Preliminary study on spectrums and structure properties of pigments from Ziziphus jujube peel

In order to investigate the pigments ’ composition and structural properties of Ziziphus jujube peel extracts, after systematic extraction, the pigments were mainly distributed in ethyl acetate (Ⅰ) , n-butanol (Ⅱ) and aqueous (Ⅲ) phases. Then, before the content measurement, the color reaction, UV- visible spectroscopy and infrared spectroscopy were detected successively. Conclusion: the colors of three phases were yellow, orange and red, respectively. Content measurement reflected that ethyl acetate phase (Ⅰ) contained the highest total flavonoids and phenolic acids, while least in aqueous phase (Ⅲ) . Both ethyl acetate (Ⅰ) and n-butanol (Ⅱ) exhibited obviously color change induced by the typical flavonoid structure substance, while the color changes of aqueous (Ⅲ) phases were weak during the color reaction. It’s observed that there were apparent peaks near 280nm for each phases, shoulder peaks near 305 and 350nm were observed in ethyl acetate (Ⅰ) and n-butanol (Ⅱ) , respectively in the UV-visible spectrum; IR spectrum revealed that 3270, 2930, 1605, 1447, 1356, 1280, 1250, 1197, 1140, 1060, 1010, 868, 817, 777, 620cm-1 were the main absorption of the three phases. It revealed that Ziziphus jujube peel extracts contained phenolic acids, flavonoids, and a kind of red pigment ( water-soluble, enriched in aqueous phase (Ⅲ) ) , according to phenomenon in aqueous phase, it could be neither flavonoid nor phenolic acids, but substances containing benzene and hydroxyl group.