RA 00048.pdf - OAR@ICRISAT

son 1969; Shepherd et al. 1970-71), conventional
roller-milling equipment (Hahn 1969; Crawford et
al. 1942; Goldberg et al. 1946; Shoup et al.
1970a), the Miag Multomat experimental flour mill
(Shoup et al. 1970b), Brabender Quadrumat Sr.
and Jr. mills (Rooney and Sullins 1970; Maxson et
al. 1971; Badi et al. 1976), the Maxima mill
(Raymond et al. 1954), and a wheat semolina mill
(Pilon et al. 1977). The general consensus appears
to be that roller milling is not very appropriate for
sorghum because the product does not have
consumer acceptability (for example, in Senegal,
Chad and Sudan) and because production costs
are relatively high due to a low extraction rate
(Perten 1977b). The gray color and speckiness of
the flours also limit the usefulness of roller milling
(Hahn 1969, 1970)
An abrasive, peeling roll was developed by
Shoup et al. (1970b) to dehull tempered sorghum.
A yield of up to 8 9 % of peeled grain was obtained,
which is probably close to the maximum possible
yield. Weinecke and Montgomery (1965) have
used the same principle. The Tropical Products
Institute, London, has recently developed and
tested a sorghum peeler in Sudan (D.A.V. Dendy,
personal communication). The SOTRAMIL process
uses abrasive rolls to obtain extraction rates
of 6 5 - 7 5 % (millet) after hammer milling (Adrian
et al. 1975). In the SEPIAL process, conditioned
grains are peeled by the action of paddles in an
apparatus with a vertical axis. Then by vigorous
rubbing in a brushing machine a protein-rich
fraction (aleurone plus adjacent layers) and decorticated
grain is produced (Adrian et al. 1975). The
latter two processes have mainly been applied to
millet.
Application of Rice-Milling Equipment
Since rice dehullers and polishers have been used
on rice for many years, a detailed description of
the principle of operation of these machines is
available elsewhere (Borasio and Gariboldi 1979).
The Ce Co Co dehuller (Ce Co Co, Chuo Boeki
Goshi Kaisha, P.O. Box 8, Ibaraki, Osaka 567,
Japan) has been used to dehull tempered sorghum
in the National Research Council of Canada,
NRCC, integrated milling process (Anderson and
Burbridge 1971; Anderson et al. 1977). Shepherd
et al. (1970-71) and Kapasi-Kakama (1977) also
used the Ce Co Co to dehull sorghum successfully.
Three models of the machine are available with
throughputs of 420-840 kg per hour of sorghum
and power requirements of 5 - 1 0 hp.
Viraktamath et al. (1971) tested three types of
rice-milling equipment: a rice huller (a horizontal
ribbed rotor), a Gota machine (a horizontal truncated
cone), and a Dandekar-type rice mill (a
vertical inverted truncated cone rice polisher).
Only the latter produced satisfactorily dehulled
sorghum from the tempered grain.
A Squiers rice huller, consisting of a solid-cast
rotor with several bars surrounded by a screen
provides abrasive action as the grains rub against
the rotor, screen, and one another. Anderson et al.
(1969) used this dehuller on tempered sorghum
followed by impact milling and sieving.
A Satake rice whitening machine (Satake Engineering
Co., Ltd., Tokyo, Japan) has been tested
by Robinson Reunert Ltd., Thora Crescent, Wynberg,
Sandton 2199, South Africa and good results
were apparently obtained (personal communication).
An Engleberg rice huller or similar dehullers
have been tested (Raghavendra Rao and Desikachar
1964) and are used in several West
African countries (e.g., Ouagadougou, Upper Volta
and Bamako, Mali). The machine consists of a
ribbed rotor rotating within a slotted screen.
In general, many of the rice dehullers, particularly
those like the Engleberg type do not work well
on sorghum probably because it is much softer
than rice. Private industry and others have therefore
resorted to the development of other types of
dehullers, especially the abrasive- and attritiontypes.
Abrasive-type Dehullers
Abrasion-milling employs carborundum or other
abrasive surfaces mounted on a vertical or horizontal
rotor to progressively abrade the outer
layers of the grain. Some of the rice dehullers
mentioned in the last section also operate on this
principle.
Bavaria Record
Etablissements Rohr (11, rue Jacques-Duclos B.P.
19, 95204 Sarcelles CEDEX) distributes three
types of Bavaria Record machines. The dehullerscourer
type is sold in eight models (A to H) With
machine lengths varying from 110 to 227 cm. The
weight varies from 230 to 500 kg, with throughputs
(on wheat) from about 450 kg/hr for the
smallest model to about 1800 kg/hr. In these
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