Effect of sodium caseinate and xanthan gum biopolymers concentration on oleogel production capability based on oil-in-water emulsion system

Food industry researchers are looking for suitable alternatives for solid fat to reduce the adverse effects of saturated, hydrogenated and trans fats, including a new method called "oleogel". One of the oleogel production approaches is emulsion preparation. Therefore, the purpose of this study was to prepare an oleogel by emulsion production using sodium caseinate (emulsifier) and xanthan gum (thickening agent) biopolymers. To investigate the possibility of producing oleogel in this way, first emulsions with different concentration of sodium caseinate (2% and 4%) and xanthan gum (0.2% and 0.4%) with vegetable oil (60% wt / wt) were prepared then the particle size, zeta potential, microscopic images and rheological properties (viscosity, loss and storage modulus) of the samples were studied. Based on the results, increasing sodium caseinate concentration significantly reduced droplet size but the effect of xanthan gum concentration on the mentioned parameter was insignificant, therefore the droplet size in the CX44 sample reduce to 13.75 microns (P>0.05). The results of rheological tests showed that the storage modulus was higher than the loss modulus, indicating strong gel formation for the oleogel production with a desirable texture. Oleogel was then prepared using freeze drier. The results of the hardness of the dried samples and oil loss in the respective oleogels showed a significant effect of the two biopolymers concentration in which with increased biopolymers concentration hardness of dried products improved and the oil loss decreased where the hardness and the oil loss of the sample containing the highest concentration of two biopolymers (CX44) reached to 18.22 N and 0.162%, respectively. Therefore, the emulsion preparation method is a suitable approach for oleogel production with desirable properties for the replacement of high saturated and trans fat products which can guarantee public health.