Effect of the Hofmeister series anion salts on the ice recrystallization inhibition activity of tamarind seed polysaccharide

Tamarind seed polysaccharide (TSP) has been identified as an ice recrystallization inhibition (IRI)-active polysaccharide with potential applications in food cryoprotection. In this study, the IRI performance of TSP was investigated using the splat assay in the presence of different salts containing Hofmeister series anions (Na2SO4, NaH2PO4, NaCl, and NaNO3). The results showed that the IRI activity of TSP in different salt solutions depended on the type of ion present, in agreement with the reverse Hofmeister anion sequence: NO3- > Cl- > H2PO4- > SO42-. It was discovered that the Hofmeister series anion salts modulate the IRI activity of TSP by inducing changes in the aggregation and hydration properties of polysaccharides. In particular, TSP exhibited greater IRI activity when characterized by a lower aggregation and higher hydration degree in the presence of chaotropic ions. These findings highlight the influence of additives present in cryopreservation media and contribute to a fundamental understanding of the mechanism underlying the differential influence on the performance of IRI-active polysaccharides.