Effects of process parameters on 3-MCPD and glycidyl ester formation during steam distillation of olive oil and olive pomace oil

Abstract

Steam distillation was applied to lampante olive oil and olive pomace oil in a laboratory-scale steam distillation equipment, and effects of process parameters (temperature, pressure and stripping steam) were determined and modeled on bound 3-MCPD and glycidyl ester formation. Levels of process parameters were optimized to minimize bound 3-MCPD and glycidyl ester formation using response surface methodology. According to the results of the study, olive pomace oil has a significant content (4.1 mg/kg) of bound 3-MCPD prior to steam distillation. Results showed that temperature of the steam distillation was highly effective on bound 3-MCPD and glycidyl ester formation. Interaction between stripping steam rate and temperature was statistically significant for glycidyl ester formation. Effects of process parameters were visualized by using perturbation plots. Perturbation plots showed that stripping steam rate was possibly effective not only on glycidyl ester formation, but also on bound 3-MCPD formation in the case of steam distillation carried out at wide-ranged process conditions. According to the optimization results, optimum steam distillation temperature is 230 °C, water flow rate is 1.2 ml/min, and pressure is 4 mbar for olive oil, and temperature is 230 °C, water flow rate is 1 ml/min, and pressure is 2 mbar for olive pomace oil to minimize the bound 3-MCPD and glycidyl ester formation.