**2.1. Anthocyanin in pigmented corn kernel**

Anthocyanin in corn is found in kernel, cob, husk, silk, leaves and stem [5, 6]. In terms of anthocyanins, kernel is the most studied and anthocyanins are found in pericarp and aleurone layer. Pericarp can be transparent, orange, red or brown while aleurone layer can be transparent, red or purple [7]. Currently, researches in corn are focused on major production of anthocyanins, so there are some strategies to find new and better source of pigmented corns. One of them is the study of Mexican maize due to an excellent source for the production of anthocyanins because there are more than 60 native races of corn that have been little studied. However, Mendoza had studied the anthocyanins content in different corn lines and found corns with higher anthocyanins [8]. Other strategy is hybrid corn which is also studied; nevertheless, the anthocyanins content is not better than other pigmented native corns.

**2.2. Anthocyanin in pigmented corn cob**

**Figure 4.** Structure of anthocyanin found in pigmented corn.

**2.3. Anthocyanin in pigmented corn silk**

HPLS-MS [15, 40].

Cob is considered as a by-product from the corn and represents the 20.6–26.2% of the plant and it is used as animal feed. However, it has a chemical high value due to their high anthocyanin concentration and other phenolic compounds. Purple corn cob anthocyanin concentration is 3–3900 mg/100 g according to the last years' review (**Table 2**). Differences are due to corn variety and also, but in a lesser way, extraction method. Anthocyanin composition in cob is similar to the kernel, finding the six main anthocyanins, and identification has made by

Bioactive Compounds in Pigmented Maize http://dx.doi.org/10.5772/intechopen.78340 73

Corn silk can be yellow, green or purple depending on the corn variety. Silk is used in local community as medicinal herbs; however, it does not take advantage and is considered a waste [34].

The later research about anthocyanin characterization shows a similar profile include cyanidin-3-glucoside and cyanidin-3-(6"malonyl) glucoside as the main anthocyanins. **Figure 4** shows anthocyanins found in pigmented corn. However, the variety of colors on pigmented corns is due to the difference on the concentration of each anthocyanin depending on genetics [9]. Peonidin-3-glucoside and pelargonidin-3-glucoside and their derivatives are the anthocyanins that have major variability and a major concentration of pelargonidin-3-(6"malonyl) glucoside are found in red corn [10] while blue corn has neither pelargonidin-3-glucoside nor peonidin-3-glucoside as purple corn has [11], moreover blue corn has more cyanidin-3-(6″ malonyl)glucoside than purple corn; however, its total concentration is much less than purple corn as shown in **Table 1** [9].

#### **2.2. Anthocyanin in pigmented corn cob**

**2.1. Anthocyanin in pigmented corn kernel**

72 Corn - Production and Human Health in Changing Climate

**Figure 3.** Purple corn and Cacahuacintle corn with purple cornhusk and corn cob.

corn as shown in **Table 1** [9].

Anthocyanin in corn is found in kernel, cob, husk, silk, leaves and stem [5, 6]. In terms of anthocyanins, kernel is the most studied and anthocyanins are found in pericarp and aleurone layer. Pericarp can be transparent, orange, red or brown while aleurone layer can be transparent, red or purple [7]. Currently, researches in corn are focused on major production of anthocyanins, so there are some strategies to find new and better source of pigmented corns. One of them is the study of Mexican maize due to an excellent source for the production of anthocyanins because there are more than 60 native races of corn that have been little studied. However, Mendoza had studied the anthocyanins content in different corn lines and found corns with higher anthocyanins [8]. Other strategy is hybrid corn which is also studied; nevertheless, the anthocyanins content is not better than other pigmented native corns. The later research about anthocyanin characterization shows a similar profile include cyanidin-3-glucoside and cyanidin-3-(6"malonyl) glucoside as the main anthocyanins. **Figure 4** shows anthocyanins found in pigmented corn. However, the variety of colors on pigmented corns is due to the difference on the concentration of each anthocyanin depending on genetics [9]. Peonidin-3-glucoside and pelargonidin-3-glucoside and their derivatives are the anthocyanins that have major variability and a major concentration of pelargonidin-3-(6"malonyl) glucoside are found in red corn [10] while blue corn has neither pelargonidin-3-glucoside nor peonidin-3-glucoside as purple corn has [11], moreover blue corn has more cyanidin-3-(6″ malonyl)glucoside than purple corn; however, its total concentration is much less than purple

