Maize flour (Zea mays)

Maize flour is produced mainly by dry milling of maize kernels and can be whole-ground (germ and pericarp retained) or degermed (germ largely removed). Commercial forms include yellow or white corn meal, stone-ground vs steel-milled, and various grinds (coarse/medium/fine). It is distinct from nixtamalized flours (masa harina), which undergo alkaline cooking and have different functionality.

Caloric value (dry product, 100 g)
Approximately 350–380 kcal per 100 g (typical ≈ 365 kcal/100 g; varies with moisture, particle size, and degree of degermination).

Average composition (indicative, per 100 g)
Total carbohydrates: ~73–79 g (predominantly starch).
Protein: ~7–9 g (lysine and tryptophan limiting).
Fat: ~1–6 g (lower in degermed, higher in whole-ground).
Dietary fiber: ~2–9 g (higher in whole-ground).
Micronutrients: potassium, magnesium, phosphorus; traces of iron and zinc; carotenoids (lutein, zeaxanthin) especially in yellow varieties. “Enriched” products may contain thiamin, niacin, folate, and iron per local standards.

Residual lipid profile (intrinsic corn oil, % of total fat)
PUFA: predominantly linoleic (omega-6).
MUFA: substantial oleic fraction.
SFA: smaller palmitic/stearic fraction.
ALA: traces. Because total fat in corn meal is low, the lipid contribution per 100 g is modest; degermination further reduces rancidity risk.

Process technology and particle sizes
Dry milling with tempering, degermination, and sifting yields grits, meal, and flour cuts in fine/medium/coarse classes. Particle size governs water absorption, viscosity, and texture (coarser cuts give more structured porridge/polenta). Thermal pre-cooking (instant/pregelatinized) partially gelatinizes starch and shortens cook time. Stone-ground meal retains more germ/bran and flavor but has a shorter shelf life.

Sensory and functional properties
Golden color from xanthophylls; sweet-cereal aroma with light toasted notes in pre-cooked or flaked materials.
Predictable thermal viscosity (corn starch gelatinization typically ~62–72 °C), good water absorption, and granular structure that promotes crispness in coatings and baked snacks.
Light and oxygen can fade carotenoids; whole-ground meal is more prone to oxidative staling than degermed.

Nixtamalization versus conventional meal (note)
Masa from alkaline treatment (cal) is not equivalent to conventional corn meal: it develops unique doughability and flavor for tortillas/tamales that are not replicated by non-nixtamalized meal.

Food applications
Polenta and porridges; cornbread, muffins, and quick breads; hushpuppies and Johnnycakes; breadings/coatings; crackers, grissini, and extruded snacks; batters and enriched pastas. It is not a substitute for masa in tortilla/tamale production.

Nutrition and health
Corn meal provides mainly starch-based energy with moderate protein quality; pairing with legumes, dairy, or eggs improves the amino-acid profile.
Carotenoids (lutein/zeaxanthin) contribute color and minor antioxidant capacity.
Residual lipids are low; when present, they are largely PUFA/MUFA with limited SFA.
Naturally gluten-free, but cross-contact with gluten can occur in non-dedicated mills.

Quality and specifications (typical themes)
Moisture: ≤13.5–14.0% for storability.
Ash/bran: aligned with degree of degermination.
Total fat: ~1–3% in degermed; higher in stone-ground whole-meal.
Particle size: distribution per application (reference sieves).
Color: consistent yellow (or white) hue; absence of specks and foreign matter.
Microbiology: appropriate to category (TPC/yeasts–molds).
Mycotoxins: verify corn lots (for example fumonisins, aflatoxins, DON/zearalenone) per regulation.
Residues: pesticides and heavy metals within legal limits.

Storage and shelf life
Store cool, dry, and protected from light/odors in barrier packaging. Degermed meal commonly holds 6–12 months; whole-ground/stone-ground has shorter life due to higher oil. Moisture uptake leads to caking and quality loss; use FIFO rotation and reseal tightly after opening.

Allergens and safety
Maize does not contain gluten, but cross-contact with wheat/rye/barley is possible in shared facilities; label accordingly or use certified gluten-free lines. Manage dust and foreign-body controls per good manufacturing practice.

Troubleshooting
Dense or gluey porridge: grind too fine or water too low; increase granulation or adjust hydration/cook time.
Stale/paint-like notes: oxidative aging—check age, storage, and prefer lower-fat degermed cuts for long shelf life.
Faded color: carotenoid degradation from light/oxygen—improve packaging barrier.
Lumping in dough/batter: inadequate dispersion—improve dry premix, hydrate progressively, or increase agitation.

Sustainability and supply chain
Dry milling requires relatively little process water and yields co-products (bran, grits) for feed or other value streams. Quality reflects agronomy (hybrids, rapid post-harvest drying) and robust in-field and storage mycotoxin risk management.

Conclusion
Maize flour delivers color, mild sweetness, and versatile functionality, with degermed variants offering superior oxidative stability. Appropriate grind selection, moisture control, and disciplined raw-material quality and hygiene enable consistent, safe products across a wide range of applications.

