The effect of polyvinylpyrrolidone addition on microstructure, surface aspects, the glass transition temperature and structural strength of honey and coconut sugar powders

Abstract

Deep knowledge of the microstructure and physicochemical properties of polymeric food systems, such as honey powders (HP) and coconut sugars (CS), has practical importance for industry and end users. This study investigated the effect of polyvinylpyrrolidone (PVP) addition on microstructure, roughness, glass transition, α-relaxation temperatures and structural strength (S) of anhydrous complex carbohydrates mixtures. The addition of PVP slightly increased the glass transition and α-relaxation temperature for HP and CS systems as high molecular weight components. Systems with PVP addition showed “stronger” behaviour according to the S approach. Polarized light, scanning electron and atomic force microscopies showed slight differences in transparency and shapes between controls and systems with PVP addition. Surface morphological changes and roughness were investigated in this study to provide insight into HP and CS particles’ structural changes. Moreover, S-involved structural diagrams were built to determine S parameters for controlling the structural transformation of HP and CS systems with and without PVP addition. The results obtained in this work provide new information on polymer-carbohydrate interactions in complex food systems and structural transformations during their production and storage.

Keywords

• Honey powder
• Coconut sugar powder
• Structural strength
• Scanning electron microscopy
• Atomic force microscopy
• Glass transition