Fecha de publicación: 07/01/2025 Fuente: Ultrasounds Extraction Byproducts Abstract
In this study, the physicochemical characteristics, mineral contents, and bioactivity of the famous grape cultivar ‘Karaerik (Vitis vinifera spp., Cimin)’ grown in Türkiye, and raisins (seeded and seedless) produced via sun drying were investigated. As a result of the study, the titration acidity, total solids, total sugar, reducing sugar, sucrose, protein and ash contents and the antioxidant capacity of the raisin samples were significantly increased by the drying process than in the fresh ‘Karaerik’ grapes (P < 0.01). The ‘Karaerik’ grape retained its characteristic black color even after drying. ICP–MS results revealed that raisins and grape seed samples are good sources of minerals (K, P, Ca, Mg, Na, Fe, Cu, Mn, Zn, and Se). The total phenolic content (TPC), total flavonoid content (TFC), total monomeric anthocyanin (TMA) content and total antioxidant capacity (DPPH•, CUPRAC, and FRAP) of the fresh ‘Karaerik’ grapes, raisins and grape seeds varied between 1.45–235.05 mg GAE/g, 2.46–704.36 mg QE/g, 1.92–292.53 mg Cyn-3-glu/100 g, 1.09–335.66 mg TE/g, 4.77–986.67 mg TE/g and 1.32–236.26 mg TE/g, respectively (P < 0.01). The difference between the conventional and ultrasonic-assisted extraction methods was not significant (P > 0.05). The order of antioxidant capacity was grape seeds > seeded raisins > seedless raisins > fresh grapes. The results revealed that dried grapes (especially seeded raisins) are a rich source of bioactive compounds. Additionally, byproduct grape seeds obtained during the drying of ‘Karaerik’ grapes for seedless raisins were found to be an important source of minerals, nutrients and bioactive compounds.

Graphic abstract