Abstract: β-acids-lycopene/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex was prepared by a grinding method, and its structure was characterized by ultraviolet/visible (UV-Vis) absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). Then the stability of β-acids and lycopene in an aqueous solution of the inclusion complex was evaluated under light, thermal and acidic-alkaline conditions. The results showed that the inclusion complex was successfully prepared, which significantly increased the water solubility of β-acids and lycopene to 3.47 and 0.53 mg/mL, respectively. The inclusion complex could retain more than 80% of β-acids and 60% of lycopene after 16 days of storage in the dark compared to UV and natural light, and more than 70% of both compounds were retained in the inclusion complex held at 10–90 ℃ for 12 h. Under acidic condition (pH < 5), β-acids was crystallized, while acid-base conditions had no significant effect on lycopene. These results indicated that HP-β-CD inclusion had a positive effect on improving the photothermal stability of β-acids and lycopene, and it could be more suitable for neutral and alkaline foods.

Key words: β-acids; lycopene; HP-β-CD; inclusion complex; stability