Purification of Whole Brown Flaxseed Meal from Coloring Pigments by Treatment in Hydrogen Peroxide Solutions: Impact on Meal Color

Abstract

The main objective of the present project was the purification of brown flaxseed meal from coloring pigments in order to improve its potential use as ingredient in food formulations. Thus, this work was aimed to study the bleaching of non-defatted brown flaxseed meal in dilute hydrogen peroxide solutions. Bleaching was evaluated according to the Hunter L, (a), and (b) color scale as function of the hydrogen peroxide concentration (1%, 2%, and 3% v/v), the meal concentration (2.5%, 5%, and 10% w/w), the bleaching time (10, 20, and 30 min), and the pH (3, 7, and 9). Effect of all the independent variables was significant. The L value was the most significantly affected parameter and increased as the concentration of hydrogen peroxide increased, but decreased as the concentration of flaxseed meal increased. The L value was observed to be higher at pH 9 than at pH 3 and 7. The b value, which represents the yellowness, was significantly increased from 18.70 ± 0.01 (control sample) to 35.45 ± 0.04 after the meal was treated with a 3% hydrogen peroxide solution at pH 9. Total phenolics content significantly decreased when the meal was treated with 3% (v/v) hydrogen peroxide solution. This concentration yielded the higher L color value (highly bleached meal).