**2. Diversity of chili pepper landraces in Mexico**

**1. Introduction**

406 Flavonoids - From Biosynthesis to Human Health

Chili pepper (*Capsicum* spp.) has been used in Mexico as food and a condiment for over eight centuries [1] and is an integral component of the diet and cultural identity of Mexico. Although various chili species grow wild and are cultivated in the United States of America, Mexico is the center of origin, domestication and diversification of *Capsicum annuum* L. [2, 3]. Wild variants continue diversifying (*C. annuum* var. *glabriusculum* [Dunal] Heiser & Pickersgill) and are distributed throughout the country [4, 5]. In this Mesoamerican biocultural context and using traditional management, farmers preserve and utilize a great diversity of chili landraces.

A total of slightly more than 150 landraces, occupying extensive planted surfaces and providing for great consumption, have been described in Mexico. The central and south-southeastern regions are more diverse and relevant for the in situ preservation of chilis. In these regions, approximately 80 landraces have been preserved. In Mexico, 153,565 ha are cultivated annually, resulting in an average production of 2.8 million tons of dry and fresh fruits. Annually, approximately 2 million tons of fresh and dry chilis are consumed, and in some years, imports range between 20,757 and 41,000 tons [6]. Consumption per capita in urban areas is from 8 to

The health benefits of chili consumption and its active ingredients continue to be investigated using in vitro and in vitro biological models as well as theoretical and experimental models. Capsaicinoids and flavonoids are the determinant compounds of color, flavor, texture and aroma of food prepared with chilis. A common question among health specialists is whether chili consumption improves health or contributes to disease development. The chili fruit contains up to 15 or more capsaicinoid compounds. Among the majority are capsaicin, dihydrocapsaicin and nordihydrocapsaicin; in flavonoid content, quercetin, apigenin and luteolin are notable as well

Flavonoids contain phenolic hydroxyl groups in their chemical structure and possess excellent chelating properties of iron and other transition metals—characteristics that confer on chilis a high antioxidant capacity and anti-free-radical properties, generating protection against oxidative damage [7]. Flavonoids have positive effects on health although their mechanisms of action continue to be investigated because it is difficult to quantify daily intake and their direct effects on health. Thus far, flavonoids are associated with antisclerotic, anti-inflammatory, antitumoral, antithromobogenic, antiviral and antiosteoporotic effects and may function

Capsaicinoids are synthesized in the placenta of the fruit and are genetically determined (*Pun1* allele of pungency) by the presence of the *Pun1* or *pun1* gene with EST- or AT3-type cofactors that induce a quantitative effect of the gene and variations in the pungency of the fruit. Therefore, not all chili peppers are spicy, and various consumers consider chili varieties that carry the *pun1* recessive gene to be sweet fruits [11]. In addition, genetic or genotypic factors, crop management, cultivation environments, maturity of the fruit upon cutting, postharvest management of fruit and forms of processing or cooking the fruit for consumption influence

, B2

and C, minerals,

9 kg, and in rural communities, it varies between 13 and 17 kg.

carotenoids and phenols by chili consumption.

as a preventive agent in cancer, among other effects [8–10].

the level of pungency and flavor at the time of consumption [12].

as some catechins and cyanidins. Thus, one does not only ingest vitamins B1

Depending on the archaeobotanic, genetic and pre-Columbian sociocultural diversity, it has been established that chili peppers (*Capsicum annum* L. and *C. frutescen* L.) have been collected, cultivated and consumed in Mexico for hundreds of years. For example, analysis of archaeological remains from the Tehuacán Valley in Mexico indicates that there were wild forms 8000 years ago, and different cultivation and domestication events of *C. annuum* occurred with evidence dating to 6000 years ago [19, 20]. Perry and Flannery [1], from excavations, collection and dating of archaeobotanic samples of the Silvia and Guila Naquitz´s caves in Oaxaca, indicated that cultivated forms of *C. annuum* and *C. frutescens* have existed for nearly 8000 years. In Chiapas, Mexico, from a sample of ceramic residue, extensive culinary use of chili peppers was demonstrated [2]. In general, archaeobotanic, genetic and cultural linguistic evidence identifies the Mesoamerican region as the center of origin, domestication and diversification of *C. annuum* and *C. frutescens*, and those species continued to evolve under domestication or as wild forms [3].

In Mexico, wild species of *Capsicum* have certain characteristics in common, such as being small spicy fruits of round, elongated or conical forms that regularly ripen in red or yellow colors. The regularly erect fruits are easily separated from the calyx. They have small seeds, which form a portion of the diet of birds and facilitate the chilis' dispersal over long distances. Today, wild forms have a wide distribution from the southern United States of America to South America (Argentina). Among these cases, *C. annuum* var. *annuum* and *C. annuum* var. *glabriusculum* (Dunal) Heiser & Pickersgill are notable [5, 21–23].

