Color of enzyme-retted flax fibers affected by processing, cleaning, and cottonizing

Twenty-seven samples representing variations of retted flax fibers are analyzed using a color spectrophotometer and CIELAB models. Variables included enzyme or dew retting, fiber or seed flax, enzyme and chelator concentrations, and sequential cleaning steps. In addition to differences in color with enzyme or dew retting, the variables involved in enzyme retting also contribute to differences in the lightness, redness-greenness, and yellowness-blueness of the resulting fibers. Dew retted fiber flax, as well as seed flax that has weathered during storage prior to enzyme retting, is significantly darker than non-weathered, enzyme retted fiber flax. Pairwise comparisons show that lower enzyme concentrations (0.05% v/v as commercially supplied) produce redder and yellower fiber samples than those retted with higher (0.3% v/v) enzyme levels. Higher chelator levels, (i.e., 50 versus 25 mmol ethylenediaminetetraacetic acid) produce redder fibers. Fiber lightness significantly increases with additional cleaning steps. Results indicate that objective color measurements and color standards can define important fiber properties in order to tailor raw materials for specific industrial applications.