The Impact of Esterification Degree and Source of Pectins on Complex Coacervation as a Tool to Mask the Bitterness of Potato Protein Isolates

There is an increasing interest in the food industry to use potato protein as an alternative plant protein. However, its bitter taste often limits the utilization in novel foods and beverages. Coacervation is a promising technique to mask bitterness of certain food compounds. In the present study, we aimed to reduce the degree of bitterness of potato protein by generating protein-pectin complexes based on coacervation. Potato protein isolate and pectins derived from various origins having different degree of esterification (DE) were initially mixed under acidic conditions to promote the formation of complexes. Single and complex biopolymers were then characterized in terms of surface charge, solubility, rheological and sensorial properties as a function of protein pectin ratio, pectin source, and the degree of esterification, respectively. The protein-pectin ratio and degree of esterification of pectins substantially influenced the interaction behaviour and phase separation of the protein-pectin mixtures. The bitterness score decreased with increasing surface charge and pectin concentration. Bitterness was strongly reduced for complexes formed with high DE citrus pectin at a protein pectin ratio 0.33. The complexes generated at this ratio were relatively stable based on visual observation and microscopic images. Our results might have significant implications for the utilization of potato proteins in beverage applications.