Use the cob (the internal and spongy part of the cob, usually discarded) of colored corn to obtain anthocyanins, naturally rich in pigments for red, blue, purple and purple colors, and use them in the textile, pharmaceutical and veterinary fields for the production of natural dyes and food supplements. The University of Milan has published in ‘Acs Sustainable Chemistry & Engineering – American Chemical Society’ a study to recover agricultural waste from pigmented corn through a biorefinery system. The research work is coordinated by Roberto Pilu, professor of genetic improvement of plants, and by Fabrizio Adani, professor of Biomass and Waste Recycling Promoting the Circular Economy, of the Department of Agricultural and Environmental Sciences and of the Ricicla Group.
The raw material is pigmented corn – explains the university in a note – which enters an extraction cycle for the recovery of anthocyanins, through the use of green solvents: in this way the properties of anthocyanins which are coloring molecules are exploited, antioxidants and anti-inflammatories and also natural antibacterial compounds. The research was developed according to a biorefinery approach with the aim of extracting the anthocyanins present in a selected hybrid of pigmented corn, cultivated at the Didactic-Experimental Agricultural Company of the ‘Angelo Menozzi’ University of Milan in Landriano (Pv).
Anthocyanins are a class of plant pigments belonging to the flavonoid family which in the purple corn cob are distributed almost equally between the grain (55%) and the cob (45%), which is inedible. Corn cob is a plant biomass that is difficult to biodegrade due to the low water content and the lignocellulosic nature of its constituents, organized in the rigid and compact structure of the cell walls.
These characteristics make the purple corn cob a special material, stable over time and rich in anthocyanins: in fact these molecules can be extracted at any time of the year, unlike what happens with red edible fruits, which are also a source. of anthocyanins, such as berries, grapes, currants and cherries, linked to seasonality.
The corn cob, therefore, instead of waste, becomes a valuable resource. In particular, the proposed process allows to recover anthocyanins and use them for dyeing purposes (with natural colors and fibers) and nutraceuticals (supplements intended for human and animal nutrition)..
At the end of the extraction process, the spent cob residue is proposed as litter for animals with particular characteristics, since anthocyanins are still present. The residual litter for animals is, in fact, destined for separate collection with food waste, producing compost and / or biogas and fertilizers, closing the cycle with zero waste, according to the principles of the circular bioeconomy. The project (Pastel project) is funded by the Cariplo Foundation.