Effects of heat treatment on protein denaturation and starch gelatinisation in wheat flour

摘要

In the EU, chlorination of soft wheat flour has been replaced in recent years, to some extent, by heattreatment for baking of high ratio cakes. The heat treated flour has enabled recipes to be developed whichgenerate products with longer shelf life, finer texture, moist crumb and sweeter taste. It is not fullyunderstood how heat treatment improves the flour; however, it is known that during the heat treatmentprocess, protein denaturation and partial gelatinisation of starch granules occur. Therefore, it is important toquantify these property variations as they have a marked affect on the quality characteristics of bakedproducts.Heat treated flour was prepared by heating base flour in a laboratory fluidised bed dryer using a range oftemperatures and times. The gluten was extracted from the flour and its quality was tested in an extensibilitygluten rig attached to a texture analyser to obtain objective and comparative information on the extent ofprotein denaturation. Another portion of the flour was used to measure gelatinisation temperature and peakviscosity.The results indicated that heat treatment of flour decreases gluten extensibility showing that proteindenaturation occurred. Also, partial gelatinisation of the starch granules took place. The effects improve thebaking quality of the cake product such as texture, height and volume.