Evaluation of a centrifugal impaction-type decorticator for shelling tung fruits

Abstract

Tung, a potential tree-borne oilseed has many applications in paints, varnishes, foods and other non-food industries. De-shelling of tung fruit is an important process prior to its oil extraction. Manual de-shelling of tung fruits is a time consuming and tedious operation. Therefore, the effectiveness of a centrifugal impaction type decorticator for tung fruits was studied and evaluated for performance parameters. The performance test for maximum seed yield was evaluated on the basis of various performance indicators, which includes percentage of whole seed, broken seed, partially shelled fruit, unshelled fruit, machine efficiency and decortication efficiency. These performance indicators of the decorticator were evaluated at three different fruit moisture contents (8.65%, 12.13% and 15.61% d.b.) and at different speeds of rotating blades (1600, 1800 and 2000rpm). The clearance between rotating blade and striking plate was fixed at 100mm for optimum force. The best results of 52.24% recovery of whole seeds and machine efficiency of 74.63% were recorded at fruit moisture content of 8.65% (d.b.) with a blade speed of 1800rpm. These set of conditions were preferred, because of its rapid operation, low human-energy, low breakage factor for the seed as well as relatively little amount of dust being emitted during de-shelling. Its wider use is thus recommended for a healthier working atmosphere.