Monolayer values at 30°C of various spices as computed by the BET and GAB models

• DOI: 10.1007/s002170050046
• Publication Date: 2002-08-25T07:47:25Z
• Authors: Begoña Marcos; Mark´a Asunción E...; Pascual López; Manuel Alcalá; Rafael Gómez; José Espejo; Andrés Marcos
• Keywords: 0404 agricultural biotechnology; 04 agricultural and veterinary sciences

The monolayer values at 30°C of 17 spices of various botanical families, obtained from different parts of the plant and commercially marketed in diverse forms, were determined from stepwise moisture adsorption data at four relative humidities over the lower 50% of water activity (a w) values by using the BET and GAB equations. Fitting was similarly good for five spices, better by the BET equation for five other spices, and better by the GAB equation for another three, the experimental results provided by the remaining four species being fitted by neither equation. The monolayer values determined by the three-parameter GAB model were not always larger than those obtained by use of the simpler two-parameter BET equation, which appears to be more accurate in those cases where only sorption data for the low a w range are available.