Cob is considered as a by-product from the corn and represents the 20.6–26.2% of the plant and it is used as animal feed. However, it has a chemical high value due to their high anthocyanin concentration and other phenolic compounds. Purple corn cob anthocyanin concentration is 3–3900 mg/100 g according to the last years' review (**Table 2**). Differences are due to corn variety and also, but in a lesser way, extraction method. Anthocyanin composition in cob is similar to the kernel, finding the six main anthocyanins, and identification has made by HPLS-MS [15, 40].

#### **2.3. Anthocyanin in pigmented corn silk**

Corn silk can be yellow, green or purple depending on the corn variety. Silk is used in local community as medicinal herbs; however, it does not take advantage and is considered a waste [34].


**Part of the corn Corn phenotype Anthocyanin Ref.**

Cy-3-malonylglu (29.0%)<sup>11</sup> (8.4%)<sup>12</sup> Pg-3-malonylglu (11.0%)<sup>12</sup> Cy-3-succinylglu (20.8%)<sup>12</sup> Cy-3-glu monomalonate (1.0%)<sup>11</sup> Pg-3-glu (~1.5%)<sup>11</sup> (2.0%)<sup>12</sup> Cy-3-malonylglu (6.3%)<sup>11</sup> Pn-3-glu (0.9%)<sup>11</sup>

[19]11, [20] 12 75

Bioactive Compounds in Pigmented Maize http://dx.doi.org/10.5772/intechopen.78340

[21]

**Ref.**

**content (mg/100 g)**

878.9/26.2 [22]

473 [11]

310 [23]

55.8 [15]

Cy-3-glu dimalonate (3.9%)<sup>11</sup> Cy-3-dimalonylglu (35%)<sup>11</sup> Pn-3-malonylglu (2.0%)<sup>11</sup> Pg-3-dimalonylglu (1.5%)<sup>11</sup> Pn-3-dimalonylglu (1.4%)<sup>11</sup>

Cy-3-malonylglu Pg-3-glu Pn-3-glu

Superscript indicates the correlation of the concentration of anthocyanins with its reference.

**Part of corn Maize phenotype Extraction method Anthocyanins** 

Heat water 60 min

40:1 liquid-to-solid 3 extractions

1–3 extractions

Kernel Red corn (ZM01-ZM22) Methanol acid 0.8–33.4 [29]

ethanol) with acid (85:15 v/v)

Purple (AREQ-516540TL) 850 [24] Purple (EP24) 153 [25] Purple (race Conico) 97–426 [26] Purple corn 1600 [27] Purple (KKU-WX) 74.5 [28] Purple corn (ZM01-ZM22) 0.8–111.7 [29]

Husk Purple corn Cy-3-glu (11.7%)<sup>11</sup> (39.8%)<sup>12</sup>

Silk Purple corn Cy-3-glu

Maceration

Kernel Purple/Blue (*Zea mays var. saccharata*)

Zihei)

**Table 1.** Composition of Anthocyanins found in pigmented corn plant.

Kernel Purple Corn 2% formic acid, 2 h

Purple (*Zea mays* L., cv

Kernel Purple (AREQ-084) Alcoholic extraction (Methanol or


Superscript indicates the correlation of the concentration of anthocyanins with its reference.

