Session: General Poster:

Some fungal contamination in the production of the common Korean fermented soybean products Doenjang, Ganjang, and Gochujang sauces can produce harmful aflatoxins (AFs); therefore, there is a need for simple and effective methods for AF determination in these complex food matrices. AFs in three commercially available Korean fermented soybean sauces were analyzed by HPLC with fluorescence detection. The best AF extraction efficiency from Doenjang, Ganjang, and Gochujang sauces was achieved using methanol:water (70:30, v/v) as the solvent, and polyethylene glycol as the extraction additive. Pre-column derivatization of the AF extracts was performed using trifluoroacetic acid (TFA), and post-column derivatization was performed in a photochemical reactor for enhanced detection (PHRED). Both derivatization methods resulted in acceptable performances with suitable linearity (R2>0.999), recovery (71–118%), and precision (<10.6%) values. The mean recovery and precision obtained with pre- and post-column derivatization were similar, but the limit of detection and limit of quantification were superior with post-column derivatization. The procedures based on TFA or PHRED described herein can therefore be implemented for the routine AF analysis of Korean Jang products and but also various types of fermented soybean products, such as Japanese Miso and Shoyu, Chinese Dajiang, Doubanjiang and Chiangyu, and Nepal Kinema. The validated method was applied in the analysis of commercial Doenjang, Ganjang and Gochujang, which showed that their contamination levels were extremely low. Among the 42 tested samples, 26% were contaminated with at least one AF in the concentration range of 0.08–0.41 μg/kg, which are significantly lower values than those of current regulatory limits.

Dr. Fei Tian

Appearances