Abstract
According to the paper chromatographic test on the kidney bean's (Phaseolus vulgaris, cultiva. Kintoki) extracts, it was found that the orange red colour was due to four kinds of anthocyanins. For the identification of these anthocyanin pigments, Kintoki beans were treated as follows.
Kintoki beans were macerated with 1% methanolic hydrochloric acid and the filtered extracts were concentrated under reduced pressure. To remove nonpigment constituents water extracts of pigments were applied to ion exchange resins (Amberlite CG-50). The pigments were eluted from the resins with methanol containing small amount of HC1. After concentration of the eluates, four pigments were separated from each other by cellulose coloum chromatography. After purification on mass paper chromatographic method, each pigment (A, B, C and D) was crystallized from 1% methanolic HCl.
The aglycone and the sugar obtained by acid hydrolysis of each purified anthocyanin were determined by paper chromatography. In order to determine the position and number of sugar residues in the anthocyanins, the partial acid hydrolysis method was used. Rf values and the spectrophotometric data of the anthocyanins were compared with the authentic specimens.
From these cumulative evidence, it was concluded that the anthocyanins in Kintoki beans were pelargonidin-3-monoglucoside, cyanidin-3-monoglucoside, pelargonidin-3, 5-diglucoside and cyanidin-3, 5-diglucoside.
