Microencapsulation of kenaf seed oil by co-extrusion technology

• The microencapsulated kenaf seed oil was produced by a Buchi Encapsulator B-390.
• 1.5% w/w sodium alginate and HMP–alginate were used as shell formulations.
• The effects of different parameters were evaluated.
• Microencapsulation by co-extrusion technology is a feasible approach for encapsulating oil.

The aim of this study was to evaluate the effect of different processing parameters such as different flow rates for shell and core feed, vibrational frequencies, drying methods and shell formulations on the characteristics of microencapsulated kenaf seed oil (MKSO) by using co-extrusion technology. Optical microscopy revealed that the MKSO produced at vibrational frequency of 500 Hz and core–shell flow rate of 0.2–7.2 mL/min (for 1.5% alginate) and 0.2–7.0 mL/min (for high methoxyl pectin (HMP)-enhanced alginate) appeared to be the best processing conditions and the MKSO exhibited the highest microencapsulation efficiency at these conditions. Besides that, freeze drying presented as a better drying method to dry the MKSO than air drying. HMP-enhanced alginate seems as a better shell formulation to produce MKSO with a smaller size (450–575 μm), having a stable water activity (0.280) against oxidative deterioration, and higher microencapsulation efficiency (76.62%) but less spherical in the shape of MKSO compared to 1.5% alginate. It was demonstrated that production of MKSO by co-extrusion is possible and that the process is stable and reproducible.