Microstructure of retrograded starch: Quantification from lacunarity analysis of SEM micrographs

Three starches from different botanical sources were stored at different temperatures during four days in order to monitor their retrogradation by means of fractal analysis. To this end, digital images were obtained by sample sectioning and scanning electron microscopy (SEM). Fractal dimension estimation and lacunarity analysis were performed over SEM micrographs, showing that (i) as already reported in the recent literature, fractal dimension is directly related to gelatinization temperature, and (ii) the storage temperature and the starch botanical source affect strongly the heterogeneity (quantified in terms of lacunarity) of retrograded starches. Overall, the results in this work yield important insight on retrogradation, providing guidelines for predicting growth models for retrogradation.

► Fractal analysis based on image processing is used for starch retrogradation quantification.
► Fractal dimension quantifies retrogradation extent while lacunarity accounts for micro-structure homogeneity.
► Fractal properties of retrograded starch depend of botanical source and storage temperature.