The need of more suitable information concerning coffee seeds processing led to the present research whose objectives were to verify the possibility of using the pre-cleaning machine, air-screen cleaner and gravity table for separate coffee seed lots into fractions according to the physical seeds characteristics and to study their effects on physical seed quality. One seed lot of 'Catuaí Amarelo IAC 62' was processed by several operational sequences in a pre-cleaning machine, in an air-screen cleaner and in a gravity table, according to technical recommendations for seed processing. The fractions retained over the screens with 22/64 and 20/64 inch circular holes of the air-screen cleaner were processed separately in the gravity table. The seeds were evaluated in the laboratory as to their purity, weight of thousand seeds, weight of hectoliter, moisture content, predominant seed types and endocarp integrity. It was observed that: a) The pre-cleaning machine, the air-screen cleaner and the gravity table were effective for separating and classifying coffee seed lots into homogeneous size classes, promoting the best seed quality in the complete sequence of the processing; b) The air-screen cleaner with oblong hole screens and cleaner with circular hole screens promoted the separation of peaberry seeds, seeds with exocarp fragments and seeds without endocarp, improving the appearance and physical quality of the coffee seed lot; c) The gravity table promoted better separation of seeds with damaged endocarp, improving favorable alterations in the physical seed characteristics and improving quality of the seed lot; d) The small seeds retained by screens with smallest holes of the air-screen cleaner and the light seeds, classified or not by size and discharged on the lowest spout of the gravity table, showed inferior physical quality.
Coffea arabica; seeds; grading; physical seed quality
