PEA PROTEIN AND CHIA MUCILAGE EMULSION-FILLED HYDROGELS

Hydrogels are water-swollen cross-linked hydrophilic polymeric networks. They have various applications, including drug delivery, tissue engineering, and food applications. Structuring plant-based materials to mimic animal products, such as cheese and meat, is a challenge for the food industry. Achieving the sensory characteristics of animal products only with vegetable proteins is even harder. To improve the texture and elastic characteristics of plant-based analogues, a fibrous network material with good water and oil holding capacity combined with saturated oil can be interesting. This study aimed to evaluate the formation of emulsion-filled hydrogels using coconut oil and electrostatic interactions between pea protein and chia mucilage as a substitute for animal products. To evaluate these interactions, four processes were carried out. In the first test, we prepared an emulsion by adding coconut oil to a pre-homogenized pea protein solution and mixing using an Ultra-Turrax (14500 rpm, 3 min). In the second experiment, chia mucilage was mixed with the pea protein emulsion, and the pH was adjusted to 7. The third test was carried out similarly to the second test, but the pH was adjusted to 3.5 to promote electrostatic interaction between the biopolymers. For the fourth experiment we previously complexed the biopolymers before the emulsion preparation. All preparations were heated to 95 ° C for 30 minutes to promote thermal gelation and stored at 4 ° C for 10 days. The micromorphology was accessed using an optical microscope with fluorescence filters; the proteins were stained with FITC while coconut oil was stained with Nile red. Pea protein emulsions were not stable and separated into three distinct phases after 1 hour. All three other samples were stable within the 10-day storage but showed different aspects. The second experiment resulted in a homogeneous suspension with uniform oil droplets dispersed throughout the material, in this condition both the protein and the chia mucilage were negatively charged promoting the co-solubility of the biopolymers. The hydrogel formed by the combination of the polymers using the second process had large visible pores, with oil interspersed in the biopolymeric network. The fourth sample resulted in a compact hydrogel, also with oil interspersed and the polymer network. The suspension (2nd sample) showed high viscosity and stability, resembling dairy beverage. On the other hand, the hydrogels were structured and resistant to flowing, resembling cheeses like ricotta or cream cheese. Our results indicate that it is possible to obtain products with different visual aspects similar to dairy products with chia mucilage and pea protein only by changing processing conditions.