. 2022 Aug 28;12(9):806. doi: 10.3390/metabo12090806

Table 4.

Composition and/or bioactivity determined in maize of different types (Zea mays L.) and applied treatments.

Corn	Treatments	Compounds and/or Products	Bioactivity	Reference
Mexican corn (13 pigmented grain): Arrocillo Amarillo (red, blue), Bolita (red, blue), Chihuahua Crystal Blue (blue, red), chalqueño corn (red, blue).	Nixtamalization with alkali (0.8% of the grain weight) for 30 min, followed by resting for 14–16 h, ambient drying, grinding, and sieving (0.5 mm).	Decreases the anthocyanin concentration of corn grains in the pericarp by 73 to 100%, varying according to the type of corn and portion.		[63]
Mexican corn (18 phenotypes).	White corn. Yellow corn.	Total phenolic content: - White corn: 170 mg GA 100 g⁻¹ sample. - Yellow corn: 551 mg GA 100 g⁻¹ sample. Total anthocyanin content: - White corn: 1.54 mg c3-G 100 g⁻¹ sample. - Yellow corn: 70.2 mg c3-G 100 g⁻¹ sample.	Antioxidant capacity: - Yellow corn: 89.4% by ABTS. - White corn: 26% by ABTS. - Red colored (phenotype Pinto): 100% by DPPH.	[65]
White, red, blue and purple corn (var Ver 42)	Ethanolic extracts (95%) from nixtamalized grains. Tortilla with nixtamalized grain.	The treatments reduced total phenols, and anthocyanins. Total phenolic content and anthocyanin (respectively): - Purple maize (1760 mg 100 g⁻¹, 325.1 mg 100 g⁻¹), - Red maize (465 mg 100 g⁻¹, 82.3 mg 100 g⁻¹), - Blue maize (343 mg 100 g⁻¹, 63.1 mg 100 g⁻¹), - White maize (170 mg 100 g⁻¹, 1.59 mg 100 g⁻¹).	The processing negatively affected the capacities of the grains. Quinone reductase induction (QR): purple > White > red > blue (anticancer activity). The purple genotype (Ver 42) and its products (dough and tortilla) showed the highest antioxidant capacity (70% by ABTS, 55% by PRAC) and QR (induction twice at 125 g mL⁻¹).	[66]
Creole maize races (Zea mays L.) and pigmented varieties (yellow, red and blue).	Nixtamalization (alkaline boiling) and production of dough (grinding, drying) and tortillas.	Carotenoid content (μg of β-carotene eq g⁻¹ extract) of raw maize grains and their products (masa, tortilla) respectively: - White (0.39, 0.17, 0.18) - Yellow (0.49, 0.28, 0.56) - Red (1.01, 1.14, 1.01) - Blue (0.18, 0.23, 0.22) For white grains, nixtamalization reduced carotenoids by 53 to 56%. Yellow grain suffered the highest losses from anthocyanins (174.44 to 10.30 mg of c3-GE 100 g⁻¹ DW), not detectable in white maize and its products. The anthocyanin content of all grains was 174.44 to 963.00 mg of c3-GE 100 g⁻¹ DW.	White corn (≈30%) and products (dough ≈20%, tortilla ≈25%) had higher antiradical (DPPH) activity than BHT (≈10% to 100 µM). Yellow corn (≈22%) and products (dough ≈18%, tortilla ≈29%) had higher antiradical activity (DPPH) than BHT (≈10% to 100 µM). Red (50%) and blue (40%) maize grain showed the highest antiradical activity. The antimutagenic activity (S. typhimurium TA98) of the grains: - White grain (35%) - Yellow (4 3%) - Red (53%) - Blue (56%)	[64]
18 samples of blue/purple grain of conical corn (EC), Chalqueño (CHAL), and Bolita (BOL) maize races.	40 grains without the germ, crushed, sieved (0.5 mm), and dried in an oven (40 °C, 18 h). Analysis extract by methanol (acidified to 1% with trifluoroacetic acid) and sonicated for 15 min.	Anthocyanins totals (AT) content (CHAL): varied from 579.4 to 1046.1 mg c3-GE kg⁻¹ DW. The total soluble phenols (TSP) (CHAL): varied from 918.9 to 1479.2 mg GAE kg⁻¹ DW. AT content (EC): varied from 997.8 to 1332.2 mg c3-GE kg⁻¹ DW. TSP (EC): varied from 1328.6 to 1626.7 mg GAE kg⁻¹ DW. AT content (BOL): varied from 304.1 to 528.0 mg c3-GE kg⁻¹ DW. TSP (BOL): varied from 875.0 to 1276.2 mg GAE kg⁻¹ DW.	Antioxidant activity (AA) (Chalqueño): 34 to 60.3% by DPPH. AA (Elote cónico): 46.6 to 60.4% by DPPH. AA (Bolita): 21.0 to 39.5% by DPPH.	[67]
Whole grains of 10 different colored corn (Zea mays L.) genotypes (landrace and an inbred line, over the year 2010).	Combined extracts: acetone/methanol/water (7:7:6, v/v/v), with alkaline hydrolysis and extracted with ethyl acetate and diethyl ether (1:1, v/v).	White and yellow corn: - Flavonoids (248.64 and 281.20 mg CE kg⁻¹ DW), - β-carotene (0.21 and 0.70 mg kg⁻¹ DW), - lutein (not detected and 5.91 mg kg⁻¹ DW), - total phenolic content (5227.1 and 5393.2 mg GAE kg⁻¹ DW), respectively. The light blue genotype had the highest content of total phenols (10,528.8 mg GAE kg⁻¹ DW), flavonoids, and ferulic acid.	White and yellow showed antioxidant capacity (ABTS) between 15 and 20 mmol Trolox kg⁻¹ DW. The light blue genotype had the highest scavenging activity (ABTS: 35.66 mmol Trolox kg⁻¹ DW).	[68]
