Top-spray fluidized bed coater performance for coated rice

Abstract

Performance of top-spray fluidized bed coating (TSFBC) depends on many factors such as operating parameters, coating solution properties and core materials properties. Therefore, the objective of this study was to investigate the effects of operating parameters, including the fluidizing air velocities (Vf), atomization air pressures (Ap) and percentages of recycle air (Ra) on the performance of TSFBC for producing the turmeric extract coated rice (TECR). Its performance was evaluated in terms of TECR qualities and coating efficiency. It was found that Vf, Ap and Ra had significant effect on the final moisture content (MC) of TERC. Operating at 0% of Ra not only provided the low final MC of TCER but also provided a high number of fissure kernels. Coating at Vf of 2 m/s provided the low coating efficiency of TSFBC, more number of uncoated white rice and low redness value (a*) of TECR. At Vf of 2 m/s an increase in Ap improved the coating efficiency of TSFBC, but the percentage of uncoated white rice of TECR was still high. When the Vf was increased to 2.5 or 3 m/s, the coating efficiency of TSFBC was higher than 80%. Operating at Vf of 2.5 and 3 m/s. the Ap and Ra had a small effect on the coating efficiency of TSFBC.