Interaction and 3D plots of trans-resveratrol accumulation of Kalecik Karası grape skin as affected by physical characteristic of the grape, incubation time, US application method, US frequency and US treatment time. a Physical characteristic of the grape and incubation time, b physical characteristic of the grape and US frequency, c incubation time and US application method, d incubation time and US frequency, e US application method and US treatment time, f US frequency and US treatment time