Abstract: In this paper, inclusion complexes of tea polyphenol (TP) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) were prepared by the co-precipitation method with different molar ratios (1:0.5, 1:1 and 1:2) of HP-β-CD to TP. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to analyze the structure of TP and its inclusion complexes. The results showed that HP-β-CD/TP inclusion complexes were successfully prepared, and the one with HP-β-CD:TP molar ratio of 1:2 had the strongest antioxidant activity in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. Further, different concentrations (0, 0.1, 0.5 and 1.0 mg/mL) of this inclusion complex were used to immerse ovine tripe, which was then stored at 4 ℃ for up to seven days, in order to explore its effect on myofibrillar protein (MP) oxidation during the storage period. The results showed that the inclusion complex could significantly inhibit the increase in the carbonyl content, surface hydrophobicity and turbidity and the decrease in the total sulfhydryl content, free amino content and solubility of MP from ovine tripe (P < 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that the TP/ HP-β-CD inclusion complex had an inhibitory effect on MP degradation which increased with increasing concentration up to 1 mg/mL. Therefore, the interaction with the HP-β-CD/TP inclusion complex can effectively delay the denaturation and degradation of MP, and inhibit the deterioration of the functional properties of ovine tripe.

Key words: tea polyphenol; 2-hydroxypropyl-β-cyclodextrin; inclusion complex; ovine tripe; myofibrillar protein