The effect of processing parameters on microencapsulation of oregano essential with maltodextrin:gum arabic using a disk atomiser spray-dryer was evaluated. By means of response surface methodology, the feed flow rate and inlet air temperature were optimised. Powder yield, moisture content, essential oil retention, and antioxidant activity of microparticles were evaluated. The best conditions to produce microencapsulated oregano essential oil were 0.6 L h−1 for feed flow rate and 200 °C for inlet air temperature. With this combination a microencapsulated powder with 89.8% powder yield, 2.1% moisture content, 92.1% essential oil retention, 76 s solubilisation time, 12.9 g of water/100 g of dry matter, 0.3371 g mL−1 bulk density, 0.5826 g mL−1 tapped density, and 8.2 μm of average particle size was produced. The microencapsulation of oregano essential oil preserves the antioxidant and antimicrobial activities of its bioactive compounds.

This work aimed to evaluate the influence of the addition of microencapsulated oregano (Origanum vulgare L.) essential oil as a natural antioxidant in the stability of mayonnaise. Three formulations were developed with microencapsulated oregano essential oil at different concentrations (0.0, 0.26, and 0.44%). Mayonnaises were packed and stored at 35, 45, and 55 ºC until their deterioration. During the accelerated storage, the titratable acidity and peroxide index were determined. The peroxide index was subjected to linear regression analysis as a function of time. The parameters of the Arrhenius model (k and Ea) for the variation of the peroxide index and the temperature acceleration factor (Q10) were also determined. Some physical and chemical indicators were determined for the mayonnaise selected according to its greater stability during the accelerated storage. Mayonnaise with 0.44% microencapsulated oregano essential oil presented the highest stability during accelerated storage in terms of delaying the increase in the peroxide index, as an indicator of the deterioration of this type of product. The addition of the microencapsulated essential oil did not affect (p > 0.05) the sensory attributes of the product, although the judges reported its influence on the typical odor and flavor, compared to the control mayonnaise. The variation of the peroxide index during the accelerated storage was adjusted, in all cases, to a zero-order reaction. Linear models were obtained to estimate the shelf life of mayonnaise for each treatment.