Kinetics studies of some physico-chemical substances during roasting and preparation of beverage made by Cassia occidentalis seeds

Cassia occidentalis seeds are commonly used in West of Africa to prepare a beverage which serves as a substitute for coffee. A study was carried out to investigate the effect of roasting conditions on some organic compounds in the seeds and to determine the extraction rate of some physico-chemical constituents into an aqueous infusion. With the exception of phytate, the results showed that roasting significantly decreased (P⩽0.05) the level of the chemical parameters measured (proteins, carbohydrates, total phenols and tannins). Degradation of these compounds during roasting follows first-order reaction and this degradation conforms to the Arrhenius equation. From the rates of increase of the physico-chemical concentration of beverage with extraction time, first order rate constants of infusion were determined and kinetic extraction was found to follow the quasi-steady-state theory of extraction from spherical particles.