Preparation and Sustained Release Behavior of Cinnamon Essential Oil/ Sodium Alginate/Bentonite Composite Gel Microspheres

Used sodium alginate/bentonite (SA/BT) blend modified composite as a carrier, gel microspheres loaded with cinnamon essential oil were prepared by extruded exogenous gel method. Then factors influencing the encapsulation rate of gel microspheres were investigated, including sodium alginate concentration, bentonite addition, ratio of cinnamon essential oil to carrier, CaCl₂ concentration, tween-80 concentration. At the same time, the preparation process was optimized. Then, gel microspheres were released at different temperatures and humidity, and the release curves of cinnamon essential oil were fitted with Zero-order, First-order, Ritger-peppas, Hixson-crowell and other kinetic models. The experimental results showed that the optimal preparation conditions were sodium alginate concentration of 2%, bentonite content of 1.1%, cinnamon essential oil to carrier ratio of 2.1:1, CaCl₂ concentration of 1.5%, tween-80 concentration of 0.2%, and encapsulation rate of up to 80.74%. At different temperatures (25, 40, 60, 80℃) and relative humidity (55%, 75%, 90%), the release rate of cinnamon essential oil by sodium alginate/bentonite composite gel microspheres was lower than that by single alginate gel microspheres. Meanwhile, it was found that Ritger-Peppas kinetic model was more consistent with the release law of cinnamon essential oil under different conditions. The results would provide a certain theoretical basis for the wider application of cinnamon essential oil and improve its application value.