33A-16 |
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I. Guerrero, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F:, Mexico, L. Vázquez-Chávez, Departamento de Biotecnología, Universidad Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, and E. PONCE-ALQUICIRA, Departamento de Biotecnologia, Universidad Autonoma Metropolitana, Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Mexico D.F., 09340, Mexico. Drying is an usual process applied to wheat as initial step in breadmaking. However, the time-temperature relationship could affect wheat breadmaking ability. No tests are available to a priori determine the effect of thermal processing on wheat breadmaking quality. The objective of this work was to study the efficiency of a fast and simple test in predicting wheat breadmaking quality parameters. Soft and hard wheat were subjected to heat treatment (40oC for 360 and 210 minutes; 60oC for 120 and 90 minutes; 70oC for 60, 45 and 30 minutes; 80oC for 30 minutes; and 100oC for 20 minutes); the wheat was then milled. Flour-soluble protein was spectrophotometrically determined at 595 nm; sedimentation rate and volume was also analyzed. Bread was then prepared by the direct method and loaf volume was measured. High sedimentation volume was obtained when hard wheat was used, an indication of good protein functionality. However, low sedimentation volumes were obtained when the wheat was dried at low temperature and long time, as well as at short time and high temperature. Sedimentation rate was very low in both wheat varieties, with no significant difference. It can be concluded that this test was not efficient to determine damage in heat-dried wheat. Conversely, soluble protein analysis was efficient and fast to detect heat damaged gluten. Color development depended on protein solubility which, in turn, decreased as heat treatment severity increased as a result of protein aggregation during drying, stabilized by covalent bonds. Loaf volume also showed that severe heat treatments resulted in gluten damage, therefore decreasing wheat quality. Results can be applied as a means to predict wheat quality in a fast and reliable way when a process is established for the first time.
Session 33A, Carbohydrate: General
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