Researching the tactile material qualities of citrus biopolymers and their value for design.


In contrast to the striking colouring, the special leather-like material character of the peel of citrus fruits is hardly noticed. This very robust protective shell contains a range of different biopolymers, such as pectins, cellulose and acid, which prevent the fruit from drying out, promote its ripening and protect it from predators. They are mainly used in the cosmetics, food and medical sectors. This project is about their use in the production of biological plastics.

Overall, bioplastics have great potential to replace conventional plastics, but not yet in the field of so-called high-performance plastics. Their qualities lie above all in their sustainability and biodegradability, but also in their special, nature-like feel. The challenge is to use precisely these „new“ plastic qualities adequately in terms of design and to give them sustainable added value.


Insoles from citrus peels.


In addition to their biocompatibility and sustainability, bio-plastics offer other interesting material qualities. In the case of organic plastics made from citrus peel, various pectins and other bio-polymers ensure that they absorb water vapour, are permeable to air and thus act as climate regulators.

The surface has an anti-microbial effect, which is important to skin irritations or skin diseases. Especially for people with wounds on their feet, as is often the case with diabetics and elderly people, these properties can be beneficial.

As a result of my material tests with various pectines from citrus peels, the material is suitable for use in shoe insoles. The insoles are covered with an elastic relief structure which follows the ergonomic rolling behaviour of the foot. Perforations and thin-walled joints collect excess moisture and improve air exchange in the shoe. The soft and flexible material offers cushioning comfort and distributes the pressure load on the foot.