Study of the thermal properties of corn flours produced by thermal-alkaline treatment

The design of a controlled cooking system (SCC) for the production of threshed cornmeal is presented. The system allows reproducibility in sample processing through time and temperature control. The corn treatment was carried out with a cooking time of 120 minutes at 92.5oC, adding calcium hydroxide (Ca (OH) 2) concentrations between 0 and 0.5% in relation to the corn mass. The cooking process was monitored with measures of moisture in the grain and pH of the solution. Flours were manufactured by adding wet milling, dehydration, dry grinding and sieving operations. The samples obtained were analyzed using the differential scanning calorimetry (MDSC) and thermogravimetric analysis (TGA) technique to study both the thermal stability of the flour and its physical variables: gelatinization interval (ΔT), enthalpy of gelatinization (ΔH), change in heat capacity (ΔCp), maximum decomposition rate (Tmd) and residue after decomposition (Rs). TGA analyzes show that the addition of calcium hydroxide improves the thermal stability of the flour, since the degradation temperature shifts to higher temperatures as the amount of calcium hydroxide increases. MDSC and TGA allowed to observe that the addition Ca (OH) 2 produces a gelatinization shift and the maximum rate of decomposition towards higher temperatures. The results were compared with the same analyzes performed on unprocessed corn. With this study an experimental method is proposed, including a controlled cooking system for the production of flour enriched with calcium, which could have a high impact in the field of nutrition.

• Autores: Pineda–Gómez, P.; F Coral, Diego; Ramos-Rivera, DA.; Rivera, Rosales
• Fecha de publicación: 2011
• Institución: Universidad EAFIT
• Repositorio: Repositorio EAFIT
• Idioma: spa
• OAI Identifier: oai:repository.eafit.edu.co:10784/14467
• Acceso en línea: http://hdl.handle.net/10784/14467
• Palabra clave: Cornmeal; Ca (Oh) 2; Heat-Alkaline Treatment; Gelatinization; Harina De Maíz; Ca(Oh)2; Tratamiento Térmico-Alcalino; Gelatinización
• License: Copyright (c) 2011 H M Martínez, J Torres, L D López-Carreño, J E Alfonso, Luis Moreno, A Pardo