Abstract:
Sunflower meal represents a by-product massively obtained after the extraction of oil from
sunflower seeds. With its relatively low price, high protein content, and optimal amino acid
composition it can be potentially suitable as an emulsifying agent. Thus, the aim of this study
was to investigate the influence of the addition of the sunflower meal on the stability of oil-inwater
emulsions. Five sunflower meal fractions, each with different protein content (16.78,
23.23, 29.67, 36.12, and 42.56%) were obtained and used in stabilization of 10% oil/water
emulsions. The obtained emulsions were analyzed, where responsive variables were:
creaming index, droplet size and droplet size distribution, and zeta potential. Creaming of
investigated emulsions was monitored visually for seven days and the creaming index was
calculated. Droplet size and droplet size distribution were measured using the laser light
scattering method, while zeta potential was measured by using Zetasizer Nano ZS. Results
indicated higher physical stability of the emulsions stabilized using the sunflower meal
fractions with higher protein content. The creaming index decreased with an increase in
protein content whereas emulsion with a protein content of 42.56%, after seven days, had the
lowest creaming index of 58%. The obtained emulsion droplet D4.3 diameter ranged from
238.61 (sunflower meal fraction with lowest protein content) to 86.7 sunflower meal
fraction with highest protein content), while higher protein content contributed to the lower
zeta potential values of observed emulsions. Zeta potential of emulsion obtained from
sunflower meal fraction with a protein content of 16.78% was -6,80 mV, while zeta potential
of emulsion obtained from sunflower meal fraction with a protein content of 42.56% was -
12,20 mV.
