Pneumatic polishing of rice in a horizontal abrasive pipe: A new approach in rice polishing

•A new type of pneumatic rice polisher has been developed.•The developed polishing system does not have any moving parts•It gives uniform polishing of rice with less breakage of kernels•At same polishing level, system gives less broken than commercial abrasive polisher

A pneumatic rice polishing system, based on jet-polishing technique of metal surface, has been developed to minimize broken. This consists of 5 cm diameter polythene pipe; inner surface is lined with hard abrasive material, a blower and a collection system, and no moving part. Brown rice and air are fed through 180° scroll and flow through abrasive pipe. The system used 28.2 m s− 1 airflow, 0.45 kg min− 1 feed rate and different pipe lengths (1.0–4.0 m; interval 0.5 m). Degree of polish and broken varied with both pipe length (L) and number of passes (N; 5–50). System showed uniform polishing, and degree of polish (Dp) varied from 3.72% (1 m) to 9.97% (4 m), and linearly with N. 8.52% broken was obtained (4 m pipe) while laboratory abrasive polisher yielded 20% at equal Dp level. Effects of N and L and their interactions were found significant (p < 0.05) on Dp.Industrial relevance•The technology will yield higher head rice and less breakage of kernels•System is very simple with no moving part•Maintenance and operating cost will be much less.