During the domestication process, chili fruits and plants have undergone various genetic transformations in response to human and natural selection. Thus, by the processes of natural environmental and artificial selection, the forms, sizes, colors and flavors of the fruit began to change. Obtaining a larger fruit and greater productivity per plant is, even today, one of the goals of breeders and growers. In the domesticated or cultivated forms of chili, the fruits are hanging and remain on the plant upon ripening, and in some cases, the fruit is covered and hidden from birds; the plant is interdependent with man to survive. That is, domesticated or cultivated species do not survive in their wild state because the plants have lost various defense mechanisms against natural enemies, including their seed dispersion mechanisms. In commercial varieties, the fruits and seeds are generally larger (e.g., Bell types) compared with wild forms [3, 24]. One of the evident changes during the domestication syndrome was the increase in the germination rate of cultivated forms [4].

The domestication of chili peppers generated heritable genotypic changes, which are expressed in several known phenotypic variants. Environmental and human selection modified several morphological characteristics of the fruit and plant and continues to generate significant changes to adapt to different cultivation systems (e.g., greenhouse and high input use). Current cultivation and genetic improvement impose strong selection pressures to the point of dividing cultivated forms into highly pungent, intermediate and sweet or non-pungent groups. In all cases, sources of resistance or tolerance to disease and pests are sought but with high productive efficiency [25, 26]. Chili consumers seek a great diversity of fruits with varied grades of pungency, flavor, aroma, color and sizes of ripe, immature, fresh or dry fruits. In rural households, a few plants grown in the garden or backyard produce enough fruit to satisfy the needs of a family. Traditionally, small producers keep the produced seed from a small number of cultivated plants year after year; the seeds tend to be homogeneous or homozygotic because of regular self-pollination or crossing one another. All of these factors generate high differentiation among cultivated populations [23, 24, 27].

The extensive diversity of landraces of chili in Mexico and Mesoamerica is the product of the geographic convergence of wild and cultivated species. Among the cultivated endemic species, *C. annuum* and *C. frutescens* are notable, and species introduced from South America to Mexico are *C. chinense* Jacq. and *C. pubescens* R. & P. among *C. annuum, C. frutescens* and *C. chinense*, there is a strong crosslinking capacity, called the white flower *annuum-chinensefrutescens* species complex; this complex has a high likelihood of crossing with wild variants of *C. annuum* var. *glabriusculum*, particularly when the latter acts as a male parent [28, 29]. In this biogeographical context, diversity of landraces in Mexico is generated by crossing related species, genetic flow generated by the dispersal of seeds and the selection of cultivators, including the effects of genetic drift products from the low number of plants and geographic isolation [4, 5, 27, 30–32].

In addition to the high diversity of landraces, in the Mesoamerican region of Mexico, there is a large ethnolinguistic diversity, with the presence of 28 indigenous groups including Otomí, Mazahua, Náhuatl, Popolucas, Zapoteco, Mixteco, Mixe, Amuzgo, Triqui, Mazateco, Chinanteco, Mayas, Chontales, Huaves, Chatino, Cuicateco, Chontal, Tzetzal, Tzotzil, Purépecha, Totonaco, Ocuilteco and Matlazinca [33]. Pre-Columbian cultures represented by current indigenous groups exerted a strong selection pressure on chili cultivation to satisfy all food requirements such as medicinal, cultural and ritual. Brown et al. [34] and Kraft et al. [3] studied paleobiolinguistic evidence of the domestication of *Capsicum* in Mexico. Among the primary findings was evidence of 17 words of proto-languages to designate the various cultivated and wild variants or populations of chili; among these terms are Uto-Aztecan, Otomanguean, Popolocan-Zapotecan, Chinantecan, Mixe-Zoquean, Zapotecan, Mayan, Chiapanec-Mangue, Sonoran, Tonacan, Otomapean, Mixtecan, Amuzgo-Mixtecan, Totozoquean and Popolocan, all related to the indigenous groups mentioned here. This renders it possible to distinguish relations between a high diversity of landraces and the extensive gastronomic diversity of dishes [35].

Based on the phenotypic and genetic diversity of chili peppers in Mexico, here, we use the concept of landraces as a combination of definitions proposed by Zeven [36] and Camacho-Villa et al. [37] and the dimensions of seed lots managed by growers proposed by Louette et al. [38]. Thus, a chili landrace is understood to be a dynamic population of cultivated plants in the backyard or crop plots with defined, highly variable or uniform evolutionary origins of the characteristics of the plant, strong similarity in the form of fruit, seed lots that are managed independently and high locally adapted genetic diversity, occasionally with a different name associated with traditional forms of consumption and cultivation. In various cases, the forms, flavors and aromas of the fruit are phenotypically distinguishable, and differentiation frequently obeys geographic-reproductive isolation and selection that farmers utilize. Nevertheless, from that diversity of landraces, numerous traditional and improved commercial varieties have been generated and continue to be generated.

