Effect of Polysaccharide Addition on the Stability and Gel Properties of Rabbit Myofibrillar Pickering Emulsion

In this study, rabbit myofibrillar protein (RMP) was extracted, and Pickering emulsion and the emulsion gel were prepared with soybean oil as the oil phase. The effects of different pH environment (3~10), carrageenan (0.25%~0.50%) and sodium alginate (0.25%~0.50%) on the stability and gel properties of Pickering emulsion were investigated, in order to prepare Pickering emulsion gel with high stability by using RMP. The results showed that when pH value was 9, the absolute value of ζ-potential of RMP emulsion was the largest (33.60 mV). The absolute value of ζ-potential (72.97±0.60), emulsifying activity index (EAI) (5.09±0.09 m²·g⁻¹) and emulsifying stability index (ESI) (46.07%±3.74%) of RMP-Pickering emulsion all reached the maximum value when the oil phase volume was 50% and the concentration of carrageenan and sodium alginate polysaccharide were both 0.35% at pH9. In the range of polysaccharide concentration from 0.25% to 0.35%, the water holding capacity, hardness and elasticity of RMP-Pickering emulsion gel with carrageenan and sodium alginate added all increased gradually, and these indicators reached the maximum value at the polysaccharide concentration of 0.35%. Besides, the sodium alginate-RMP Pickering emulsion gel had lower hardness and higher water holding capacity and elasticity than carrageenan-RMP gel, in the range of polysaccharide concentration from 0.35% to 0.50%. Infrared spectrum analysis showed that, with the increase of polysaccharide concentration, the content of β-folded of the RMP Pickering emulsion gel stabilized by the two polysaccharides increased first and then decreased, and the secondary structure of proteins changed from disordered to ordered. When both concentration of polysaccharides were 0.35%, the β-folded content reached the maximum (carrageenan group: 30.34%±0.04%, sodium alginate group: 29.70%±0.12%). According to analysis of macro and micro structures and gel force, hydrophobic interaction and disulfide bond both played a role in maintaining gel structure of carrageenan- and sodium alginate-RMP Pickering emulsion gel. In conclusion, when the final concentrations of carrageenan and sodium alginate were both 0.35%, the polysaccharides-RMP-Pickering emulsion system could be distributed more evenly, and aggregation was not easy to occur, and the emulsion gel with good texture characteristics could be further formed.