Effect of bioactive Rosa roxburghii Tratt fruit polysaccharide on the structure and emulsifying property of lactoferrin protein.

Lactoferrin protein (LF) is a natural protein with certain emulsifying ability, but is sensitive to be affected by environmental factors and has poor oxidative stability to be used as emulsifier. In this study, the emulsifying ability of LF was significantly improved after conjugation with Rosa roxburghii Tratt fruit polysaccharides (RTFP), and the emulsion stability mechanism of LF-RTFP conjugates (L-R) were elucidated through the utilization of CLSM (confocal laser scanning microscopy), interfacial tension, apparent viscosity, and protein adsorption rate. The emulsion stabilized by L-R showed the smaller particle size (17.17 ± 0.13 μm), which reduced by 51 % compared with that of LF. After conjugation with RTFP, the hydrophobic amino acids that are originally inside the structure of LF would be exposed on the protein surface. In addition, the protein adsorption rate of L-R stabilized emulsion interface was 62.70 ± 0.71 %, 2.4 times higher than that of LF. The optical microscopy and CLSM experiments indicated that the glycosylation with RTFP increased the bridged flocculation and further formed gel network structure in the emulsion stabilized by LF. These findings suggested that the novel emulsifier prepared by the Maillard reaction between LF and RTFP showed potential to stable emulsion.