#### **2.1. Phenotypic and genetic diversity among landraces**

During the domestication process, chili fruits and plants have undergone various genetic transformations in response to human and natural selection. Thus, by the processes of natural environmental and artificial selection, the forms, sizes, colors and flavors of the fruit began to change. Obtaining a larger fruit and greater productivity per plant is, even today, one of the goals of breeders and growers. In the domesticated or cultivated forms of chili, the fruits are hanging and remain on the plant upon ripening, and in some cases, the fruit is covered and hidden from birds; the plant is interdependent with man to survive. That is, domesticated or cultivated species do not survive in their wild state because the plants have lost various defense mechanisms against natural enemies, including their seed dispersion mechanisms. In commercial varieties, the fruits and seeds are generally larger (e.g., Bell types) compared with wild forms [3, 24]. One of the evident changes during the domestication syndrome was the

The domestication of chili peppers generated heritable genotypic changes, which are expressed in several known phenotypic variants. Environmental and human selection modified several morphological characteristics of the fruit and plant and continues to generate significant changes to adapt to different cultivation systems (e.g., greenhouse and high input use). Current cultivation and genetic improvement impose strong selection pressures to the point of dividing cultivated forms into highly pungent, intermediate and sweet or non-pungent groups. In all cases, sources of resistance or tolerance to disease and pests are sought but with high productive efficiency [25, 26]. Chili consumers seek a great diversity of fruits with varied grades of pungency, flavor, aroma, color and sizes of ripe, immature, fresh or dry fruits. In rural households, a few plants grown in the garden or backyard produce enough fruit to satisfy the needs of a family. Traditionally, small producers keep the produced seed from a small number of cultivated plants year after year; the seeds tend to be homogeneous or homozygotic because of regular self-pollination or crossing one another. All of these factors

The extensive diversity of landraces of chili in Mexico and Mesoamerica is the product of the geographic convergence of wild and cultivated species. Among the cultivated endemic species, *C. annuum* and *C. frutescens* are notable, and species introduced from South America to Mexico are *C. chinense* Jacq. and *C. pubescens* R. & P. among *C. annuum, C. frutescens* and *C. chinense*, there is a strong crosslinking capacity, called the white flower *annuum-chinensefrutescens* species complex; this complex has a high likelihood of crossing with wild variants of *C. annuum* var. *glabriusculum*, particularly when the latter acts as a male parent [28, 29]. In this biogeographical context, diversity of landraces in Mexico is generated by crossing related species, genetic flow generated by the dispersal of seeds and the selection of cultivators, including the effects of genetic drift products from the low number of plants and geo-

In addition to the high diversity of landraces, in the Mesoamerican region of Mexico, there is a large ethnolinguistic diversity, with the presence of 28 indigenous groups including Otomí, Mazahua, Náhuatl, Popolucas, Zapoteco, Mixteco, Mixe, Amuzgo, Triqui, Mazateco, Chinanteco, Mayas, Chontales, Huaves, Chatino, Cuicateco, Chontal, Tzetzal, Tzotzil, Purépecha, Totonaco, Ocuilteco and Matlazinca [33]. Pre-Columbian cultures represented by current indigenous groups exerted a strong selection pressure on chili cultivation to satisfy all food requirements

increase in the germination rate of cultivated forms [4].

408 Flavonoids - From Biosynthesis to Human Health

generate high differentiation among cultivated populations [23, 24, 27].

graphic isolation [4, 5, 27, 30–32].

The wild and cultivated chili of Mexico have been known since pre-Columbian times and are the result of genetic recombination between wild and cultivated forms, only cultivated forms or between primary and secondary genepools. Today we know these genepools as indigenous, traditional and regional varieties or landraces of high phenotypic variation in fruit and plant traits. However, these landraces have suffered genetic erosion as a result of habitat loss, changes in the use of soil from forests to cultivated or urban zones and displacement by improved varieties introduced and imposed by the demands of national or international markets [24].

There are marked phenotypic divergences among landraces, relative to sizes, forms, colors and pungency of the fruit. For example, Piquin has a fruit diameter of 2–20 mm compared with Chilaca, which has a cylindrical-elongated form that is 15–35 cm in length with a 2–6 cm diameter. Anchos are conical-triangular fruits that vary from 12 to 15 cm in length and from 8 to 10 cm in width [39]. Colors vary from coffee-reddish, yellow, light greens, dark greens, whitish and very light greens with purple anthocyaninic stains such as in the Pico Paloma and Tusta types of south-southeastern Mexican chili peppers (**Table 1**).

With regard to consumption, landraces can be classified as fresh or dry. The largest number of landraces are consumed fresh or dry; among the latter are Piquin, Guajillo or Mirasol, Costeño, Puya, Cascabel, Catarina, Canica, Chilhuacle, Ancho, Mulato, De árbol or Cola de Rata and Pasilla. A special case is the preparation of the Chipotle chili (a form of drying by smoking or by oven and pickled); Jalapeno variants are used before ripening, and the fruit is dehydrated and dried in an oven or smoked. In some cases, the fruit is dried in the sun or shade or by smoking [32, 39, 42].


