Wet-Milling of Flours from Red, White and Low-Polyphenol Oxidase White Wheats

Abstract

Straight-grade and high-yield flours milled from red, white and low-polyphenol oxidase (PPO) activity white wheats were wet-milled to give gluten, starch, tailings and water-soluble fractions. Wet gluten fractions were either oven-dried or freeze-dried and ground to obtain dry gluten. White wheats yielded slightly more flour with higher lightness ( L*) than the red wheat. The wet-milling properties of all flours were comparable. The wet and oven-dried gluten fractions isolated from the low-PPO flours were the lightest, followed by the gluten fractions from the white and red wheat flours. The L* of the oven-dried gluten fractions from the low-PPO flours were ~ 1-3% higher than those from the white and red wheat flours. As the flour yield increased, the L* of the dry gluten fractions from all flours decreased likewise. However, the high-yield low-PPO white wheat flour gave the dry gluten with almost equal L* to the gluten isolated from the straight-grade red wheat flour, indicating the potential of the low-PPO white wheat flour in manufacturing brighter gluten.