Natural pigments and useful raw materials from autumn leaves for industry.
VTT Technical Research Centre of Finland is developing leaf-processing technologies that could be used by the cosmetics, textile, feed and food industries.
Autumn leaves contain a range of substances such as pigments, carbohydrates, proteins and compounds that inhibit the growth of harmful bacteria, VTT noted, but little use has been made of fallen leaves so far. They are usually left on the ground, composted or burned, resulting in full landfills and a growing carbon dioxide load.
Autumn leaves derive their color from orange and yellow carotenoids and red anthocyanins. In addition to pigments, autumn leaves contain many beneficial compounds, such as phenols, lignin, carbohydrates and protein, said VTT.
There is a fast-growing need for natural pigments in various industries around the world. For example, these natural pigments can even have health-promoting effects and use as nutraceuticals.
In a process developed by VTT, leaves gathered in gardens and parks are dried and ground, and compounds are extracted. The processing stages were developed by VTT in laboratory experiments. Research and development have now entered the piloting stage, using leaf material collected in the Otaniemi area of Finland by waste disposal company Lassila & Tikanoja. Special attention has been paid to the environmental friendliness of the overall process and the safety of the compounds produced.
“In laboratory experiments, we discovered several promising alternative ways of utilizing leaves,” said Liisa Nohynek, senior scientist at VTT. “Piloting assays are under way in which we are examining how our methods work in practice and what quantities of valuable compounds can be extracted from the leaves.”
Pigments from autumn leaves can be used to color cosmetics and textiles. The chemical composition of leaves varies largely between different tree species. Added value can be obtained by processing the autumn leaves of certain tree types, producing well-defined compounds suitable for new products.
Residual biomass that remains after extraction is high in nutrients and suitable for soil improvement in home gardens. On the other hand, this waste can also be further processed to compounds that inhibit the growth of harmful microbes, making them suitable for cosmetic and hygiene products.
Nohynek believes that the methods developed by VTT are applicable for raw material processors in textile and cosmetic industries. In addition, the residual material offers business opportunities for firms in the horticultural, cosmetics, hygiene and pharmaceutical sectors.