**1. Introduction**

*Cynara cardunculus* L. is a herbaceous perennial diploid plant. It is the most widespread species of the genus *Cynara* and belongs to the Asteraceae family. Recent revisions about *Cynara* genus classification have sparked discussion over whether wild cardoon (*C. cardunculus* var. *sylvestris*), cultivated cardoon (*C. cardunculus* var. *altilis*) and globe artichoke (*C. cardunculus* var. *scolymus* L.) should be classified as different species, or as subspecies [1]. Studies about morphology and phytogeography of the *Cynara* genus supports that the referred plants belongs to a single species and should consequently be classified as subspecies [2–8]. Regardless the subspecies, cardoon is part of Mediterranean flora, distributed throughout the Mediterranean basin, Macaronesia (Madeira and Canary Islands), North Africa, Cyprus and Turkey [2, 9–11], is also a colonizer in Mexico, California, Argentina, Chile, Peru, Australia, China and West Africa [11–13]. Regarding artichoke, its production is worldwide disseminated, with great economic impact, especially in Italy, Spain, France and Turkey [12]. The production of cultivated cardoon seems to be more restricted to South Europe, namely in Spain, Italy, France, Greece and Portugal [13–17].

Artichoke extracts make part of commercial dietary juices and capsules for digestion dysfunction treatment, being related with the bioactive extractives composition [30]. Nevertheless, cultivated cardoon leaves can be a good substitute for green forage during wintertime [14], and a great biomass source of the sesquiterpenic lactone cynaropicrin [31]. Moreover *C. cardunculus* L. presents diverse nutraceutical, pharmacologic and/or therapeutic properties [32–38].

In Portugal, *C. cardunculus* is known as "cardo de coalho" or "cardo hortense" [39, 40]. The richness of inflorescence pistils in aspartic proteases, named cardosins, has potentiated its wide use for cheesemaking for centuries [41]. Aqueous extracts of *C. cardunculus* pistils have been successfully employed for centuries in the manufacture of French, Italian, Spanish and Portuguese cheeses, and legally required to manufacture a number of protected designation of origin (PDO) cheeses in Portugal and Spain. The coagulant enzymes extracted from *C. cardunculus L*. flowers, cardosins, are aspartic proteinases, which have been assigned specific and technologic consequences, namely in sheep cheeses [42]. In cheesemaking, these enzymes show a similar action to other aspartic proteinases used in cheesemaking, such as chymosin. Cleaving the Phe105-Met106 binding of ovine and bovine κ-caseins [43–45] allowing the casein micelles aggregation by the milk ionic calcium. Cardosins reveal a more intense

The most recent knowledge regarding the use, conservation, preparation and application of *Cynara cardunculus* plants in cheesemaking and others biotechnological applications are

The taxonomy on the gender *Cynara* has evolved over time, and it seems to exist some confusion about the type of plants that fall under the designation of *C. cardunculus* L. species; even for the use in cheese manufacture, the descriptions of plants have been a little variable. In fact, the definition of the species that comprises the genus *Cynara* is somewhat complex, because some of them take different names, appearing eventually placed in other genera, with which there are affinities. For example, the number of species considered in the genus review of Wiklund [2] is eight, whereas the previous treatment of the same genus, in 1838, considered only three.

Illustrating the designations complexity or classification, Bailey and Bailey [46] refer to 10 Mediterranean species, 7 of which are referred to by Tutin et al. [47] as European: *C. scolymus*, *C. tournefortii*, *C. humilis*, *C. cardunculus*, *C. cornigera*, *C. alba* and *C. algarbiensis*. However, the species *C. humilis* is often identified as belonging to the genus *Bourgea* (*Bourgea humilis* L.) [2, 48] and *C. alba* corresponds, according to Valdes et al. [48], to the species *C. baetica*, also referred as belonging to the genus *Cirsium*. From this, one species, *Cirsium vulgare*, was used by Wiklund [2] as a test for its study of the genus *Cynara*. *C. scolymus* is referred to as spontaneously unknown by Tutin et al. [47] and Franco [49]. Moreover, Foury [3] distinguish only three species: (i) *C. cardunculus*, whose distribution coincides with that found by Wiklund [2]


*Cynara cardunculus:* Use in Cheesemaking and Pharmaceutical Applications

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secondary proteolytic action on cheese α<sup>s</sup>

reviewed in the present chapter.

