REQUIMTE-LAQV, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
REQUIMTE-LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, R. Dr. António Bernardino de Almeida 431, 4249-015 Porto, Portugal.
Molecules. 2019 Jul 31;24(15):2787. doi: 10.3390/molecules24152787.
The chemical composition and daily mineral intake (DMI) of six macro (calcium, magnesium, sodium, potassium, phosphorous, and chloride) and four microminerals (copper, iron, manganese, and zinc) were determined in four types of Portuguese breads (white wheat, maize, wheat/maize, and maize/rye breads). Samples were processed with microwave assisted digestion and mineral composition was determined with a high-resolution continuum-source atomic absorption spectrometer with flame and graphite furnace. Bread contributes to an equilibrated diet since it is rich in several minerals (0.21 mg/100 g of copper in wheat bread to 537 mg/100 g of sodium in maize/rye bread). Maize/rye bread presented the highest content of all minerals (except phosphorous and chloride), while the lowest levels were mainly found in wheat bread. Median sodium concentrations (422-537 mg/100 g) represented more than 28% of the recommended daily allowance, being in close range of the maximum Portuguese limit (550 mg/100 g). Maize/rye bread exhibited the highest DMI of manganese (181%), sodium (36%), magnesium (32%), copper (32%), zinc (24%), iron (22%), potassium (20%), and calcium (3.0%). A Principal Component Analysis (PCA) model based on the mineral content allowed the differentiation among white wheat, maize, and maize/rye bread. Zinc, magnesium, manganese, iron, phosphorus, potassium, copper, and calcium proved to be good chemical markers to differentiate bread compositions.
测定了四种葡萄牙面包（白小麦、玉米、小麦/玉米和玉米/黑麦面包）中六种常量（钙、镁、钠、钾、磷和氯）和四种微量元素（铜、铁、锰和锌）的化学成分和每日矿物质摄入量（DMI）。样品采用微波辅助消解处理，采用高分辨率连续光源原子吸收光谱仪进行火焰和石墨炉矿物成分测定。面包是均衡饮食的一部分，因为它富含多种矿物质（小麦面包中铜含量为 0.21 毫克/100 克，玉米/黑麦面包中钠含量为 537 毫克/100 克）。玉米/黑麦面包中所有矿物质（磷和氯除外）的含量最高，而小麦面包中的含量最低。钠浓度中位数（422-537 毫克/100 克）占推荐日摄入量的 28%以上，接近葡萄牙最高限量（550 毫克/100 克）。玉米/黑麦面包表现出最高的锰 DMI（181%）、钠（36%）、镁（32%）、铜（32%）、锌（24%）、铁（22%）、钾（20%）和钙（3.0%）。基于矿物质含量的主成分分析（PCA）模型允许区分白小麦、玉米和玉米/黑麦面包。锌、镁、锰、铁、磷、钾、铜和钙被证明是区分面包成分的良好化学标志物。
