British Journal of Nutrition

Papers of direct relevance to Clinical and Human Nutrition

An in vitro method for estimating biologically available vitamin B6 in processed foods

Athula Ekanayakea1 p1 and Philip E. Nelsona1

a1 Department of Food Science, Purdue University, West Lafuyette, IN 47907, USA

Abstract

1. An in vitro method which used enzymic digestion of the food matrix to release biologically available vitamin B6 is described.

2. Vitamin B6-fortified liquid model foods were thermally processed. After these foods had been freeze-dried, one part was subjected to enzymic hydrolysis at pH 2.0 with pepsin (EC 3.4.23.1) followed by a hydrolysis at pH 8.0 with pancreatin. The vitamins that were found in the supernatant fraction, after an acidified methanol treatment of the hydrolysate, were estimated by high-performance liquid chromatography (HPLC). The other part was given to rats who were kept on a vitamin B6-depleted diet.

3. The biologically available vitamin B6 content of the processed model foods, as determined by rat bioassay, showed good correlation with the vitamin B6 determined by HPLC.

4. It has proved possible to use this in vitro, two-stage enzymic digestion system followed by HPLC determination to determine biologically available vitamin B6 in vitamin B6-fortified processed model foods.

(Received March 15 1985)

(Accepted September 26 1985)

Correspondence:

p1 Biochemistry Division, Tea Research Institute of Sri Lanka, Talawakelle, Sri Lanka.