Development of an LC-MS/MS-based analytical method for quantification of soybean allergen Gly m 4 in soybean grains and processed foods

Gly m 4 is one of important soybean allergens, which has property to cross-react with birch pollen allergen. However, a universal method for quantifying soybean allergen is unavailable. We aimed to develop an LC-MS/MS-based method for Gly m 4 quantification. A recombinant Gly m 4 (rGly m 4) was used to plot a standard curve and conduct a recovery test. The recovery of rGly m 4 from soybean grain extracts was 128% and the intra- and inter-day coefficients of variation were 12.8% and 13.2%, respectively. The method had a limit of quantification of 0.1 µg/mL. Using a validated method, Gly m 4 content was found to range from 309 to 421 µg/g in soybean grains and 2.7–67 µg/g in soybean processed foods. The newly developed method demonstrated sufficient reproducibility, sensitivity and accuracy, and might be helpful for individuals with soybean allergy to control Gly m 4 intake from food products.