Simulated digestion of an olive pomace water-soluble ingredient: relationship between the bioaccessibility of compounds and their potential health benefits

Olive pomace is a semisolid by-product with great potential as a source of bioactive compounds. Using its soluble fraction, a liquid-enriched powder (LOPP) was obtained, exhibiting a rich composition in sugars, polyphenols and minerals, with potential antioxidant, antihypertensive and antidiabetic health benefits. To validate the potential of LOPP as a functional ingredient the effect of the gastrointestinal tract on its bioactive composition and bioactivities was examined. Polyphenols and minerals were the most affected compounds; however, a significant bioaccessibility of potassium and hydroxytyrosol was verified (>= 57%). As a consequence, the LOPP bioactivities were only moderately affected (losses around 50%). For example, 57.82 +/- 1.27% of the recovered antioxidant activity by ORAC was serum-available. From an initial alpha-glucosidase inhibition activity of 87.11 +/- 1.04%, at least 50% of the initial potential was retained (43.82 +/- 1.14%). Regarding the initial ACE inhibitory activity (91.98 +/- 3.24%), after gastrointestinal tract losses, significant antihypertensive activity was retained in the serum-available fraction (43.4 +/- 3.65%). The colon-available fraction also exhibited an abundant composition in phenolics and minerals. LOPP showed to be a potential functional ingredient not only with potential benefits in preventing cardiovascular diseases but also in gut health.