Effect of Gelatin Cross-linking on the Characteristics of Fish Oil Powder

We recently focused on the gelatin/transglutaminase (TGase) cross-linking reaction, and successfully prepared powdered fish oil (PFO) by mixing fish oil with water, emulsifiers, gelatin, and TGase, with subsequent freeze-drying and pulverization of the mixture. Since the cross-linking reaction is considered key in the preparation of PFO, we investigated its role by preparing PFO with and without TGase. As a result, both PFOs contained high amounts of lipids (about 73 % by dry weight). PFO prepared with TGase showed good oxidation stability and slow-release property in vitro compared to PFO prepared without TGase. Microscopic observation revealed almost no changes in shape and oil distribution during preservation of both powers. Atomic force microscopy revealed that the cross linking reaction increased the molecular density of the gelatin surface. This might be related to differences in the properties (i.e., oxidation stability and slow-release property) of the powders. Hence, the production of high quality PFO by using the cross-linking technique is possible.