Background and Objectives: Flax seed oil is unsaturated oil that contains 55% linolenic acid, is highly sensitive to oxidation. In this research, the physicochemical and sensory properties of enriched milk with encapsulated flaxseed oil were studied using complex conservation method .

 Materials and Methods: Flaxseed oil was extracted from flaxseed using solvent cold extraction. Gelatin, gum Arabic, lactose and transglutaminase were used as encapsulating materials. The microcapsulated flaxseed oil was added to milk. The physicochemical and sensory properties, peroxide value, and release of fortified and control sample were evaluated in the enriched milk during one week cold storage.

• The results of FTIR showed that new chemical bonds were not formed in the flaxseed oil microencapsulated by gelatin, gum Arabic and transglutaminase. The milk contained microcapsulated flaxseed oil showed higher acidity than the control. During storage, a significant difference (p= 5%) in peroxide values was observed in the samples containing free flaxseed oil as compared to the samples containing microencapsulated flaxseed oil (206% meq/kg vs. 72% meq/kg, respectively). The color of sample enriched with encapsulated oil was whiter. The sensory evaluation showed that the acceptability of the samples enriched with microcapsulated flaxseed oil was significantly lower the control (p= 5%).
• Microcapsulation of flaxseed oil using the complex conservation method is an effective way to prevent its oxidation in enriched milk. The sensory properties (taste and smell) of the milk enriched with encapsulated oil, however, showed a significant decrease. As a solution, the flavor agents can be used to promote sensorial quality of milk enriched with encapsulated flaxseed oil.

Keywords: Flaxseed oil, Linolenic acid, Microencapsulation, Coacervation, Oxidation