Study On The Purification Of Maltose By Ion Exchange Chromatography And Its Crystallization

With good qualities such as special light and mild flavor, low sweetness, heat-resisting, acid-resisting, as well as unique physiological characteristics of metabolism without the presence of insulin, maltose has a broad prospect of application in the food processing, pharmaceutical and health care products production area. Meanwhile, maltose can also be used as the production material of crystalline maltitol, maltose fatty acid ester, etc, thus its application value grows increasingly, which also put forward higher request for the maltose purity.Maltose is one of the main products of starch by enzyme hydrolysis. Due to the specific hydrolysis way of a–amylase, the product will inevitably be mixed with a few glucose and other undesired oligosaccharides, which lead to the reduction of the purity of maltose products, and inhibition on the subsequent crystallization process as well. In order to solve this problem, a chromatography method was employed in this paper to study the separation of glucose from maltose; aims to find a suitable resin filling that could be used especially for the separation of maltose and glucose to make the purity of the maltose syrup meet the high demand of the crystalline maltose production. Besides, the trial of crystallization maltose preparation was carried out to get more understanding about the crystallization properties of maltose. The main research results are as follows:(1) The purity of rich maltose component, maltose yield and rich maltose component recovery rate were chosen as the main indexes for evaluation of the purification effect. Eight types of calcification resins were adopted in this experiment to separate glucose from maltose, including gel type resins of 732, C107, C108, C110, C100/6100 H, and macroporous type resins of C151, C150, C160. The result showed that C110 gel type cationic resin exhibited best separation effect among the chosen resins: the purity of rich maltose component was 66.58%, which increased the maltose purity by 33.16% compared to raw syrup, and a higher maltose recovery rate of 70.84%.(2) The cationic resin C110 was used to separate and purify maltose, five factors were studied to find out their influence on the purification process, including the elution temperature, eluant flow velocity, resin column height-diameter ratio, sample volume, and the concentration of sample. Proper operating conditions were obtained: temperature 70℃; eluant flow velocity 0.5 mL/min; the height-diameter ratio 53; sample volume 5.0 mL; and sample concentration 2.0 mg/mL. Under these conditions, the total sugar elution peak of C110 cationic resin was good, the resolution between the two sugars can be improved to 0.80. The purity of rich maltose component collected was 72.31%, which increased the maltose purity by 44.62% compared to raw syrup; at the same time the maltose yield achieved 70.13%, and rich maltose components recovery rate was 58.60%.(3) With the high purity maltose reagent used as the crystallization material, solvent-ultrasonic ethanol-ultrasonic nucleation approach was employed for the production of maltose seed crystal. Four factors were studied to find out their influence on the nucleus form of maltose seed crystals, including the solids content of supersaturated maltose syrup, ethanol dosage, ultrasonic power, and ultrasonic processing time. Proper operating conditions were obtained: the solids content of supersaturated maltose syrup 78%, ethanol dosage 0.5 mL/g, ultrasonic power 80 W, and ultrasonic processing time 2 min. The maltose seed paste prepared under this condition was used to prepare the crystal maltose in a constant temperature water-bath water shock environment of 50℃, supersaturated maltose syrup were added properly to promote the growth of the crystal. The maltose massecuite was separated by centrifugal separation, and the final crystallization product was dried in a vacuum to constant heavy, the crystallization rate was 65%.