**Table 1.** Composition of Anthocyanins found in pigmented corn plant.

**Part of the corn Corn phenotype Anthocyanin Ref.**

Cy-3-glu (45.8%)<sup>2</sup>

Pg-3-gluc (2.0%)<sup>2</sup>

Pn-3-gluc (9.3%)<sup>2</sup>

Cy-3-malonylglu (17.2%)<sup>2</sup>

Pg-3-malonylglu (2.4%)<sup>2</sup>

Pn-3-malonylglu (3.1%)<sup>2</sup>

Condensed form (16.8%)<sup>2</sup>

Condensed forms<sup>1</sup>

Pn-3-dimalonylglu<sup>1</sup>

Pg-3-glu (13.88%)8 Pn-3-glu (3.39%)8 Cy-3-malonylglu (56.6%)7 Pg-3-malonylglu (9.1%)7 Pn-3-malonylglu (10.4%)7 Cy-3-succinylglu (3.62%)8 Cy-3-disuccinylglu (4.56%)8

; Pn-3-gluc<sup>5</sup>

Cy-3-glu<sup>5</sup>

, (45.8%)<sup>3</sup>

(3.3%)<sup>3</sup>

, (4.,1%)<sup>3</sup>

, (47.3%)<sup>4</sup>

, (11.9%)<sup>4</sup>

, (11.9%)<sup>4</sup>

, (2.1%)<sup>4</sup>

, (6.0%)<sup>4</sup>

, (11.2%)<sup>4</sup>

; Cy-3-glu1,2,3,5,6, Pg-3-

gluc1,2,6,9; Pn-3-gluc1,2,5,6,9; Cy-3-malonylglu1,2,3,5; Pg-3-malonylglu1,2,3,5; Cy-3-dimalonylglu<sup>1</sup>

Pn-3-malonylglu1,2,3; Pg-3-dimalonylglu1,2;

(61.50%)8

; Cy-3-malonylglu<sup>5</sup>

Cy/Pg/Pn 3-(3″,6″-dimalonylhexoside)

Cy-3-glu9, 10; Cy-3-malonylglu9, 10; Pn-3-glu9, 10; Pn-3-malonylglu9, 10; Pg-3-glu9, 10; Pg-3-

(Epi)catechin-Cy/Pg-3,5 diglu (Epi)catechin (4-8)-Cy/Pn/Pg 3,5 diglu (Epi)catechin (4-8)-Cy 3-malonylglu-5 glu

Cy- 3,5 diglu Cy/Pg/Dp/Pn 3-glu Cy 3-malonylhexoside Cy/Pg/Pn 3-(6″-malonylglu) Pn-3-(6″-malonylhexoside)

malonylglu9, 10

Pn-3-glu (8.55%) Pg-3-glu (16.16%)

Purple corn (Peru) Cy-3-glu (75.28%)

, (4.7%)<sup>4</sup>

(73.62%)<sup>6</sup>

[11]4 , [12]2 , [13]3

[9] 5 , [10] 1 , [12] 2 ,

[14]6 , [15]<sup>9</sup>

[11] 7 , [16] 8

[17]

[15] 9 , [18] 10

[14]

(10.88%)<sup>6</sup>

;

; Pn-3-malonylglu<sup>5</sup> [9]5

; Cy-3-malonylglu<sup>5</sup> [9]5

(15.50%)<sup>6</sup>

Kernel Purple corn<sup>2</sup>

Purple corn bran<sup>3</sup> Purple corn pericarp<sup>6</sup>

74 Corn - Production and Human Health in Changing Climate

Purple corn V1-V9<sup>1</sup> Purple corn2,3,9

R11)<sup>5</sup>

Cob Purple corn9

Purple corn (Peru)10

x LH287 R8)<sup>5</sup>

Purple Hybrid (WenveiiR5

Red hybrid corn (Wenwei2 R6

Blue corn Cy-3-glu (24.4%)7

Blue hybrid corn (Lfy blue RI)<sup>5</sup> Cy-3-glu<sup>5</sup>

Germ Purple corn sprouts Direct condensed



But silk has a great potential to obtain phenolic compound, among them, anthocyanins. Research of silk is about its quantification and characterization of anthocyanins and results showed that

**Part of corn Maize phenotype Extraction method Anthocyanins** 

Mixed 24 h, 4°C

Germinated Purple corn (PMW-581) 240 [17]

60°C, 120 min

15 min

method

method

method

(30–45 min)

Water-ethanol 1:3

Water-ethanol 1:1

Water-ethanol 1:1

1:25/80 solid-to solvent

1:20 solid-solvent ratio

Supercritical CO2EthanolH<sup>2</sup>

Subcritical solvent extraction

Sample-to-solvent ratio 1:20)

