The Detailed Comparison of the Effect of Optimum Thermosonication and Potash Solution Pretreatments on Quality Attributes of Dried Black Grapes

ABSTRACT This study evaluated the impact of optimized thermosonication pretreatment (UT) (743.1 J/g, 16.6°C) on the physical and chemical quality of dried black grapes, comparing it with the traditional potash treatment. Dried grapes showed high dry matter (89.53%–91.41%) and controlled water activity (0.415–0.467), with significant changes in color parameters. Thermosonication pretreatment significantly reduced rehydration capacity, unlike potash. Potash increased sucrose content and negatively impacted fructose, while UT significantly reduced sucrose. UT‐treated samples retained the highest organic acid contents and exhibited the lowest HMF and furfural contents, demonstrating an advantage over potash in minimizing these undesirable compounds. Potash enhanced total phenolic content (TPC) and total monomeric anthocyanin content (TMAC), whereas UT only increased antioxidant activity. Untreated control samples generally scored highest in sensory attributes, particularly appearance and overall acceptability. This research indicates that optimized thermosonication offers specific benefits like HMF/furfural reduction and organic acid preservation, though its overall quality impact varies compared to conventional treatments.