**2.1. Origin and population structure**

the cheeses biochemical and sensory properties.

**2. The species** *Cynara cardunculus* **L.**

Wild cardoon grows spontaneously in marginal areas of field crops, pastures and along paths in dry areas and in soils of various characteristics. The plant, either cultivated or wild, can persist for a number of years, over 10 years, re-sprouting annually from its large perennial taproot [18, 19]. New seedlings usually germinate after the autumn rains, then first cotyledons emerge, growing slowly through in a rosette arrangement. Cardoon plants hold in the rosette stage during winter and early spring, when stalks start to elongate. As the flower stems develop, the lower rosette leaves begin to die off. Plants usually flower in the early summer, followed by the dieback of their aerial growth. Seedlings do not generally flower in their first year, as their energy is absorbed on the development of its deep taproot. New growth occurs with the autumn rains, and the cycle starts over [16].

Both plant agronomic characteristics and human selection of certain phenotypes, over the years, can possibly explain the use specificity, of each subspecies, for different purposes. *C. cardunculus* L. species lignocellulosic fraction shows great potential as solid biofuel [14], as well as for biogas production [20, 21] and bioethanol [22, 23]. *C. cardunculus* L. biomass productions can reach 14–20 t DW/ha per year, while according the studies of Pesce et al. [24], the wild cardoon accession was less productive in terms of biomass accumulation (11.8 t DW/ ha per year) compared to cultivated forms (*Altilis* 41′ and 'Bianco avorio') producing, respectively, 19.1 t and 16.8 t DW/ha per year. Stalks and capitula of cultivated cardoon may also be used to produce pulp fibers [14, 25, 26]. In Southern Portugal, a region characterized by very hot and dry summers, a large scale cultivation of the cardoon *C. cardunculus* L. for biomass production was installed in a total of 77.4 ha. The field biomass yield was estimated at 7.5 t/ha, and the seed yield was 603 kg/ha after the second growing season [16].

*C. cardunculus* seed's oil fatty acid composition has also revealed a great potential for biodiesel production [14, 27]. *C. cardunculus* seed yield, and see oil composition is quite similar to sunflower oil. *Cynara* crop seed yield has been estimated at 1.36 t/ha per year [28], and a maximum seed oil content of 32.47% has been described by Curt et al. [29], while oil composition is on average 11% palmitic, 4% stearic, 25% oleic and 60% linoleic fatty acids.

Artichoke extracts make part of commercial dietary juices and capsules for digestion dysfunction treatment, being related with the bioactive extractives composition [30]. Nevertheless, cultivated cardoon leaves can be a good substitute for green forage during wintertime [14], and a great biomass source of the sesquiterpenic lactone cynaropicrin [31]. Moreover *C. cardunculus* L. presents diverse nutraceutical, pharmacologic and/or therapeutic properties [32–38].

In Portugal, *C. cardunculus* is known as "cardo de coalho" or "cardo hortense" [39, 40]. The richness of inflorescence pistils in aspartic proteases, named cardosins, has potentiated its wide use for cheesemaking for centuries [41]. Aqueous extracts of *C. cardunculus* pistils have been successfully employed for centuries in the manufacture of French, Italian, Spanish and Portuguese cheeses, and legally required to manufacture a number of protected designation of origin (PDO) cheeses in Portugal and Spain. The coagulant enzymes extracted from *C. cardunculus L*. flowers, cardosins, are aspartic proteinases, which have been assigned specific and technologic consequences, namely in sheep cheeses [42]. In cheesemaking, these enzymes show a similar action to other aspartic proteinases used in cheesemaking, such as chymosin. Cleaving the Phe105-Met106 binding of ovine and bovine κ-caseins [43–45] allowing the casein micelles aggregation by the milk ionic calcium. Cardosins reveal a more intense secondary proteolytic action on cheese α<sup>s</sup> - and β-casein than other coagulants, with impact on the cheeses biochemical and sensory properties.

The most recent knowledge regarding the use, conservation, preparation and application of *Cynara cardunculus* plants in cheesemaking and others biotechnological applications are reviewed in the present chapter.
