Concentration of phenolic acids and flavonoids in aronia melanocarpa (choke berry) juice by osmotic membrane distillation

 Membrane distillation (MD) has been tested as a low temperature replacement of traditional falling film evaporators for juice concentration. Compared to other membrane processes, MD is non-pressure driven performing a high degree of concentration in the same versatile installation[1].

Aronia melanocarpa is among the red fruits with the highest content of antioxidants [2] and has gained must interest due to the content of phenolic acids, procyanidins and polyphenolic compounds as anthocyanins [3].

In this study, osmotic membrane distillation (OMD) has been tested for the concentration of not only sugars, but in particular potentially bioactive components such as phenolic acids and flavonoids.

OMD is carried out on 37 kg aronia juice at 30°C and the juice is concentrated from 12 wt% to 74 wt% dry matter. The juice is filtered to remove kernels, peel residues etc before concentration by OMD.

Analysis of 14 specific phenolic acids and flavonoids such as neochlorogenic acid and quercitin during concentration show complete retention of the bioactive compounds in the juice. The produced concentrate is a product with great market potential due to the high nutritional value.