Inhibition mechanisms of xanthan gum on high-dose gallic acid-induced functional deterioration of myofibrillar protein: Focusing on gelling and emulsification behaviors.

For purpose of overcoming the negative impact of high-dose phenols on meat quality, xanthan gum (XG), a natural anionic polysaccharide, was employed to prevent the undesirable interaction between myofibrillar protein (MP) and gallic acid (GA, 150 μmol/g) and ameliorate the gel and emulsification characteristics of MP. XG dose-dependently alleviated the structural damage of MP caused by GA and reduced protein aggregation, manifested as the decrease in surface hydrophobicity, turbidity and aggregate size (p < 0.05) and increase in α-helix content and intrinsic fluorescence. As a result, more proteins participated in establishing an ordered cross-linked network, favoring the entrapment of immobilized water and imparting the gel with improved rheological properties and gel strength (from 2.2 N·mm to 3.1-5.5 N·mm) and a decreased cooking loss (from 13.6 % to 3.2 %-7.7 %). In addition, the presence of XG reduced oil-water interfacial tension of MP, promoting uniform distribution of emulsion droplets in a smaller size. The emulsifying activity and stability increased from 6.5 m/g to 8.1-8.4 m/g, and 41.5 % to 81.2 %-93.2 %, respectively, and the creaming index decreased from 52 % to 0 %-24 %. The multiple light scattering and microrheology results further demonstrated the enhancement of emulsion stability. The competition mechanism of XG, along with its hydrophilicity, electronegativity and viscosity, collectively contributed to the improvement of gel and emulsion quality. Our paper exploited the potential of dual application of polysaccharides and polyphenols in meat products for simultaneously reducing protein oxidation and quality deterioration.