Comparison of Conjugase Treatment Procedures in the Microbiological Assay for Food Folacin

Abstract

Variations in the conjugase treatment step of the microbiological assay for food folacin were investigated. The source of the conjugase-fresh hog kidney, fresh chicken pancreas or commercial dried chicken pancreasdid not significantly affect the measurable folacin activity of spinach. However, the buffer, pH. incubation time, sequence of steps in extraction and conjugase treatment, and method of sample filtration (filter paper vs centrifuge) used prior to conjugase treatment were all found to significantly affect the folacin activity of spinach..

International inter-laboratory analyses of food folate

“…This finding is consistent with the observation by Tamura and Stokstad (1973) who showed no difference in food folate contents after the treatments with folate conjugase from hog kidney or chicken pancreas. Kirsch and Chen (1984) also reported no difference in folate content in spinach after the treatment with folate conjugase isolated from chicken pancreas or hog kidney. However, Phillips and Wright (1983) showed that the use of folate conjugase from hog kidney resulted in a 50% increase in measurable folate compared to that from chicken pancreas.…”

Determination of folate contents in selected Indian foods using the tri-enzyme extraction and estimated folate intakes of the population based on 24-h recall

“…Besides the cooking conditions, the ascorbic acid concentration can play an important role in the folate value of particular foods (Kirsch and Chen 1984;Pederson 1988;Gregory 1989;Tamura 1998). This is evident from the values obtained for tomatobased preparations such as tomato chutney and rasam in Table III.…”

Radioassay of Folacin in Foodstuffs

“…Determination of folacin content in foodstuffs is dependent on the method of sample preparation. Commonly, the method using conjugase treatment to release monoglutamate from polyglutamate is applied (KaS and &ma 1980;Kirsch and Chen 1984). Recently it was proved that another bound folacin form is present in foodstuffs containing polysaccharides (Cerna and KBS 1983).…”