Optimization of eugenol-loaded microcapsules obtained by spray drying using a simplex-centroid mixture design

Eugenol antioxidant and antibacterial properties have suggested its use as a natural preservative for food matrices. Eugenol application is compromised due to its high volatility and sensibility to external agents, such as light, heat, oxygen, and moisture. Thus, microencapsulation is viable to increase the eugenol stability. Results have showed that carrageenan combined with rice protein and bovine albumin allow high-quality eugenol microcapsules. These materials show excellent properties, favoring the microcapsules use in food matrices. This study aimed to optimize microcapsules formulation by spray drying, using a simplex-centroid mixture design. Blends of low-lactose whey protein (WP) and/or rice bran protein (RBP) and/or bovine serum albumin (BSA) with carrageenan were used as wall materials. Blends influenced the eugenol retention, microencapsulation efficiency, and size. Pure WP was not efficient for eugenol encapsulation. The highest eugenol retention values, 89.7% and 86.5% were obtained by combining carrageenan with RBP or BSA. RBP and BSA binary interaction with carrageenan showed the highest encapsulation value (80.5%). Scanning electron microscopy, infrared spectroscopy, and thermogravimetry confirmed eugenol inside the microcapsules.

Keywords:
encapsulation efficiency; bovine serum albumin; low-lactose whey protein; rice bran protein