从等电母液中蒸发结晶得到的二次结晶谷氨酸,其硫酸铵、色素等杂质含量高,不能直接精制生产味精,转晶是提高二次结晶谷氨酸质量的途径之一。实验研究了转晶温度、pH值、转晶料水比等因素对谷氨酸转晶的影响,得到比较理想的转晶条件:转晶温度95℃,pH值4.5,转晶料水1∶2.5,活性炭添加量为1%(1g活性炭/100g二次结晶谷氨酸)。

GASCP was produced from the isoelectric liquor by evaporative crystallization process,in which a large amount of impurities such as pigments,(NH4)2SO4 remained.This made the product cannot be further purified to produce MSG.The solution mediated transformation(SMT) of L-glutamic acid is one of the ways to improve the quality of the GASCP.The effects of temperature,pH,ratio of GASCP/water and the use of activated carbon on the SMT of GASCP were investigated.Based on the researches,the ideal conditions for SMT of GASCP were determined as follows: temperature was 95℃,pH 4.5,the ratio of GASCP/water was 1∶ 2.5,the mount of activated carbon was 1%.