Extraction Process Optimization of Hydroxytyrosol from Olive Pomace by Response Surface Methodology

Ultrasonic assisted hydrolysis and oscillatory water bath hydrolysis were compared to extract hydroxy tyrosol from olive fruit dregs in this study. On the basis of single factor experiment, the extraction temperature, concentration of hydrochloric acid, ratio of material to liquid and hydrolysis time were taken as experimental factors. The extraction process was further optimized by response surface method (RSM) using the hydroxy tyrosol extraction amount (mg/g) as the index. The results showed that the optimum extraction conditions were as follows:extraction temperature 88℃, concentration of hydrochloric acid 1.2 mol/L, ratio of material to liquid 1:36 g/mL, hydrolysis time 86 min, and the actual extraction amount of hydroxy tyrosol was (3.38±0.12) mg/g, which had no significant difference with the theoretical value. The linear range of hydroxytyrosol was 1.28~203.40 μg/g, and the precision and stability were all up to the detection requirements. This study was useful for the extraction of hydroxytyrosol from olive pomace.