Characterisation of hydrogels and aerogels as carriers for sea buckthorn pomace extract

In this study, aerogels were prepared from kognac glucomannan (KG) or whey proteins loaded with bioactive sea buckthorn pomace extract. KG was diacetylated with Na2CO3 (0.1; 0.2; 0.3; 0.4 m) resulting hydrogel formation that were further freeze-dried to obtain an aerogel structure. Whey protein aerogels were prepared by removing pore fluid from alcogels using supercritical CO2 drying. Produced aerogels evaluated for microstructure, porosity, specific surface area, absorption capacity, encapsulation efficiency and antioxidant capacity of the extract. It was found that higher concentration of alkali induced higher hardness, resilience and elastic modulus values. It was also obtained that pores in the konjac glucomannan aerogels were irregular in shape and a decrease in total pore volume (0.026 to 0.019 cc/g) and surface area (12.39 to 11.40 m(2)/g) after increasing the carbonate concentration was observed. These aerogels were found to have better encapsulation efficiency properties for sea buckthorn pomace extract (17 to 20%) in comparison to whey protein aerogels (0.05 to 0.36%). Overall, the KG aerogels show potential for applications in the food industry as a carrier of bioactive sea buckthorn pomace extract, while whey proteins must be used in combination with other biopolymers to enhance their bioactive compound loading capacity.