Abstract: Oat β-glucan (OG) was used to replace salt in mutton mince at levels of 0%, 0.4%, 0.8%, 1.2% and 1.6%. To determine the appropriate level of OG replacement, the cooking loss, water-holding capacity (WHC), water distribution and content, color, gel strength, texture, secondary structure of myofibrillar protein, scanning electron micrograph (SEM) of mince samples with 2.0% salt, 0.4% OG + 1.6% salt, 0.8% OG + 1.2% salt, 1.2% OG + 0.8% salt and 1.6% OG + 0.4% salt were measured. The results showed that with increasing level of OG replacement, the cooking loss of mutton mince gels decreased first and then increased gradually, while the WHC showed the opposite trend. A significant decrease in the WHC was observed when 1.6% OG was added (P < 0.05). Low-field nuclear magnetic resonance (NMR) analysis indicated that high levels of OG replacement caused the transformation of weakly bound and free water into immobilized water in the gels. The brightness (L*) and whiteness of the gels increased gradually (P < 0.05), and the transverse cross-section showed an obvious white color. The rupture force and rupture distance of the gel with 0.4% OG replacement were good, indicating improved gel strength. High levels of OG replacement were unfavorable to the gel strength. The gel hardness, cohesiveness, chewiness and resilience significantly decreased at a substitution level of 0.8% (P < 0.05), and the gel elasticity showed a similar trend but with no significant difference between them (P > 0.05). The secondary structure of myofibrillar protein in the gel with high levels of OG replacement (> 0.8%) was similar to that in the control (P > 0.05), and the SEM image showed more loose structure with increased porosity. Through correlation analysis and principal component analysis (PCA), it was found that the synthetic score of the gel with 0.4% OG was higher than that of the other groups, which could ensure further reduction of salt intake while maintaining the gel quality of mutton mince.

Key words: oat β-glucan; low salt; mince gel; gel properties; principal component analysis