Development of a Powered– Decorticator for Producing White Pepper from Black Pepper

Abstract

A powered black pepper decorticator for producing white pepper from black pepper was developed, tested and its performance evaluated. The major parts are grinding surfaces, feed hopper, cylindrical collecting tray, water distribution assembly, 0.5 hp motor and reduction gear of 5:1 gear ratio. The decortication of the pepper berries was performed by compressive and shearing forces between the grinding surfaces. The experiment was conducted at different soaking time, speed and grinding surfaces. A 2- factor, experiment in Completely Randomized Design (CRD) with speed and soaking time as factors were adopted. The maximum decorticating efficiency observed for MS Plate, rexin sheet, teflon and grinding stone were 46.10, 51.30, 47.50 and 61.52 at 17 h -71 rpm, 17 h -71 rpm, 18 h -57 rpm and 17 h- 71 rpm soaking time - speed combinations. The wholeness of kernels show a decreasing trend at higher speeds that is crushing of berries increases. Generally, the mechanical damage also shows the similar trend. The maximum overall decorticating efficiency for various surfaces were 37.38 of 17 h -71 rpm, 38.99 17h- 71rpm, 35.63 of 18h- 57rpm and 51.06 of 17h -71rpm. The study shows that the parameters of speed and soaking time have significant influence on decorticating efficiency, wholeness of kernels, mechanical damage and overall decorticating efficiency. The quality of white pepper obtained from grinding stone coupled with polyurethane was superior to those obtained by other surfaces. The overall decorticating efficiency of powered decorticator was found maximum (51.06 %) at 71 rpm and 17 hour soaking period. The capacity of the developed machine was 1.23 kg/h.