ISHS Acta Horticulturae 744: I International Symposium on Human Health Effects of Fruits and Vegetables
ASSESSING BIOAVAILABILITY OF SOFT FRUIT POLYPHENOLS IN VITRO |
| Authors: | G. McDougall, P. Dobson, F. Shpiro, P. Smith, D. Stewart, S. Fyffe |
| Keywords: | anthocyanins, berries, ellagitannins, gastrointestinal, stability |
| DOI: | 10.17660/ActaHortic.2007.744.13 |
| Abstract:
An in vitro digestion procedure, previously validated for predicting iron bioavailability, was tested for its potential for assessing the bioavailability of polyphenol components of soft fruit extracts. The procedure, which simulates the digestive processes of the upper gastrointestinal tract, was tested on a range of soft fruits (blackcurrant, blueberry, cloudberry, lingonberry, raspberry, strawberry and sweet rowan) which encompass the spectrum of polyphenolic components eaten by humans. The majority of the total polyphenol content survived the gastric digestion but substantially less survived pancreatic digestion and partitioned between the IN fraction (designated as “serum available”) and the OUT fraction (designated as “colon-available”). Total anthocyanins were generally less stable to the pancreatic digestion and were particularly poorly recovered in the IN fraction with yields often around 1%, which was similar to serum anthocyanin levels previously discovered in human and animal feeding trials. Samples of the post-gastric, the IN and OUT fractions were analysed by liquid chromatography mass spectrometry to assess which polyphenol components survived the procedure and which may be transformed to other bioavailable products. The loss of anthocyanin content after pancreatic digestion as measured by colorimetric assays was reflected in the recovery of individual anthocyanins, although there were differences in the relative stability of particular structures. The recovery of individual polyphenol components differed between fruits with different polyphenol compositions which suggested that certain components can be sacrificially protected by other more labile components. Information on the stability and relative bioavailability of different polyphenolic components is important to put in context the range of bio-activities and health benefits attributed to these compounds. | |
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