Spray drying and rehydration of macadamia oil-in-water emulsions: Impact of macadamia protein isolate to chitosan hydrochloride ratio.

• Spry-dried oil powders were stabilized by MPI & CHC. • MPI/CHC composites (5:1 or 3:1) gave high encapsulation efficiencies. • MPI/CHC composites protected powdered macadamia oil from oxidation. • Rehydrated emulsions with the highest stability could be produced at MPI/CHC = 5:1. The utilization of oils in the food industry can be facilitated by converting into a powdered form using microencapsulation technologies. In this study, coatings formed from macadamia protein isolate (MPI) and chitosan hydrochloride (CHC) were assessed for their ability to facilitate the microencapsulation of macadamia oil by spray dried, and all encapsulation efficiency was higher than 87.0%. The physicochemical properties of macadamia oil powders were then characterized. In addition, changes in the particle size, aggregation state, and creaming stability of rehydrated emulsions were analyzed during storage. The addition of CHC significantly enhanced the water-solubility and wettability but decreased the flowability of microencapsulated oil. Powdered macadamia oil produced at MPI/CHC = 5:1 had the highest encapsulation efficiency (94.2%), best oxidation stability (<4 meq/kg), and best rehydration properties. Overall, MPI/CHC could be used as a good emulsifier for producing stable rehydrated emulsion, which may therefore be useful in certain food applications. [ABSTRACT FROM AUTHOR]