Abstract
Many investigators have measured folate content in various foods using different methods over the past 50 years. These methods include the detection using microbiological assay, fluorometric or spectrophotometric methods in combination with various column chromatogaphies including HPLC. However, it has been known that the information in food folate tables is notoriously inaccurate. Recently, several groups of investigators have demonstrated that trienzyme treatment is essential to obtain the maximum possible value of folate in foods. Trienzyme treatment includes α-amylase and protease treatments for the extraction of food folate trapped or bound to protein or carbohydrate matrices, in addition to traditional folate conjugase treatment for the hydrolysis of polyglutamyl folates in foods. It is becoming clear that the conditions of pH and the duration of incubation for α-amylase and protease treatments vary significantly among individual food items. It is labor intensive and time consuming to identify the best conditions and perform trienzyme treatment in each food; therefore, it is a monumental task to make reliable and accurate food folate tables. However, it is important to establish dependable food folate tables in order to accurately estimate dietary intake of folate and to recommend adequate dietary folate intake in general populations, since the importance of folate nutriture for the maintenance of health as well as the prevention of certain diseases has become evident in recent years.
