Processing blackcurrants dramatically reduces the content and does not enhance the urinary yield of anthocyanins in human subjects

Wendy Hollands; Gary M Brett; Pauline Radreau; Shikha Saha; Birgit Teucher; Richard N Bennett; Paul A Kroon

doi:10.1016/j.foodchem.2007.11.052

Processing blackcurrants dramatically reduces the content and does not enhance the urinary yield of anthocyanins in human subjects

Food Chem. 2008 Jun 1;108(3):869-78. doi: 10.1016/j.foodchem.2007.11.052. Epub 2007 Nov 29.

Authors

Wendy Hollands¹, Gary M Brett¹, Pauline Radreau², Shikha Saha¹, Birgit Teucher³, Richard N Bennett⁴, Paul A Kroon⁵

Affiliations

¹ Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK.
² Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK; School of Chemistry and Pharmacy, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK.
³ Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK; MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK.
⁴ Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK; CECEA-Departamento de Fitotecnia e Engenharia Rural, Edificio Agrarias Ciençias, Universidade de Trás-os-Montes e Alto Douro (UTAD), 5001-801 Vila Real, Portugal.
⁵ Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK. Electronic address: paul.kroon@bbsrc.ac.uk.

PMID: 26065747
DOI: 10.1016/j.foodchem.2007.11.052

Abstract

Blackcurrant (BC) fruits are a rich source of biologically active anthocyanins but little is known of the anthocyanin content of commonly consumed BC products or how processing affects the absorption. We report that whereas fresh and frozen whole BC were a rich source of anthocyanins, containing 897 and 642mg (100gFW)(-1) of total anthocyanins the levels in all other products were substantially lower (0.05-10.3% of the levels in fresh fruit). Further, when the absorption and excretion of BC was assessed in volunteers consuming a portion (100g) of frozen whole BC (642mg total anthocyanins) and, 300g of a BC drink made by diluting concentrated syrup (33.6mg total anthocyanins), only small quantities of BC anthocyanins were excreted in urine (fruit, 0.053±0.022%; drink, 0.036±0.043%; mean percent urinary yield±SD) and they were not detected in plasma. These data indicate that fresh and frozen BC, but not processed products, are rich sources of anthocyanins but, regardless of the food source, these anthocyanins are poorly bioavailable.

Keywords: Bioavailability; Flavonoids; Human metabolism; Phenolics; Polyphenols.