**2.4. Anthocyanin in pigmented corn husk**

Husk is the least studied part of the corn; there is limited research about their anthocyanin composition; however, they had a high concentration of anthocyanins depending on corn variety [20]. Most recent reports show a deeper studied of the type of anthocyanins in purple husk which has more anthocyanin diacylated [19] but there is other report that found cyaniding-3-succinylglucoside instead of diacylated anthocyanin [20]. For that reason, more research is needed; due to the low information, it is not possible to ensure that corn husk composition is different from other parts.

**2.7. Applications of pigmented corn anthocyanins**

of the corn including cob, husk and silk.

**3. Phenolic acids in pigmented corn**

**Table 4.** Use of anthocyanins found in pigmented corn.

Blue popping corn and dark-red popping corn (*Zea mays*

**3.1. Phenolic acid in pigmented corn kernel**

highest concentration with 5.50 mg/100 g [53].

literature (**Figure 5**).

L. spp. Everta)

Purple corn is used traditionally to make tortillas, atole, chips, popcorn and other type of food products. However, chemical studies of these food products are limited. Food industry is more interested in elaboration of products with a major quality and bioactive compounds content; in consequence, the development of new products with purple corn have been the most studied. Some of the developed products are presented in **Table 4**, where the main

Additionally, the anthocyanins are used to make photosensitizers from different colored parts

Furthermore, due to the low stability of anthocyanins, there are some studies related to this topic. The stability of anthocyanins has been improved using intermolecular copigmentation with gallic ferulic, caffeic acids, and results show that those acids do not protect the anthocyanins only have a hypochromic effect. There is a better protection by self-association. Other strategy is the encapsulated of anthocyanins in alginate-pectin hydrogel [49] and the spray-dried purple corn found that 5% of maltodextrin, 150°C and water are the best condition to obtain a soluble product with the major anthocyanin concentration [50]. Haggard in 2018 also found that beverage with more pelargonidin-3-glucoside concentration has a major half-life [10].

**Corn phenotype Use Ref.** Purple corn Beverage [12]

Purple corn (husk, cob and silk) Photosensitizers [48]

Bakery (cookies) with higher phenolic content [4, 35]

Bioactive Compounds in Pigmented Maize http://dx.doi.org/10.5772/intechopen.78340 79

Pigmented corns are good source of phenolic acids; mainly hydroxycinnamic acids but also hydroxybenzoic and chlorogenic acids. These compounds are distributed in whole plant. **Table 4** shows the main phenolic acids found in different parts of the plant reported in the

In white, yellow and pigmented maize, ferulic acid is the most abundant phenolic acid. There are reports that in white and yellow corn it can be found in the forms of dimers, trimers and tetramers [51]. Other authors have reported 1.94 mg/100 g [52] of free diferulic acid in blue

Free ferulic acid concentration in a variety of pigmented kernel is similar among Mexican and Khao Niew Dum varieties (2.02–3.99 mg/100 g) [24, 52]; however, Peruvian variety has the

Mexican corn which is the most abundant in that variety (**Table 5**).

purpose was to find the best process to keep the major anthocyanins concentration.

## **2.5. Extraction methods and characterization of anthocyanins in pigmented corn**

Extraction of anthocyanin is made with methanol solvent acid and the method most used is ultrasound-assisted extraction that shows better efficiency, although, microwave-assisted extraction, ohmic heating extraction and supercritical solvent extraction are also used. Liquid chromatography techniques are the most used in anthocyanin identification. **Table 2** shows the extraction methods used until 2018 and the anthocyanin content.

#### **2.6. Biological activity of pigmented corn anthocyanins**

Structural anthocyanins have conjugation that provides stabilization of free radicals. Antioxidant activity is plenty reported in pigmented corn. Additionally, anthocyanin extract of pigmented corn has been used in *in vitro* and *in vivo* assays, **Table 3** shows some of the activities studied where anti-obesity is the most recurrent.


**Table 3.** Biological activity found in purple corn.
