Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2005
Publication Date: 3/26/2005
Citation: Wu, X., Prior, R.L. 2005. Identification and characterization of anthocyanins by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry in common foods in the united states: vegetables, nuts, and grains. Journal of Agricultural and Food Chemistry. 53(8):3010-3113.
Interpretive Summary: Anthocyanins are the components in foods that give the dark red, blue or black colors in many foods, particularly fruits and berries. Because of the number of different sugars and other chemical structures that can be attached to the basic anthocyanin molecule, there are over 600 different compounds that have been identified. In this publication, anthocyanins in common foods in the U.S., other than fruits and berries, were systematically identified and characterized. Of all the 40+ vegetables, nuts and grains screened, seven vegetables, one nut and one grain were found to contain anthocyanins; the number of anthocyanins detected varied from two in pistachio nuts to 34 in red radish. Anthocyanins in certain vegetables such as red cabbage and red radish had very complex chemical structures which were highly conjugated with various sugars and other groups. Three varieties of sorghum were found to contain anthocyanins with a different basic anthocyanin structure compared to other foods. A large number of new anthocyanins were identified in the foods studied. This is the first time that common foods have been studied for their anthocyanin content under the same experimental conditions which allows for much more detailed identification of specific anthocyanins in foods.
Technical Abstract: Anthocyanins in common foods in the United States, other than fruits and berries, were identified and characterized by high-performance liquid chromatography (HPLC)-electrospray ionization-tandem mass spectrometry coupled with diode array detection. Of all of the 40+ vegetables, nuts, and grains screened, seven vegetables, one nut, and one grain were found to contain anthocyanins; the number of anthocyanins detected varied from two in pistachio nuts to 34 in red radishes. The individual anthocyanins were identified by comparing their mass spectrometric data and retention times with those of standards, published data, and reference food samples. In all of the samples analyzed, except for sorghum, only six common anthocyanidins (delphinidin, cyanidin, pelargonidin, petunidin, peonidin, and malvidin) were found as their glycosides. Anthocyanins in certain vegetables such as red cabbage and red radish were highly conjugated with sugars and acylated groups, and thus, their structures were very complicated. Eight different either aliphatic or aromatic acylated groups (acetoyl, coumaroyl, malonoyl, p-hydroxybenzoyl, feruoyl, caffeoyl, sinapoyl, and oxaloyl) were identified in the anthocyanins. In addition to glucose, six other sugar moieties (galactose, xylose, rhamnose, rutinose, sambubiose, and laminaribiose) were observed. Three varieties of sorghum were found to contain 3-deoxyanthocyanidins and their derivatives as major anthocyanins. A number of new anthocyanins were identified in the foods studied. This paper presents complete HPLC profiles and MS spectrometric data, obtained under the same experimental conditions, for common vegetables, pistachio nuts, and sorghum that contain anthocyanins.