Sodium Caseinate/Sunflower Oil Emulsion-Based Gels for Structuring Food

JUAN M. MONTES DE OCA AVALOS; ROBERTO J. CANDAL; MARIA LIDIA HERRERA; CRISTIÁN HUCK IRIART

FOOD AND BIOPROCESS TECHNOLOGY

SPRINGER

Lugar: Berlin; Año: 2016 vol. 9 p. 981 - 992

1935-5130

Protein gels have attired attention since they allowstructuring foods with no trans or saturated fats. The effects ofprotein concentration and sucrose addition on gelation kineticsand on physical properties of sodium caseinate (NaCas)/sunflower oil emulsion-based gels were studied by twomethods: a new application of backscattering of light (BS)using a Turbiscan equipment and by dynamic oscillatory rheology.Structure of gels was also described by confocal laserscanning microscopy (CLSM) and small angle X-ray scattering(SAXS). Tgel values decreased with increasing sucrose orNaCas concentration. BS method sensed early changes instructure, while rheological measurements were less sensitiveto those changes. However, tendencies found by rheological measurements were the same as the ones found by BS experiments.CLSM images of gels formed from emulsions containinghigh sucrose and protein concentrations had big oildroplets that were not present in initial emulsions. Gels withsucrose concentrations between 15 and 30 wt/wt% releasedoil. SAXS patterns showed that NaCas nanoaggregate sizes inthe aqueous phase were smaller with increasing sucrose concentration.Polar groups of protein interacted with sucrose,and therefore, interactions among protein molecules diminished.As a result of weaker protein molecule interactions,nanoaggregates were smaller. However, this effect was beneficial.In the macroscale, rheological properties and visual appearanceof gels were improved. The gel formulated with5 wt/wt% NaCas and 10 wt/wt%sucrose had a smooth surfaceand was stable to syneresis and oil release. This formulationwas a good alternative to trans fat.