title: Rheological of chocolate-flavored, reduced-calories coating as a function of conching process.
abstract: Continuous flow and linear viscoelasticity rheology of chocolate coating is studied in this work using fat substitute gums (xanthan, GX). An alternative conching process, using a Rotor-Estator (RE) type impeller, is proposed. The objective is to obtain a chocolate coating material with improved flow properties. Characterization of the final material through particle size distribution (PSD), differential scanning calorimetry (DSC) and proximal analysis is reported. Particle size distribution of the final material showed less polydispersity and therefore, greater homogeneity; fusion points were also generated at around 20 °C assuming crystal type I (β'2) and II (α). Moreover, the final material exhibited crossover points (higher structure material), whereas the commercial brand chocolate used for comparison did not. The best conditions to produce the coating were maturing of 36 h and 35 °C, showing crossover points around 76 Pa and a 0.505 solids particle dispersion (average particle diameter of 0.364 μm), and a fusion point at 20.04 °C with a ΔHf of 1.40 (J/g). The results indicate that xanthan gum is a good substitute for cocoa butter and provides stability to the final product.
authors: Facultad de Química, Departamento de Ingeniería Química, Conjunto E, Universidad Nacional Autónoma de México (UNAM), México, D.F. 04510 México.
authors: Luis
authors: L
authors: Medina-Torres
authors: CIATEC, A.C. Omega 201, Fracc. Industrial Delta, CP 37545, León, Gto., México.
authors: Guadalupe
authors: G
authors: Sanchez-Olivares
authors: Instituto Tecnológico de Durango, Departamento de Ingeniería Química y Bioquímica, Felipe Pescador #1803 Ote., CP 34080, Durango, Dgo, México.
authors: Diola Marina
authors: DM
authors: Nuñez-Ramirez
authors: Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), México, D. F. 04510 México.
authors: Leonardo
authors: L
authors: Moreno
authors: Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), México, D. F. 04510 México.
authors: Fausto
authors: F
authors: Calderas
keywords: Chocolate coating; Lineal viscoelasticity; Melting enthalpy (ΔHf); Particle size distribution, (PSD); Xantham gum