Sweet Cherry/Cherry Fruit

Carbohydrates are the main chemical compounds in cherries (12–17%) and the dietary fiber representing 1.3–2.1% of total compounds. Sugar content typically ranges from 11 to 15% (Table 1), depending on climatic conditions, cultivation system and rootstock. Sugar composition is directly related to total soluble solids (TSS), one of the most important factors determining consumer acceptability. Sweetness and acidity are important indicators of fresh fruit quality and taste. Malic, shikimic, fumaric, quinic and citric acids have been detected in sweet cherries with malic acid accounting for over 98% of the total organic acid content. However, acidity decreases during development and ripening (Blando & Oomah, 2019)

Amount per 138g cherries

Source: USDA Food Data Central

Sweet cherries are also good sources of indolamines. Cherries are considered a good source of potassium (170–260 mg/100 g FW) and other minerals occur in low concentrations, including phosphorous, calcium and magnesium. Ascorbic acid (vitamin C) generally ranges between 6 and 10 mg/100 g FW, although some Estonian cultivars contain up to 27 mg/ 100 g FW, while other cultivars have lower than 4 mg/100 g FW.

Fonte: USDA Food Data Central

In cherry, as in other red fruits, the ripening process is related to a change from the initial green colour to red, with the accumulation of polyphenolic compounds and anthocyanins, associated with the degradation of chlorophyll. Phenolic compounds are concentrated in the skin and contribute to sensory and organoleptic qualities of fruits, such as taste and astringency. Furthermore, it has been demonstrated that they are bioactive compounds. The phenols contained in sour and sweet cherries have been characterized (Serrano et al., 2005). Cyanidin 3- glucoside, cyanidin 3-rutinoside, cyanidin 3-sophoroside, pelargonidin 3-glucoside, pelargonidin 3- rutinoside, 3-glucoside, and peonidin 3-rutinoside have been identified in sweet and sour cherries (Mozeti~ et al., n.d.; Vodopivec et al., n.d.). Among phenolic acids, hydroxycinnamates (neochlorogenic acid and p-coumaroylquinic acid) have been determined both in sweet and sour cherries. Flavonols and flavan-3-ols such as catechin, epicatechin, quercetin 3-glucoside, quercetin 3-rutinoside, and kaempferol 3-rutinoside were also found in sweet and sour cherries (Chaovanalikit & Wrolstad, 2004b). The higher levels of total phenolics in sour cherries have been attributed to higher concentrations of anthocyanins and hydroxycinnamic acids (Kim et al., 2005).

Besides these features, sweet cherries are also appreciated for their nutritional properties, particularly their content of bioactive compounds (BCs) with additional health benefits. The edible thin protective exocarp (skin) of mature cherries contains the highest concentration of phytochemicals with substantially less in the plump mesocarp (Blando & Oomah, 2019).

Total phenolic content of sweet cherries depends on cultivars (Chaovanalikit & Wrolstad, 2004a; Chockchaisawasdee et al., 2016), and the environment (growing location), for example, cultivars grown in southern Europe display higher total phenolic content (82–192 mg/100 g) than those in northern Europe (44.3–87.9 mg/100 g) (Blando & Oomah, 2019). In sweet cherries, gallic (0.73–10.64 mg per 100 g of FW), p-hydroxybenzoic (0.73–10.64mg per 100 g of FW), and 2,5-dihydroxybenzoic acids (0.46–1.64mg per 100g of FW) are the most prevalent. On the other hand, hydroxycinnamic acids are composed of nine carbon atoms, and the main compounds are caffeic, coumaric, ferulic, and sinapic acids, which are present in widely consumed foods. The major one is the caffeic acid, which typically occurs combined with quinin acid, forming the 5-O-caffeoylquinic acid (chlorogenic acid). In sweet cherries, 40 chlorogenic acids were identified, corresponding to 61.9%–91.5% of the total noncolored phenolic compounds. The most abundant ones are the 3-O-caffeoylquinic (neochlorogenic), the p-coumaroylquinic, and the 5-O-caffeoylquinic acids (4.74–11.9 mg, 0.77–7.20 mg, and 0.60–2.61 mg per 100 g of FW, respectively). The presence of hydroxybenzoic and hydroxycinnamic acids and their derivatives in sweet cherries has been associated with their nutritional, sensory, flavour, and colour characteristics, and with their antioxidant properties (Gonçalves et al., 2018).

