ABSTRACT
The aim of this work was to obtain chitosan nanoparticles (<1000 nm) with chincho (Tagetes elliptica Sp.) essential oil (CEO-CSNPs) using the ionic gelation method. A Box−Behnken design (BBD) was applied, using chitosan solution (CS) pH (4.0, 4.4, 4.8); the mass ratio of CS/CEO (1:0.7, 1:0.85, 1:1.0) and the mass ratio of CS/CS-tripolyphosphate (1:0.46, 1:0.58, 1:0.7) as independent variables. The formulation-dependent variables, encapsulation efficiency (EE) and loading capacity (LC) of the CEO-CSNPs were evaluated. BBD determined that optimal conditions for CEO-CSNPs were pH: 4.4, CS/CEO mass ratio 1:0.7 and CS/TPP mass ratio 1:0.46. Once the optimization was defined, particle size (PS), zeta potential (ZP), polydispersity index (PDI), CEO-CSNPs morphological studies, in vitro CEO release, and antibacterial activity were determined. The CEO-CSNPs showed an EE of 52.64% and a LC of 11.56%, with a diameter of 458.5 nm, with a ZP of 23.30mV, and a PDI of 0.418. The SEM studies showed that the nanoparticles were rounded and had uniform shapes. In addition, CEO-CSNPs showed a minimum inhibitory concentration against Staphylococcus aureus, Salmonella infantis and Escherichia coli of 5.29, 10.57 and 10.57 µg/mL, respectively. These results could be very useful for the stabilization of chincho essential oil for food industry purposes. However, several studies about the release, as well as interaction with food matrices, will be necessary.
ABSTRACT
BACKGROUND: Betalains are presently gaining popularity as pigments for use as natural colorants and/or bioactive compounds in functional foods. Quinoa (Chenopodium quinoa Willd.) has been recognized as an extremely nutritious grain and has recently been found to be a novel and good betalain source. Microencapsulation has been studied as a protected-delivery procedure to stabilize betalains. There are no studies about microencapsulation of betacyanins extracted from quinoa using spray-drying technology. RESULTS: Optimal microencapsulation was obtained at a drying temperature of 165 °C, a rotameter air flow rate of 47 mm (940 L h-1 ) and 10% w/w maltodextrin, which produced good encapsulation yield (58.1%) and efficiency (100%). Optimized maltodextrin-betacyanin microcapsules (diameter 4.4 µm) have low moisture (1.64 ± 0.08%) and water activity (0.127 ± 0.006), a betacyanin content of 0.1995 ± 0.0017 g kg-1 and saponin content <0.080 mg kg-1 . The oxygen consumption rate by betacyanin was -4.373 × 10-5 bar min-1 at 80 °C and -6.67 × 10-5 bar min-1 at 90 °C, which was accompanied by fading of the color. CONCLUSION: Microencapsulated betacyanin was optimized by response surface methodology, and its stability was measured under accelerated conditions by oxygen consumption. Microencapsulations contain betacyanin and low saponin concentration, which might confer unique health-promoting properties. © 2018 Society of Chemical Industry.
