Influence of domestic processing on the bioaccessibility of selenium from selected food grains and composite meals

Selenium, an ultra trace element with several health
beneficial attributes, should be mainly derived from dietary
sources. Since food processing is likely to alter the bioavailability
of micronutrients, the influence of such processing
such as germination and fermentation on selenium content
and bioaccessibility, information on which is lacking, was
examined in this study. Bioaccessibility of selenium from four
cereal-based composite meals was also studied. Chickpea,
green gram and finger millet were employed to study the
effect of germination, and for effect of fermentation, batters
used in preparation dosa, idli and dhokla were used. Soaking
the grains in water as a part of germination and fermentation
brought about a decrease in selenium content, while its bioaccessibility
was not affected. The information on the loss of
selenium during soaking and heat processing of the germinated
grains is novel. Fermentation resulted in a further decrease
in selenium content, the percent decrease ranging from 26 to
47 in the batters. Similar decreases were seen in the bioaccessible
selenium content as a result of soaking and fermentation.
Cooking of the fermented batters, however, significantly enhanced
the bioaccessibility of selenium from dosa and dhokla
by 44 and 71 %, respectively. Selenium content of the four
meals ranged from 150 to 228.8 ng/g. Bioaccessible selenium
was highest in the finger millet-based meal (32.8 ng/g),
followed by sorghum, wheat and rice-based meals. The present
investigation thus provides vital and novel information on
selenium content and bioaccessibility from foods subjected to
processing as is commonly practiced in Indian households.