Background:
Difficult-to-mill kinds of pulses, viz., pigeonpea, urd, and moong require pitting or scratching of whole grains for ease of water or oil absorption applied for pretreatment. Pitting also reduces treatment time. In vertical chakki, small size whole grains pass as such without splitting. Both of the issues, adversely affect the quality of dal. Chakki could not dehusk flat seed of lentil for which abrasive rollers are more suitable:
Technology Details:
To get uniform grain size and remove impurities, a reciprocating grader was attached with the IIPR Dal Chakki. Raw grains must be graded at the time of arrival. Cleaned and graded uniform size grains can be passed through an abrasive roller, attached with the unit for pitting or scratching, in the first pass prior to water soaking or oil application pretreatment. Conditioning for several hours is followed by sun-drying of treated grains for several days, which loosens the grip of husk over cotyledons. The second pass of treated grains is made through rubber-steel disk vertical chakki. The Uniform size of grains allows the constant gap between two disks and minimizes the problem of whole grains in the dal. The abrasive dehusking roller can also be used for dehusking lentils and other difficult-to-mill kinds of pulses. The soft dehusking mechanism in the second pass, causes minimum scouring to precious cotyledons. Powdering losses are more with a repeated pass in abrasive rollers commercially used. Driven by a 2.0 hp single phase motor IIPR Mini Dal Mill gives the capacity of 75-125 kg/h for different pulses.