Assessment of polyphenolic profile stability and changes in the antioxidant potential of maqui berry (Aristotelia chilensis (Molina) Stuntz) during in vitro gastrointestinal digestion

Maqui berry (Aristotelia chilensis (Molina) Stuntz) has demonstrated a great potential as functional ingredient. However, determining the effect to which the maqui extract or its phytochemicals will benefit the consumers requires further knowledge. Thus, the aim of the present study was to determine the effect of in vitro gastrointestinal digestion (GID) on (i) the recovery and bioaccessibility indexes, (ii) the stability of polyphenolic compounds (phenolic acids, flavonoids and anthocyanins) and (iii) the changes in antioxidant activity of maqui berry grown in Chile. The extracts obtained in each phase (oral, gastric and intestinal) of GID were used to analyse the stability of polyphenolic compounds by means of HPLC whereas the antioxidant activity was determined using four different methodologies. All polyphenolic compounds decreased their concentration after GID and principally the anthocyanins content which was severely affected. The GID process decreased the scavenging properties in 89.9% and 84.2% with DPPH and ABTS assays, respectively, as well as the reducing power 74.1% with respect to non-digested sample. On the other hand, the chelating activity was increased (126.8%). At the end of GID process, the bioaccessibility of phenolic and flavonoid compounds was 78.19 and 14.20%, respectively. The results obtained suggest that although a great amount of maqui berry polyphenolic compounds are lost during digestion process they still have a great potential as antioxidants agents.