The effect of genotype and drying condition on the bioactive compounds of sour cherry pomace

Sour cherry (Prunus cerasus L.) contains substantial quantities of phenolic compounds, specifically anthocyanins, and is mainly processed into different products including juice, whose by-product, namely sour cherry pomace (SCP), represents a potential source of high added bioactive compounds currently underutilized. Oven drying and freeze drying (FD) are simple methods, often used to stabilize food matrices, and can be also successfully employed for the stabilization of sour cherry pomace. In the present study, the influence of genotype (Bianchi d’Offagna and Montmorency cvs), drying method and their interaction on the extractability of phenolic and anthocyanin profiles of sour cherry pomace were evaluated. Both genotype and drying method significantly influenced (p ≤ 0.001) the overall phytochemical content (total monomeric anthocyanin, total flavan-3-ol, total phenolic, and vitamin C) of the analyzed pomaces. The interrelationships between the parameters analyzed, the genotype, and the different drying conditions, as well as the relationships among variables, were investigated by principal component analysis (PCA). PCA results pointed out that the phytochemical content of sour cherry pomace was firstly influenced by the cultivar (which accounted for about 70% of the total variance), followed by the drying process (about 18% of the total variance), and their interaction (about 12% of the total variance), with the exception of total flavan-3-ols, where a similar contribution (about 50%) of the two factors was observed. Besides, the antidiabetic potential of SCPs was also investigated, showing Bianchi D’Offagna FD pomace to be the most active. The obtained results point out that the SCP stabilized by means of the freeze-drying process is a valuable second-generation biorefinery for food supplements and nutraceutical and pharmaceutical markets.