Encapsulation of probiotics in protein-polysaccharide complex coacervates has been proven to be as an effective method for improving the viability of probiotics during human digestion. In recent years, plant protein gains popularity for number of reasons such as affordable price, sustainable protein sources. As such, the main purpose of this study was to investigate the impact of different protein sources (animal <i>vs</i> plant) and drying methods on physicochemical properties and the viability of encapsulated probiotics <i>Lactobacillus rhamnosus</i> GG (LGG) in simulated sequential gastrointestinal (GI) digestion. Casein sodium salt (CS) and pea protein isolate (PPI) were selected to represent the animal and plant protein source, respectively. Complex coacervates was formed between CS, or PPI to sugar beet pectin (SBP) at ratios (5:1 and 2:1) under pH 3, and subsequently probiotics contained liquid coacervates was dried by two drying methods, spray-dry and freeze-dry. According to the state diagram, ζ–potential and viscoelastic measurements, complex coacervates were successfully formed at tested conditions and the Fourier transform infrared (FTIR) results confirmed the formation of non-covalent bonds between proteins and SBP. In terms of impacts of drying processing on particle size of probiotics encapsulated powders, the spray-dried CS-SBP samples tended to form bigger particles than that of PPI, and as the SBP ratio increased, the particle size increased as well. With respect to the protective effects of the coacervates on the encapsulated LGG, the spray-dry process turned the coacervates into spherical particles with smooth and intact surface which seemed to favor the protection of LGG, compared to the extreme porous and weak structure formed through freeze-dry process. Moreover, the drastic loss of viable cells (~2 Log CFU/g) in CS-SBP samples in the first hour of intestinal digestion indicated that the protein source played an important role on the protective effects by means of complex coacervates.

Protein-polysaccharide complex coacervates improve the viability of encapsulated probiotics during simulated sequential gastrointestinal digestion: Effect of protein source, protein to polysaccharide ratio and drying method

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.