18:30 13 June 2018
A team from the University of Leeds has developed non-toxic hair dyes using waste created after berries have been pressed for juice. The team used a patented technology designed to extract natural colouring from leftover skins, which have high concentrations of anthocyanins, pigments that provide colour to many berries, flowers, fruits and vegetables.
Dr Richard Blackburn said the berries "represent a sustainable supply of raw material because of how much blackcurrant cordial we drink". He added that the university wanted “to develop biodegradable alternatives that minimise the potential risks to health” due to concerns about conventional dyes.
Dr Blackburn said: "They are non-toxic, water soluble and responsible for pink, red, purple, violet and blue colours and are widely used as natural food colourants all over the world.
"We knew they bound strongly with proteins - hair is a protein - so we thought if we could find an appropriate source of these natural colours, we might be able to dye hair."
According to the research published in the Journal for Agricultural and Food Chemistry, the colours last for at least 12 washes. The blackcurrant-based dyes are expected to go on sale this summer through a university spin-off company.