2.3. Preparation of oleogels and emulgels
Oleogel preparation followed parameters set forth elsewhere with
modifications (Willett & Akoh, 2019). Oleogels were developed in
triplicate by dissolving either monolaurin or MAG/DAG in 10 g of algal
oil at 90 °C. Oleogels were prepared with concentrations of 8, 10, or
12% gelator (w/w). Gel mixtures were stirred constantly for 10 min
until fully dissolved and then transferred to Ace Glass vials purchased
from VWR™ (Radnor, PA, USA). Samples were flushed with
nitrogen using an Organomation 12-position N-EVAP (Organomation
Associates, Inc., Berlin, MA, USA) and placed at 4 °C to develop the gel
network and to store for further analysis. All oleogel treatments were
prepared in triplicate.
Emulgels were prepared by first developing emulsions following steps
from previous studies (Hyatt, Zhang, & Akoh, 2021). Emulsions were made
in bulk using a U.S. Solid 600W Ultrasonic homogenizer (U.S. Solid,
Cleveland, OH, USA) with a 13 mm probe for 10 min with a 3 sec on/off
pulse method at 80% power. Temperature was controlled using a
Cole-Parmer® Polystat® digital
refrigerated circulating water bath (Cole-Parmer, Vernon Hills, IL, USA)
set at 1 °C. Emulsions were made within a double-jacketed reaction
vessel to allow for a stable temperature throughout the homogenizing
process, which was monitored and kept at 1 °C (± 0.1 °C).
Once bulk O/W emulsions were developed the preparation of emulgels
followed parameters from another study with slight modifications (Chang,
Hu, Huang, Hseih, & Ting, 2020). Emulgels were developed by dissolving
either monolaurin or MAG/DAG mixture at 8, 10, and 12 % gelator (w/w)
with 10 g of emulsion. Once dissolved, emulgel mixtures were then placed
in the same type of glass vials as oleogels and flushed with nitrogen in
the same manner as oleogels. Mixtures were then stored at 4 °C to set
the gel and to store for further analysis. All emulgel treatments were
prepared in triplicate.