminishes as the
kernel surrounding the water begins to harden.
Fat:-
Water of unripe nut contains 0.12% and the water of
ripe nut contains 0.15%; the fat content in the
kernel of the unripe nut being 1.4%. The reduction
in sugar content is also associated with an increase
in the oil percentage of the kernel. Changes in fat
content and fatty acid composition of coconut water
during maturation are given in
Effervescence and flavour:-
Tender coconut water is reported to be under
hydrostatic pressure , which might facilitate the
dissolution of Co2 in water. Therefore
effervescence appears in the water on opening a
tender nut at proper stage. Depletion of water on
maturation causes an empty space into which the
gases escape and therefore effervescence is usually
not observed in the matured nut water. It has been
reported that the gas occupying the free space in
the ripe nut is essentially nitrogen. The
characteristic and pleasant flavour of tender
coconut water is contributed by delta lactones
,which are found to diminish slowly with maturity /
ageing . It is this labile flavour which is sought
after by the consumers.
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