Fundamental understanding of the role of gelatin in stabilizing milk protein systems during acidification
Zhihua Pang, Yuwan Luo, Peipei Ma, Cunshe Chen, Xinqi Liu
Abstract
The effect of two types of gelatin (A &B) on the stability of the dispersions with 1% milk proteins during acidification was studied. A dramatically different effect was observed with gelatin concentration from 0.1% to 1%. Gelatin B showed no significant effect on the zeta potential of the dispersions, while gelatin A changed the zeta potential from negative to positive with an increase in concentration. From the microrheology results, gelatin B showed little effect on elasticity index (EI), except that the samples containing higher concentrations led to slight decrease in EI values due to the steric inference. Conversely, gelatin A showed greater influence on EI, and the effect was more significant at low concentrations than high concentrations. Both static and dynamic light scattering (SLS & DLS) showed that low concentrations of gelatin A induced faster aggregation of milk proteins, while both types of gelatin showed stabilizing effect at high concentrations. CD spectra indicated that the gelatin/casein interaction could be the major attribute for the different effects of two types of gelatin on milk proteins.