Partially removing galactose unit on tamarind gum improves the gel-related features of tamarind gum/xanthan gels by strengthening their synergistic assembly

Abstract

The amalgamation of tamarind gum (TMG) and xanthan generates synergistic interaction gels (SIGs), which have been used to design novel textural systems and to develop cell-cultured meat as well as health foods tailored for elderly individuals with dysphagia. However, the strong aggregated tendency of TMG chains limited the expose of active sites, thereby hindering full binding with xanthan and resulting in suboptimal gel properties. This study demonstrated that the removal of galactose units from TMG enhances specific interactions between TMG and xanthan by modulating the aggregation behavior of TMG chains. After removing galactose to 71.30 %, the reduced steric hindrance facilitated the transformation of disordered TMG chains into a helical structure, thereby exposing more binding sites (i.e., hydrophilic groups) to interact with pyruvate groups on xanthan. This enhanced the specific interactions, as evidenced by an increase in enthalpy change from 2.80 × 10⁻² J/g to 3.90 × 10⁻² J/g, and thus the gel structure (suggested by the increased n and reduced ${\xi }_{chain}$ values in Table 1) and gel strength both in G′ and gel hardness. However, further removal of galactose reduced the dissociation ability of TMG chains from clusters and resulted in the formation of elongated clusters, thereby decreasing the contact surface between TMG and xanthan, which weakened their specific interactions and gel strength. These results provide insights for the design and development of SIG-based systems in food industry.