Salt content in bread and dough from northern Portugal: Method development and comparison

• Published in: Journal of food composition and analysis 2012-08, Vol.27 (1), p.14-20
• Main Authors: Plácido, A., Kupers, R., Paíga, P., Magalhães, J., Nouws, H.P.A., Delerue-Matos, C., Oliveira, M.B.P.P.
• Format: Article
• Language: English
• Subjects: Atomic absorption spectrometry; Biological and medical sciences; Bread; Cereal and baking product industries; Food analysis; Food composition; Food industries; Food legislation; Fundamental and applied biological sciences. Psychology; General aspects; Ion-selective electrode; Methods of analysis, processing and quality control, regulation, standards; Potentiometry; Salt; Sodium chloride
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2012.04.004

► High sodium intake requires accurate and fast analysis of sodium chloride in bread. ► Reference methods and a newly developed ISE were evaluated. ► Significant differences were found between chloride-based and sodium-based methods. ► Authorities should indicate the analytical procedure for compliance monitoring. In the initial stage of this work, two potentiometric methods were used to determine the salt (sodium chloride) content in bread and dough samples from several cities in the north of Portugal. A reference method (potentiometric precipitation titration) and a newly developed ion-selective chloride electrode (ISE) were applied. Both methods determine the sodium chloride content through the quantification of chloride. To evaluate the accuracy of the ISE, bread and respective dough samples were analyzed by both methods. Statistical analysis (0.05 significance level) indicated that the results of these methods did not differ significantly. Therefore the ISE is an adequate alternative for the determination of chloride in the analyzed samples. To compare the results of these chloride-based methods with a sodium-based method, sodium was quantified in the same samples by a reference method (atomic absorption spectrometry). Significant differences between the results were verified. In several cases the sodium chloride content exceeded the legal limit when the chloride-based methods were used, but when the sodium-based method was applied this was not the case. This could lead to the erroneous application of fines and therefore the authorities should supply additional information regarding the analytical procedure for this particular control.