Interaction of curcumin with phosphocasein micelles processed or not by dynamic high-pressure

The binding of curcumin to native-like phosphocaseins (PC) dispersed in simulated milk ultrafiltrate at pH 6.6 was assessed by fluorescence spectrophotometry. Curcumin binds to native-like PC micelles with ∼1 binding site per casein molecule, and a binding constant of 0.6–5.6 × 104 M−1. Dynamic high pressure (or ultra-high pressure homogenisation, UHPH) at 200 MPa did not affect the binding parameters of curcumin to processed PC. UHPH-processing of PC dispersions at 300 MPa was followed by a slight but significant (p = 0.05) increase in the binding constant of curcumin to processed PC, which may result from the significant UHPH-induced dissociation of initial PC micelles into neo-micelles of smaller sizes, and from the corresponding 1.5–2-fold increase in micelle surface area. PC–curcumin complexes were resistant to pepsin but were degraded by pancreatin, providing the possibility of a spatiotemporally controlled release and protection of bound biomolecules. UHPH-processed PC did not induce TC7-cell damage or major inflammation as assessed by LDH release or IL-8 secretion, respectively, compared with native-like PC. PC micelles could provide a valuable submicron system to vectorise drugs and nutrients.

► The binding of curcumin to phosphocaseins (PC) processed or not by ultra-high pressure homogenisation (UHPH) was investigated. ► UHPH induced a significant decrease in PC micelle size. ► Curcumin binds to PC processed or not, as assessed by fluorescence spectroscopy. ► PC−curcumin complexes resisted pepsin digestion but were degraded by pancreatin. ► Native-like PC or UHPH-processed PC did not induce TC7 cell damage or inflammation.