Studies

Contents of carotenoids in maize or maize (1):

• Lutein: 60%
• Zeaxanthin: 25%
• Neoxanthine and violetxanthin: 9%
• Criptoxanthin: 5%
• Lycopene: 0%
• Alpha carotene: 0
• Beta carotene: 0

The results of this study suggest that, although there were pigment losses, pigments from creole maize show antioxidant and antimutagenic activity after the nixtamalization process (2).

From maize, the following are industrially extracted:

• Fructose syrup, or HFCS (High Fructose Corn Syrup)
• Glucose syrup
• Glucose-fructose syrup
• Corn syrup (an unusual term, as the content should also be specified—whether fructose or glucose. 

Glucose is sugar, so it is a component to be consumed in moderation. Fructose is a sweetening carbohydrate that, frankly, should be avoided).
It has a low caloric content.

GMO corn (maize)

Genetically modified (GMO) crops were introduced into commercial agriculture in 1996, and by 2014 approximately 181.5 million hectares of GMOs were cultivated worldwide. These GMOs have produced significant benefits over the past two decades (Clive, 2015). A recent meta-analysis by Klümper and Qaim concluded that the widespread adoption of GMO technology has reduced the use of chemical pesticides, as well as increased crop yields to improve farmers’ profits (Wilhelm and Matin, 2014). Despite the evident positive effects of GMOs, disputes are still ongoing regarding unintended, unexpected, and uncontrolled negative effects of GMOs. There is considerable concern that the introduction of exogenous DNA sequences and enzymes into the genome of the target plant in GMOs could lead to undesirable effects, and these negative effects may impact human health and environmental safety (Ioset et al., 2006) (3).

Maize studies

References____________________________________________________________________________

(1) Sommerburg O, Keunen JE, Bird AC, van Kuijk FJ. Fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes. Br J Ophthalmol. 1998 Aug;82(8):907-10. doi: 10.1136/bjo.82.8.907. 

(2) Mendoza-Díaz S, Ortiz-Valerio Mdel C, Castaño-Tostado E, Figueroa-Cárdenas Jde D, Reynoso-Camacho R, Ramos-Gómez M, Campos-Vega R, Loarca-Piña G.  Antioxidant capacity and antimutagenic activity of anthocyanin and carotenoid extracts from nixtamalized pigmented Creole maize races (Zea mays L.).   Plant Foods Hum Nutr. 2012 Dec;67(4):442-9. doi: 10.1007/s11130-012-0326-9

Abstract. Nixtamalization process is the first step to obtain maize based products, like tortillas; however, in both the traditional and commercial processes, white grain is generally preferred. Creole maize races, mainly pigmented varieties, have increasingly attention since these are rich in anthocyanins and carotenoids. The aim of this investigation was to evaluate the antioxidant and antimutagenic activity of rich anthocyanins and carotenoids extracts from creole maize races before (grain) and after (masa and tortilla) the nixtamalization process. Most anthocyanins and carotenoids were lost during nixtamalization. Before nixtamalization, blue and red genotypes contained either higher antioxidant capacity and anthocyanin contents (963 ± 10.0 and 212.36 ± 0.36 mg of cyanidin-3-glucoside eq/100 g, respectively) than the white and yellow genotypes. However, the highest carotenoid levels were displayed by red grains (1.01 ± 0.07 to 1.14 ± 0.08 μg of β-carotene eq/g extract). Anthocyanins losses were observed when the blue grains were processed into masa (83 %) and tortillas (64 %). Anthocyanins content correlated with antiradical activity (r = 0.57) and with 2-aminoanthracene -induced mutagenicity inhibition on TA98 and TA100 (r = -0.62 and r = -0.44, respectively). For white grains, nixtamalization also reduced carotenoids (53 to 56 %), but not antioxidant activity and 2-Aa-induced mutagenicity. Throughout the nixtamalization process steps, all the extracts showed antimutagenic activity against 2-aminoanthracene-induced mutagenicity (23 to 90 %), displaying higher potential to inhibit base changes mutations than frameshift mutations in the genome of the tasted microorganism (TA100 and TA98, respectively). The results suggest that even though there were pigment losses, creole maize pigments show antioxidant and antimutagenic activities after nixtamalization process.

Amador-Rodríguez KY, Martínez-Bustos F, Silos-Espino H. Effect of High-Energy Milling on Bioactive Compounds and Antioxidant Capacity in Nixtamalized Creole Corn Flours. Plant Foods Hum Nutr. 2019 Jun;74(2):241-246. doi: 10.1007/s11130-019-00727-9.