#### **Species and botanical Regionalization for cropping and on-farm conservation of landraces (local and regional**

<sup>m</sup>Maya, <sup>s</sup> Español, c Cuicateco and z Zapoteco (local languages).

**Regions of distribution**: (a) **Península de Yucatán** = Estados de Quintana Roo, Yucatán and Campeche, (b) **Southsouthern**: Include the south region from Veracruz, Tabasco, Chiapas, Oaxaca and Guerrero, (c) **Central**: Cover the states of Jalisco, Colima, Michoacán, Estado de México, Guanajuato, Querétaro, Hidalgo, Morelos, Tlaxcala, Puebla and Central region of Veracruz, (d) **Northwest**: Include Zacatecas Aguascalientes, Nayarit, Sinaloa, Durango Sonora, Chihuahua Baja California Norte and Baja California Sur, and (e) **Northeast**: From North of Zacatecas, San Luis Potosí, North of Veracruz, Tamaulipas, Nuevo León and Coahuila.

Sources: González-Jara et al. [4], Pozo-Campodonic et al. [39], Votava et al. [31], Aguilar-Meléndez et al. [32], Pérez-Castañeda et al. [29], Cazáres-Sánchez et al. [40], Castañón-Nájera et al. [41], Vela [42]; Aguilar-Rincón et al. [43], Narez-Jiménez et al. [44], Loaiza-Figueroa et al. [45].

**Table 1.** Regionalization of the diversity of *Capsicum annuum* landraces in Mexico.

With regard to the level of pungency or spiciness, chili peppers are classified as quite pungent, fairly pungent, sweet or without spiciness. Any consumer of chili in Mexico recognizes Habanero and Manzano as the most spicy chilis; both variants were introduced to the country and belong to the species *C. chinense* (150,000–325,000 Scoville units) and *C. pubescens* (30,000–60,000 Scoville units), respectively [42]. After these two, De Árbol, Serrano, Jalapeño and Piquín variants follow in order of pungency. Finally, there are the moderately pungent or sweet chilis such as Dulce (sweet) chili of the Yucatan Peninsula, De agua from Oaxaca, Poblano and Güero that are particularly notable. Pungent or spicy chilis are more often preferred for the preparation of numerous dishes (**Table 1**).

**Species and botanical** 

**names)**

410 Flavonoids - From Biosynthesis to Human Health

Coxle o Chicoxlec

Ardilla, Totic de Chiapas

Península de Yucatán: Pico de Paloma<sup>s</sup>

o Tornachile, Ozuluamero, Canica del Bajío

Península de Yucatán: Maax<sup>m</sup> o Mashito, Piquín

Mirasol de Oaxaca, Miraparriba, Tabasqueño de la Frailesca

**Regions of distribution**: (a) **Península de Yucatán** = Estados de Quintana Roo, Yucatán and Campeche, (b) **Southsouthern**: Include the south region from Veracruz, Tabasco, Chiapas, Oaxaca and Guerrero, (c) **Central**: Cover the states of Jalisco, Colima, Michoacán, Estado de México, Guanajuato, Querétaro, Hidalgo, Morelos, Tlaxcala, Puebla and Central region of Veracruz, (d) **Northwest**: Include Zacatecas Aguascalientes, Nayarit, Sinaloa, Durango Sonora, Chihuahua Baja California Norte and Baja California Sur, and (e) **Northeast**: From North of Zacatecas, San Luis Potosí, North of

Sources: González-Jara et al. [4], Pozo-Campodonic et al. [39], Votava et al. [31], Aguilar-Meléndez et al. [32], Pérez-Castañeda et al. [29], Cazáres-Sánchez et al. [40], Castañón-Nájera et al. [41], Vela [42]; Aguilar-Rincón et al. [43], Narez-

, Chilpete de Jalisco

Rata o Yahualica, Cora, Piquín

Vallero de Chihuahua

Central: Piquín o Chiltepín Northwest: Piquín o Chiltepín Northeast: Piquín o Chiltepín

Península de Yucatán: Mashito<sup>m</sup>

Central: Pico de Paloma, Zacapaleño

**Table 1.** Regionalization of the diversity of *Capsicum annuum* landraces in Mexico.

Zapoteco (local languages).

Northwest: Chilpaya

Cuicateco and z

Veracruz, Tamaulipas, Nuevo León and Coahuila.

Jiménez et al. [44], Loaiza-Figueroa et al. [45].

