Total Folate Contents of 15 Edible Plants Consumed in Korea Using Trienzyme Extraction Method

Trienzyme digestion (AOAC Official Method 2004.05) procedure using protease, α-amylase, and chicken pancreas conjugase was evaluated to determine its usefulness in the microbiological quantitation of total folate in foods. Folate values obtained by alkali hydrolysis (Korean Food Standards Codex) were compared to those obtained by the trienzyme method for four certified reference materials (CRM) representing diverse matrixes. Trienzyme treatment increased measurable folate from most CRM compared to levels found after alkali hydrolysis. The largest increases were observed with CRM 487 (pig liver, 5.8-fold) and CRM 121 (whole meal flour, 3.1-fold) after trienzyme digestion. Using trienzyme digestion method, total folate contents of raw and blanched edible plants were determined. Eleutherococcus senticosus (146.9 μg/100 g) showed the highest total folate content, followed by Aster glehni F. Schmidt (142.8 μg/100 g) and Ledebouriella seseloides H. Wolff (140.4 μg/100 g) on a wet weight basis. Blanching of samples resulted in an insignificant decrease in folate content for five samples and 11~63% reduction for nine samples. Our finding suggests that trienzyme digestion method is accurate for the determination of food folate in leafy vegetables.