Blue corn flour	Nixtamalization. Maize grain in cooking (1:2, grain: water), 1.0% (w/w) of calcium hydroxide to 90 °C for 23 min, was soaked for 16 h at ambient temperature, was grounded, and passed through a flash dryer (260 °C for 4 s), the obtained flour was grounded in a mill using a hammer head and a 0.5 mm mesh screen.	Not change the resistant starch content or slow digestion.	The tortilla made with blue corn nixtamalized presented a lower glycemic index (58) and presented antioxidant capacity in the different fractions. They suggest a direct relationship between polyphenol content and antioxidant activity.	[69]
Spanish maize kernels, white (WF, Rebordanes variety), yellow (YF, Sarreaus variety) and purple (PF, Meiro variety).	Air-drying the maize kernels using a pilot-scale tray dryer (45 °C, 2 m s⁻¹, 30% relative humidity, 5 kg m⁻² of loading density, until an average maize moisture content of 11% DW), crushed, ground, and sieved (200 y 500 µm).	Total starch (TS, % w/w, DW) content of tested maize flours, yellow, white, and purple, ranged from 60.1 (whole flour 500 µm) up to 75.2 (purple 200 µm) and no clear differences between varieties were found.	No significant differences were observed among water desorption isotherms of maize varieties.	[70]
Five blue hybrid maize genotypes and Chalqueño and conic kernels were used as native genotypes cultivated in the highlands of Mexico.	Homogenized with 80% ethanol for 10 min, alkaline digestion (2 M NaOH), acidification (HCl), extraction with ethyl acetate.	The total anthocyanins and anthocyanins in free phenolics of the natives, chalqueño and conic are 646 and 892 mg c3-G kg⁻¹ and 48.7 and 60.3%, respectively. The total anthocyanins and anthocyanins in free phenolics of the hybrid genotypes are in the range of 835–1052 mg c3-G kg⁻¹ and 62.4–80.6%, respectively.	Antioxidant capacity (free and bound phenols, respectively): - Chalqueño (≈166 and ≈1600 mg TE kg⁻¹). - Cónico (≈166 and ≈1700 mg TE kg⁻¹). The range of antioxidant capacity of free and bound phenols of hybrid genotypes was 166–820 and 862–1533 mg TE kg⁻¹, respectively.	[71]
White corn. Yellow corn.		White corn kernel (anthocyanin free). Yellow corn kernel (702 mg c3-GE kg⁻¹)	Antioxidant capacity of: - White corn with 17.4 µM TE g⁻¹ sample, - Yellow corn with 90% by ABTS.	[72]
Native Mexican blue corn (Zea mays L.).	Nixtamalization (maize kernels were cooked (1:3, maize grains/water) with 5.4 g of Ca(OH)₂ L⁻¹ water; 31 min, 85 °C, 8.1 h). Wet nixtamal was dried (55 °C/12 h), cooled, and milled to pass through an 80-US mesh (0.180 mm).	Increases the relative percentage of glycosylated anthocyanins and decreases acylated anthocyanins. The most abundant compounds (cyanidin-3-(6″-succinylglucoside) (Cy-Suc-Glu) and cyanidin-3-(6″-disuccinylglucoside) (Cy-diSuc-Glu)).		[73]
Blue and white cornmeal	Cooked samples were prepared in water (1:10 w/v) by a heating bath with shaking for 30 min.	Extractable polyphenols: - Blue maize flour (165 mg GA g⁻¹ DW), - White maize flour (127 mg GA g⁻¹ DW). Condensed tannins: - Blue maize flour (198.9 mg GA g⁻¹ DW), - White maize flour (38.31 mg GA g⁻¹ DW).	Antioxidant capacity and alpha-amylase inhibition (AAI): - Blue maize flour: 6.8 mg ET g⁻¹ DW (DPPH), 13.1 mg ET g⁻¹ DW (ABTS), 15.5 mg ET g⁻¹ DW (FRAP), and 96.8% AAI. - White maize flour: 5.3 mg ET g⁻¹ DW (DPPH), 11 mg ET g⁻¹ DW (ABTS), 10.6 mg ET g⁻¹ DW (FRAP), and 90.9% AAI. Increase in the total phenolic content and antioxidant capacity of cooked blue corn flours, compared to raw ones.	[60]
Purple corn grain flours (control: White corn)	Mixtures of various families (genotypes) of purple corn. Homogenized with ethanol (96%)/HCl (1 N) (85:15 v/v), 30 min.	White corn presented a total phenol concentration: 319 mg GAE 100 g⁻¹. Total phenols (mixtures genotype) (range): 438 to 1933 mg GAE 100 g⁻¹. Total phenols (original genotype): 1328 mg GAE 100 g⁻¹.		[74]