Abstract. This study aimed at evaluating the effect of high-energy milling (HEM) and traditional nixtamalization (TN) on bioactive compounds and antioxidant capacity in nixtamalized creole corn flours obtained from a maize genotype cultivated under rainy temporal conditions in the Mexican semidesert. Four creole grains, including San José de Gracia white and blue (WG and BG), Negritas (NG), and Ahualulco white corn grains (SG), were used. For HEM nixtamalization, corn grains were hammer-milled; then, two different conditions were evaluated: treatment H1, with raw flours with 14% moisture content and 1.1% Ca(OH)2, and treatment H2, with raw corn flours with a 23% moisture content and 1.4% Ca(OH)2. The TN process was utilized as a control. TN recorded significant losses in luminosity value L* (p < 0.05), while HEM nixtamalized blue corn flours remained close to -b* values, that is, near to those of raw flour. Anthocyanin content showed higher content values in HEM treatments compared with TN (759.55 and 252.53 mg cyanidin 3-O-β-D-glucoside (C3G)/kg, respectively) (p < 0.05). Total soluble phenolic content was higher in HEM nixtamalization compared with the traditional process, except for WH2 and SH2 (H2 treatment for WG and SG). Two redundant radical scavenging assays were used: antioxidant capacity (DPPH assay) exhibited less value in nixtamalized flours than in raw flour (p < 0.05). Antioxidant activity by (ABTS) assay was higher in HEM than in TN. Nixtamalized flours produced by HEM demonstrated more improvement in nutraceutical properties than those produced employing TN.

(3) Tan Y, Yi X, Wang L, Peng C, Sun Y, Wang D, Zhang J, Guo A, Wang X.  -- Comparative Proteomics of Leaves from Phytase-Transgenic Maize and Its Non-transgenic Isogenic Variety.    Front Plant Sci. 2016 Aug

 Abstract. To investigate unintended effects in genetically modified crops (GMCs), a comparative proteomic analysis between the leaves of the phytase-transgenic maize and the non-transgenic plants was performed using two-dimensional gel electrophoresis and mass spectrometry. A total of 57 differentially expressed proteins (DEPs) were successfully identified, which represents 44 unique proteins. Functional classification of the identified proteins showed that these DEPs were predominantly involved in carbohydrate transport and metabolism category, followed by post-translational modification. KEGG pathway analysis revealed that most of the DEPs participated in carbon fixation in photosynthesis. Among them, 15 proteins were found to show protein-protein interactions with each other, and these proteins were mainly participated in glycolysis and carbon fixation. Comparison of the changes in the protein and tanscript levels of the identified proteins showed that most proteins had a similar pattern of changes between proteins and transcripts. Our results suggested that although some significant differences were observed, the proteomic patterns were not substantially different between the leaves of the phytase-transgenic maize and the non-transgenic isogenic type. Moreover, none of the DEPs was identified as a new toxic protein or an allergenic protein. The differences between the leaf proteome might be attributed to both genetic modification and hybrid influence.

Tan Y, Tong Z, Yang Q, Sun Y, Jin X, Peng C, Guo A, Wang X. Proteomic analysis of phytase transgenic and non-transgenic maize seeds. Sci Rep. 2017 Aug 23;7(1):9246. doi: 10.1038/s41598-017-09557-8. 

Abstract. Proteomics has become a powerful technique for investigating unintended effects in genetically modified crops. In this study, we performed a comparative proteomics of the seeds of phytase-transgenic (PT) and non-transgenic (NT) maize using 2-DE and iTRAQ techniques. A total of 148 differentially expressed proteins (DEPs), including 106 down-regulated and 42 up-regulated proteins in PT, were identified. Of these proteins, 32 were identified through 2-DE and 116 were generated by iTRAQ. It is noteworthy that only three proteins could be detected via both iTRAQ and 2-DE, and most of the identified DEPs were not newly produced proteins but proteins with altered abundance. These results indicated that many DEPs could be detected in the proteome of PT maize seeds and the corresponding wild type after overexpression of the target gene, but the changes in these proteins were not substantial. Functional classification revealed many DEPs involved in posttranscriptional modifications and some ribosomal proteins and heat-shock proteins that may generate adaptive effects in response to the insertion of exogenous genes. Protein-protein interaction analysis demonstrated that the detected interacting proteins were mainly ribosomal proteins and heat-shock proteins. Our data provided new information on such unintended effects through a proteomic analysis of maize seeds.

Mini-glossary of lipid acronyms 
MUFA — MonoUnsaturated Fatty Acids: Generally favorable for heart and lipid profile (for example oleic acid).
PUFA — PolyUnsaturated Fatty Acids: Include omega-3 and omega-6; beneficial, but keep a balanced omega-6:omega-3 ratio.
SFA — Saturated Fatty Acids: To moderate; impact depends on overall diet and the replacement nutrient.
ALA/EPA/DHA (omega-3) — Alpha-linolenic acid / Eicosapentaenoic acid / Docosahexaenoic acid: Support heart and brain health, with stronger evidence for EPA/DHA.
TFA — Trans Fatty Acids: To avoid; associated with increased cardiovascular risk.
MCT — Medium-Chain Triglycerides: Rapidly absorbed; useful in specific contexts, but still count toward total calories.