Development Of Purple Sweet Potato Color Preparations And Metabolism Research

As a natural pigment,purple sweet potato color has a variety of physiological functions,internal researches mostly focused on the extraction,purification and physiological functions,but the technology of pigment preparation needs to be further studied,and the metabolism of pigment in the body is lack of research.In this paper,three kinds of purple sweet potato color preparations were prepared,and the stability and in vitro release of pigment preparations were analyzed,at the same time,the metabolism of purple sweet potato color in vitro and in vivo was studied,the metabolic products were preliminarily discussed.Microcrystalline cellulose was selected as the matrix material of the pigment adsorption,through the static adsorption experiment,the optimum adsorption conditions were determined:adsorption temperature was 25℃,adsorption time was 30 min,the dosage of absorbent was 0.2 g,the initial concentration of pigment was0.6 mg/mL,under this condition the adsorption capacity was 22.4 mg/g.The adsorption of the pigment on the microcrystalline cellulose was in accordance with the Langmuir adsorption isotherm equation,the dynamic characteristic analysis found that the internal diffusion model is more consistent with the dynamic behavior.The alginate and alginate-chitosan were selected as the matrix material of the pigment embedding,two kinds of pigment microcapsules were prepared by orifice method,the optimal embedding conditions of two kinds of pigment microcapsules were determined respectively.The optimum conditions were sodium alginate concentration 2%,core wall ratio 1:4,CaCl₂ concentration 2%,curing time 120 min and sodium alginate concentration 1.5%,core wall ratio 1:3,CaCl₂ concentration 1%,chitosan concentration 0.6%,embedding rate was 76.2%and 85.6%respectively.The two kinds of pigment microcapsules both can improve the stability of the pigment,in vitro release experiments showed that the two kinds of pigment microcapsules had good slow release or control release effect.To detect the plasma metabolites of purple sweet potato pigment,protein precipitation method was selected as the method of plasma sample pretreatment,the precipitating agent was 1% formic acid acidification of acetonitrile,detection of pigment in the plasma not only in the presence of a prototype,but also detected the presence of other metabolites,suggested that the metabolites were alycones and the product of the alycones phase II metabolism.The absorption and metabolism of the pigment in gastrointestinal tract is mainly located in the small intestine,and in the stomach,the time is short.In vitro metabolism experiments proved that the metabolism of pigment depends on the function of enzymes and microorganisms,hydrolyze and phase II metabolism play the major role,has a good correlation with in vivo metabolism.