The primary by-product of apple processing used in the juice industry is known as apple pomace, and it is thought to be a source of polyphenols with a number of health benefits. Therefore, the goal of this study is to establish the use of a sonotrode for the extraction of total phenolic compounds from apple pomace, specifically phloretin and phloridzin, which have significant antioxidant activity. With 15 tests and 3 independent parameters (ethanol (%), duration (min), and amplitude (%), we employed a Box-Behnken design. The results were determined by HPLC-MS-ESI-TOF for the total phenolic compounds, phloretin and phloridzin, and by DPPH, ABTS, and FRAP for the antioxidant activity. ANOVA provided proof that the model was valid. Additionally, several apple pomaces with or without seeds that were extracted under ideal conditions were compared. 7% to 32% of the total phenolic compounds in the apple pomaces were phloretin and phloridzin. Gala apple pomace had the highest phenolic content and antioxidant activity out of all the apple pomace studied. Apple pomaces with seeds were found to contain the cyanogenic component amygdalin as well as increased levels of phloretin and phloridzin but lower levels of flavan-3-ols.
