Plant-based dye transfer inhibitor for color detergents

When fabrics of different colors are washed, this can result in dye being transferred. The dye molecules can be released from one fabric and be deposited on another, causing it to become discolored and gray. To avoid dyes being transferred in this way, additives are used in special color detergent formulations to act as dye transfer inhibitors. Synthetic polymers such as polyvinylpyrrolidone (PVP) or polyvinylimidazole (PVI) are generally added as color-binding inhibitors. 

Protection against dye transfer for ecological detergents

Eco-certified detergents and cleaning agents consciously avoid all petroleum-based, genetically modified or persistent ingredients, as well as those that require such ingredients in their manufacturing processes. They are therefore particularly environmentally friendly and readily biodegradable. To date, however, there are no dye transfer inhibitors that satisfy the criteria of eco-certified detergents. To make eco-certified detergents an attractive option for a larger customer group, the detergents need to be more than simply ecologically sound — they also need to demonstrate comparable wash performance characteristics to conventional products. With this in mind, the ProColor project is aiming to develop a new plant-based dye transfer inhibitor for use in powder color detergents.

Plant-based proteins in detergents

Plant-based protein preparations are already in use in some modern detergents. For example, wheat protein hydrolysates are able to form a protective film around wool fibers, enabling them to protect fabrics against mechanical stress during the washing process. Wheat protein is also used in detergents to increase the wettability of fabrics and, as a result, to improve cleaning performance during washing.

What’s more, plant-based proteins boast a vast array of additional functional properties on account of their complex structure. These proteins are set to be used in this project to develop a high-performance dye transfer inhibitor. 

Project results – “ProColor”

Efficient optimization of plant proteins as dye transfer inhibitors

The project results show that the techno-functional properties of plant proteins as dye transfer inhibitors can be optimized through selection and targeted enzymatic modification. On a laboratory scale, the optimized proteins inhibited the dye Direct Orange 39 by more than 60% within 65 minutes at 30 °C. In addition, suitable mechanical treatment methods further increased the inhibition performance.

Evaluation of the color-transfer-inhibiting effect

The experts systematically characterized the identified proteins in terms of their techno-functional properties, including protein solubility, foam formation, and viscosity. In addition, they developed a spectrophotometric assay that enables a rapid and straightforward evaluation of the color-transfer-inhibiting effect.

Factors influencing color transfer

The studies clarified the structure-activity relationships between protein and dye as a decisive factor influencing the interaction. Furthermore, the results demonstrate that the presence of salts and surfactants does not impair the binding effects. Finally, the experts determined an optimal protein concentration for formulation and application tests. Overall, the results achieved provide a solid foundation for the further development of marketable, powdered color detergents using optimized plant-based protein preparations.