Influence of dextran molecular weight on structural characteristics and rheological properties of whey protein/dextran Maillard conjugates

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. 39 p. 223 - 230

0268-005X

It is well known that protein/polysaccharide conjugates obtained by Maillard reaction (MR) have good emulsifying properties. However, there is little information about the use of these conjugates in gel systems. Structural characteristics and rheological properties of conjugates obtained by MR of whey protein isolate (WPI) and dextrans (DX) of various molecular weight (MW: 6, 40 and 70 kDa) were studied. Conjugation was confirmed by electrophoresis; browning intensity was measured by absorbance at 420 nm; and conformational changes were studied by fluorescence emission of tryptophan (Trp) (lex ¼ 280 nm). Rheological properties were determined by oscillatory rheometry with temperature ramp (25e90 _C). After each measure, a mechanical spectrum (at 25 _C) was obtained. The electrophoresis indicated the presence of WPI/DX conjugates in all systems. Browning intensity increased with decreasing MW of DX. Fluorescence emission of WPI incubated increased, but decreased in WPI/DX incubated systems. The gelation time (obtained by G0eG00 crossover) and G0 value at 25 _C increased in conjugate systems compared with WPI alone. Stability of gel structures were shown by frequency sweeps