Shirunduuz

Maax<sup>m</sup>, Canica, Sucurre, Kum<sup>m</sup>

**Regionalization for cropping and on-farm conservation of landraces (local and regional** 

South-southeastern: Guajillo o Mirasol, Pasilla o Chilaca, Ancho o Poblano, Taviche, De Agua, Costeño, Miahuateco, Mulato, Gordo, Huacle o Chilhuacle, Jalapeño, Serrano, Loco,

Apaxtleco, Achilito, Nanche, Tusta, Piquín, Piquín de Simojovel, Chocolate, De Onza, Paradito o Escuchito, Lajoyero o Joyeño o Chilaquita, Parado de Zitlala, De Monte, Tecpín de Zitlala, Morrón, Garbanzo, Ojo de Cangrejo, Güero, Bojo, Blanco de Chiapas y Tabasco, Bandeño de Guerrero, Bolita de la Frailesca, Siete Caldos, Morado, Serranito, De Gallo,

Central: Ancho o Poblano, Miahuateco, Mulato, De Chorro o Cristalino, Pasilla o Chilaca, Tecomatlán, Loco, Rayado, Jalapeño, Serrano, Criollo de Morelos, Soledad, Copi de Puebla, Guajillo o Mirasol, Tabaquero, Mirador o Chalinguero, Pico de Paloma, Piquín o Piquín Huasteco, Cascabel, Soltero, Morron, Morita, Güero, De Chorro, Comapeño de Veracruz, Catarino del Bajío, Chilacate de Jalisco, Pahueteco, Altamira Serrano de Guanajuato, Carricilo

Northwest: Ancho, Mulato, Pasilla o Chilaca, Guajillo o Mirasol, Puya, De Árbol o Cola de

Northeast: Ancho, Mulato, De Árbol o Cola de Rata o Yahualica, Guajillo o Mirasol, Serrano, Puya, Cora, Piquín, Cascabel, De Chorro, Corazón de Durango, Caloro de Chihuahua, Guajón de Zacatecas, Sarta de Sonora, Negro de Chihuahua, Sinahuisa Serrano de Sonora,

South-southeastern: Mashito o Amashito, Amashito Grande, Ojo de Cangrejo, Garbanzo, Bolita, Chingolito Amarillo, Piquín de Tabasco, Piquín Amarillo de Chiapas, Güiña

South-southeastern: Chilpaya, Tabasco, Mashito, Pico de Paloma, Bolita, Güiña Shuladiz

,

, Xcat'ik<sup>m</sup>, Ya'ax ik<sup>m</sup> o Cha'hua<sup>m</sup>, Dulce, Jalapeño,

, Gallo-Gallina, De Árbol o Cola de Rata o Yahualica, Tabaquero, Taviche,

**varieties**

*C. annuum* var. *annuum* (Cultivated and wild forms)

*C. annuum* var. *glabriusculum* (commonly as wild

forms)

*C. frutescens* (cultivated a wild

forms)

<sup>m</sup>Maya, <sup>s</sup>

Español, c

A total of slightly more than 150 landraces that are extensively planted and consumed have been described. The distribution of the diversity of chili landraces in Mexico can be divided into five regions. The Yucatan Peninsula includes the states of Quintana Roo, Yucatan and Campeche. Here, the Sucurre, Maax, Xcat'ik, Yaax ik and Dulce variants, among others, occur most frequently. Two regions are quite relevant to the in situ preservation of landraces: southsoutheast and central, in which regionally, more than 80 local varieties are preserved (**Table 1**). In these regions, the greatest diversity of indigenous groups is also concentrated; therefore, current indigenous people preserve the great diversity of landraces. The landraces of northern Mexico (northeast and northwest) are less diverse than in central and south-southeastern areas.

Wild and cultivated forms of chilis of greater diversity, endemism and distribution in Mexico are *C. annuum* var. *annuum, C. annuum* var. *glabriusculum* and *C. frutescens*. Despite advances in the distribution, classification and quantification of the genetic diversity of *Capsicum*, interest-specific hybridizations in the *C. annuum*-*C. frutescens*-*C. chinense* complex that converges in Mexico remain unexplored, including the variability generated by hybridization between landraces and improved introduced varieties. Among landraces, strong genetic divergences have been documented by differences in regionally distributed populations. For example, by nine isoenzymatic systems, Loaiza-Figueroa et al. [45] determined high isoenzymatic diversity by the population description of 186 accessions.

The preservation of a large diversity of landraces is associated with a culture of exploitation of the species that originated in pre-Columbian times [1–3]. Among the aspects that continue to draw attention to gastronomic use are the variety of flavors, aromas and spicy characteristics, including variations in color in dishes and perceptions that are associated with compositions of the fruit in terms of capsaicinoids, flavonoids and polyphenols, among other compounds. In a traditional rural Mexican family, it is quite unlikely that the diet does not include chilis as a condiment, sauce or main dish.

