Polyphenols structure-dependent bioaccessibility as affected by formulation and processing

Polyphenols are suggested to be a group of natural health promoting compounds found mostly in fruit and vegetables, and known to undergo modifications and degradation during processing, storage and digestion¹. The plant food matrix, consist mainly of cell wall material (CWM), may interact with the plant polyphenols and influence their stability and bioaccessibility¹. In addition, both traditional and novel processing methods might affect differently the absorption of phenolic compounds in our body. Limited data exist regarding polyphenols bioaccessibility, complicating the discussion regarding possible health-promoting properties.

We have extracted and quantified the bioaccessibility of 16 compounds from various polyphenolic groups from strawberries, utilizing a semi-dynamic in vitro digestion method. The bioaccessibility was examined with the influence of CWM, pH of pre-digested samples, thermal (TP) and novel high pressure processing (HPP).

Binding interactions of polyphenols and CWM were clearly seen by CWM particle size quantification with and without polyphenols. Structure-dependent bioaccessibility was observed, and anthocyanins were revealed as the most affected polyphenols from the intestinal environment. HPP did not influence the bioaccessibility of polyphenols in most cases or even increased it, while TP had a negative impact on the polyphenols intestinal bioaccessibility. Surprisingly, processing had impact on the polyphenols bioaccessibility trend in advanced digestive stages, even if no influence was observed at the beginning. The presence of CWM displayed different effects on polyphenols bioaccessibility as a function of processing and pH combinations.

In conclusion, chemical structures, type of processing and formulation have a great influence on the bioaccessibility of the polyphenolic compounds, and may greatly affect the health promoting capacity of polyphenol rich products.

1. Eran Nagar E, Okun Z, Shpigelman A. Digestive fate of polyphenols: updated view of the influence of chemical structure and the presence of cell wall material. Current Opinion in Food Science. 2019.