Total, soluble and insoluble oxalate content of bran and bran products

Author: Patchanee Boontaganon ¹, Eva Jéhanno ² and G. P. Savage ^3*

Received 8 July 2009, accepted 2 October 2009.

Abstract

The total and soluble oxalate content of various wheat, oat and rice bran products available in supermarkets and health food shops were analyzed using HPLC chromatography. The total oxalate contents of the individual bran samples analyzed ranged from 37.0 mg/100 g dry matter (DM) for oat bran to 392.7 mg/100 g DM for wheat bran flakes while the soluble oxalate contents ranged from 8.9 mg/100 g DM (Oat Bran Weet-Bix) to 109.6 mg/100 g DM (wheat bran flakes), respectively. The mean data showed that oat bran products contained the lowest level of total oxalate (67.2 mg/100 g DM) and soluble oxalate (8.9 mg/100 g DM) compared to rice bran (total oxalate 139.5 mg/100 g DM, soluble oxalate 65.3 mg/100 g DM) and wheat bran (total oxalate 220.8 mg/100 g DM, soluble oxalate 60.8 mg/100 g DM). The data suggests that a daily portion of bran products, particularly wheat bran, would supply a constant intake of soluble and insoluble oxalate but this would be a relatively small intake compared to other oxalate containing foods that may be eaten in the diet. The effect of the soluble oxalate intake could be mitigated by the consumption of high calcium foods at the same time.