Development of a paddy rice de-husking cum polishing machine

Locally processed rice by small to medium scale processors are still not fully appreciated due to low quality. Paddy rice de-husking cum polishing machine was designed, fabricated and evaluated for its performance efficiency. The effects of paddy moisture content, speed of rotation, and polishing time on the machine performance and milling properties were evaluated. The economic analysis of the machine was also evaluated. Moisture content and speed of rotation of the shaft had effect on the throughput capacity (TC), head rice yield (HRY), percentage broken rice (BR), but not on the percentage un-dehusked (PUD) in production of brown rice. The moisture content, speed of rotation, and polishing time had effect on the BR and PUD, but not on the HRY in the production of polished rice. The minimum and maximum values for brown rice were TC (25.38 and 41.25 Kg/hr), PUD (15.77 and 46.42 %), HRY (50.47 and 67.75 %), BR (2.17 and 12.03 %). Minimum and maximum values for polished rice were PUD (1.12 and 7.34 %), HRY (78.97 and 90.50 %), BR (2.77 and 10.41 %). Economic evaluation shows that the developed de-husker cum polisher is beneficial and can be adopted by small to medium scale rice processors

Effect of polishing duration on physical, milling, cooking, and sensory properties of a novel mix‐colored Nigerian parboiled rice

Background and objectives Polishing is a step of milling process to produce white rice. It influences rice quality. This study evaluates the effect of increased polishing duration (0, 1, 2, and 3 min) on the physical, milling, cooking, and sensory properties of novel mix‐coloured Nigerian rice. These quality parameters influence the consumers’ choice. Findings Polishing duration had a significant effect on the physical, milling, cooking, and sensory properties of the milled rice. As the polishing duration increased, the length, width, length/width ratio, 1000‐grain weight, bulk density, true density, porosity, optimum cooking time, cooking loss, aroma, and flavour of the milled rice reduced while increased polishing duration increased the head rice yield, percentage broken rice, milled rice yield, percentage dockage, kernel elongation ratio, width expansion ratio, water uptake ratio, texture, appearance, and overall acceptability of the milled rice. The correlations between physical, milling, cooking and sensory properties were strongly significant (P˂0.01 and P˂0.05). Conclusions This study revealed that increasing the polishing duration improves the cooking, head rice yield, milled rice yield and some sensory quality attributes of the mix‐coloured parboiled rice, but reduced its physical attributes. Significance and novelty The mix‐coloured rice showed an improved milling, cooking, and sensory attributes but poor physical characteristics during polishing which is very vital to Rice milling industry