Effect of Adsorption Conditions on Effective Diffusivity and Textural Property of Dry Banana Foam Mat

Abstract

Foamed banana product, a crispy snack, can quickly adsorb the moisture from the moist air, leading to loss of textural property. The main purpose of this research was therefore to study moisture adsorption kinetics of dry banana foam mat and its texture quality change. The adsorption isotherm experiments were carried out with a standard static method using saturated salt solutions over a wide range of relative humidities from 32 to 82% and temperatures of 35, 40, and 45°C. Three dry banana foam densities of 0.21, 0.26, and 0.30 g/cm³ adsorbed water vapor under controlled conditions. Fick's second law coupled with an optimization technique was used to estimate the effective moisture diffusivity at sorption conditions. Empirical equations with two and three constant parameters for describing the dependence of the effective moisture diffusivity on moisture content were tested. The two constant parameters could suitably describe the variation of the effective moisture diffusivity with moisture content. The initial foam density, relative humidity, and temperature significantly affected the effective moisture diffusivity. The banana foam mats for all densities lost their crispy texture at moisture content of 0.078 kg/kg db.

Keywords:

• Adsorption kinetics
• Capillary condensation
• Crispness
• Food foam
• Snack

ACKNOWLEDGMENTS

The authors express their appreciation to the Commission on Higher Education, Thailand, for supporting this research by a grant fund under the program Strategic Scholarships for Frontier Research Network for the Ph.D. Program Thai Doctoral Degree. This work was also supported in part by Thailand Research Fund and King Mongkut's University of Technology, Thonburi, and the National Science and Technology Development Agency.