Technological properties of the furcellaran–whey protein isolate emulgels with various evening primrose oil concentration

Effect of different evening primrose oil content (1-20 %) on the rheological, mechanical, textural and microstructure of furcellaran/whey protein isolate emulsion gels were investigated at neutral, unmodified pH environment. The results indicate that, irrespective of the concentration, the oil acted as an inactive filler and was not chemically bound in the polymer network but only physically immobilized in it. The increasing oil amount in the material from 1 to 20 % resulted in a percentage decrease in hardness (52 %), gumminess (71 %) and stress relaxation ratio (17 %) which means that presence of the hydrophobic components weakens the structure of the material, but all samples exhibit elastic behaviour. The swelling ratio values of the emulgels increased with growing oil additions. Zeta potential values of the emulsion gel solutions were not linear correlate with formulation. Colour of the material was strongly depended on the oil amount. Both whitening and yellowness index values increased with increasing fat fraction in the sample. The microstructural image shows irregular oil droplets on the matrix network.