Many authors have demonstrated that there is great genetic diversity among the populations of a landrace. With regard to diversity between and within landraces, Contreras-Toledo et al. [46] and Toledo-Aguilar et al. [47], using microsatellite markers, demonstrated great genetic diversity within the Ancho or Poblano, Piquín, Guajillo and Chilaca landraces. Kraft et al. [27] indicated that divergences among landraces are fundamentally a result of the form of selection of the seed and isolated management of the crop. This same pattern is observed among wild forms (e.g., Piquín), which grow spontaneously in backyards [4]. Pacheco-Olivera et al. [23], in evaluations of the genetic diversity of Mexican chili peppers by microsatellites, observed that the diversity and genetic differentiation of three landraces were statistically similar to the evaluated pattern in seven commercial hybrids.

#### **2.2. Regionalization of production and consumption of chili landraces**

In Mexico, the cultivation and consumption of chili peppers have great economic and social importance. In 2015, 153,565 ha were cultivated, with an average production of 2.8 million tons of dried and fresh fruit. Of the total production, 22,143 and 793,501 tons of dry and fresh fruit were exported, respectively. National consumption neared 2 million tons, and in some years, imports of approximately 20,757–41,000 tons have been reported [6]. Consumption per capita in urban areas is from 8 to 9 kg, and in rural communities, it varies from 14 to 17 kg. Landraces and varieties of greater production and consumption are Jalapeño, Ancho, Serrano, Guajillo, Poblano and Mirasol, with more than 9000 hectares planted. The varieties of highest consumption dried are Ancho, Guajillo and Mirasol. Serrano, Jalapeño and Ancho are grown throughout in nearly all of Mexico (**Table 2**).


Flavonoid and Capsaicinoid Contents and Consumption of Mexican Chili Pepper (*Capsicum annuum* L.) Landraces http://dx.doi.org/10.5772/68076 413


1 SIAP [6]; Species: p*C. pubescens*, c *C. chinense* and without superscript are *C. annuum*.

observed that the diversity and genetic differentiation of three landraces were statistically

In Mexico, the cultivation and consumption of chili peppers have great economic and social importance. In 2015, 153,565 ha were cultivated, with an average production of 2.8 million tons of dried and fresh fruit. Of the total production, 22,143 and 793,501 tons of dry and fresh fruit were exported, respectively. National consumption neared 2 million tons, and in some years, imports of approximately 20,757–41,000 tons have been reported [6]. Consumption per capita in urban areas is from 8 to 9 kg, and in rural communities, it varies from 14 to 17 kg. Landraces and varieties of greater production and consumption are Jalapeño, Ancho, Serrano, Guajillo, Poblano and Mirasol, with more than 9000 hectares planted. The varieties of highest consumption dried are Ancho, Guajillo and Mirasol. Serrano, Jalapeño and Ancho are grown

**State of production origin1 Landraces, improved varieties and local populations of** 

Baja California Sur Bell, Anaheim, Caloro, Jalapeño, Serrano, Poblano,

Durango Ancho, Puya, Jalapeño, Poblano, Anaheim, Bell Guanajuato Chilaca, Serrano, Jalapeño, Poblano, Bell, Anaheim Guerrero Ancho, Costeño, Puya, Chilaca, Guajillo, Mirasol, Serrano

Hidalgo De Árbol o Cola de Rata, Jalapeño, Serrano, Bell,

México Manzanop, Jalapeño, Serrano

Morelos Anaheim, Serrano, Jalapeño

Jalisco De Árbol o Cola de Rata, Tabaquero, Anaheim, Caloro,

Anaheim

**fresh and dry chili peppers**

, Jalapeño

Paprika, Poblano, Serrano,

Serrano, Bell, Anaheim

, Jalapeño, Serrano

, Serrano, Costeño

Chilaca, Jalapeño, Poblano, Serrano, Bell

Cristal, Jalapeño, Serrano, Anaheim, Bell

, Bell, Anaheim, Serrano, Poblano, Jalapeño

, Ancho, Colorado, De Árbol o Cola de Rata,

, Pasilla, Caloro, Chilaca, De Árbol o Cola de Rata, Jalapeño, Manzano o Peronp, Piquín, Poblano,

, Cascabel, De Árbol o Cola de Rata, Caloro,

Mirasol, Pasilla, Caloro, Cayenne, Chilaca, Jalapeño,

similar to the evaluated pattern in seven commercial hybrids.

throughout in nearly all of Mexico (**Table 2**).

412 Flavonoids - From Biosynthesis to Human Health

**2.2. Regionalization of production and consumption of chili landraces**

Aguascalientes Guajillo, Poblano o Ancho Baja California Norte Serrano, Jalapeño, Anaheim, Bell

Campeche Habaneroc

Coahuila Habaneroc

Colima Habaneroc

Chiapas Habaneroc

Chihuahua Habaneroc

Michoacan Habaneroc

Nayarit Habaneoc

**Table 2.** Regionalization of landraces and improved varieties cropping by production origin.

According to the geography, altitude and climates of Mexico, there are six primary patterns of cultivation: (a) Habanero variants (*C. chinense*) are sown preponderantly in Yucatán, Quintana Roo and Campeche, although recently, Habanero was cultivated in Coahuila, Chihuahua, Colima, Nayarit and Michoacán, (b) diverse Manzano (*C. pubescens*) chilis are cultivated in Central Mexico in Michoacán, Estado de México, Puebla and Veracruz, (c) the commercial Morrón (sweet bell) varieties are preponderantly distributed in the north such as in Bell, Anaheim, California and Victoria, which are exported to the United States of America, (d) Ancho, Guajillo, Poblano and Pasilla variants are grown from Guanajuato to Zacatecas and Tamaulipas and finally, (e) varieties with regional distribution include Chilhuacle in Oaxaca and Guerrero, Tabaquero in Tabasco and Soledad in Veracruz and Oaxaca, among other patterns (**Table 2**).

