Effect of drying technique and particle size of bilberry press cake on the extraction efficiency of anthocyanins by pressurized carbon dioxide extraction

• To improve the extraction efficiency of anthocyanins from bilberry press cake using pressurized carbon dioxide, the combined effect of drying technique and bilberry press cake particle size was assessed. Pressurized carbon dioxide using ethanol as co-solvent was compared with a simple and efficient solvent extraction using methanol. The press cake with large (>710 mm) size particles had a higher anthocyanins content (84 g/kg dry matter to 87 g/kg dry matter) than did the small (<710 mm) size particles (60 g/kg dry matter to 65 g/kg dry matter). Although, the large size particles contained more anthocyanins, more efficient anthocyanins extraction using pressurized carbon dioxide extraction was obtained with the small than the large size particles. The press cake dried by freeze-drying generated a powder with smaller particles and lower bulk density than either the microwave-assisted hot-air-dried or hot-airdried powders. In comparison to methanol extraction, the most efficient anthocyanins extraction was obtained from the freeze-dried small size particles. This work showed that there is a potential to improve the extraction efficiency of anthocyanins extracted by pressurized carbon dioxide by selecting appropriate drying technology and particle size distribution of the press cake.

Keyword

Extraction efficiency

Freeze-drying

Microwave drying

Particle size distribution

Anthocyanins

Carbon dioxide

Drying

Efficiency

Light transmission

Low temperature drying

Methanol

Organic solvents

Particle size

Particle size analysis

Presses (machine tools)

Size distribution

Solvent extraction

Supercritical fluid extraction

Drying technology

Extraction efficiencies

Freeze drying

Large-size particles

Microwave assisted

Pressurized carbon dioxide

Small size particles

Extraction

Publication and Content Type

ref (subject category)

art (subject category)