Cooking Behavior of Rice And Black Gram in the Preparation of Idli: A Traditional Fermented Product of Indian Origin, by Viscography

Pasting profile of coarse rice, fine rice as well as black gram was carried
out individually, in combination, in flour as well as in batter form, before and
after fermentation by Brabender Viscoamylograph. Lowest gelatinization temperature
was seen in black gram among the three commodities studied. Coarse
rice registered a peak viscosity (PV) of 1,300 BU, fine rice 1,030 BU and black
gram 1,080 BU. Cold paste viscosity (CPV) was highest in fine rice, lowest in
black gram and intermediate in coarse rice. Breakdown (BD) was least in fine
rice, highest in coarse rice and black gram lay in between. Values of total
setback indicated the strong reason for use of coarse rice in parboiling as well
as in idli and dosa preparations. Physical combination of black gram, with fine
as well as coarse rice, reduced PV on an average to an extent of 26–30%. CPV
was highest in fine rice and black gram combination compared with that of
coarse rice and black gram. BD was high in the physical mix of coarse rice
and black gram. In comparison with physical mix of fine rice and black gram,
in the batter form before fermentation, the PV and CPV reduced by 23 and
34%, respectively, but there was no BD in this mix, indicating restricted
swelling behavior in the batter before fermentation. Almost all viscographic
parameters reduced before fermentation in coarse rice and black gram compared
with their physical combination. Highest relative BD (BDr) was noticed
in the pasting profile of black gram alone, probably because of the presence of
mucilaginous principle. BDr values increased in batter form to various extents,
before and after fermentation, compared with physical combination of rice and
black gram. After fermentation, in coarse rice and black gram, the BDr value
was low compared with that in fine rice and black gram.