Thermal Processing and Fortification with Ayocote and Quintonil Flours Affect Blue Maize Tortilla and Tortilla Chip Properties

Abstract

Modern food systems face the challenge of improving nutritional quality while reducing environmental impact and conserving agrobiodiversity. This study evaluated the effects of thermal processing and fortification with ayocote (Phaseolus coccineus) and quintonil (Amaranthus hybridus) flours on the physicochemical, nutritional, and functional properties of blue maize tortillas, baked tortilla chips (BTCs), and fried tortilla chips (FTCs). Two nominal fortification levels (F1: 6% and F2: 9%) were incorporated into nixtamalized blue maize flour. The resulting products were characterized for proximate composition, mineral profile, color, texture, phenolic and flavonoid contents, antioxidant activity, and in vitro phenolic bioaccessibility. Fortification significantly increased protein, ash, mineral, phenolic, and flavonoid contents, particularly in F2 formulations, while maintaining adequate technological quality. Thermal processing influenced phytochemical content and antioxidant activity, although these effects depended on the parameter evaluated. BTCs generally exhibited higher flavonoid content and antioxidant capacity, whereas total phenolic content remained comparable between BTCs and FTCs. Fortification improved tortilla flexibility but increased tortilla chip hardness. During simulated gastrointestinal digestion, fortified products released more phenolics than the controls. BTC-F2 maintained the highest phenolic content after digestion, whereas tortilla formulations exhibited the greatest relative phenolic bioaccessibility. These findings demonstrate the potential of the underutilized native species ayocote and quintonil to enhance the nutritional and functional value of maize-based products.