脱色和干燥方式对普鲁兰多糖品质的影响

Influence of decolorization and drying methods on the quality of pullulan polysaccharides

研究了脱色和干燥方式对普鲁兰多糖品质的影响。从四种型号的活性炭中选出效果最好的ZY-24×48-B型活性炭,在单因素的基础上,采用正交实验优化活性炭脱色工艺。结果表明最佳的脱色条件:活性炭添加量1.0%(w/v)、pH5.0,时间40min,温度40℃,此时脱色率为94.98%,多糖得率为91.24%。之后通过研究微波干燥、喷雾干燥及冷冻干燥三种工艺对普鲁兰多糖样品的纯度、微观表征、溶解度及色泽的影响,确定最佳的工业化生产的干燥方式。结果表明,喷雾干燥所得到样品纯度可达91.07%,色泽较白,溶解度较好;冷冻干燥所得样品溶解度最好,L值(95±0.21)最高,但干燥时间长且成本高;微波干燥得到样品出现褐变,L值(89±0.68)最低。综合考虑产品品质及能耗成本等因素,喷雾干燥最适合普鲁兰多糖的工业化生产。

The decoloration and the influence of drying methods on the quality of pullulan polysaccharides were mainly studied. First,the type of ZY-24×48-B was selected from four types of activated carbon. Based on the single factor result,orthogonal experiment was performed to select the best condition for decoloration of puilulan. The best technological process of decoloration was adding 1.0% （w/v） activated carbon to pullulan solution at 40℃ ,with pH at 5.0 and decoloring the solution for 40min. The decolorization rate was 94.98%, pullulan polysaccharide yield was 91.24%. Then the suitable drying methods of pullulan polysaccharides for industrialized production was determined which was depended on the effect of microwave drying,spray drying and vacuum freeze drying on the quality of the purity of pullulan polysaccharides,tmicroscopic characterization,solubility and colour. The test indicated that the colour of spray dried product were better than that of microwave dried （L=89 ±0.68） but less than vacuum freeze dried（L=95±0.21 ）. The purity of pullulan polysaccharides was 91.07% which was obtained by spray drying,and exhibited the better solubility and colour. The vacuum freeze dried product had the best solubility,but it had long time and high cost. Among the three drying methods,spray drying was the most suitable for the actual industrial production.