Optimizing encapsulation of black carrot extract using complex coacervation technique: Maximizing the bioaccessibility and release kinetics in different food matrixes

The encapsulation of bioactive compounds at the micro-scale presents an advanced approach for the food and nutraceutical industries. However, the challenge lies in determining optimal encapsulation parameters for each specific bioactive compound and encapsulation method. In addressing this, our study demonstrates the application of statistical programs to streamline the optimization of wet-lab experimental designs. Focusing on the encapsulation technique of complex coacervates for black carrot phenolic extract (BCPE), the response surface methodology was employed to optimize encapsulation parameters in terms of coating material, the core-to-coating material ratio, and the pH of the encapsulation environment. The optimum conditions predicted by RSM to produce BCPE-loaded complex coacervates were found to be a pH of 3.02, a core-to-coating ratio of 10g/100g, and a coating material composition of 59.10g/100 mL maltodextrin, and 0.90g/100 mL whey protein isolate. According to the RSM pattern with 84% desirability, encapsulation efficiency was found 86.08%. In addition, the effect of different food matrixes was examined on the in vitro bioaccessibility of spray-dried BCPE loaded complex coacervated powder (BCPE-CCp). To explore the impact of protein and carbohydrate richness, along with food temperature on capsule stability, the BCPE-CCp was incorporated into skim milk, apple juice, and chocolate beverages (1g/100 mL). Notably, heat treatment had no significant effect on the in vitro bioaccessibility of BCPE-CCp in terms of total phenolic compound and antioxidant activity (p < 0.05), indicating its suitability for hot formulations. Furthermore, the release of BCPE in a protein-rich environment was observed to be higher than in a carbohydrate-rich food matrix under both gastric and intestinal conditions. These findings provide valuable insights into the stability and release dynamics of BCPE-CCp in different food settings, supporting its adaptability for diverse formulations, including those involving elevated temperatures.