Polyphenols associated with dietary fibre in wine: A wine Polyphenols gap?

The presence of polyphenolic compounds associated with dietary fibre is a characteristic feature of polyphenol-rich plant foods. It was recently reported that soluble dietary fibre is a common constituent of wine. The objective of this work was to ascertain whether significant amounts of wine polyphenols are associated with dietary fibre. Total phenolics, antioxidant capacity, and HPLC analysis were determined in wines and in corresponding dietary fibre solutions obtained after enzymatic treatments and dialysis. Results showed that 35–60% of total polyphenols in red wine and about 9% in white wine are associated with dietary fibre. These polyphenols are not detected by the usual HPLC analytical techniques and consequently may be ignored in most chemical and biological studies – what we call “the wine polyphenols gap”. Our findings suggest that a significant part of wine polyphenols are not bioaccesible in the human small intestine and reach the colon along with dietary fibre.