Abstract: In this study, the pH-driven method was employed to construct tilapia myofibrillar protein (TMP)/κ-carrageenan oligosaccharide (κCOS) nanocomplexes for encapsulating curcumin (CUR), aiming to address the issues of its low bioavailability and poor stability. The nanocomplex prepared under optimized conditions (TMP concentration = 12 mg/mL, κCOS concentration = 4 mg/mL) had the following properties: an average particle size of (291.16 ± 5.37) nm, a zeta potential of (−29.80 ± 1.67) mV, and a polydispersity index (PDI) of 0.34 ± 0.04. Furthermore, the nanocomplex formed a three-dimensional network structure. At a concentration of 0.2 mg/mL, CUR could be effectively loaded into the nanocomplex, with a high loading rate of (76.76 ± 0.04)%. The results of infrared (IR) and circular dichroism (CD) spectroscopy indicated that TMP and κCOS were combined through hydrophobic and electrostatic interactions, and the content of α-helix significantly increased after binding, from 22% (TMP) to 76% (TMP/κCOS). The in vitro release results indicated that the cumulative release rate of CUR from the TMP/κCOS/CUR complex was only (14.43 ± 0.85)% after 60 min, while it reached (74.71 ± 0.70)% after 180 min. This nanocomplex could effectively improve the ionic and thermal stability of CUR. This study provides a reliable process for the construction of TMP/κCOS nano-delivery systems and also indicates its good application potential in the field of hydrophobic active ingredient delivery.

Key words: nanocomplexes; myofibrillar protein; κ-carrageenan oligosaccharides; curcumin; pH-driven method