A rapid and quantitative method for assessing the whiteness of whitened lignin based on an in-depth analysis of reported methods

Nano-Structured Lignin as Green Antioxidant and UV Shielding Ingredient for Sunscreen Applications

“…In this latter case, the acetylation process was responsible for the inhibition of the auxochrome effect of the phenolic moieties, as a consequence of its electron withdrawing effect. Acetylation prevented demulsification processes due to the fine control of the polarity of lignin [158]. As a general trend the lightening process slightly interferes with the antioxidant and UV shielding properties.…”

“…The dark color of lignin, that is mainly due to the harsh conditions of physical and chemical treatments (e.g., high temperature and oxidative transformations), hinders the promotion of lignin-based cosmetics on the market [157]. The principal methods to assess the lignin color are the Munsell and CIELAB procedures [158]. The Munsell color system determines the classification of the color by measuring the human perceptual response, and consists in the evaluation of three independent variables, represented by the color hue (measured in degrees on a horizontal circle), saturation (measured radially from the neutral gray axis outwards), and brightness (measured vertically on the gray axis from 0 for black and to 10 for white) parameters.…”