Heteroprotein complex coacervates of soy protein isolate and type-A gelatin: Formation mechanism, structure and rheological properties

Abstract

Substitution of animal proteins by plant proteins to reduce the consumption of animal proteins is a trend in the field of food consumption. Heteroprotein complex coacervation (HPCC) as a simple and effective technique allows the combination of plant and animal proteins to form novel food materials. In the present work, soy protein isolate (SPI) and type-A gelatin (GA), which are commonly used in food proteins, were used as raw materials to explore their complex coacervation mechanism and the potential of the coacervate to be utilized as a gel. The results showed that the best complex coacervation was achieved at SPI:GA = 1:5, pH = 6.5, and that electrostatic interactions with hydrogen bonding were responsible for this process. The SPI spherical structure was encapsulated in the GA constitutive network structure, and the final polymer morphology took on a spherical-like shape. The final polymer is assembled into a weak gel with a network structure and has favorable viscoelasticity, creep recovery, and thermal stability. These properties of the SPI-GA coacervate may allow its potential use in novel materials for food.