Sweet cherry (Prunus avium L.): valorization of six Italian ancient varieties and recovery of industrial waste by natural deep eutectic solvents.

Prunus avium L. (Rosaceae) fruits, commonly known as sweet cherries, are well known for their health benefit properties mainly in the prevention of chronic degenerative pathologies [1], due to their composition, consisting in a considerable amount of phenolic compounds. In Italy, cherry fruits have a long-held tradition concerning their cultivation and are used both for eating and producing juices, jams, and drinks [2]. Therefore, a consistent amount of waste is generated and its recycle into a new chain of values in terms of circular economy is of increasing demand. In this context, six ancient Italian sweet cherry varieties were investigated by HPLC-MS for their chemical constituents and compared by a bioinformatic approach. All varieties showed fruits rich in flavonol glycosides, anthocyanins and coumaroyl quinic acids, while the petiole chemical composition was characterized by flavonoid glycosides and B type proanthocyanidins. In order to optimize the recovery of these bioactive compounds from cherry waste by using a green and innovative strategy, five different natural deep eutectic solvents (NADESs) have been designed and used as alternative to the classical volatile and toxic organic solvents for the cherry waste extraction. Results were compared to the recovery with classical solvents and the best performing NADES was evaluated in terms of phenol recovered amount.