Effect of encapsulation of D-limonene on the moisture adsorption property of ß-cyclodextrin

The effect of encapsulation of D-limonene (0, 3.0 g/100 g, 7.5 g/100 g and 9.68 g/100 g) on the moisture adsorption property of β-cyclodextrin (β-CD) were studied. The increasing limonene oil content significantly lowered the moisture adsorption capacity of β-CD, which was probably caused by the decreased moisture adsorption sites and monolayer moisture content of β-CD molecules. However, the values of net isoteric heat of adsorption were increased after the β-CD was complexed with the limonene oil, indicating the energy of the remaining water molecule binding sites of β-CD were stronger. Samples at all level of oil encapsulations showed a sigmoid type (type II) adsorption and the GAB model was determined to be the best mathematical model for prediction of their moisture adsorption behaviours. The GAB parameters were different at different limonene encapsulation levels