Microencapsulation of Fish Oil-milk Based Emulsion by Spray Drying: Impact on Oxidative Stability

Omega-3 poly unsaturated fatty acids (PUFA) have numerous human health benefits. Fish oil has been known as a source of PUFA, but their addition to foods is limited by oxidative rancidity. Hence, fish oil has to be protected against oxidation preferably by microencapsulation. In the present study, an attempt was made to prepare fish oil encapsulates. Fish oil-milk based emulsion was prepared and encapsulated by spray drying using either fish gelatin or maltodextrin as wall materials. Fish oil and wall material was used at the ratio of 1:2. In order to study the effect of natural antioxidants on the fish oil encapsulates, ginger essential oil was added at 0.25% concentration. Morphological characterization of fish oil encapsulates by scanning electron microscopy (SEM) revealed spherical shape of particles without any cracks. Encapsulation efficiency was improved significantly (p<0.05) from 34.48-35.52% to 44.42-49.34% by the addition of fish gelatin or maltodextrin as wall material. Fish oil encapsulates were packed in two different ways which include normal and vacuum packing and stored at room temperature (28 +/- 2 degrees C). Oxidative stability of the fish oil encapsulates showed better protective effect against oxidation (1.99 mg malonaldehyde kg(-1)) for fish oil encapsulates prepared with fish gelatin and ginger essential oil and packed in vacuum condition than the control (8.22 mg malonaldehyde kg(-1)). Results from the study indicated that fish gelatin was able to encapsulate fish oil and it was comparable with that of maltodextrin. Addition of essential oil as natural antioxidant improved the oxidative stability of fish oil encapsulates.