Effect of sodium alginate with three molecular weight forms on the water holding capacity of chicken breast myosin gel

•SA with three molecular weight forms increased the WHC of myosin-SA gels.•The stronger inter-molecular interactions and the network lead to a higher WHC.•It is interesting to select high-efficiently SA for developing low-fat meat products. The effect of 0.1–0.5% (w/w) sodium-alginate (SA) with three molecular-weights (2660, 3890 and 4640kDa) on the water-holding capacity (WHC) of chicken-breast myosin gels was investigated. The results showed that 0.1–0.5% SA of three molecular-weights increased the WHC of myosin-SA gels, and the heavier SA induced a higher WHC. Electrostatic-interactions and hydrogen-bonding contributed to the intermolecular aggregation in the myosin-SA system and enhanced its intermolecular interactions by overcoming the steric hindrance effect of SA with heavier molecules. This aggregation induced the increased turbidity, transition temperature and the decreased surface hydrophobicity of myosin-SA solutions and the formation of an inhomogeneous network with large cavities for entrapping water. The combined effects of stronger intermolecular interactions and the network induced a higher WHC of the gel with heavier SA. It is interesting to understand the gelling mechanism for the protein-polysaccharide system and to efficiently select SA for developing low-fat meat products in industry.