Subcritical solvent extraction

Sample-to-solvent ratio 1:20)

Subcritical solvent extraction

Sample-to-solvent ratio 1:30)

High-pressure processing 700 MPa

Two extractions

Kernel Purple corn bran 400 W 362 [13]

Foliar Purple corn (Jingzi No. 1) Ethanol 60% with citric acid 1%

Kernel Purple corn 96% ethanol and 1.5 N HCl (85:15)

Cob Dried cob of purple waxy 65°C, 35 min

Kernel Purple corn pericarp (Peru) 50°C, 400 bar

Kernel Purple waxy corn (*Zea mays* L. var. ceratina)

Cob Purple waxy corn (*Zea mays* L. var. ceratina)

Silk Purple waxy corn (*Zea mays* L. var. ceratina)

*Zea mays L. ceratina*

**Table 2.** Anthocyanins extraction methods and concentration.

Peru

Kernel Purple waxy corn

Methanol-1% citric acid (80:20 v/v)

Silk Red/Purple waxy corn

Ultrasound assisted extraction

Supercritical fluid technology

**1.** KKU-WX111031

**2.** KKU-OP **3.** hybrid **4.** commercial **content (mg/100 g)**

Bioactive Compounds in Pigmented Maize http://dx.doi.org/10.5772/intechopen.78340

1780 [36]

2.4 [37]

1060 [14]

99 [38]

1240–1270 [14, 38]

1550 [38]

116 [39]

**1.** 78/478 **2.** 408/419 **3.** 289/456 **4.** 249/500

10–300 (kernel) 70–3700 (pericarp)

O

**Ref.**

77

[5]

[8]

has the highest anthocyanins concentration of the whole plant [41].


**Table 2.** Anthocyanins extraction methods and concentration.

**Part of corn Maize phenotype Extraction method Anthocyanins** 

Mixed 24 h, 4°C

Methanol Shaken for 2 h

Two extractions

6 h, room temperature

Methanol-1% citric acid (80:20 v/v)

Methanol acidified with 1 N

1:10

Mixed 24 h, 4°C

(85:15 v/v) Shaking by 30 min 70°C, 1.5 h

Ratio 1:1 w/v 5 min

Kernel Blue pericarp Alcoholic extraction (Methanol or

Cob Red/Purple waxy corn

**1.** KKU-WX111031

76 Corn - Production and Human Health in Changing Climate

**2.** KKU-OP **3.** hybrid **4.** commercial

Cob Purple waxy corn (red to black)

Cob Purple hybrid corn (KPSC 901)

Husk Red/Purple waxy corn

Silk Purple (ZPEXP)/Pink (ZP341)

Husk Purple corn husk 0.1 N HCl

**1.** KKU-WX111031

Purple hybrid (PWC1-5)

Silk Purple corn Ethanol 50%

**2.** KKU-OP **3.** hybrid **4.** commercial

Kernel Pink (ZM01-ZM22) Methanol acid 0.3–1.4 [29]

Pink (EP24) 0.018 [25]

ethanol) with acid (85:15 v/v) One to three extractions

Blue (ZM01-ZM22) 7.3–7.4 [29] Blue (race Chalqueño) 64.6 [30] Blue (race Conico) 89.2 [30] Blue hybrid corn 73.0–105.2 [30] Blue hybrid corn 27.39–78.28 [31]

Methanol-1% citric acid (80:20 v/v)

**content (mg/100 g)**

**1.** 34/37 **2.** 116/179 **3.** 17/189 **4.** 27/336

Conventional heating 3660 [33]

Microwave 3970 Ultrasound 3830 Ohmic heating 3280

39 [11]

202–1423 [32]

3500 [19]

970 [21]

[5]

[34, 35]

**1.** 5/3 **2.** 34/130 **3.** 48/494 **4.** 5/213

193/1.49 0.44–2.38 **Ref.**

[5]

But silk has a great potential to obtain phenolic compound, among them, anthocyanins. Research of silk is about its quantification and characterization of anthocyanins and results showed that has the highest anthocyanins concentration of the whole plant [41].
