The effects of different mass fractions of L-arginine (0.0%, 0.5%, 1.0%, and 1.5%) on the emulsifying characteristics of pork sarcoplasmic protein were studied. The findings indicated that addition of L-arginine (≥ 1%) significantly enhanced the emulsifying activity and emulsion stability of sarcoplasmic protein (P < 0.05) and decreased the particle size (D_4,3, D₅₀, and D₉₀) of sarcoplasmic protein-stabilized emulsion (P < 0.05). The Turbiscan stability index (TSI) decreased after addition of L-arginine. The results of interfacial rheology showed that L-arginine increased the oil-water interfacial tension. The results of surface hydrophobicity and ultraviolet (UV) absorption spectroscopy implied that L-arginine promoted the exposure of protein hydrophobic groups (tryptophan and tyrosine residues). Raman spectroscopy showed that L-arginine was beneficial for the secondary structure transformation of sarcoplasmic protein from α-helix to β-turn. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the basic composition of sarcoplasmic protein was not affected by L-arginine. In summary, L-arginine could significantly improve the emulsifying properties of sarcoplasmic protein by changing emulsion physicochemical properties, protein interfacial characteristics, and protein secondary and tertiary structures.

The differences in physicochemical properties of oat, pea and apple dietary fibers and the effects of their addition on gel properties of low-salt (1% NaCl, m/m) chicken breast surimi were studied. The results showed that the water-holding capacity and swelling power of the three dietary fibers in descending order were pea dietary fiber > apple dietary fiber > oat dietary fiber. The addition of each of these dietary fibers could significantly improve the cooking yield, hardness and chewiness of low-salt chicken breast surimi (P < 0.05), and the effect of pea and apple dietary fibers was more pronounced than that of oat dietary fiber. All the dietary fibers could increase the storage modulus (Gʹ), shorten the transverse relaxation time of free water (T₂₂), increase the relative contents of weakly bound water (P_2b) and immobilized water (P₂₁) in the gel, and promote the formation of a compact and dense three-dimensional network structure. Pea dietary fiber significantly increased the relative content of β-sheet structure (P < 0.05), whereas apple and oat dietary fibers significantly increased the relative content of β-turn (P < 0.05). In conclusion, oat, pea and apple dietary fibers can significantly improve the water-holding capacity and texture properties of low-salt chicken breast surimi gel by changing the rheological properties, water mobility and distribution, microstructure and protein secondary structure.

The effect of combined treatment of different mass fractions (0.25%, 0.5%, 0.75% and 1.0%) L-lysine and 0.5%transglutaminase (TGase) on the water-holding capacity (WHC), texture, water mobility and distribution, microstructure and protein conformation of low-salt chicken meat batter (LCMB) gels was studied. The results showed that TGase alone had no significant effect on the WHC (P > 0.05), but significantly increased the hardness of LCMB gels (P < 0.05). In the presence of TGase, the hardness, springiness, cohesiveness and chewiness of LCMB gels showed an increasing trend with increased content L-lysine. The results of low-field nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and Raman spectroscopy indicated that L-lysine combined with TGase could increase the relative content of immobilized water (P₂₁) and decrease the relative content of free water (P₂₂) in LCMB gels, promote the formation of a three-dimensional ordered, compact and continuous gel network structure, and enhance the exposure of tryptophan, tyrosine and aliphatic amino acid residues in meat proteins. In conclusion, L-lysine combined with TGase treatment can improve the gel quality of LCMB by affecting its water distribution, microstructure and protein conformation.