The main flavonoid subclasses found in sweet cherries include flavanols, flavan-3-ols, and anthocyanins, and in small level, flavones, flavanonols, and flavanones. They are considered responsible for the health benefits resulting from the consumption of these fresh fruits (Gonçalves et al., 2018).

Flavonols

In sweet cherries, quercetin-3-O-rutinoside is the main flavanol detected, ranging from 5.13 ± 0.13 to 51.97 ± 2.29 mg per 100 g of FW, followed by quercetin-3-O-glucoside (0.39 ± 0.00–26.55 ± 0.35 mg per 100 g of FW), kaempferol-3-O-rutinoside (1.30 ± 0.01–8.13 ± 0.06 mg per 100 g of FW), and kaempferol-3-O-glucoside (0.40 ± 0.01–1.36 ± 0.03 mg per 100 g of FW). Trace amounts of quercetin-3-O-hexoside, quercetin-7-O-glucoside-3-O-rutinoside, kaempferol-rutinoside-hexoside, isorhamnetin-3-O-rutinoside, and myricetin-3-O-rutinoside are also reported in sweet cherries (Gonçalves et al., 2018), (Blando & Oomah, 2019).(Chaovanalikit & Wrolstad, 2004a).

Flavan-3-ols

Relative to their presence in sweet cherries, (-)-epicatechin is the dominant flavan-3-ol, varying between 6.33 ± 0.29 and 14.84 ± 0.45 mg per 100 g of FW, followed by (+)-catechin (2.92 ± 0.12–9.03 ± 0.06 mg per 100 g of FW). Catechin glucoside (2.03 ± 0.05–10.16 ± 0.02mg per 100 g of FW) and epicatechin-3-gallate (1.82 ± 0.03–3.12 ± 0.07 mg per 100 g of FW) are also reported, as well as proanthocyanidins (ranging from 7.2 to 20.2 mg per 100 g of FW) (Gonçalves et al., 2018).

Anthocyanins

Twelve different anthocyanins have been reported in sweet cherries. Cyanidin-3-O-rutinoside is the main one (2.05 ± 0.06–389.90 ± 12.15 mg per 100 g of FW), followed by cyanidin-3-O-glucoside (0.01 ± 0.00–142.03 ± 0.85 mg per 100 g of FW), peonidin-3-O-rutinoside (2.27 ± 0.04–50.50 ± 0.70 mg per 100 g of FW), and pelargonidin-3-O-rutinoside (0.12 ± 0.00– 7.97 ± 0.32 mg per 100 g of FW). Some of the sweet cherry cultivars most rich in anthocyanins are Burlat, Navalinda, Hedelfinger, Saco, and Pico Negro. On the other hand, Satin was reported as one of the poorest in anthocyanins (Gonçalves et al., 2018). Great amounts of apigenin and luteolin are also found in sweet cherry fruits.

Flavanones: In sweet cherries the presence of hesperetin, naringenin-hexoside, sakuranetin and sakuranin were reported, accounting less than 1% of total phenolic compounds.

Flavanonols: In sweet cherries, the presence of two isomers of taxifolin-O-hexoside and another two isomers of taxifolin-O-rutinosides was reported, representing 9.94% of total phenolics, along with three aromadendrin derivatives (Gonçalves et al., 2018).

The physiological benefits of cherries on humans have focused primarily on sports nutrition for muscle recovery, although the extent of this assumption is controversial. Instead, their anti-gout effects are demonstrated through the attenuation of plasma urate, C-reactive protein and nitric oxide (NO) concentrations, without affecting plasma albumin and tumour necrosis factor-α after cherry consumption. Anthocyanins from cherries exert their beneficial effects through mechanisms including anti-inflammatory and anti-proliferative activities. Studies in vivo and in vitro have shown that sweet cherry anthocyanins inhibit NO production and other pro-inflammatory factors (such as TNF-α), as well as cyclooxygenase II, the pro-inflammatory class of enzymes playing an important role in inflammation and other pathological disorders. Moreover, they exert their antioxidant function by inhibiting lipid peroxidation more potently than classic antioxidants, preventing the atherogenic LDL oxidation and therefore preventing cardiovascular disease. These features make cherries not only an appealing fruit for their good taste, but the ‘healing fruits’ as they have been defined. Nevertheless, further human feeding studies are still needed to assess the dose-response of standardized cherry produce, to conclusively association between cherries consumption and the reported health benefits.