CROP RESIDUES AS FIBROUS AND FUNCTIONAL COMPOUNDS FOR PAPER PRODUCTION

Abstract: Due to the high lignocellulose content, as well as the high content of phenolic compounds, agro-industrial vegetable waste is well suited for valorization in packaging materials. As specialized packing materials, these materials may offer competitive advantages to paper producers, utilizing a low cost feedstock to produce a bespoke product of good quality. In our contribution, we focus on the production residues of various plant streams (e.g. growing and processing of onions, olives and pomegranates), to demonstrate how such diverse agro-industrial bio-waste materials could be fully exploited even before their reformulation. Onion skins and olive leaves both showed high antioxidant activity and the possibility to recover relatively high yields of bioactive compounds (roughly 100 mg of quercetin or oleuropein per g of dry extract). However, in pomegranate peel, the content of the antocyanins (roughly 0.3 mg of antocyanins per g of dry extract) was low. All three plant residues sources produced unique paper materials. Olive skins and olive leaves were used as two individual feedstocks, whereas the pomegranate peel was required to be added to cellulose. The resulting papers exhibited good technological properties, as well as interesting texture and appearance and might as such be suited for the production of special papers. The determined characteristics of the samples demonstrate a good potential for cascading use where paper production should be further studied following the extraction of bioactive components.