TRIENZYME TREATMENT FOR FOOD FOLATE ANALYSIS - OPTIMAL PH AND INCUBATION-TIME FOR ALPHA-AMYLASE AND PROTEASE TREATMENTS

Recent reports have indicated that trienzyme treatment before folate d etermination is essential to obtain the proper folate content in foods . Trienzyme treatment is performed by using alpha-amylase and protease for folate extraction from carbohydrate and protein matrices, and fol ate conjugase for the hydrolysis of polyglutamyl folates. We evaluated the conditions of pH and incubation time for the treatment with alpha -amylase and protease. Four food items, including fresh beef, white br ead, cow's milk, and fresh spinach, were selected for this investigati on. We found that optimal pHs for alpha-amylase treatment of beef and cow's milk were 7.0 and 5.0, respectively, whereas those for white bre ad and spinach were not distinctive at pHs from 2.0 to 7.0. The optima l incubation time for alpha-amylase was 4 h for fresh beef and cow's m ilk, whereas no distinctive optimal incubation period was found for wh ite bread and fresh spinach. Our data indicate that the conditions for enzyme treatments vary depending on food items. Trienzyme treatment r esulted in an increase of more than 50% in the mean folate content ove r folate conjugase treatment alone. It is necessary to treat food samp les with not only traditional folate conjugase, but also with alpha-am ylase and protease before folate determination to obtain the actual fo late content.