Comunicaciones orales


Daniela Igartúa1, Gonzalo Palazolo1, Dario Marcelino Cabezas1.

1Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos (LIFTA - UNQ) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Argentina. email:

Background and aim. The food industry has grown steeply in recent years, especially in the development of vitamin-enriched foods. However, these vitamins must be incorporated into nanosystems that protect them from food processing and storage conditions. The protein-polysaccharide complexes are effective for this purpose. Therefore, this work aims to optimize the electrostatic complexation of whey protein isolate (WPI) and soluble soybean polysaccharide (SSPS) to obtain nanosystems capable of encapsulating and stabilizing vitamins in beverages.

Methods. Proteins and polysaccharides were combined in different WPI:SSPS ratios (1:1 to 1:0.1), pH (6.5 to 2.0), and salt-added (0-100 mM NaCl) conditions. The dispersions were monitored through optical density, Z-potential, and phase diagrams.

Results. SSPS presented negative net charges and resulted in stable translucent dispersions throughout the pH and salt-added conditions. WPI precipitated in pH close to pI (pH=4.25). WPI and SSPS could form electrostatic complexes at a pH lower than 4.25, where proteins have a positive net charge. Due to the WPI-SSPS interactions, no precipitation was observed in any sample, which demonstrated that SSPS increased the stability and dispersibility of WPI. Furthermore, as the amount of SSPS increased, a wider pH range for complex formation was observed. As the salt-added concentration increased, greater turbidity was observed in the dispersions, which may be due to the formation of larger complexes.

Conclusions. WPI and SSPS formed electrostatic complexes at pH 3.0-4.0, for all WPI:SSPS ratio and salt-added conditions. Due to the amphiphilic character of proteins and polysaccharides, both biopolymers would interact with both hydrophobic and hydrophilic vitamins. The protein-polysaccharide complexes would also stabilize them in the food matrix and release them in a controlled manner in the gastrointestinal tract. The optimized WPI-SSPS nanocomplexes are expected to encapsulate and stabilize folic acid in a functional beverage.

Keywords: proteins; polysaccharides; electrostatic complexes.