Sodium polyacrylate (SPA) and propylene glycol alginate (PGA) are food additives that act as thickeners and stabilizers in foods. Diversification of food additives has been demanded according to the development of processed foods and the range of use has been widening. However, the development of methods for the analysis of food additives in food was insufficient. Therefore, there was a difficulty in the management inspection of whether the use prohibited additive was used in the product inspection or whether the limit of the use amount of the food additive was exceeded. Therefore, this study establishes the analytical method of SPA and PGA and confirms the reliability and validity of the test method by examining the recovery rate, linearity, limit of quantification, detection limit, uncertainty and so on. And to investigate the content of each component.

This study consists of two chapters:

Chapter Ⅰ. Establishment and monitoring of sodium polyacrylate in food
Chapter Ⅱ. Establishment and monitoring of propylene glycol alginate in food

Sodium phosphate buffer was suitable for the standard solution of SPA, and it was judged to be suitable for the food additive because the standard product showed different molecular weight from the research use. Analysis of SPA was carried out using size-exclusion chromatography, and GF-7M HQ column was found to be suitable. The detector was examined for UV/VIS detector (210 nm), RI and ELSD, and it was confirmed that the UV/VIS detector (210 nm) was suitable for peak shape and linearity. The flow rate was 0.6 mL/min and the column oven was 45℃. The mobile phase was selected as 50 mM sodium phosphate buffer pH 9.0. A sample pretreatment method was established to analyze SPA in food samples. In order to remove fat and protein in the sample, hexane and trichloroacetic acid (TCA) or trifluoroacetic acid (TFA) were treated, but it was not suitable for SPA analysis. As a result of treatment at 20, 40, 60, and 121℃ for extraction of SPA in samples. 20℃, and it was confirmed that extraction with 50 mM sodium phosphate buffer pH 7.0 was better than that with extraction solvent. Therefore, the HPLC-SEC method of SPA was performed using GF-7M HQ column, column oven at 45℃, a mobile phase of 50 mM sodium phosphate buffer pH 9.0 at 0.6 mL/min, and a UV/VIS detector (210 nm). The extraction conditions were as follows: extraction with 50 mM sodium phosphate buffer pH 7.0 at 20℃ and 150 rpm for 3 hr.
The analytical method validation showed proper selectivity and the calibration curve was selected in the range of 50~500 mg/L, and the correlation coefficient of the calibration curve was over 0.99. The LOD of SPA was 10.95 mg/kg and the LOQ was 33.19 mg/kg. The accuracy of the SPA was 3.0~2.6% for intra day and 1.3 2.6% for inter day. The accuracy of recovery was 99.6~127.6% for intra day and 94.3~121.9% for inter day. The content of SPA in the foods were analyzed and 40 out of 125 samples were detected. The detected concentrations were found to be less than 0.2%, which was limited by the Food Additives Code.
It has been confirmed that water or sodium phosphate was suitable as a dissolving solvent for standard products of PGA. Size-exclusion chromatography, and the column was confirmed to be suitable for the GF-7M HQ column. The detector was suitable for peak shape or linearity in ELSD. For the mobile phase, water was used singly and flow rate 0.8 mL/min was suitable.
The pretreatment method for the analysis of PGA was suitable for 3 hr extraction at 20℃ and 150 rpm according to the extraction temperature. The selectivity of the analytical method was confirmed, and it was confirmed that it was detected without influence of the sample matrix. The calibration curve was prepared at 300~1,500 mg/kg of standard solution and the correlation coefficient (R2) was excellent more than 0.98. The limit of detection and limit of quantitation were 171.43 mg/kg and 519.50 mg/kg, respectively.
As a result of analyzing the content of PGA by securing foods in domestic distribution, it was confirmed that there were 15 cases of fermented beverages and 10 cases of alcoholic beverage among 134 samples.
PGA was detected in 1 case of pickled food, 5 cases of confection, 2 cases of dressing, 3 cases of processed product, 8 cases of cheese, 7 cases of tomato ketchup and 14 cases of noodle. However, all of them were confirmed to be less than 1%.
In conclusion, HPLC-SEC method was established for the analysis of SPA and PGA in food, and a sample pretreatment method was also established. In addition, the reliability and validity of the analytical method established through this study were also confirmed. Monitoring of the foods in distribution was able to confirm the contents. Therefore, this method was considered to be applicable to food additives test in food.