Separation of functional compounds in citrus wastes and evaluation of total phenol

In this thesis, valuable components of orange peels, which are generated as waste in fruit processing industry, were recoverd by using Supercritical-CO2 extraction (SK- CO2), Soxhlet extraction and ultrasound assisted extraction methods. Basic operating parameters which influence the extraction efficiency of the phenolic substances such as extraction time, temperature (40 – 61.5 C), pressure, (8.5 –31.5 MPa) were designed using Box-Behnken methodology and the effects of parameters on recovery were investigated. In the Soxhlet extraction method and ultrasound assisted extraction method, extraction processes were carried out at 50%, 80%, 100% ethanol/water ratios in a 2-hour extraction period. Comparisons of the recovery efficiencies were carried out by analyzing total phenolic content (TF), antioxidant activity and total flavonoid content (TFC) in the extracts. Maximum recovered TF in SK-CO2 extraction was found as 8.5 mg GAE/g DM at 61.5 C, 20Mpa, this value was found as 22.5 mg GAE/g DM in Soxhlet extraction and 36.8 mg GAE/g DM in ultrasound assisted extraction methods.