Abstract

Effect of roasting on proximate content, some anti-nutritional and colour (L* a* and b* values) attributes of soya bean flour were evaluated at roasting temperature of (160, 180 and 200oC) and roasting time of (5, 10, 15 and 20 min.). There were significant difference (p<0.05) among the values of protein and moisture content. These both decreased with increase in roasting temperature and time. The values ranged from 11.00-14.85% and 8.02- 16.03%, respectively. Fat content increased with increase in roasting temperature and time, with values between 21.00-59.00%. There was significant difference (p<0.05) in the anti nutrition evaluated. Trypsin inhibitor and saponin values decreased with increase in roasting temperature and time. These were between 0.00–0.50mg/100g and 16.67–106.67mg/100g, respectively. The L* values of roasted soya bean decreased with increased temperatures and time, while a* and b* behaved contrary. The most preferred range of roasting temperature and time combination for production of soya bean flour was 160-1800C at 15–20 min. This range had low anti-nutritional properties and colour close to the natural soya bean. At this condition, it may be incorporated into other flour products at varying percentages. The colour attributes could be used to monitor the roasting quality of soya bean flour at varying temperature and time combination.

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