ORIGINAL PAPER Evaluation of Image Analysis Tools for Characterization of Sweet Bread Crumb Structure Reynold R. Farrera-Rebollo & Ma. de la Paz Salgado-Cruz & Jorge Chanona-Pérez & Gustavo F. Gutiérrez-López & Liliana Alamilla-Beltrán & Georgina Calderón-Domínguez Received: 10 June 2009 / Accepted: 5 January 2011 / Published online: 20 January 2011 # Springer Science+Business Media, LLC 2011 Abstract Many approaches to evaluate bread crumb features by applying free or at least not too expensive image analysis (IA) software have been published; however, the described procedures showed noticeable differences. The aim of this work was to compare different image scanning resolutions and thresholding techniques to quantify sweet bread crumb features (cell density, mean cell area, shape factor) and their relation with fractal dimension. Two sets of experiments were carried out, one to determine the effect of scanning resolution and thersholding method and the other to validate the previous results by evaluating breads with different crumb structures. Nine different scanning resolutions (75, 100, 150, 200, 300, 355, 435, 515, 555 dpi) and two segmentation procedures (Otsu and Manual) were tested. Three different types of commercial sweet breads and a yeasted sweet bread added with different concentrations (six, 12%) of Chia flour (Salvia hispanica) were evaluated. Results showed that the percent- age of particles with areas between 0.1 and 4.0 mm 2 remained almost constant when using 350 dpi or larger resolution values, while the smallest particles (<0.1 mm 2 ) increased their proportion up to 87% at the highest scanning resolution for both thresholding methods. IA was useful to detect crumb structure differences among commercial breads and breads added with Chia flour as obtained from cell density (154 ± 4.6–246 ± 2.5) and mean cell area (0.81 ± 0.02–0.7 ± 0.03) results. However, the number of selected objects to calculate these parameters produced different results. The addition of 6% of Chia flour did not affect the bread crumb features, while at the largest proportion more and smaller pores were obtained. Fractal texture was useful to evaluate bread crumb structure, as it not depends on the number of particles detected. Keywords Image analysis . Sweet bread . Crumb structure . Fractal dimension of texture Introduction Structure of bread crumb has been traditionally analyzed based on the experience of baker who evaluates compact- ness and uniformity of the bread grain, as visually perceived traits dealing with the size, shape, uniformity and wall thickness of crumb cells or pores (Rogers et al. 1995; Pyler 1988) all of them representing, at a macro- scopic level, the solid and fluid phases of bread crumb (Scanlon and Aghal 2001). The fluid phase also named as cells or pores (Fig. 1) can be divided in three groups: closed, blind and flow-through pores or cells, covering diameters of a few microns to several thousand microns (Datta et al. 2007). In recent years, image analysis (IA) has been used as quantitative tool for the assessment of crumb features (Zayas 1993; Sapirstein et al. 1994; Crowley et al. 2000; Riva and Liviero 2000; Lagrain et al. 2006; Gonzales-Barron and Butler 2006; Calderón-Domínguez et al. 2008; Ribotta et al. 2010) and digital scanners to capture bread crumb two dimensions (2D) high-resolution images (Esteller and Lannes 2008; Datta et al. 2007; Lassoued et al. 2007; This research was financed by projects 20071179, 20080517 from the Instituto Politécnico Nacional (IPN, Mexico), and 84287, 59730 from Consejo Nacional de Ciencia y Tecnología (CONACYT-México). R. R. Farrera-Rebollo : M. Salgado-Cruz : J. Chanona-Pérez : G. F. Gutiérrez-López : L. Alamilla-Beltrán : G. Calderón-Domínguez (*) Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala. Casco de Sto. Tomás, México D.F. CP. 11340, México e-mail: gcalderon@ipn.mx Food Bioprocess Technol (2012) 5:474–484 DOI 10.1007/s11947-011-0513-y