Several references contrast the beneficial and harmful effects of capsaicinoids consumed by chilis. Despite advances in the demythification of harmful effects, studies nevertheless refer to capsaicin as a risk factor for cancer [14, 48]. Recent studies indicate a lack of direct association between chili peppers and capsaicinoid consumption and cancer or several other diseases. Capsaicin is used as a topically applied analgesic to decrease pain in rheumatoid arthritis, osteoarthritis, neuralgias, neuropathic diabetes, neuronal inflammations and dysfunctions, among others [15, 17]. The use of capsaicinoids is controversial, and it is necessary to further investigate their effects on human health because among other aspects, it is not possible to extrapolate from biological studies of animals (e.g., rats) to humans [13, 17].

#### **2.3. Chili peppers in Mexican gastronomy**

The varied forms of chili consumption are characteristic of traditional Mexican cuisine and are ancestral and living cultural expressions of the community, a part of the Mexican national identity [49]. In Mexico, there is a great preference for spicy chili, whose consumption is more common in people who live in hot, tropical or subtropical climates than in people who live in temperateto-cold regions [50]. The sensation of heat or sting is the result of the presence of various types of capsaicinoids such as capsaicin, dihydrocapsaicin, homodihydrocapsaicin, nordihydrocapsaicin and homocapsaicin, among others, which have vanillin, 8-methyl-N-Vanillyl-6-nonemide, as a base compound. During ingestion, chemo-static stimuli are generated that affect chemical stimulation of thermoreceptors, nociceptors and somatosensory receptors [51].

The populations of Mexico, Central and South America show evolutionary adaptations according to the food these people consumed. Culinary culture in Mexico is as diverse as differences in ethnicity, geography and ecology; the current cuisine is a combination of indigenous pre-Columbian, Spanish and French cuisines and, in some regions, Lebanese. Recent times have seen a marked influence of American culture, increasing Mexicans' consumption of carbohydrates. In Mexican families, food consumption practices are taught from childhood; mothers give chili to children from 1 to 3 years of age. This evidence of cultural reinforcement is primarily focused on distinguishing the flavonoid principles of food consumption. Common foods are bean broth, soups prepared with tomato (*Solanum lycopersicum* L.) and dishes flavored with chili; as the child grows, chili consumption increases. Consuming such foods helps to transmit identity from parents to children and implicitly strengthens the food culture [52].

In practical terms, the continued consumption of chili pepper through several generations has engendered genetic modifications in the population of Mexican consumers. Capsaicin tolerance is closely associated with AVI (alanine, valine and isoleucine) allelic variants of the TAS2R38 type 2 gene in the tongue and palate. Consequently, homozygotic carriers of the AVI haplotype of the taste receptor perceive only a slight "burning" sensation. This genetic variant is also associated with a low perception of a bitter flavor. That is, a lower perception of bitterness in other foods and a lower perception of the burning of chili are because of TAS2R38 [50, 53, 54].

The Mexican consumer of chili has an extensive variety of landraces that the consumer produces himself or can buy in local and regional markets, from the "sweet" types or types without spice to moderately spicy and extremely spicy, and all are widely used in regional cuisine and family diets. Chilies are consumed in whole, ground, sliced, diced, dried, roasted forms or can be acquired pickled in cans from nearly all landraces. Chilis are essential to Mexican gastronomy and played a decisive role in UNESCO's designating Mexican cuisine the "intangible cultural heritage of mankind" (Decision 5.COM 6.30, 2010) [55].

The variety of chili landraces is directly associated with a wide variety of processing forms for consumption. Among chili and forms of consumption are the following groups of peppers and preparation styles:

Capsaicin is used as a topically applied analgesic to decrease pain in rheumatoid arthritis, osteoarthritis, neuralgias, neuropathic diabetes, neuronal inflammations and dysfunctions, among others [15, 17]. The use of capsaicinoids is controversial, and it is necessary to further investigate their effects on human health because among other aspects, it is not possible to

