Cyanidin-3-monoglucoside

There are five anthocyanidins in the grape delphinidin 1, petunidin 2, malvidin 3, cyanidin 4, and peonidin 5. These aglycones exist in different heterosidic forms or as anthocyanins 3-monoglucosides, 3,5-diglucosides, and acylated heterosides, whose structures, in the case of malvidin, are represented by formulas 6, 7, and 8. In the acylated anthocyanins, one molecule of cinnamic acid, more generally p-coumaric acid, is esterified with the —OH group in the sixth position of a glucose molecule (12). 

Two series of ions are evident, representing monoglucosides (1-5) and acetylglucosides (6-10) of the following aglycones cyanidin (1, 6 1.40), peonidin (2, 7 1.41), delphinidin (3, 8 1.42), petunidin (4, 9 1.43) and malvidin (5, 10 1.44). These results were obtained with a first-generation (continuous mode) MALDI mass spectrometer that did not have delayed... 

Anthocyanidins (aglycones), flavyliun salts (chlorides), are shown generally by (1), the anthocyanins (3-monoglucosides) by (2), and 3,5-diglucosides by (3). The major anthocyanidins are cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin and the substituents in their structures are shown below for the formula (1). Table 3... 

These molecules are much more stable in glycoside (anthocyanin) than in aglycone (antho-cyanidin) form. Only monoglucoside anthocyanins (Figure 6.10) and acylated monoglucoside anthocyanins have been identified in Vitis vinifera grapes and wines acylation is made with p-coumaric (Figure 6.10), caffeic and acetic acids. 

Apart from these, very few identifications of anthocyanins in foods seem to have been made, though some of those listed have since been confirmed. Thus Sondheimer and Kertesz (1948) have confirmed that the pigment of strawberries is pelargonidin monoglucoside. In Jonathan and Stayman Winesap apples the pigment has been identified as cyanidin-3-galactoside (Sando, 1937). 

Anthocyanins are the most abundant pigments in red grape skins (Fig. 83.2a). These water-soluble pigments are responsible for blue, red, and purple color in red grape skin and red wine. Anthocyanins of Vitis are monoglucosides of five anthocyanidins, namely, delphinidin, cyanidin, petunidin, peonidin, and malvidin. Acylated anthocyanins are esters of the glucose moiety of the free anthocyanins with acetic, p-coumaric, or caffeic acids (Fig. 83.2a). 

---