Micro/nanoparticles obtention due to thermodynamic incompatibility between food grade biopolymers.

NIELSEN NS; BEA L; VEYÑ M; INGRASSIA R; RISSO P; HIDALGO ME

Capital Federal

Jornada; XX ANNUAL MEETING OF THE ARGENTINEAN BIOLOGY SOCIETY (SAB) XVII MEETING OF THE URUGUAYAN SOCIETY OF BIOSCIENCES (SUB); 2018

Sociedad Argentina de Biología (SAB)

Foods contain proteins (PT) and polysaccharides (PS) in form of complex multicomponent mixtures, and so it is often difficult todisentangle the separate roles of the biopolymers in terms of their functional properties, responsible for the structure, mechanical,textural, and other physicochemical properties. These functional properties are affected by the interaction between biopolymers andother components of food systems. Therefore, the study of the interactions in PT-PS mixtures and their adequate formulation maycontribute to the elaboration of food products with special microstructure, rheological, and textural characteristics. Segregative phaseseparation by thermodynamic incompatibility is commonly observed in ionic and nonionic biopolymer mixtures. At low biopolymerconcentrations, the mixture remains a single phase. However, above a critical concentration ratio, PT-PS mixtures form a system withtwo separated phases, in which each phase is enriched in one of the biopolymers. The limited thermodynamic compatibility betweenPT and PS may be exploited to obtain micro/nanoparticles, by controlling the size of the aggregates (e.g. by selecting the PS, thetemperature, and the relative concentrations of PT and PS). On the other hand, a process that has gained the attention of the foodindustry is the acidification of milk by addition of glucono- -lactone (GDL). It is known that the gelation process rate affects thehardness and elasticity of the resulting acid gels. In PT-PS mixtures, the presence of PS may produce changes in the protein gelformation kinetics, leading to the formation of gels with different microstructural and textural characteristics. This behavior may bedue to the competition between the gelation process and the phase micro-separation generated by thermodynamic incompatibility. Inthis work, PT and PS assayed were bovine sodium caseinate (NaCAS) and soy protein isolate (SPI), and locust bean gum (LBG) andtara gum (TG), respectively. For each PT-PS mixture, thermodynamic incompatibility was analyzed. Besides, the effect of thepresence of PS on the PT acid gels formation, the textural and the microstructure characteristics of acid gels were studied. In general,the presence of PS affected the formation and the microstructure of protein acid gels and, at a certain ratio of concentrations, proteinmicroparticles were obtained. These microparticles may be formed due to a competition between the kinetics of phase separation andthe acid gelation process. Under these conditions, these acid gels present different microstructural and textural characteristics.