The varied forms of chili consumption are characteristic of traditional Mexican cuisine and are ancestral and living cultural expressions of the community, a part of the Mexican national identity [49]. In Mexico, there is a great preference for spicy chili, whose consumption is more common in people who live in hot, tropical or subtropical climates than in people who live in temperateto-cold regions [50]. The sensation of heat or sting is the result of the presence of various types of capsaicinoids such as capsaicin, dihydrocapsaicin, homodihydrocapsaicin, nordihydrocapsaicin and homocapsaicin, among others, which have vanillin, 8-methyl-N-Vanillyl-6-nonemide, as a base compound. During ingestion, chemo-static stimuli are generated that affect chemical stimu-

The populations of Mexico, Central and South America show evolutionary adaptations according to the food these people consumed. Culinary culture in Mexico is as diverse as differences in ethnicity, geography and ecology; the current cuisine is a combination of indigenous pre-Columbian, Spanish and French cuisines and, in some regions, Lebanese. Recent times have seen a marked influence of American culture, increasing Mexicans' consumption of carbohydrates. In Mexican families, food consumption practices are taught from childhood; mothers give chili to children from 1 to 3 years of age. This evidence of cultural reinforcement is primarily focused on distinguishing the flavonoid principles of food consumption. Common foods are bean broth, soups prepared with tomato (*Solanum lycopersicum* L.) and dishes flavored with chili; as the child grows, chili consumption increases. Consuming such foods helps to transmit

In practical terms, the continued consumption of chili pepper through several generations has engendered genetic modifications in the population of Mexican consumers. Capsaicin tolerance is closely associated with AVI (alanine, valine and isoleucine) allelic variants of the TAS2R38 type 2 gene in the tongue and palate. Consequently, homozygotic carriers of the AVI haplotype of the taste receptor perceive only a slight "burning" sensation. This genetic variant is also associated with a low perception of a bitter flavor. That is, a lower perception of bitterness in other foods and a lower perception of the burning of chili are because of TAS2R38 [50, 53, 54]. The Mexican consumer of chili has an extensive variety of landraces that the consumer produces himself or can buy in local and regional markets, from the "sweet" types or types without spice to moderately spicy and extremely spicy, and all are widely used in regional cuisine and family diets. Chilies are consumed in whole, ground, sliced, diced, dried, roasted forms or can be acquired pickled in cans from nearly all landraces. Chilis are essential to Mexican gastronomy and played a decisive role in UNESCO's designating Mexican cuisine the "intan-

extrapolate from biological studies of animals (e.g., rats) to humans [13, 17].

lation of thermoreceptors, nociceptors and somatosensory receptors [51].

identity from parents to children and implicitly strengthens the food culture [52].

gible cultural heritage of mankind" (Decision 5.COM 6.30, 2010) [55].

**2.3. Chili peppers in Mexican gastronomy**

414 Flavonoids - From Biosynthesis to Human Health


Mole is a typical Mexican national dish resulting from the fusion of Spanish and pre-Columbian indigenous cuisines. The word *mole* (in Spanish) comes from the indigenous language Nahuatl "*molli*", which means a mix of ingredients and flavors. Ingredients and forms of preparation vary from region to region or between states. For example, moles from Puebla, Oaxaca, Tlaxcala, Estado de México, Querétaro, Michoacán and Hidalgo are quite popular. The dish is a combination of different chili landraces (e.g., Ancho, Pasilla, Morita and others) and various fruits, seeds and bulbs, depending on the mole variant (**Table 3**). However, the essential ingredients, according to connoisseurs, are the chilis. In Oaxaca, seven types of moles are prepared, and the most popular are "negro (black mole) with Chilhuacle", "verde" (green mole) with Jalapeño or Serrano chilis, "coloradito" (reddish mole) with Ancho and Guajillo chilis, red mole with Ancho and Guajillo chilis and Amarillo (yellow mole) with Anchos, Guajillos and Costeños. Additionally, "chichilo" and "manchamantel" ("tablecloth-staining") moles are mentioned. For each type of mole, the complementary condiments vary [56].

Another common dish of Mexican cuisine is from spicy to extremely spicy salsas, which are prepared with fresh or dried chilis, cooked or uncooked, and are a traditional form of promoting spicy flavors (capsaicinoids), flavonoids, aromatic compounds and phenolic compounds. Occasionally, chilis are roasted and ground with green tomato (husk tomato, *Physalis ixocarpa* Brot.), red tomato (*S. lycopersicum*), garlic, onion, salt and water. In other cases, all of the ingredients are cooked and then ground (**Table 3**). From one region to another, the primary ingredients and forms of preparation vary. In this sense, Mexican guacamole is the addition of avocado to green salsa (e.g., Jalapeño or Serrano chilis cooked with green tomato, plus garlic and water) in which pieces of avocado are mashed slightly once the green salsa is ground, all of this in a "molcajete" (a rock with a hole) [57]. A group of Mexican dishes prepared with different local varieties of chilis is listed on **Table 3**. It is unlikely that the level of consumption of chilis in Mexico will decrease in the short term.


**Table 3.** Typical dishes of the Mexican cuisine where main ingredients are the diversity of landraces or improved varieties of chili pepper.
