Evaluation of optical microscopy efficacy in evaluating cassava starch biofilms microstructure

With the aim to evaluate optical microscopy efficacy as an imaging tool for evaluating bio-based films microstructure, plasticizing sugars (sucrose and inverted sugar), other additives (gelatin, soybean oil, sodium phosphate, and propylene glycol), and pH variation effect on cassava starch biofilms crystallization and phase separation during storage were investigated. Material crystallization, when using sucrose as additive, was observed through non-polarized and confirmed with polarized light microscopy. Scanning electron microscopy (SEM) and X-ray diffraction analysis have reinforced the observed results. Light microscopy also has indicated phase separation when soybean oil was added. Light microscopy analysis may be a fast and simple image tool to indicate crystallization and phase separation during bio-based materials storage. (C) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.