Effect of Traditional Nixtamalization and Extrusion Processes on Bioaccessibility and Antioxidant Activity of Phenolic Compounds in Blue Maize Tortillas During In Vitro Fermentation by Human Colonic Microbiota

In recent years, tortillas made with pigmented maize have garnered interest due to their contribution of polyphenols, considered natural antioxidant compounds with antihypertensive, antidiabetic, and anti-carcinogenic properties. In maize, the greatest contribution of polyphenols is in insoluble form. These secondary metabolites are released by the colonic microbiota making them more bioaccessible to the organism. In the present work, bioaccessibility, release of phenolic compounds, and antioxidant activity by colonic microbiota in tortillas, made with nixtamalized (NMT) and extruded (EMT) blue maize, were evaluated and compared. EMT had higher protein, lipid, and ash content than NMT. However, NMT had higher anthocyanin content than its counterpart EMT (4.01 and 2.28 mg CGE/100 g, dw). The bound phenolic fraction in both tortillas represents > 80 %. At 5 h of in vitro fermentation by colonic microbiota, NMT showed the highest average in phenolic release, bioaccessibility, and antioxidant activity [11.78 mg GAE/ g, dw, 88.23 %, and 569.82 (ORAC) and 26.76 (ABTS) µmol TE/g] than EMT. The use of traditional nixtamalization to produce maize tortillas will continue to be the main process that brings health benefits to consumers.