Combined dyeing and antioxidative properties of some plant by-products

Aqueous extracts of plant by-products (carrot, onion, black carrot, sage, spinach and thyme) were investigated for dyeing capacity on fibres and for both colorant and antioxidant potential using colorimetric and chromatographic tools, and FTC assay, respectively. Regarding fibres, classical correlations between measured colours and phytochemical patterns of dyeing extracts were verified. Light fastness of onion, sage and thyme samples, evaluated following a normalised test, was very promising considering industrial restrictions; moreover, antioxidative activities of those aqueous plant extracts were very attractive when compared to the three others and to alpha-tocopherol used as standard. Our results were of great interest underlining new complementary valorisations for plant by-products, becoming in this way new and inexpensive natural resources for various industries.