Enyan F, Banful BKB, Kumah P
Field studies were conducted at Kwahu Bepong in the Eastern region of Ghana with laboratory support at the Cocoa Research Institute of Ghana (CRIG) and the Department of Horticulture of Kwame Nkrumah University of Science and Technology from November, 2010 to March, 2011. The objectives were to determine independently and in combination, the effects of drying methods and depths of drying on the physical and organoleptic qualities of Robusta coffee beans. The experimental design was a 3 x 3 factorial arrangement in randomized complete block with three replications. The first factor was methods of drying at three levels - M1:- drying on a raised raffia mat at 0.8 m above ground; M2:- drying on a concrete floor and M3:- drying on a black polythene sheet on concrete floor. The second factor was the depth of drying at three levels - D1:- 5 cm; D2:- 10 cm and D3:- 15 cm. Temperature and moisture levels within bean heaps were monitored. Other data collected included number of days to drying, percent caffeine and crude protein contents and sound and defective beans, insect-damaged beans, broken beans and shriveled and/or black beans. The number of days to drying, temperature and moisture within heaps, differed significantly (P < 0.05) with respect to drying methods and depth of drying of the coffee beans. However, the treatments did not have any effect on the caffeine contents. There was a significant relationship between percentage crude protein content and temperature within the heap of coffee beans. The temperature in the heap of coffee beans during drying accounted for 77% of the variation in total crude protein content (Y = 0.891 + 0.098X; R2 = 0.77; P = 0.002). The study concluded that drying coffee beans on black polythene sheet on concrete floor at a depth of 5 cm resulted in desirable effects similar to those obtained using the raised raffia mat. The desirable effects included faster drying time and increased crude protein content of beans. Consequently, in the absence of a raised raffia mat due to the unavailability of its basic materials, the black polythene sheet on concrete floor could be a worthy substitute without compromising on coffee bean quality with its consequent effect on cup quality.
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