The major
constituents of the areca nut are carbohydrates, lipids, proteins,
crude fiber, phenolic compounds (flavonoids, phenolic acids and polyphenols),
alkaloids and mineral matter. Jayalakshmi & Mathew (1982) have reported
that the unripe areca nut of 6-7 months’ maturity will generally have a
moisture content in the range of 69.4–74.1% (by weight) whereas the ripe fruit will have moisture content in the range of 38.9–56.7
%. The moisture content will vary depending upon the variety, agroclimatic conditions and the agriculture practices.
The major chemical of unripe green (6-7 months’ maturity) and ripe areca nuts are given below on dry weight basis except for moisture (Adapted from
As per the
report of Mathew et al., (1964) from CFTRI Mysore, who had studied the
composition of areca nuts harvested at 2 months, 4-5 months, 6-7 months and 9
months’ maturity collected from Kyatsandra, Mysore, Thirthahalli and Vittal in Karnataka
state and Pudupady in Kerala, the lipid (oil) content of the areca nut increased
from a low, 1-4 %, in the tender stages to a high, 10-15 %, in the ripe stage.
Similarly, the polysaccharide (starch and cellulose) content also starts with a
low value at the tender stage and increases progressively until at ripe stage.
Crude fibre (cellulose and hemicellulose) starts with a very low value (1-2 %)
and with maturity and ripening fibre will be formed continuously and the rate
of formation increases until the ripe areca nut showed a value of about 15 %.
Rapid protein accumulation happens till the fruits are 3 months old and
thereafter the value remained more or less constant. Phenolic substances start
with a high value in the early stage and progressively decrease during the
developmental stage and reaches the lowest value in the fully ripened fruit. The
considerable increase in the hardness of the nut coincides with drop in
moisture content and build-up of polysaccharides and crude fibre. Lignification
(formation of lignin) and high degree of polyphenol polymerization occur in
matured fruit, contributing to the larger insoluble residue and increased
hardness of the nut. While the trend in changes of physical and chemical
properties with maturity for the samples from different regions was the same,
individual variations in relative proportion of constituents were significant.
The study by Jayalakshmi
& Mathew (1982) and Mathew et al. (1964) clearly demonstrates that the protein
content, lipid content and crude fiber content will be highest in the mature
fruit (9-10 months maturity) which is used for making Chali (White supari) and
Niradike (Doma, fermented Areca nut). Water content in the areca nut keeps
decreasing during the developmental stage and reaches the minimum value in the
matured fruit compared to its early stages.
Other major constituents such as Phenolic compounds and alkaloids shall be discussed in my subsequent Blogs.
Reference:
1.
Jayalakshmi A, Mathew AG (1982) Chemical composition and
processing. In: Bavappa KVA, Nair MK, Kumar TP (eds) The areca nut palm.
Central Plantation Corps Research Institute, Kerala, pp 225–244.
2.
Mathew A.G, Venkataramu S.D, Govindarajan V.S (1964). Studies
on Arecanut: Part I - Changes in Chemical Composition & Physical
Characteristics of Nuts with Maturity. Indian Journal of Technology, Vol. 2,
No.3, pp. 90-96.
***
