Hydrophobin-stabilized nanoemulsion produced by a low-energy emulsification process: A promising carrier for nutraceuticals

Abstract

Hydrophobin II (HFBII) is an amphiphilic biopolymer that could be explored to stabilize oil-in-water nanoemulsions as nutraceutical delivery systems. This study reports the production of HFBII-stabilized nanoemulsions by a spontaneous emulsification process using copaiba oil as a bioactive lipid. HFBII was isolated from a wild-type Trichoderma reesei and characterized. A 23 full factorial design with three central points was used to obtain an optimal nanoemulsion system, whose physical-chemical properties were studied under different ionic strength and pH. The peptide similarity search allowed the identification of a series of 6 ion fragments from the isolated fraction, which can be attributed to the amino acid sequences of the HFBII database. The optimal nanoemulsion system presented a nanoscale droplet size (<200 nm), a narrow size distribution (PDI <0.2) and a negative zeta potential of ≈ −30 mV, which was stable at low salt content and pH values close to the neutrality. These results demonstrated the feasibility of using HFBII as a biopolymer to stabilize nanoemulsion systems. Furthermore, the HFBII-stabilized nanoemulsion is a promising carrier for nutraceuticals in food technology applications.