Subcritical water, which is an effective solvent for polar and nonpolar substances, has been used to extract numerous natural ingredients. In this study, subcritical water was used to extract bioactive substances from apple peel in a batch process in the temperature range of 100-175 °C for 5-60 min. The Fourier-transform infrared spectroscopy results revealed that phenolic compounds were released from apple peel in the aforementioned temperature range. The ultraviolet-visible spectra of the liquid products at 280 nm revealed the high content of phenolic compounds in the extracts. The high-performance liquid chromatography results demonstrated that the yield of procyanidin B2 was approximately 2.28 mg/g of dried apple peel when extraction was performed at 150 °C for 15 min.
- Apple fruit
- Subcritical water