Avaliação da conformidade com as directrizes nacionais dos níveis de ferro em farinhas de trigo e milho fortificadas comercializadas em Maputo

Abstract

Micronutrient deficiency is a serious global public health problem, with significant impacts, especially in developing countries such as Mozambique, with more than half of children under 5 years of age suffering from this condition throughout the country. To combat this problem, the Mozambican government introduced a law by decree no. 9/2016, requiring the fortification of wheat and corn flours with 20 to 140 mg/kg of iron. Given the vital function of iron in the body, it is essential to ensure the adequate amount of this micronutrient in fortified foods, as required by national legislation. Therefore, the primary objective of this study was to analyze the iron content present in fortified wheat and corn flours sold in the market of the city of Maputo. The analysis was carried out on 12 samples of wheat and corn flour, one of which was unfortified, using molecular absorption spectrophotometry and atomic absorption spectrophotometry methods, and on two samples using the reference method in force at the LNHAA. The molecular absorption spectrophotometry method was validated by evaluating nine parameters, which included working range, linearity, sensitivity, selectivity, accuracy, precision, detection limit, quantification limit and robustness. All the parameters evaluated were satisfactory, with the exception of sensitivity, which, according to the Student's t-test, there was not enough evidence to consider it satisfactory at a 95% confidence level. Once the method was validated, the iron content in the wheat and corn flour samples collected at the Zimpeto Wholesale Market, Shoprite in Praça da Paz and Zimpeto, at Padaria Guebo and the unfortified sample was analyzed. Using the Student's t-test, there were no significant differences in the results obtained by the molecular absorption spectrophotometry (MAZ) and flame atomic absorption spectrophotometry (FAAS) methods. However, a significant difference was observed in the ATS sample, which presented an iron content of 74.645±4.003 mg/kg and 78.525±0.460 mg/kg for FAAS and MAZ, respectively. Regarding the comparison with the minimum and maximum limits established by current national legislation, all samples presented iron content in accordance with the legislation. Although all samples analyzed met the minimum and maximum limits established by current national legislation, it is important to highlight that 58.34% of the samples (APP, AWM, AWS, ACS, AIS, AXM and AXS) presented iron contents equivalent to the minimum limit of 20 mg/kg. This level is equivalent to the iron content found in unfortified corn flour (ANF), being 20.202±0.320 mg/kg in analyses performed by FAAS and 19.511±0.829 mg/kg in analyses performed by EAM, and may be insufficient to meet the nutritional needs of vulnerable groups, when the diet is not combined with other foods rich in iron, due to low bioavailability and variability of intake(TRADUÇÃO NOSSA)