Study On Extraction And Purification Process Of The Anthocyanins From Black Bean Peal

The black soybean could be used as food and medicinal materials and are planted in most provinces and areas of China. The red pigment from black bean peal is a natural pigment. Its main ingredient is anthocyanins. The harmless natural edible pigment was conspicuous topic in the phyto-chemistry and the food scientific research in recent years. The anthocyanins from the black bean peal are important natural organic compound, besides taking the edible pigment, it also has the vital significance to treatments and the prevention disease, such as tumor, senile, cardiovascular of humanity. Black bean peal are so facile and cheap that they can meet the expectation of industry. There are great potential applications of anthocyanins in food and medicine fields. In this paper, Black bean peal produced in Shaanxi was used as the experimental material, the extraction and purification of icariin had been studied. The main research is as follows.Firstly, this paper compared the two extracting methods which were circumfluence extraction by ethanol and uitrasonic extraction. The optimum extracting conditions obtained from the orthogonal design were: the extractant was consisted of pH2.0,50% ethanol,the black bean peal were soaked in extractant for 120 minutes at 50℃,under the condition the ratio of raw material and extractant was 1:50(g:mL). The rate of extraction was 86.7%. The result of experiments showed that the optimal conditions of extracting anthocyanins pigment with ultrasonic method were: the extractant was consisted of pH2.0,50%ehtanol,the black soybean hull were soaked in extractant for 15 min at 50℃under ultrasonic condition,the ratio of raw material and extractant was 1:25.The rate of extraction was 95.2%.In order to determinate the content of anthocyanins in pigment,the pH differential method was studied. The anthocyanins content of black bean peal was 3.836mg/g calculated by the pH differential method. Two methods to purify anthocyanins pigment were studied. First remove the polysaccharides,proteins and other impurities by 60%and 70%,80%,95% ethanol solution in sequence. The colour characteristic of anthocyanins pigment purified by precipitation method was 43.6.Then the anthocyanins pigmet was further purified by macroporous resins. Through comparisons among four kinds of resins' adsorption,desorption property and adsorption dynamic,AB-8 resin was selected as the adsorbent. Effects of pH value,flow rate on adsorption and effects of eluent flow rate,pH value on desorption were also studied. The result was as follow: when the pH value in solution of pigment was 4.0,the flow rate was 1.0mL/min,the adsorption content was 10.046mg/g(resin); while 90% ethanol with pH1.5 as eluent,flow rate at 0.5mL/min,the desorption rate was 91.6%. The color characteristics of purified anthocyaninspigment was 50.5.