Bee bread: Sorption isotherms, thermodynamic characteristics of moisture adsorption and evaluation of adsorbed water

Abstract

Bee bread is a value-added apiculture product produced from bee pollen by mixed lactic acid fermentation. Although many studies focused on the bioactive components and health effects of the bee bread, there is no study concerned with understanding its moisture adsorption properties. Herein, it was aimed to evaluate moisture adsorption properties and thermodynamics of bee bread using different sorption models at 25 and 35 degrees C. The water adsorption of bee bread had Type II characteristics, and the monolayer moisture content was calculated with BET, GAB, and Caurie models between 3.58 and 5.80 g/100 g. The Peleg and Caurie models ensured better prediction for adsorption. The stability of bee bread was high at 25 degrees C according to the smaller ratio of Type III to Type II-bound water. The entropy of adsorption was 16.01-25.78 kJ/mol.K and it decreased with the moisture adsorption. Besides, the moisture adsorption needs external energy from the environment because of triangle G > 0.