Surface Modification of Food Fiber by Dry Particle Coating.

Abstract

In this study, a new methodology for surface modification of food fibers is proposed via a dry particle coating technology. Basically, in the dry particle coating processing, a mechano-chemical reaction between hydrophilic OH groups of food fiber and silanol groups—Si(OH)—on the surface of hydrophilic silica is used. As a result of this reaction, dehydration (H + OH → H2O) is expected, leading to suppression of the hygroscopic properties of food fibers for the purposes of better handling and enhancement of the preservative property. For the dry particle coating, a horizontal particle composite equipment with an ellipse shaped rotor was used. The surface of the food fiber was coated with a very fine hydrophilic silica (SiO2) and a mechano-chemical reaction was activated by a high shear stress and an impaction force in the equipment. The coated powders were prepared under various operating parameters of vessel rotational speed and operation time. The surface properties of the coated powders were evaluated by angle of repose (flowability), specific surface area, particle size, and a scanning electron microscopy (SEM) observation. The hygroscopic property was analyzed using a water adsorption method in a temperature and humidity controlled chamber. Interaction between OH and silanol groups was analyzed by a Fourier Transform Infrared Spectroscopy (FT-IR) method.As a result, the optimum operating conditions for preventing hygroscopic property of food fiber can be determined and the mechanism of the mechano-chemical reaction can be elucidated.