Particle size of milled chokeberry pomace did not influence in vitro cellular absorption and transport efficiencies of anthocyanins, phenolic acids and flavonols

Abstract

Industrial chokeberry pomace is very rich in polyphenols. The main focus here lies on the possible relationship between the particle size of chokeberry milled pomace and an enhanced absorption and transport of polyphenols by Caco-2 cells. Wet milling was used to produce materials with particle size distributions in the micrometre and in the sub-micrometre to nanometre ranges starting from chokeberry pomace. Milled materials with about 50% of the particles with a mean size (x_50,3) of 223 ± 13 µm (coarse milling) and about 90% of the particles with x_50,3 of 160 ± 40 nm (fine milling, sonication) were obtained. None of the milled materials exhibited cytotoxic effects within the tested concentration-ranges. The polyphenol absorption and the transport efficiencies from the fine and the coarse milled materials were similar. Thus, no effect of the particle size upon cellular uptake and transport could be established, but agglomeration of particle during incubation cannot be excluded as the cause. Furthermore, based on polyphenol stability we postulate that direct milling may be applied to valorise the processing by-product from commercial fruit juice production.

Keywords:

• Processing by-products
• wet micro-milling
• polyphenols
• stability
• Caco-2 cells

Acknowledgements

Chokeberry (Aronia melanocarpa) pomace was kindly supplied by Aronia Original Naturprodukte GmbH (Dresden, Germany). The authors thank Ramona Ring and Konstanze Schelm for excellent technical assistance, Sabine Beissmann for HPLC-MSMS measurements and Fabian Mohr, Andrea Tauer for their support with PSD measurements.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was financially supported by the German Ministry of Nutrition and Agriculture (BMEL) (Sondermittel Nano).