Stabilization of milk–orange juice mixture using Persian gum: Efficiency and mechanism

•Stabilizing capability of Persian gum (PG), a natural biopolymer, was confirmed.•The possible stabilization mechanism of PG was elucidated.•Effect of PG on the rheology of milk–orange juice mixture investigated.•The potential applicability of PG in dairy based drinks was introduced.

Acidified milk drinks, including milk–orange juice mixture, suffer from serum separation because of low pH (<4.6). Therefore, in the present study, the efficiency and mechanism of Persian gum (PG), its soluble (SFPG) and insoluble (IFPG) fractions and a mixture of SFPG and soluble fraction of gum tragacanth (SFGT) on stabilization were investigated. PG, SFPG, and SFPG:SFGT effectively prevented serum separation at concentrations of 2.20, 1.00 and 0.37% (80:20), respectively. The best fitted model for stabilized mixtures was Power law and dominant behaviors at low and high frequencies were viscous and elastic, respectively. PG and SFPG considerably changed the zeta potentials. It can be hypothesized that SFPG is a type of adsorbing hydrocolloids that adsorbs onto caseins and induces stabilization via electrostatic and steric repulsions. SFPG and SFGT are highly compatible adsorbing hydrocolloids where the presence of the latter can improve the effectiveness of the former one.