Fabrication and optimization of ultra-long stable microencapsulated chlorophyll using combinations of wall material via response surface methodology

Nowadays, the need to use natural pigments instead of artificial colorants in food has increased due to health risks. Chlorophyll is a natural colorant with antioxidant properties. Chlorophyll is a natural pigment with superior antioxidant properties. However, this pigment is unstable in the different conditions of food processing. To increase the stability of chlorophyll extracted from Ulva intestinalis algae, encapsulation of chlorophyll with maltodextrin (MD) and whey protein isolate (WPI) carriers by two drying methods including spray drying and freeze drying was achieved. The optimum combination of wall and core materials to achieve the highest response including encapsulation efficiency (EE) and chlorophyll content (CC) was obtained by response surface methodology and central composite design. The optimal chlorophyll microcapsule (Chl-M) obtained was chosen for subsequent tests containing solubility, moisture content, and antioxidant properties. The results showed that the highest EE and CC were 90.27 ± 0.21%, 55.36 ± 0.36 μg/mL, and 90.46 ± 0.62%, 85.85 ± 0.43 μg/mL, respectively in SD and FD. The microcapsules produced by the freeze dryer (FD) had higher antioxidant activity (79.1 ± 0.24) than the microcapsules produced by the spray dryer (SD) (67.5 ± 0.16). The highest solubility (95.32%) and the lowest moisture content (3.7 ± 0.05) were related to the SD. Freeze drying method (FDM) had the highest EE (91.2%), CC (89.67 μg/mL), and antioxidant properties (79.1%). It is hoped that the encapsulated chlorophyll can be used as a health-promoting food color additive in the food industry.