Abstract

Stable oil-in-water nanoemulsions were generated by ultra-high-pressure homogenization (UHPH) at 140 and 210 MPa for use as nano-vesicular vehicles (NVV) to carry hydrophobic generally recognized as safe (GRAS) curcumin (CU) by whey protein isolate (WPI) in aqueous nutraceutical systems. Curcumin was used for its antioxidant activity and participation in the Michael reaction with nucleophiles at pHs above 8.0. Two variables, (1) addition of casein hydrolysate (CH) (2%, w/w of WPI) and, (2) use of UHPH (140 and 210 MPa), were studied for their effect on the stabilization of monodispersed NVV and antioxidant capacity of the CU as cargo in the NVV throughout storage. CH and Tween 20 both were added to increase dispersibility and stability of the NVV. Addition of CH reduced nano-particle size (d_vs) by 17% at 210 MPa when compared to140 MPa (P<0.05), and increased the stability with UHPH pressure as reflected by a 63% smaller d_vs at 210 MPa as compared to 140 MPa (P<0.05). The nanoparticle distribution was not changed by the addition of CU, with d_vs’s of 101 and 93 nm at 140 MPa and 73 and 92 at 210 MPa for NVV and CU-NVV, respectively. The NVV system was stable for 28 days as observed in zeta-potential, contact angle, and surface energy, and can be used to deliver CU and maintain its antioxidant activity.

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