**1. Introduction**

Radicchio (*Cichorium intybus* L.; Asteraceae) is a popular salad vegetable in the Mediterranean region, and its usage is increasing in Europe. Other cultivated types of this species are Italian chicory, French endive, witloof, sugarloaf, and succory. It has been known since 1616, when it was first mentioned in Germany. Cultivation began in England in 1886 and later in 1926 also France. There is a discussion about whether radicchio should be classified as a root or a leafy vegetable crop. It can be produced for leaves, rosettes, or heads with a wide range of colors [1]. Radicchio is typically consumed as a raw vegetable in various fresh, mixed, or garnished salads [2,3].Itspopularity among consumers andits nutritional characteristics have greatpotentialfor growth in the local markets as well as in the international ones. Most radicchio varieties thrive best during cooler, moist weather and do not tolerate high temperature. Radicchio is a leafy vegetable that can withstand low temperatures, which gives it an advantage for consumption in the winter time of the year when the supply of fresh leafy vegetable in the market is limited [4]. In addition, radicchio represents a plant with several medicinal properties and effects [5].

Vegetable production in many countries depends on high-input systems to maximize yield and product quality, while they try to achieve low production costs, which keep local products competitive in international markets [6]. Conventional high-input farming system is often associated with problems, such as nitrate leaching and ground water pollution, degradation of soil structure, and pesticide contamination [7–10]. The answers to problems associated with conventional practices are alternative cropping systems. Over the past decade, criteria have been developed, which define organic crop production requirements [11]. Now, there exist several national systems of designated requirements to have vegetable products marketed as » organically produced«. In fresh vegetable market, organically grown products of reasonable quality are readily available, but their price is usually much higher compared to those grown by the other than organic manner [12,13].

The polyphenol compositions of vegetable depend on several factors. It is influenced by genetic as well as environmental factors, such as temperature, light, moisture, and the nutritional status of the soil in which the vegetable is grown [14,15]. It is also influenced by the growing manner, phase of maturity, postharvest managements, and storage conditions. Moreover, many vegetables are processed before they are used for consumption. Processing methods, such as cooking and canning, can also influence the polyphenol composition of the vegetable. Regular consumption of vegetables is proven to be associated with lower risks of various types of modern diseases, such as chronic or cardiovascular diseases [7,16].

Polyphenols are organic compounds widely distributed in vegetables. All phenolic com‐ pounds have an aromatic ring that contains various attached substituent groups, such as hydroxyl, carboxyl, and methyl groups, and often other nonaromatic ring structures. Phenolics differ from lipids in higher solubility in water and lower solubility in nonpolar organic solvents. These properties greatly aid in the separation of phenolics from one another and from other compounds. Many phenolics arise from the shikimic acid pathway and its subsequent reactions. Among these are cinnamic, *p*-coumaric, caffeic, ferulic, chlorogenic, protocatechuic, and gallic phenolic acids. They are important not because they are abundant in uncombined (free) form but because they are converted into several derivatives besides proteins. These derivatives include phytoalexins, coumarins, lignin, and various flavonoids, such as the anthocyanins [17]. Chlorogenic acid is widely distributed in various parts of many plants and usually occurs in easily detectable quantities. Both chlorogenic and protocatechuic acids have special functions in disease resistance of plants. Gallic acid is important because of its conver‐ sion to gallotannins, which are heterogeneous polymers containing numerous gallic acid molecules connected in various ways to one another, to glucose, and to other sugars [18].

**1. Introduction**

310 Organic Fertilizers - From Basic Concepts to Applied Outcomes

by the other than organic manner [12,13].

Radicchio (*Cichorium intybus* L.; Asteraceae) is a popular salad vegetable in the Mediterranean region, and its usage is increasing in Europe. Other cultivated types of this species are Italian chicory, French endive, witloof, sugarloaf, and succory. It has been known since 1616, when it was first mentioned in Germany. Cultivation began in England in 1886 and later in 1926 also France. There is a discussion about whether radicchio should be classified as a root or a leafy vegetable crop. It can be produced for leaves, rosettes, or heads with a wide range of colors [1]. Radicchio is typically consumed as a raw vegetable in various fresh, mixed, or garnished salads [2,3].Itspopularity among consumers andits nutritional characteristics have greatpotentialfor growth in the local markets as well as in the international ones. Most radicchio varieties thrive best during cooler, moist weather and do not tolerate high temperature. Radicchio is a leafy vegetable that can withstand low temperatures, which gives it an advantage for consumption in the winter time of the year when the supply of fresh leafy vegetable in the market is limited [4]. In addition, radicchio represents a plant with several medicinal properties and effects [5]. Vegetable production in many countries depends on high-input systems to maximize yield and product quality, while they try to achieve low production costs, which keep local products competitive in international markets [6]. Conventional high-input farming system is often associated with problems, such as nitrate leaching and ground water pollution, degradation of soil structure, and pesticide contamination [7–10]. The answers to problems associated with conventional practices are alternative cropping systems. Over the past decade, criteria have been developed, which define organic crop production requirements [11]. Now, there exist several national systems of designated requirements to have vegetable products marketed as » organically produced«. In fresh vegetable market, organically grown products of reasonable quality are readily available, but their price is usually much higher compared to those grown

