Effect of heat treatment of sorghum grains on storage stability of flour.

Sorghum flour is susceptible to rancidity and develops off-flavor within a short duration when stored.
Heat treatment on the development of rancidity after long-term storage of flour was studied. Heat
treatment varying in severity was applied to the whole grains of different varieties of sorghum viz.,
CSH-9, CSH-5, M35-1 and a local variety varying in their morphological features. A trend was seen that
when the thermal duration was for a shorter time, the shorter was the storage duration in certain
varieties. Exposure of grains to moist heat for 15 min retarded hydrolytic rancidity significantly (p < 0.05)
in CSH-5 until 6 months of storage and in the remaining varieties until 8 months of storage, Heat
application for 15 min retarded the development of rancidity irrespective of the morphological variations
and the oil content. Lipase activity varied among the varieties with CSH-5 recording higher activity when
compared to the other varieties. No major differences in the physicochemical properties were observed
in flours from 15 min heat-processed grains when compared to flours from unprocessed grains.