Optimization of coffee oil flavor encapsulation using response surface methodology

• Roasted coffee oil was extracted using Sc–CO2.
• The oil was successfully encapsulated using PEG by PGSS process.
• The PGSS process parameters were optimized using Box Behnkendesign.
• The optimum conditions were 40 °C, 260.14bar and 6.57:1polymer-oil ratio.

This study aimed the encapsulation of coffee oil flavor and optimizing the process conditions which affect the encapsulation efficiency (EE). Oil was extracted from roasted Coffea arabica, (Yrigachefe, Ethiopia) using supercritical carbon dioxide (Sc–CO2). Then, the extracted oil was encapsulated by polyethyleneglycol (PEG) using particles from gas-saturated solutions (PGSS) process. Process parameters which affect the EE such as, temperature (T, 40–50 °C), pressure (P, 200–300 bar) and polymer-oil ratios (R, 5:1–10:1 g/g) were optimized via Box Behnken design (BBD). The optimal conditions were (T, 40.0 °C, P, 260.14 bar and R, 6.57:1 g/g) with a maximum EE of 79.78%. The encapsulated oil showed peroxide value of 4.56 meq peroxide/kg oil after 12 weeks of storage. Less than 2% loss of fatty acid composition was observed after encapsulation. Moreover, flavor profiles of particles obtained using optimal condition showed very good preservation of flavors. Therefore, microencapsulation using PGSS process could be employed for production of freely flowing powdered particles that can be used in food processing industries.