Ubiquinone contents in Korean fermented foods and average daily intakes

Coenzyme Q (CoQs, ubiquinones) in food may have antioxidative and other beneficial effects on human health. Data on the ubiquinones (CoQ10 and CoQ9) content of Korean fermented foods were determined, then the Korean daily intake of ubiquinones from those foods was estimated. The analytical method employed saponification before solvent extraction and quantification HPLC/MS equipped with diode array detection. Contents of CoQs in the fermented foods varied from 315.9 ± 12.6 μg/g (Jeotgal, a fermented fish) to below the detection limit (Soy sauce) on a dry basis. Doenjang (a fermented soy paste) was the richest sources of CoQ9 (110.1 μg/g), while CoQ10 was found highest contents in Jeotgal (291.0 μg/g). However, the major fermented food source of CoQs intake in the Korean population was Kimchi, representing 88.2% of the total CoQs (Q9 + Q10) intake. The estimated daily intake of total CoQs from the analyzed fermented foods was 11.6 mg/day/person, which was significantly higher than those of other populations reported (3–6 mg). It could be suggested that Korean fermented foods may have higher ubiquinone than unfermented foods due to their diverse microflora during the process of fermentation.