Carvacrol encapsulation system based on casein-chitosan coacervates: Stability regulation and mechanism of ultrasonication-assisted core-shell microcapsules

Carvacrol (CAR) is a naturally occurring bioactive compound that is chemically unstable, and microencapsulation technology effectively protects its active components. Casein (CS) and chitosan (CH) were used for the first time as carriers to encapsulate CAR, forming highly stable carvacrol microcapsules (CAR@CS-CH). Under conditions of a 1:1 mass ratio of CS to CH and a pH of 5.5, electrostatic interactions facilitated the formation of aggregates that served as the microcapsule wall to encapsulate CAR. The encapsulation efficiency of CAR@CS-CH was 82.98 ± 0.11 %. Ultrasound enhanced the hydrogen bonding between CAR and the microcapsule wall, reducing the average particle size of CAR@CS-CH to 4.70 μm. The endothermic peak temperature increased from 118.88 °C to 135.50 °C. and after ultrasound treatment, CAR@CS-CH demonstrated high thermal stability at 70 °C. The findings provided technical support for the development of heat-resistant functional foods and highlighted the potential for efficient carvacrol utilization.