The polyphenol compositions of vegetable depend on several factors. It is influenced by genetic as well as environmental factors, such as temperature, light, moisture, and the nutritional status of the soil in which the vegetable is grown [14,15]. It is also influenced by the growing manner, phase of maturity, postharvest managements, and storage conditions. Moreover, many vegetables are processed before they are used for consumption. Processing methods, such as cooking and canning, can also influence the polyphenol composition of the vegetable. Regular consumption of vegetables is proven to be associated with lower risks of various types

Polyphenols are organic compounds widely distributed in vegetables. All phenolic com‐ pounds have an aromatic ring that contains various attached substituent groups, such as hydroxyl, carboxyl, and methyl groups, and often other nonaromatic ring structures. Phenolics differ from lipids in higher solubility in water and lower solubility in nonpolar organic solvents. These properties greatly aid in the separation of phenolics from one another and from other compounds. Many phenolics arise from the shikimic acid pathway and its subsequent reactions. Among these are cinnamic, *p*-coumaric, caffeic, ferulic, chlorogenic, protocatechuic, and gallic phenolic acids. They are important not because they are abundant in uncombined

of modern diseases, such as chronic or cardiovascular diseases [7,16].

Of the various classes of naturally occurring compounds based on the flavonoid skeleton, flavone and flavonols are collectively the most abundant group. The distinction between flavones and flavonols, which are 15 carbon compounds, is an arbitrary one, as flavonols are simply a class of flavone in which the 3-position is substituted by a hydroxyl group [19]. Anthocyanins are present as glycosides, usually containing one or two glucose or galactose units attached to the hydroxyl group in the central ring or to that hydroxyl group at the 5 position of the A ring. When the sugars are removed, the remaining parts of the molecules, which are still colored, are called anthocyanidins. Anthocyanins are soluble and reasonably stable, whereas anthocyanidins produced on acid hydrolysis are insoluble in water, unstable to light, and rapidly destroyed by alkali [20]. Flavones and flavonols are easier to identify than anthocyanins because they are more stable [21]. Several polyphenols, such as derivatives of hydroxycinnamic acids (HCA), flavonoids, and anthocyanins [4,6,22–27], previously deter‐ mined in radicchio leaves are presented in **Table 1**.


**Table 1.** Phenolic compounds reported in radicchio leaves from scientific data.

Lipids are derived from long-chain fatty acids and alcohols or closely related derivatives. They are water-insoluble components of cells that can be extracted by nonpolar solvents. In various parts of the plants, mostly in the cell membranes, are small amounts of lipids (~2%). In higher plants, the predominant fatty acid residues consist of palmitic, oleic, linoleic, and stearic acid.

Fatty acids with <12 and >20 carbon atoms are less common in nature [28]. The most common fatty acids in plants are those containing 16 or 18 carbon atoms. These include saturated palmitic (C16:0) and stearic (C18:0) acids, monounsaturated oleic acid (C18:1n9), polyunsatu‐ rated linoleic acid with two double bonds (C18:2n6), and linolenic acid with three double bonds (C18:3n3) [29]. When the carbon atoms in the hydrocarbon chain of a fatty acid hold their full complement of hydrogen, they are described as saturated. Where two adjoining carbon atoms in the hydrocarbon chain of a fatty acid each lack a hydrogen atom, a double bond forms between them. The fatty acid is then said to be unsaturated. The term polyunsaturated fatty acid (PUFA) is accepted as referring to those fatty acids that contain two or more carbon-carbon double bonds within the hydrocarbon chain [30]. Particular PUFAs, which the human system can employ as building blocks while being unable to synthesize them, have been classed as essential fatty acids. The *n*-3 (ω-3, omega-3) PUFAs found in plants refer to a number of health benefits [31]. The most common and most important PUFA is linolenic acid, which is known as a precursor of the long-chain fatty acids (eicosapentaenoic and docosahexaenoic) [32]. Modern agriculture and food industrialization are associated with large changes in the structure of contemporary Western diets. The intake of *n*-6 fatty acids has enlarged during evolution, and the intake of *n*-3 fatty acids has been reduced. Consequently, the *n*-6/*n*-3 ratio increased from 1 to 10 or, in some places, even up to 20 or even 25. These differences in food consumption led to increased risk of numerous modern diseases [33].

Over the past decade, radicchio has become popular for cultivation and consumption in different regions of the world. Scientific literature has revealed that radicchio plants contain important compounds with biological activity and several vitamins and minerals [4,18,34–36]. The effects of fertilizer managements (organic, mineral) on the phenolic and fatty acid profiles in different radicchio varieties (red, red-spotted, green) are poorly discussed in scientific data. This chapter discusses the effect of fertilizers (organic, mineral, and combination) on the total phenolics, the main phenolic classes, and the fatty acids levels of five *C. intybus* varieties. Highperformance liquid chromatography (HPLC) was used for the analysis of phenolic compounds and their classes and gas chromatography (GC) was used for the determination of fatty acid levels.
