Valorizations of carotenoids from sea buckthorn extract by microencapsulation and formulation of value-added food products

The use of highly functional carotenoids from different sources in food industry is limited mostly because of their poor water-solubility and low thermal stability. To overcome these drawbacks, the sea buckhorn (Hippophae rhamnoides L) carotenoids extract was encapsulated with whey proteins isolate and gum acacia by coacervation and freeze drying. Results from encapsulation efficiency, total carotenoids, confocal laser microscopy and FTIR indicated that the carotenoids molecules were successfully encapsulated within whey proteins isolate cages. The powder had a total carotenoids content of 2.82 ± 0.17 mg/g D.W. The confocal microscopy revealed the encapsulation of carotenoid compounds, with the formation of spheroids of 2-30 μm, whereas some of them merge together and generate coacervates that exceed 25 μm in diameter. Both the extract and the microencapsulated powder showed a significant antioxidant activity. The spectrum of the complex showed bands specific to the carotenoids, esters and dicarboxylic acids, but also bands specific for whey proteins. Also, formation of more hydrogen bonds within the coarcervates was suggested. The powder was tested further in muffins formulation. The products were characterized in terms of physico-chemical, microbiological, phytochemicals, antioxidant activity, texture, color parameters, sensory analysis and storage stability. The muffins had a total carotenoids content of 2.42 ± 1.29 mg/100 g D.W. and a corresponding antioxidant activity of 293.90 ± 2.07 μM Trolox/g D.W. A significant decrease in carotenoids content (up to 55%) and antioxidant activity was observed in the first 21 days of storage. A slight decrease in luminosity was observed, whereas no significant differences were found in a* and b* values.