**2.3. Phenolic composition of blueberries**

influence on phenolic levels. Indeed, Gonçalves et al. [26] stated that higher temperature and solar irradiation favored the biosynthesis of phenolic acids and decreased the content of antho‐ cyanins. However, the phenolic content tends to reach highest levels in the late stage of final maturity as refereed by Stöhr et al. [33]. In recent research, the preharvest application of several products to improve cherry quality, such as the oxalic acid (2 mM), has been studied, which increased anthocyanins, flavonols, neochlorogenic, and chlorogenic acids [34]. All the pheno‐ lic compounds and the antioxidant activity increased in several sweet cherry cultivars during cold storage [26, 27, 32, 35]. Also, the level of phenolics in "Canada Giant" and "Ferrovia" cherries increased during 8 days of shelf life [36]. Nevertheless, Esti et al. [37] detected a total anthocyanin content decrease of 41–52% in two sweet cherry cultivars after 15 days at 1°C and 95% RH. The use of edible coatings has been used to extend the postharvest storage of cher‐ ries. Petriccione et al. [38] specified that chitosan‐coated sweet cherries presented higher total phenolic, flavonoid, and anthocyanin levels. Moreover, increasing health‐promoting properties of cherry fruit can be achieved with the addition of methyl salicylate treatment to cherry trees. This compound also delays the fruit postharvest senescence process by increasing the activity

**Figure 1.** HPLC chromatogram of the Van sweet cherry cultivar extracts recorded at 280 nm. Adapted from

Burlat 23.8 24.7 3.8 7.2 6.7 4.8 23.2 44.6 <1.0 <1.0 2.1 Saco 153.5 12.2 9.8 10.5 10.3 11.8 5.1 38.6 n.d. <1.0 <1.0 Summit 34.4 27.5 7.2 5.8 8.2 3.1 2.4 26.0 <1.0 <1.0 <1.0 Van 65.6 5.6 4.8 3.5 4.5 4.0 3.4 28.2 <1.0 <1.0 1.5 NcAc, neochlorogenic acid; *p*CqAC, *p*‐coumaroylquinic acid; CAc, chlorogenic acid; Cat, catechin; Epi, epicatechin; Rut, Rutin; cy‐3‐glu, cyanidin‐3‐*O*‐glucoside; cy‐3‐rut, cyanidin‐3‐*O*‐rutinoside; pn‐3‐glu, peonidin‐3‐*O*‐glucoside; plg‐3‐rut,

**Table 1.** Content of several phenolic compounds in four sweet cherry cultivars (mg /100g fresh weight).

**NcAc** *p***CqAC CAc Cat Epi Rut cy‐3‐glu cy‐3‐rut pn‐3‐glu plg‐3‐rut pn‐3‐rut**

**Cultivar Hydroxycinnamic acids Flavan‐3‐ols Flavonols Anthocyannis**

pelargonidin‐3‐*O*‐rutinoside; pn‐3‐rut, peonidin‐3‐*O*‐rutinoside; n.d., not detected.

of the enzymes involved in ROS scavenging [39].

264 Phenolic Compounds - Natural Sources, Importance and Applications

Gonçalves et al. [26].

Adapted from Gonçalves et al. [26].

Blueberries are flowering plants of the genus *Vaccinium* with dark‐purple berries, whose anthocyanins are considered to be nature's most potent antioxidants [47]. The genus *Vaccinium* belongs to the *Ericaceae* family [48] and includes many popular berries consumed around the world including blueberries, huckleberries, cranberries, lingonberries, and bilberries [49]. Of the more than 400 species in the genus *Vaccinium*, highbush, lowbush, and rabbiteye blue‐ berries (*V. corymposum* L., *V. augustifolium* Ait., and *V. ashei* Reade, respectively) are of high economic importance [50]. In fact, in recent years the production of these fruits has increased rapidly in Europe and across the globe, as a result of the recognition of their high nutritive value, characteristic taste, and flavor but also due to recent press regarding the health benefits of fresh berries consumption [51, 52]. Over 89,820 acres of land are growing cultivated blue‐ berries with an estimated annual production of 280,000 tons [53]. Blueberries are both a food product and a dietary supplement, consumed not only as fresh fruits but also as frozen fruits, or in dried or preserved form in bakery products. Blueberry anthocyanins are used as a natu‐ ral food colorant [54] and blueberry extract can be used as a prebiotic [49]. The fruit quality traits and the phytochemical content of blueberries are of increasing importance to research‐ ers in the field of food and health [55]. Blueberries are a source of vitamins, minerals, dietary fiber, phenolics, and flavonoids and they are very low in fat and sodium [56]. Anthocyanins, which provide blueberry with their characteristic colors, are the major polyphenols in blue‐ berries and this group of phytochemicals is thought to be responsible for many of the health benefits of berry consumption [57]. The anthocyanins detected in blueberries are 3‐glycosidic derivatives of cyanidin, delphinidin, malvidin, petunidin, and peonidin [49]. Nevertheless, anthocyanins vary in their quantity and composition among genotypes and also depend on the environmental growth conditions, postharvest storage conditions, and the method of analysis. Anyway, malvidin‐3‐glucoside and malvidin‐3‐galactoside have been found to be the two most predominant anthocyanins in many cases [58]. Blueberries also contain varying amounts of other polyphenols, and chlorogenic acid is particularly high as compared with other food sources [59]. It is accompanied by small amounts of quercetin glycosides [60].
