Conference Contribution Details
Mandatory Fields
Macedo I. S. M., Sousa Gallagher M. J., Byrne E. P.;
40th Annual UCC Food Research Conference
Moisture Sorption Isotherms of Granola Breakfast Product
University College Cork, Ireland
Poster Presentation
Optional Fields

The sorption isotherms of dried food products are crucial to model moisture gain during storage and distribution. The aim of this study was to determine the Granola isotherms at a range of temperatures found during storage and develop an overall model which accounts for their effects on moisture content. Sorption isotherms of granola were assessed using a dynamic gravimetric vapour sorption analyzer, at different range of temperatures (10, 30 and 40C) and several models were evaluated for their goodness of fit. All the sorption isotherms of granola were found to be type II, with non-zero moisture content (4.7% d.b. at 10C, 3.7% d.b. at 30C, and 2.5% d.b. at 40C) when the water activity was approximately zero. The sorption capacity was lower at higher temperatures, for the correspondent values of water activity; this effect was more pronounced at low levels of water activity. Nevertheless, the differences of equilibrium moisture content at constant water activity were not significant at 95% significance level (p<0.05) for the different temperatures studied. From all the models fitted to the experimental data the modified Freundlich was found to give the best fit for granola, valid from 0.03 to 0.8 water activity. These results provide reliable experimental data on sorption isotherms for granola product, which is extremely important to design an optimal packaging system.