Department of Engineering Sciences and Technology

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Browsing Department of Engineering Sciences and Technology by Author "Benjamin, Y."

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    Development of a low cost machine for improved sorghum dehulling efficiency
    (2013) Lazaro, E.L.; Benjamin, Y.; Mpanduji, S.M.
    A Pedal operated sorghum dehuller for dehulling tempered grain was developed and tested for its performance using two sorghum varieties (Dionje and Jumbo). The use of short tempering duration (10 – 15 minutes) followed by a short resting period (5 – 10 Minutes) to ensured that all the tempering moisture was absorbed into the grain before the grain was introduced into the dehuller thus eliminating the clogging problem usually associated with conventional abrasive dehullers. This facilitated the removal of the seed coat from the endosperm. The obtained results showed that the developed dehuller was able to achieve high dehulling efficiency (90.1% for Jumbo and 83.4 for Dionje) and high recovery levels compared to conventional abrasive dehullers (45.6 for Jumbo and 40.3% for Dionje). The quality of the dehulled grain was also much higher as indicated by the low ash content, low crude fibre content and superior colour of the flour obtained from the grain dehulled in the developed dehuller compared to flour from grain dehulled using conventional abrasive dehullers. These results demonstrate that it is possible to achieve high quality dehulled sorghum product and high dehulling efficiency by incorporating simple and cheap traditional pretreatments in the mechanical dehulling process. Accordingly, the developed pedal operated dehuller could be very appropriate for small scale sorghum farmers and consumers in the rural areas where spare parts, electrical power and competent technicians to run and maintain the conventional abrasive dehullers are limited.
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    The effects of dehulling on physicochemical properties of seed oil and cake quality of sunflower
    (2014) Lazaro, E.; Benjamin, Y.; Robert, M.
    This paper reports on oil yield, physicochemical properties of oil and cake quality obtained by expeller extraction of dehulled and undehulled seeds from two varieties of sunflower originated from Tanzania. The results showed significant differences in oil yield between undehulled and dehulled seeds also among the varieties. Oil yield from dehulled seeds was significantly higher (31−35.1%) than the yield from undehulled seeds (~19.7%). When compared physicochemical parameters (refractory index, saponification value, iodine value, free fatty acid value and peroxide value) of oils with standard values as recommended by Tanzania Bureau of Standard, the oil extracted from dehulled seeds were found to be within the range of values specified but the oil from undehulled was of poor quality at many instances. However, the physicochemical properties of oils from the two varieties did not differ significantly in most of the properties except for peroxide value. The cake composition from dehulled seeds was characterised by high crude protein (~44%) and low crude fibre contents (~17%), indicating improved quality. The results suggest that high yield and desired properties of both oil and cake can be achieved when seeds are dehulled, therefore, this process should be incorporated by Tanzanian sunflower processors.