Kobayashi Kazuhiro, Yatsukawa Yoichi, Tanaka Masaharu, Tanabe Soichi, Tanaka Mitsuru, Suzuki Takuya
Global Food Safety Institute, Nissin Foods Holdings Co., Ltd., 2100 Tobuki-machi, Hachioji, Tokyo 192-0001, Japan.
Global Innovation Research Center, Nissin Foods Holdings Co., Ltd., 2100 Tobuki-machi, Hachioji, Tokyo 192-0001, Japan.
Heliyon. 2019 Jan 25;5(1):e01169. doi: 10.1016/j.heliyon.2019.e01169. eCollection 2019 Jan.
We developed a discriminant method based on the stable isotope ratio of carbon and nitrogen (δC and δN) to evaluate whether monosodium glutamate (MSG) is used in processed food samples. δC measurements were performed by elemental analyzer/isotope-ratio mass spectrometry (EA/IRMS) for on glutamic acid isolated from samples at high purity, and δN measurements were performed by gas chromatography/combustion/IRMS (GC/C/IRMS) following the purification and derivatization steps. By applying these methods, the δC and δN values for glutamic acid present in a wide variety of processed foods were obtained. Subsequently, discriminant analysis, which is a statistical analysis method, was performed by using the δC and δN values from seasoning MSG and glutamic acid from foodstuffs of known origin, and the discriminant function was derived. By substituting the measured δC and δN values of processed food samples into this discriminant function and classifying samples into two groups, seasoning MSG (the seasoning group) and glutamic acid in foodstuffs (the foodstuff group), we determined whether seasoning MSG had been used in the processed food samples. As a result, the accuracy of distinguishing between the seasoning group and the foodstuff group was very high, i.e., 96.2%, indicating that the proposed method is a highly robust and accurate method for determining whether seasoning MSG has been used in for processed foods.
我们开发了一种基于碳和氮稳定同位素比（δC和δN）的判别方法，以评估加工食品样品中是否使用了味精（MSG）。通过元素分析仪/同位素比率质谱仪（EA/IRMS）对从样品中高纯度分离出的谷氨酸进行δC测量，在纯化和衍生化步骤之后，通过气相色谱/燃烧/IRMS（GC/C/IRMS）进行δN测量。通过应用这些方法，获得了各种加工食品中谷氨酸的δC和δN值。随后，使用来自调味味精的δC和δN值以及已知来源食品中的谷氨酸，进行判别分析（一种统计分析方法），并得出判别函数。通过将加工食品样品的实测δC和δN值代入该判别函数，并将样品分为两组，即调味味精（调味组）和食品中的谷氨酸（食品组），我们确定了加工食品样品中是否使用了调味味精。结果，区分调味组和食品组的准确率非常高，即96.2%，这表明所提出的方法是一种用于确定加工食品中是否使用了调味味精的高度稳健且准确的方法。
