Rheological properties of whey protein and dextran conjugates at different reaction times

SPOTTI MARÍA J.; MARTINEZ MARÍA J.; PILOSOF ANA M.R.; CANDIOTI MARIO C.; RUBIOLO AMELIA C.; CARRARA CARLOS R.

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2014 vol. 38 p. 76 - 84

0268-005X

Protein/polysaccharide conjugates have been widely studied because of their good emulsifying properties and their potential use as food ingredients. However, there is little information about the use of these conjugates in gel systems. Rheological properties of conjugates of whey protein isolate (WPI) and dextran (DX) of 15 kDa obtained by Maillard reaction (RM) at different incubation times (2, 5 and 9 days) were studied. Conjugation was confirmed by electrophoresis, conformational changes were studied by DSC and rheological properties were determined in oscillatory rheometer with temperature ramp (25 to 90 °C). After each rheological measure, a mechanical spectrum from 0.01 to 10 Hz was also obtained. Electrophoresis indicated the presence of WPI/DX conjugates for all incubation days, although their molecular weight could not be determined. Both time and temperature of gelation (G´-G´´ crossover) increased in WPI/DX conjugate systems compared with WPI without DX (same time of incubation). However, these parameters were decreased in WPI/DX mixed system. G´ values at 25 ° C decreased in WPI/DX conjugates and increase in WPI/DX mixed system, with respect to WPI alone. Frequency sweeps shown that all gels were stable.