Physicochemical and antioxidant properties of a gastroprotective exopolysaccharide produced by Streptococcus thermophilus CRL1190

• Published in: Food hydrocolloids Vol. 96; pp. 625 - 633
• Main Authors: Lobo, René Emanuel, Gómez, María Inés, Font de Valdez, Graciela, Torino, María Inés
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2019
• Subjects: Exopolysaccharides (EPS); Microstructure; Streptococcus thermophilus CRL1190; Technological properties; Thermal behavior; Water and oil performance; Exopolysaccharides (EPS); Streptococcus thermophilus CRL1190; Technological properties; Water and oil performance; Microstructure; Thermal behavior
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2019.05.036

The exopolysaccharide EPS1190 was isolated with high purity from skim milk fermented by the strain Streptococcus thermophilus CRL1190, the major EPS amount being recovered at stationary growth-phase (70.7 mg/L after 16 h). This polymer revealed moderate antioxidant activity in vitro and useful technological properties such as good emulsifying and flocculating capacity at low concentrations, high aqueous solubility (9.1 mg/mL), water and oil holding capacity (528.5% and 1266%, respectively) as well as thermal behavior. Thermogravimetric, Differential Thermal Analysis and Differential Scanning Calorimetry curves showed that the biopolymer was thermally stable up to 216 °C with a crystalline deformation in an endothermic process (△H = 284.46 J) at a melting temperature of 74.08 °C. Furthermore, a degradation temperature (Td) of 295.4 °C was observed. These results postulate that EPS1190 could be used in the food industry due to its special micro-structure (scanning electron microscopy of EPS1190 demonstrated a homogeneous matrix with micro-porous and rough structure), its good performance and functionality in both aqueous and oil systems, which would remain at high temperatures. [Display omitted] •EPS1190 has functional and technological properties, useful in food processes.•Dried EPS1190 preparation showed homogeneous matrix with micro-porous and rough structure.•EPS1190 presented good solubility, flocculating, water and oil holding capacity.•EPS1190 remained thermally stable up to 215 °C with melting temperature of 74.08 °C.