谷氨酸钠(MSG,谷氨酸一钠)、5'-肌苷酸二钠(IMP)和5'-鸟苷酸二钠(GMP),是主要增味成分。I+G是IMP和GMP按照1∶1混合的物质。研究谷氨酸钠及I+G的热处理稳定性,在食品烹调和食品加工过程中具有重要意义。实验主要采用高效液相色谱法测定杀菌温度、杀菌时间、pH对谷氨酸钠和I+G含量的影响。实验发现:杀菌时间为30 min时,经85℃,100℃,121℃杀菌,谷氨酸钠浓度分别损失3.16%,13.21%和30.10%;I+G浓度分别损失8.18%,12.91%和22.97%。在100℃下,经5,15,30 min杀菌,谷氨酸钠浓度分别损失1.43%,7.25%和8.63%;I+G浓度分别损失6.08%,8.78%和10.12%。在100℃下加热15 min,pH分别为7,6,5,4,3时,谷氨酸钠浓度分别损失2.2%,10.30%,22.4%,39.09%,52.50%;I+G浓度分别损失7.59%,9.30%,10.60%,12.89%,26.33%。

Monosodium glutamate(MSG),disodium 5'-Inosinate(IMP)and guanosine 5'-monophosphate disodium salt(GMP)are main components that enhance flavour.I+G is composed of 50% IMP and 50% GMP.Study on processing stability of MSG and I+G has food production and processing significance.This experiment mainly used HPLC to measure the content change of monosodium glutamate and I+G which were treated with different sterilization temperature,sterilization time and acidity.The results showed that when sterilization temperature was 85℃,100℃,121℃ for 30 min,monosodium glutamate lost 3.16%,13.21%,30.10% respectively,and I+G lost 8.18%,12.91%,22.97% respectively.When sterilization time was 5min,15min,30minutes at 100℃,monosodium glutamate lost 1.43%,7.25%,8.63% respectively,and I+G lost 6.08%,8.78%,10.12% respectively.When acidity declined from pH 7 to pH 3(pH 7,pH 6,pH 5,pH 4,pH 3) at 100℃ for 15min,monosodium glutamate lost 2.2%,10.30%,22.4%,39.09%,52.50% respectively,and I+G lost 7.59%,9.30%,10.60%,12.89%,26.33% respectively.