ALTERNATIVE METHODS OF
PRODUCING IODIZED SALT
I N
C O O P E R AT I O N
W I T H
T H E
DEPARTMENT OF SCIENCE AND TECHNOLGY
Thaddeus P. Amado
Romylee A. Ejercito
Imee S. Martinez
Vincent Paul S. Villegas
Ma. Isidora Margarita M. Yap
Mr. Edmund Jason Baranda
Research Adviser
ABSTRACT
The aim of this research is to discover different
methods of making iodized salt. Different gadgets designed
to thoroughly mix salt and potassium iodate (KIO3) were
made. Iodometric titration method was used to determine
the iodine content of the produced salt. To determine the
efficiency of the gadgets, the Analysis of Variance Test
was performed. Satisfactory results were obtained when
iodine was evenly distributed at the standard amount of
100 parts per million (ppm). However, the appearance
and stability of the salt when stored may need some
improvement.
INTRODUCTION
Iodine deficiency diseases (IDD) are very common
in the Philippines especially in places that are far from the
sea. According to a health survey conducted in 1987, about
3.5 percent of the population is suffering from IDD.
Iodine is an element essential for the normal
functioning of the human body. Lack of iodine in the
body may result in fetal and infant death, mental and
neuromotor underdevelopment, infertility and goiter.
The aim of the research is to produce affordable
iodized salt. The product must be able to meet the standards
set for commercial iodized salt. The stability of the
processed salt must also be tested by monitoring iodine
levels over a certain period of time. Its iodine content
must also be able to withstand heat. It must be able to
retain its iodine content even after cooking.
This research project can be part of the government’s
program on health and nutrition and the production of
food supplements that are relatively cheap but effective in
the prevention and treatment of diseases related to iodine
deficiencies.
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The chemicals commonly used for salt iodination
are potassium iodate and potassium iodide. Potassium
iodate (KIO3) is recommended for use in countries where
salt is often moist. Potassium iodide (KI) was introduced
in countries where the salt is pure and the climate is
temperate.
The final design made use of a plastic motor and a plastic blade
REVIEW OF RELATED LITERATURE
About 3.5 percent of the country’s population suffer
from iodine deficiency diseases. However, more than 10
percent of the population in Mountain Province, Bukidnon,
Oriental Mindoro, Abra, Kalinga-Apayao, Marinduque,
Romblon, Ifugao, Quirino, Batangas, Cavite, Quezon,
Pangasinan and Agusan del Sur suffer from IDD. This
rate is higher than what the World Health Organization
(WHO) considers to be of public health significance.
Iodine is an element or substance needed by the body
to function properly. It is essential in the formation of
thyroid hormones T3 and T4 which are important in
regulating cellular metabolic rate. Iodine deficiency results
in fetal deaths, infant morality, low birth weight, mental
and neuromotor underdevelopment, infertility, cretinism
in infants and myxedema in adults or, if less severe, simple
goiter. The recommended minimum daily requirement is
150 µg. An iodine particle the size of a pinhead is enough
to satisfy a person’s nutritional requirement for one month.
The WHO recommends 50 ppm of iodine.
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The stability of iodine on different types of salts
may vary depending on the type of salt, crystal size, quality,
moisture, packing and storage conditions. The techniques
used in iodination are the dry mixing process, drip-feed
addition, spray-mixing and the submersion process. The
dry-mixing process involves mixing one part KIO3 and 9
parts anti-caking agent (such as CaCO3, Ca3PO4 and
MgCO3) to 100 parts salt. This process is suitable for fine
salt only. In drip-feed addition, KIO3 is discharged at a
constant rate from feed bottles, while salt is conveyed on
narrow belts beneath the bottles. In the spray-mixing
process salt is crushed to a coarse powder and receives a
fine, atomized spray of KIO3 solution. Submersion process
involves the immersion of salt in a sodium chloride solution
containing a pre-determined quantity of potassium iodate
for 10 to 15 minutes. The iodinated salt is then spread out
to dry before crushing. The iodination technique used
depends on the type of salt to be iodized.
The concentration of iodine is measured by using a
dilute solution of HCl and a starch solution mixed with
potassium iodide. However, to determine exactly the iodine
content of the salt, iodimetric titration is used. In this
method, a certain quantity of salt is dissolved and titrated
with a standard solution of sodium thiosulfate and starch
until the endpoint (when the solution becomes colorless)
is reached.
METHODOLOGY
Three devices were designed to grind and mix salt
with potassium iodate (KIO3). The first device, made up
of two iron rollers for crushing salt and an iron mixer, was
soon corroded by the salt. Painting the rollers and the blades
did not solve the problem. The second device was able to
crush the salt finely. But it does not have a mixer, a
container for crushed salt and an apparatus for spraying
potassium iodide and potassium iodate. Of the three
devices designed, the one with a plastic motor and a plastic
blade for mixing and crushing proved to be efficient. It
was able to withstand corrosion and rust.
speeds, was able to mix the salt with the iodate and reduce
it to fine crystals.
The Analysis of Variance Test showed that there was
no significant difference between the experimental and
commercial iodized salts. However, T-test results revealed
a significant difference in the distribution of iodine between
the salt processed manually and those processed using the
apparatus.
SUMMARY AND CONCLUSIONS
The KIO3 solution was prepared by mixing 0.4
grams of KIO3 with 100 millilitres (mL) of distilled water.
Two millilitres of this solution was then diluted with 3 mL
of distilled water. Using the devices, the diluted solution
was mixed with the salt.
To test the efficiency of the devices, the
concentration of iodine in the salt was determined by
applying the principles of iodometric titration. A solution
of ten (10) grams of iodinated salt and 50 mL of distilled
water was prepared. Then, one (1) mL of 2N sulfuric acid
(H2SO4) was added to five (5) mL of a 10% potassium
iodide (KI) solution. The mixture was kept away from
light for ten minutes.
A standard sodium thiosulfate (Na2S2O3) solution
was prepared by dissolving 0.124 grams of Na2S2O3 in
100 mL distilled water. This was used to titrate the salt
solution until its color turned light yellow. A starch solution,
prepared by adding 10 mL of 10 percent chemical starch
to 90 mL of saturated NaCl (analytical grade) solution,
was mixed with the solution and titrated once more until it
lost its color.
The final design was able to mix the iodate and the
salt more thoroughly and more efficiently. Due to its
relatively low cost, it can be used to produce iodized salt in
remote barrios where commercially prepared iodized salt
is not available.
There was a certain difficulty in determining the
iodine content of the salt. The test used was not effective
enough to determine the minute quantities of iodine present
in the salt mixture.
RECOMMENDATIONS
It is recommended that the device be designed so
that the iodate drips into the salt at a regulated rate. A
dropper may be used for this purpose. A sample amount
of the salt should be packed and its iodine content be
measured after several weeks to determine its stability.
The stability of the salt mixture when heated should also
be tested. Its iodine content should not change significantly
after cooking. A hand-operated version of the mixer may
also be designed for use in areas where electricity is not
available.
RESULTS AND DISCUSSIONS
The device, designed to crush the salt and mix it
with the potassium iodate solution works the way an electric
fan does. The blades of the device, which rotates at high
Note:
No part of this article may be used or reproduced in any form whatsoever without written
permission from the Philippine Science High School, Diliman, Quezon City, except in
the case of brief citation as embodied in the laws of scientific articles and reviews.
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