In vitro digestibility of phenolic compounds from edible fruits: could it be explained by chemometrics?

The health benefits of phenolic compounds depend on the ingested amount, molecular diversity and gastrointestinal digestibility. The phenolic profile of eight fruits (blackberry, blueberry, strawberry, raspberry, mulberry, pomegranate, green and red globe grapes) was chemometrically associated with their in vitro digestibility (oral, gastric, intestinal). Extractable phenols, flavonoids and anthocyanins strongly correlated with each other (r >= 0.84), proanthocyanidins with anthocyanins (r = 0.62) and hydrolysable phenols with both extractable phenols (r = 0.45) and proanthocyanidins (r = -0.54). Two principal components explained 93% of the variance [61% (free-phenols), 32% (bounded-phenols)], and four clusters were confirmed by hierarchical analysis, based in their phenolic richness (CLT 1-4: low to high) and molecular diversity. In vitro digestibility of extractable phenols and flavonoids was blackberry (CLT-4)> raspberry (CLT-2)> red grape (CLT-1) related to their phenolic richness (r >= 0.96; P < 0.001), but anthocyanins' digestibility was pH-dependent. Chemometrics is useful to predict the in vitro digestibility of phenolic compounds in the assayed fruits.