Fucoidan improves the structural integrity and the molecular stability of β-lactoglobulin
β-lactoglobulin (β-lg) was covalently bonded with fucoidan through Maillard reaction at 60 °C for 96 h under 79% RH condition. The molecular characters of the conjugate were investigated using fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and circular dichroism (CD) spectroscopy. And, its thermal properties, surface activity, and zeta-potential were compared with intact β-lg, β-lg-fucoidan mixture, and fucoidan under different pH conditions. AFM indicated that the conjugate was nano-structured, regular spherical-shaped and generally large sized compared to β-lg-fucoidan mixture. CD spectra and FT-IR showed that tertiary structure of β-lg slightly unfolded, but little change in secondary structure occurred. This explained that glycation under Maillard condition resulted in a molten globule state of β-lg. Differential scanning calorimetry (DSC) data exhibited that fucoidan shifted the temperature of phase transition and improved thermal stability of β-lg molecule. In addition, the conjugate prominently decreased the surface tension with pH-dependency.
KeywordsMaillard reaction β-lactoglobulin Fucoidan Conjugation Molten globule state
This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education (No. 2015R1D1A1A09061228).
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