Abstract
This work had as objective evaluate the effect of the sodium sulphite on the gravimetric yields in tannins, extracted from Anadenanthera peregrina bark. The tannins were extracted in laboratory autoclave at 100°C for a period of 3 hours, using a relationship liqueur/bark of 20:1; containing 0, 1,5%, 3%, 4,5% and 6% of sodium sulphite on bark dry mass. It was observed that the addition of up to 3% of sodium sulphite in the extraction increased significantly the yields in tannins. At higher concentrations, the amount of total solids increased, however the rate of Stiasny decreased.
Key words:
Stiasny index; angico-vermelho; sulphitation