Bioavailability of phenolic compounds in strawberry, raspberry and blueberry: Insights for breeding programs

Epidemiological studies have related berry intake to healthiness, which has been mainly associated with the polyphenolic content and the antioxidative properties of raw fruits. However, the digestion process can affect antioxidant release (bioaccessibility) and absorption (bioavailability) from fruit food matrices (i.e., digestibility), which also depend on their dietary fiber content, which together determine the potential health benefits of berry species. In this study, digestibility of strawberry, raspberry and blueberry phenolic compounds, was evaluated after in vitro digestion and compared to antioxidant content and capacity of their raw fruits for a more reliable assessment of their potential healthful effects. These berry species also differed in their fruit dietary fiber content. The polyphenolic profiles of fruits were quantified using spectrophotometry and HPLC. Results showed no consistency between antioxidant content and capacity of raw and digested fruits in the three berries. Blueberry showed the highest antioxidant capacity (AC) associated with higher total phenolic content in raw fruits whereas, after digestion, strawberry (with a lower dietary fiber content), showed the highest total phenolic content and AC in the bioavailable fractions ('AC-bioavailable'). These results suggested that 'AC-bioavailable' may be an useful index to select for wholesomeness genotypes within berry breeding programs.