A novel process for microencapsulation of fish oil with barley protein

This research represents the first scientific publication reporting barley protein as a wall material to encapsulate fish oil. Solid microcapsules were able to form in aqueous solution by pre-emulsifying barley proteins with a homogenizer followed a microfluidizer system. No organic solvent or cross-linking reagents were used in the preparation process. The wet status microcapsules were converted into free-flowing powder (dry status microcapsules) by a spray-drying process. The optimum microcapsule preparation conditions were 15% protein, oil/protein ratio = 1.0, and an inlet temperature of 150 °C. These microcapsules exhibited high encapsulation efficiency (EE: 92.9–100.2%), loading efficiency (LE: 46.5–50.1%) and low moisture content (0.75–0.90%). The oxidative stability of microencapsulated fish oil was tested at both dry status and in aqueous solutions (pH 7.0 and pH 2.0) in an accelerated storage test (40 °C, 8 weeks). These barley protein microcapsules possessed a strong ability to protect fish oil against oxidation, making them ideally suited for use in liquid/semi-liquid food systems. Food formulation tests confirmed their successful application in milk and yogurt for their respective shelf lives.

► Barley protein microcapsules were prepared by a microfluidizer treatment. ► No organic solvent or cross-linking reagents were used in the preparation process. ► They are efficient to encapsulate fish oil and protect it from oxidation. ► Food formulation tests confirmed their successful application in milk and yogurt.