Microstructure of ethylcellulose oleogels and its relationship to mechanical properties

Publication date: Available online 7 August 2014 Source:Food Structure Author(s): Alexander K. Zetzl , Andrew J. Gravelle , Martin Kurylowicz , John Dutcher , Shai Barbut , Alejandro G. Marangoni Small deformation rheology was used at a controlled strain of 0.05% and frequency from 1 to 100Hz to obtain G′, G″, and tan(δ) values for ethylcellulose oleogels of various compositions. Significant increases in both G′ and G″ were noted in oleogels prepared with 100cP ethylcellulose as compared to 45cP, yet no significant differences in tan(δ) were observed among gels containing the same type of vegetable oil. Oleogels prepared with increasing polymer concentration showed a significant increase in G′ only when the concentration exceeded 13%. When the surfactant sorbitan monostearate was incorporated at a level of 3.33%, a significant increase in tan(δ) was seen, indicating a decrease in elasticity of these oleogels. Cryo-scanning electron microscopy was successfully utilized to image the internal polymer network of ethylcellulose oleogels, which contained small oil-filled pores of approximately 3.0–4.5μm in size lying between the interconnected polymer chains. Decreases in pore sizes were observed with increasing polymer concentration, oil unsaturation, and high levels of surfactant incorporation. No significant change in pore size was seen among gels made with different polymer viscosities, signifying an alternate mechanism for changing oleogel hardness. D...

Source: Food Structure - November 1, 2014 Category: Food Science Source Type: research