Effects of microcapsule constitution on the quality of microencapsulated walnut oil

The encapsulation is a process by which small particles of core products are packaged within a wall material to form microcapsules. One of the most useful processes for drying thermosensitive substances that are unstable in aqueous solutions is the freeze-drying technique (lyophilization), which involves conversion of liquid oils in the form of an emulsion into dry powders. In this paper, the chemical composition of walnut oil and microencapsulation conditions (microcapsule wall material composition) have been evaluated in order to assess the influence of the microencapsulation process on the quality and shelf-life of microencapsulated walnut oil. Highest encapsulation yield was achieved when maltodextrin, carboxymethylcellulose, and lecithin were used as encapsulation agents and the ratio of oil-wall material was 1:1.5. Under these conditions all the oil was encapsulated. The presence of protein constituents in the microcapsule wall material extended the shelf-life of the microencapsulated walnut oil regardless of the use of antioxidant additives.