Influencia de la molienda en las propiedades reológicas del licor de cacao

• Autor: Ramos Quevedo, Javier
• Formato: tesis de grado
• Fecha de Publicación: 2013
• Institución: Universidad Nacional de San Martin - Tarapoto
• Repositorio: UNSM-Institucional
• Lenguaje: español
• OAI Identifier: oai:repositorio.unsm.edu.pe:11458/523
• Enlace del recurso: http://hdl.handle.net/11458/523
• Nivel de acceso: acceso abierto
• Materia: INFLUENCIA; MOLIENDA; REOLÓGICAS; LICOR; CACAO

The aim of this study was to determine the influence of milling on the rheological parameters of cocoa liquor 2 varieties (Criollo and CCN-51), the equipment used for the experiments was the concentric cylinder Brookfield rheometer DV - Ultra 111 and Rheocalc software for data collection. Finally for data analysis and statistical analysis the Origin 5.0 and Statistica 7.0 software were used respectively. The variables analyzed were: grinding time (1 to 10 hours) and temperaturas of 30 to 80ºC, and the response variables were viscosity, shear stress and shear rate. The method used was a rheological analysis to determine the rheological properties, rheological models then were used to characterize these properties (Casson, HerschelBulkley and Power Law). For statistical analysis a complete randomized factorial design (10x6) two factors (milling time and test temperatura), with two replications was used. Analysis of variance (ANOVA) shows that there is a significant effect of milling time and temperatura on the parameters: consistency index, flow index, yield stress and plastic viscosity. The rheograms for criollo cocoa liquor and CCN-51 variety, indicate similar behavior, when the case of grinding their temperaturas increase occurs because the shear stress decreases to values of 3.05 D/cm2 and 5.01 D/cm2 with temperatura of 40ºC and 2.11 D/cm2 and 3.13 D/cm2 with temperatura of 80ºC, respectively, showing a nonNewtonian fluid behavior and pseudoplastic. Statistically comparing the experimental data has to rheogram temperatura and the milling time significantly influenced (P<0.05) in the rheological properties of cocoa liquor both viscosity and shear stress as observed in the response area of each variety. Finally the chosen rheological model Herschel-Bulkley was to present a better fit (R2>0.9), and that the parameters of this equation reflect the characterization of the fluid.