May 7/Science Letter -- "Two varieties of rice crackers (RC-1 and RC-2) were packaged in two types of packaging materials, polyethylene and polypropylene pouches, and stored at 30C/75% RH and 30C/85% RH to simulate actual storage conditions and determine shelflife. The main composition differences in the samples were in their fat content (1.87% for RC-1 and 21.09% for RC-2) and initial moisture content (4.12% for RC-1 and 2.28% for RC-2)," scientists in Bangkok, Thailand report.
"The shelf-life of this product is mainly affected by moisture adsorption, as evidenced by sensory evaluation. The Guggenheim-Anderson-de Boer (GAB) model was used to fit the moisture sorption isotherm. Good precision of fit was found as measured by a determination coefficient (R-2) close to 1. The shelflife was then predicted, based on the relationship between permeability coefficient of the packaging materials and moisture adsorbed by the rice crackers determined by the GAB equation.