The Extraction, Characterization And Stability Of Pigment From Chinese Jujube

Chinese jujube （Ziziphus jujuba Mill.）, belongs to the family of Rhamnaceae, is a traditional Chinese medicine and has been reported to have many pharmacological activities, such as tonic, nourishing blood, enhancing body resistance etc. With the maturity of Chinese jujube, its peel changes from green green-white to yellow-white, half red and red. The thick red color of Chinese jujube, being regarded as“China Red”, is believed to be lucky, happy and auspicious in China. The aim of the study was to find the best extraction conditions, the characterization and the stabilities of the pigment. Besides the contents of chlorophyll a, chlorophyll b, carotenoids, flavonoids and phenolics were determined to analyze the changes of 5 forming color ingredients during fruit maturation of Chinese jujube（jinsixiaozao, zanhuangdazao, linyilizao, dongzao） and wild jujube（beiqi 11, suanzao 11, ziyuanpu D, xingtai 0619）. The results can provide academic evidence for scientific development and application of Chinese jujube pigment. The main results are as follows:1. The optimum extraction conditions were determined as followed: extraction solvent 0.5% NaHCO3, extraction temperature 50℃, solvent concentration 0.5%, extraction time 3.5h and material/solvent ratio 1:220.2. The purification process showed that dealing with 1M HCl, petroleum ether and desalination with osmosis was efficiency method to purify jujube pigment.3. Jujube pigment constitution were analyzed by Infrared and color reactions. Infrared spectrum result supplied that the pigment contains the functional group of -OH, C=C, C=O,≡CH, aromatic nucleus or heterocyclic nucleus. The phenomenon of color reactions showed that the pigment extract contains flavonoids.4. The analysis of pigment stabilities indicated that the pigment was stable in light, temperature, neutral and alkaline solution, Na+ and K+ conditions. When acid solution, Mg²⁺, Ca²⁺, Zn²⁺, Cu²⁺, Fe²⁺, Fe³⁺, Mn²⁺, Pb²⁺ and Sr²⁺conditions exist, the pigment was obviously unstable. The pigment also presented high stabilities with addition of carbohydrates, food additives and preservatives, but distinctly unstable with the existence of oxygenant and reducing agent.5. The contents of chlorophyll a, chlorophyll b, carotenoids and flavonoids during different developing stage fruits of Chinese jujube and wild jujube were falling rapidly at first then changing gradually and contents of phenolics were falling firstly, then increasing, then falling gradually. Their contents arrived all the highest levels were at the green maturing stage and these components in wild jujube were higher than Chinese jujube. The contents in jinsixiaozao at red maturing stage were chlorophyll a 0.023mg/g, chlorophyll b 0.034mg/g, carotenoids 0.015mg/g, flavonoids 0.540mg/g and phenolics 0.060mg/g respectively. The content of flavonoids constitutes 80.4% of these substances.6. The analysis about correlations of various pigment compounds in different cultivars Chinese jujube and wild jujube showed that a high content of one compound indicate the high contents of other compounds.The analysis about correlations of pigment compounds content at various maturing stage in different cultivars showed that a high contents of flavonoids and phenolics at one developing stage indicate the high contents of flavonoids and phenolics at other developing stage.The analysis about correlations of pigment compounds content in different cultivars at various maturing stage showed that a high contents of CA, Car and flavonoids in one cultivar indicate the high contents of CA, Car and flavonoids in other cultivars.7. The contents of chlorophyll a, chlorophyll b, carotenoids, flavonoids and phenolics in pigment powder were 0.001mg/g, 0.003mg/g, 0.001mg/g, 15.149mg/g and 0.232mg/g respectively. The content of flavonoids constitutes 98.5% of these substances.