Development of quick-cooking dehydrated pulses by high temperature short time pneumatic drying

Quick-cooking dehydrated pulses were made from husked split grains of red gram, black gram and Bengal gram using high temperature short time (HTST) pneumatic drying technique wherein porosity was brought about in the dried pulses by exposure of the cooked grains initially to air at a high temperature (170–200°C) for a short duration (4–6 min) in a laboratory model HTST pneumatic drier followed by finish drying at a lower temperature (60–70°C) in a conventional tray or fluidized bed drier. Optimum temperature and time for the HTST drying of the grains were worked out and the HTST dried products were evaluated with respect to their drying behaviour, rehydration characteristics and shelf stability vis-a-vis the conventional hot air dried products.
Considerable reduction in drying and rehydration times could be achieved by the HTST process. The increase in porosity achieved and the HTST treatment did not adversely affect the shelf stability of the grains to any measurable extent.
The technique involves simple equipment and less capital investment as compared to other methods of drying, such as explosive puffing, achieving the same objective. It is amenable to continuous processing as the time of high temperature drying is very short.