Corn proteins solubility changes during extrusion and traditional nixtamalization for tortilla processing: A study using size exclusion chromatography

• Corn prolamins are highly aggregated, and they further aggregate during processing.
• Masa mixing and tortilla baking are critical reducing protein solubility.
• Size exclusion chromatography allowed the study of corn proteins solubility changes.

Changes in the solubility of corn proteins occurring during traditional nixtamalization and extrusion processes used to produce tortillas were studied using size exclusion chromatography, SDS-PAGE and the Dumas method to measure 50% propanol-insoluble protein. Size exclusion chromatography (HPL-SEC) studies furthered the understanding of protein solubility changes during both processes. Extrusion caused more protein aggregation in tortilla intermediate and final products than traditional nixtamalization. Mixing during extrusion and in the intermediate step of masa production in the traditional nixtamalization process was critical in reducing protein solubility. Baking tortillas also considerably reduced the protein solubility for the traditional nixtamalization process. Baking produced aggregation that could not be disrupted with a reducing agent.