Release of phenolic compounds with antioxidant activity by human colonic microbiota after in vitro fermentation of traditional white and blue maize tortillas

Abstract

The attention gained by cereals and derived products, such as tortillas, is due to their richness in phenolic and anthocyanin compounds. Although white maize tortillas have been a staple of the Mexican diet for centuries, blue maize has been adopted as a healthier alternative because of its important natural antioxidant source. The aim of the present work was to evaluate the involvement of colonic microbiota in the release of phenolic compounds with antioxidant activity present in traditional tortillas made from commercial white (WMT) and blue (BMT) maize flours. Nutritional composition in WMT and BMT exhibited no differences in protein (9.10 and 9.20%), ash (1.33 and 1.39%), energy (384.30 and 384.70 kcal), or phenolic consumption (323.44 and 437.33 mg/day) among tortillas. The highest anthocyanin (6.61 CGE/100 g), total phenolic contents (235.76 mg GAE/100 g), and antioxidant activity (5,992.14 and 1,651.64 µmol TE/100 g in ORAC and ABTS, respectively) were observed in BMT. Through microbiota fermentation, phenolic released content (13.4 mg GAE/g), ORAC (804.6 and 880.7 µmol TE/g), ABTS (27.4 and 30.7 µmol TE/g), and bioaccessibility (> 80%) displayed the highest values at 5 h. The present work demonstrated that colonic microbiota improved bioaccessibility of insoluble phenolics present in tortillas, favouring an antioxidant environment that positively impacts colonic health.