TY  - BOOK
AU  - Jainita M Mehta 
AU  - Usha V(Guide)
TI  - Nutritional Studies on the Bioavailability of Iron From Cereals and Pulses
U1  - 640 
PY  - 1998///
CY  - Vellanikkara
PB  - Department of Home Science, College of Horticulture 
N2  - Nutritional studies to evaluate the bioavailability of iron was conducted 
among three selected cereals i.e., rice, wheat and ragi and six pulses i.e., Bengal 
gram, green gram, black gram, horse gram, cowpea and soya bean. 
The results of the study indicated that among cereals though the total iron 
was maximum for ragi but the absolute available iron was less mainly due to its 
high fibre and tannin content. Its availability was considerably improved by 
germinating ragi for 48 hours when cereals were processed, refined wheat flour had 
the maximum iron availability owing to the reduction of fibre and phytic acid 
content on refining, while ragi had the least iron availability. 
Among pulses the total and absolute available iron was maximum for 
bengal gram and soya bean and least for black gram which was found to be high in 
phytin phosphorus and tannin content. The total and absolute available iron 
increased on dehulling pulses except in the case of soyabean. This increase in iron 
was mainly due to the fact that most of the tannins reside in the seed coat of pulses 
which are removed on dehulling. A further increase in the iron content was 
observed on germinating the pulses due to the break down of antinutritional factors 
during germination. 
A slight increase in the absolute available iron of fermented and 
unfermented idli batter was observed which became more available on cooking by 
steaming. 
On germinating and roasting ragi almost a four to six fold increase in the 
absolute available iron was observed while in pulse the absolute available iron 
almost doubled on roasting bengal gram while a ten to fifteen fold increase was 
 
observed in black gram. A further increase in iron was observed on roasting the 
pulses after dehulling. Similarly, on frying cereals and pulses only a slight increase 
in total and absolute available iron was observed which considerably increased 
when pulses were fried after dehulling. 
The total iron and absolute available iron was maximum for pressure 
cooked rice rather than rice boiled by excess water method. Similar results were 
observed when pulses were boiled after soaking due to the leaching of appreciable 
quantities of tannins. A further increase in iron content was observed on pressure 
cooking the soaked pulses. 
The effect of different cooking vessels on the total and absolute available 
iron, observed by different cooking and processing methods revealed that the total 
iron was maximum for cereals and pulses cooked in iron vessels mainly due to the 
contamination of iron from the iron cook ware. The absolute available iron was 
maximum for cereals and pulses cooked in inert vessels like glass, mud and tufflon 
coated vessels and it was least in the case of aluminium vessels which react with 
food constituents forming complex compounds which makes the iron unavailable. 
Phytin phosphorus, an inhibitor of iron absorption was noted to reduce on 
dehulling and germinating of cereals and pulses thus increasing the absolute 
available iron. Among pulses, whole black gram contained the maximum amount of 
phytin phosphorus and tannins while green gram contained the least amount of 
phytin phosphorus. It was observed that the tannin content in pulses greatly reduced 
on dehulling pulses as the tannins are in the seed coat, consequently increasing the 
iron availability. When ragi was germinated the tannin content reduced increasing 
the total, ionisable and absolute available iron. 
 
On analysing the fibre content of cereals it was observed that whole 
wheat flour had the maximum amount of crude fibre which reduced to a minimum 
on refining thus increasing the absolute available iron. Similar results were 
observed when ragi was germinated where the fibre content reduced with 
increasing hours of germination up to 48 hours. 
When pulses were dehulled, fibre was seen to reduce greatly 
simultaneously increasing the iron availability. On germinating pulses, similar 
results were observed up to 48 hours of germination indicating that 48 hours of 
germination is adequate for maximum reduction in fibre content. 
Pulses do not contain ascorbic acid other than when they are germinated. 
Thus with increase in germination time the ascorbic acid is seen to increase 
simultaneously increasing the total and absolute available iron. Among the pulses 
analysed bengal gram was found to have the highest ascorbic acid content on 
germination. 
Iron absorption studies from typical Kerala diets revealed that diet III 
containing heme iron had the highest ionisable iron while all the diets were high in 
iron absorption inhibitors. Modification of the local diets by supplementing or 
substituting foods containing iron absorption enhancers or by processing methods 
increased the absolute available iron from the diets. Thus by substituting or 
supplementing locally available, low cost foods, high in bioavailable iron to rice 
based diets would enhance the absolute available iron of our diets.

UR  - https://krishikosh.egranth.ac.in/handle/1/5810150672
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