Properties of Starch and Vital Gluten Isolated from Wheat Flour by Three Different Wet-Milling Methods

Abstract

Wheat is extensively used for food, feed, seed and wet-milling. Wheat starch and vital wheat gluten isolated by wet-milling of wheat flour are utilized in numerous food and nonfood applications. Five commercial wet-milling processes, namely Martin, Batter, Alfa-Laval/Raisio, Hydrocyclone and High-Pressure Disintegration (HD), have been employed to co-produce wheat starch and vital gluten. Martin and Batter are the traditional processes, whereas Alfa-Laval/Raisio, Hydrocyclone and HD are the modern-day processes. In the traditional processes, separation of starch and gluten starts with a stiff dough or batter with optimally developed gluten and proceeds with kneading and/or screening to separate starch granules from gluten mass. In the modern-day processes, however, separation starts with a sheared flour-water or dough-water dispersion with partially developed gluten and proceeds with centrifugation to separate starch granules from gluten network. The purpose of this study was to compare the pasting properties of starches and breadmaking qualities of vital glutens isolated from RBS-98 wheat flour by three different laboratory wet-milling methods, namely highly sheared flour-water dispersion (HS-FWD), moderately sheared dough-water dispersion (MS-DWD) and dough-washing (Martin), which respectively represent the commercial wet-milling processes of HD, Hydrocyclone and Martin. Three wet-milling methods were found to be somewhat comparable in many respects, yet they differed in certain wet-milling parameters. Damaged starch levels and RVA pasting properties of A-starch fractions isolated by all three wet-milling methods were quite similar, indicating that starch was neither mechanically damaged nor physico-chemically altered during shear treatment of HS-FWD or MS-DWD methods. Similarly, breadmaking qualities of vital glutens isolated by all wet-milling methods did not fluctuate extensively, suggesting that gluten proteins were not damaged nor altered during shear treatment of HS-FWD or MS-DWD methods. In other words, wet-milling methods used for the isolation of starch and vital gluten are of almost no or limited influence on the properties of starch and vital gluten.