Components of Vitamin B6 in Grains and Cereal Products

Abstract

Extracts of 56 grains and cereal products were chromatographically separated on Dowex-50 ion exchange columns into pyridoxine, pyridoxal, and pyridoxamine fractions. These fractions were assayed microbiologically by using S. carlsbergensis. Procedures used and values obtained by the assays are presented, along with values for total vitamin B6 in unchromatographed extracts and proximate composition values for each sample.

Vitamin B6 components in some meats, fish, dairy products, and commercial infant formulas

“…Procedures for separating and determining the B6 components in hydrolyzed food extracts are important and essential developments for the vitamin B6 assay. Methods have been described for using Dowex 50 ion exchange columns to separate the vitamin B6 components of hydrolyzed food extracts into individual fractions and assaying the separated components with 5. car/sbergensis (MacArthur and Lehmann, 1959;Polansky et al, 1964; Toepfer and Lehmann, 1961). Data obtained by these procedures compare well with those obtained by rat bioassay for total vitamin B6 in a few selected food samples (Toepfer et al, 1963).…”

Conversion of pyridoxine into 6-hydroxypyridoxine by food components, especially ascorbic acid.

“…Reduction in the vitamin B6 content during food processing and storage has also been reported in plant foods (3)(4)(5)14). Since vitamin B6 in plant foods is known to occur mainly as pyridoxine (PN) and its bound forms (15)(16)(17)(18), a lowering of the vitamin B6 content should be due to a reaction(s) different from those described in animal foods. For the present, there are no available papers concerning the mechanisms of PN loss in plant foods.…”

Relative biological activity of nonphosphorylated vitamin B-6 compounds in the rat

“…Numerous studies have been conducted with pyridoxine (PN) hydrochloride as a standard in the quantitation of biologically available vitamin B-6 in food [e.g., Yen et al (1976), Gregory and Kirk (1978), Gregory (1980a), and Tarr et al (1981)]. The vitamin B-6 of animal-derived foods is comprised largely of PLP and PMP, with small amounts of PL, PM, and PN (Vanderslice et al, 1980; Gregory et al, 1981), while the majority of the vitamin in plant tissues appears to occur as PN (Polansky et al, 1964;Polansky, 1969). The use of PN as a standard in animal bioassays is based on the greater stability of this vitamer and, to some extent, the assumed equivalent biological response to PN and the other vitamin B-6 compounds.…”