Sustainable ingredients: Ribena waste offers natural hair dye opportunity

The University of Leeds in the UK has extracted natural dyes from blackcurrant waste produced during Ribena, a popular juice drink, manufacture.

Colour chemist Dr Richard Blackburn and organic chemist Professor Chris Rayner, both from the University of Leeds, worked together to identify and isolate naturally-occurring alternatives – as well as a sustainable process to produce them.

They combined expertise in extraction technology, hair science, coloration, and natural products chemistry to develop a new technology to extract anthocyanins from blackcurrant fruit waste for use in renewable dyes.

“Anthocyanins are pigments that provide colour to most berries, flowers, and many other fruits and vegetables​,” Dr Blackburn explained. “They are non-toxic, water-soluble and responsible for pink, red, purple, violet, and blue and colours and are widely used as natural food colorants 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.”​

A readily available waste product​

All but ten per cent of British blackcurrants are used in the production of Ribena, say the researchers, with the berries harvested in late summer and pressed for juice.

Neither Ribena nor its parent company, the Suntory Group, were involved in this research, although the blackcurrant waste used originated from its production.

Professor Rayner said: “After being pressed, the skins remain as a waste product. They have very high concentrations of anthocyanins, and represent a sustainable supply of raw material because of how much blackcurrant cordial we drink. ​

“The extraction technology is based on sustainable concepts – the colour is extracted using a water-based process and special filters collect the anthocyanins that we want. We believe that if we are extracting natural and food-grade products, we should not use any toxic or hazardous chemicals to get them.​”

On the back of these results, the researchers have developed a patented hair dyeing technology that provides intense reds, purples and blues on hair that, when combined with a natural yellow, could provide a wide range of colours – including browns.

The colours produced were stable for at least 12 washes – comparable with conventional semi-permanent dyes.

Full details of the research are now published in a paper in the Journal of Agricultural and Food Chemistry.