Investigation of surface properties of quince seed extract and assessment of its performance as a novel polymeric surfactant

Kırtıl, Emrah
The use of sustainable ingredients from natural sources has shown an increase in recent years. For stabilization of dispersions, proteins and polysaccharides are increasingly being used in combination for their synergistic properties. Various studies have focused on developing biopolymers that merge the functions of proteins and polysaccharides in a single molecule. Quince seed extract (QSE) is a natural biopolymer that display this exceptional attribute in its native state. However, the literature is still lacking in demonstrating its potential as a natural stabilizer through analysis of the extract's interfacial properties. This dissertation has two main objectives; to assess the performance of QSE as an emulsion stabilizer and to examine its air-water and oil-water interfacial properties. Quince seed extract provided a similar stability to emulsions compared to same concentrations of Xanthan gum but at smaller apperant viscosities. Overall, QSE concentrations >0.3 w/v yielded physically stable emulsions even after 5 months. QSE was effective in lowering surface tension at an air-water interface even at concentrations as low as 0.025 % w/v (reduction of eq. ST from 72 mN/m to 58.9 mN/m). By QSE addition alone equilibrium surface tension could be lowered to ~36 mN/m, which is lower than the lowest ST that can be achieved with many other surface active biopolymers. Critical aggregation concentration (CAC) was identified as 0.165 % w/v,. In addition to these findings, the study; provides the possibility of obtaining more information on the processes happening during adsorption and describing their mechanism with established theories.
Citation Formats
E. Kırtıl, “Investigation of surface properties of quince seed extract and assessment of its performance as a novel polymeric surfactant,” Ph.D. - Doctoral Program, Middle East Technical University, 2020.