Validation of a Fast Sample Preparation Procedure for Quantification of Sodium in Bread by Flame Photometry

Abstract

Reduction of salt intake through bread requires reliable monitorization when the control of a large number of samples is in order. The use of flame photometry is attractive; however, the usual dry-ash sample pretreatment is fastidious. Direct dissolution of bread sodium in water is a good alternative. A good correlation between results from these two sample preparation methods was obtained for sodium quantification in nine different types of bread. The proposed method was applied to the quantification of sodium in 48 bread samples of randomly chosen from local market to evaluate compliance with legislation requirements (lower than 550 mg sodium per 100 g of bread-Lei no. 75/2009).