Journal List > Korean J Nutr > v.42(4) > 1043770

Korean J Nutr. 2009 Jun;42(4):397-405. Korean.
Published online June 30, 2009.
© 2009 The Korean Nutrition Society
Folate Content of Fast Foods and Processed Foods
Hyun Jung Ji, Seungki Kim, Miyong Yon and Taisun Hyun
Department of Food and Nutrition, Chungbuk National University, Cheongju 361-763, Korea.

To whom correspondence should be addressed. (Email: )
Received April 04, 2009; Revised May 10, 2009; Accepted May 20, 2009.


A trienzyme extraction method (use of α-amylase, protease and folate conjugase) for food folate assay has been used to release folate from the food matrix. In order to reduce the incubation time with three enzymes, folate values were compared between two incubation protocols; separate incubation (SI, incubated with α-amylase and conjugase separately for 2 hours after protease treatment) and combined incubation (CI, incubated with α-amylase and conjugase together for 2 hours after protease treatment) using 88 food items from 12 kinds of fast foods and processed foods. We found that folate values by CI were comparable to or higher than those by SI, indicating that CI might be a better extraction procedure to shorten the entire incubation time. We measured folate contents in 49 fast foods and 26 processed foods by microbiological assay after CI. Mean folate contents of one serving of various burgers ranged from 43.1 to 62.0 µg. One serving of French fries, pizza, sandwich and triangled kimbab contained a mean of 53.3, 28.4, 47.4, and 25.7 µg of folate, respectively. Folate contents of non-alcoholic beverages were very low, ranging from 1.0 to 5.2 µg/100 g. Some of our values were comparable to the values in the folate database published in Korean Nutrition Society, however, some of the published values were 140 times higher than the measured values in this study. Folate values measured by the more recent modifications here can be used to update Korean folate database to accurately estimate dietary folate intake

Keywords: folate; trienzyme; fast foods; processed foods; food folate assay


Fig. 1
Flow chart of food folate assay.
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Table 1
Mean folate content in foods measured after separate incubation (SI) or combined incubation (CI)
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Table 2
Folate content in fast foods
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Table 3
Folate content in processed foods
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Table 4
Comparison of mean folate content in this study (CI) and in the current database1)
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This work was supported by the research grant of the Chungbuk National University.

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