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

LOBO, RENÉ EMANUEL; GÓMEZ, MARÍA INÉS; FONT DE VALDEZ, GRACIELA; TORINO, MARÍA INÉS

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Año: 2019

0268-005X

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.