Studies on the utilization of coffee by-products.

Trials were carried out for the recovery of caffeine from the pulp and husk of coffee berries, and also for treating the husk by physical methods. The % caffeine content of various by-products, on moisture-free basis, was: arabica pulp 0.37-0.60, robusta pulp 0.20-0.21; arabica parchment skin 0.14, robusta parchment skin 0.10; arabica cherry husk 0.12-0.52, robusta cherry husk 0.15-0.44; special leaf 0.32, middle leaf 0.33; twigs 0.35, wood 0.12. The husk was powdered in a multi-mill, and particles of different sizes were separated by sieving. The bulk density of these sieve fractions ranged from 0.48 to 0.6 g/ml, and the caffeine content from 0.13 to 0.24%.