14A-3

L. VAZQUEZ CHAVEZ¹, I. Guerrero Legarreta¹, M. Vizcarra Mendoza², A. Salazar Zazueta³, and A. Castillo Morales⁴. (1) Departamento de Biotecnologia, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, Mexico, (3) Laboratorio de Tecnologia de Cereales, INIFAP, Chapingo, Edo. de Mex., Mexico, (4) Departamento de Matemáticas, Universidad Autonoma Metropolitana-Iztapalapa, Mexico

Wheat drying whithout a proper control causes a decrease in its industrial quality. These changes are mainly due to modification in gluten proteins associated to high temperature drying. Factors such as variety, initial moisture content and drying time must be considered. Fluidized bed drying ensures a homogeneous drying as well as good temperature control, resulting in a decrease in grain damage. In order to detect temperature damage of wheat grains a number of methods have been developed among others monitoring of physical changes of the grain, as well as rheological measurements during dough development and breadmaking. The objective wof this work was to study the effect of three sources of variation (wheat variety, drying temperature and initial moisture content of the grain)in wheat quality. A factorial design was used including two criteria for Mexican wheat varieties: hard (Oasis) and soft (Salamanca), three for initial moisture content of the grain (17, 25 and 35%) and four for drying temperatures (40, 60, 80 and 100°C). Response variables were weight per hectoliter, grain hardness, mixing time as measured by a Swanson mixograph and loaf volume. The data were subjected to analysis of variance and multiple comparisons(Tukey’s test). Wheat susceptibility to undergo quality modifications promoted by fluidized bed drying was mainly affected by temperature and in a lesser extent by variety and initial moisture content. Fluidized bed drying of wheat at 40 and 60°C had an improving effect in breadmaking characteristics. Mixing time as well as loaf volume were the most sensitive parameters to measure grain damage caused by temperature. Due to the different characteristics of the wheat, drying temperature and initial moisture content must be adapted to each variety. Information of quality changes due to fluidized bed drying are necessary in order to design proper handling conditions for two of the main wheat varieties cropped in Mexico.