ABSTRACT
A trienzyme extraction method (use of alpha-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 alpha-amylase and conjugase separately for 2 hours after protease treatment) and combined incubation (CI, incubated with alpha-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 microgram. One serving of French fries, pizza, sandwich and triangled kimbab contained a mean of 53.3, 28.4, 47.4, and 25.7 microgram of folate, respectively. Folate contents of non-alcoholic beverages were very low, ranging from 1.0 to 5.2 microgram/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