Impact of nixtamalization on flavor development in traditional Mexican tortillas: a comparative analysis of aroma impact compounds

Nixtamalization, the alkaline cooking of maize kernels with lime, is fundamental to the production and sensory identity of the traditional Mexican tortilla. While its nutritional benefits are well documented, its precise impact on aroma development is less clearly understood. This thesis aims to characterize and compare the volatile profile and sensory attributes of tortillas prepared with (NIX) and without (NON-NIX) nixtamalization, using heirloom blue maize as the model system. Tortillas from both treatments were produced under identical milling, forming, and comal-cooking conditions, the only difference between them was the use—or absence—of lime (calcium hydroxide). Prior to instrumental analysis, a trained sensory panel conducted a descriptive evaluation to identify the aroma attributes that most clearly distinguished in NIX and NON-NIX tortillas. This approach allowed for the selection of four key attributes—nixtamal, roasty, meaty, and overall intensity—for detailed comparison. Statistically significant differences (p < 0.001) were found across all attributes, with nixtamal and roasty aromas being more pronounced in NIX tortillas, while meaty and overall aroma intensities were higher in NON-NIX tortillas. These findings provided a focused sensory framework that informed and guided the subsequent chemical analysis, ensuring that the instrumental work targeted odorants with confirmed perceptual relevance. Volatile compounds were isolated by direct solvent extraction followed by solvent-assisted flavor evaporation (DSE-SAFE). Odor-active constituents were located via gas chromatography-olfactometry (GC-O) and ranked by aroma extract dilution analysis (AEDA). Quantitation of selected key odorants was achieved by stable-isotope dilution analysis (SIDA) coupled with GC-MS. A trained sensory descriptive panel evaluated aroma attributes. In total, 49 odorants were detected in NIX and 46 in NON-NIX tortillas, with flavor dilution (FD) factors ranging from 1 to 2187. Of these, 32 were positively identified and selected for quantitation. In the NIX treatment, the most potent odorants included acetic acid, butanoic acid, 2- and 3-methylbutanoic acid, (E,Z)- and (E,E)-2,4-decadienal, heptanoic acid, trans-4,5-epoxy-(E)-2-decenal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone(HDMF), ethyl (E)-cinnamate, 2-methoxy-4-vinylphenol (p-vinylguaiacol), o-aminoacetophenone, phenylacetic acid, and vanillin. In contrast, NON-NIX showed high FD values only for (E,Z)-2,4-decadienal, trans-4,5-epoxy-(E)-2-decenal, the same HDMF, ethyl (E)-cinnamate, p-vinylguaiacol, and vanillin. Compounds present at the highest concentrations in both treatments included acetic acid, vanillin, 4-vinylphenol, and p-vinylguaiacol. According to Odor Activity Value (OAV) calculations, the most important odor compounds in NIX (OAV ≥ 100) were o-aminoacetophenone, (E,E)-2,4-decadienal, 3-methylbutanoic acid, dimethyl trisulfide, (E)-2-nonenal, 4-vinylphenol, p-vinylguaiacol, 3-methylbutanal, vanillin, and nonanal. For NON-NIX, the list included (E,E)-2,4-decadienal, dimethyl trisulfide, 3-methylbutanoic acid, (E)-2-nonenal, o-aminoacetophenone, vanillin, nonanal, and p-vinylguaiacol. Among odorants with OAVs between 10 and 100, similar levels were found for hexanal, trans-4,5-epoxy-(E)-2-decenal, 3-methylindole, γ-decalactone, butanoic acid, guaiacol, γ-nonalactone, and indole. Together, these results provide a clearer understanding of which volatile compounds are most relevant to tortilla aroma and offer a basis for comparison with previous literature. This study presents the first comprehensive comparison of aroma-active compounds in NIX and NON-NIX tortillas using both instrumental and sensory approaches. Findings show that nixtamalization significantly enhances key aromatic compounds associated with traditional tortilla flavor, reinforcing its role not only in improving nutritional and textural qualities, but also as a crucial driver of authentic sensory character. Future research should explore how variables such as lime concentration, steeping time, or maize variety influence the formation and stability of these key aroma compounds.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Food Science & Human Nutrition

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Velasco Hernandez, Manuel Jesus

Contributors dc:contributor

• Cadwallader, Keith R.
• Torrico, Damir
• Engeseth, Nicki

• Nixtamalization
• Tortilla
• Volatile Compounds
• Sensory Analysis
• Gas Chromatography-olfactometry (gc-o)
• Aroma Extract Dilution Analysis (aeda)
• Stable Isotope Dilution Analysis (sida)
• Odor Activity Values (oavs)
• Solvent-assisted Flavor Evaporation (safe)
• Key Odorants
• O-aminoacetophenone

Statement dc:rights

• © 2025 Manuel Jesus Velasco Hernandez

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/130221

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F130221