Avaliação da concentração total e da fração bioacessível de minerais em pêssegos e relação do conteúdo de polifenóis totais com a bioacessibilidade

Abstract

In this work, an analytical method was developed to evaluate the total concentration and bioaccessible fraction of Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na and Zn in peach, including peel, unpeeled pulp and peeled pulp. As a sample preparation method, acid decomposition with a reflux system was used, in which parameters such as acid dilution, mass, temperature and decomposition time were optimized. After choosing the most suitable decomposition conditions (500 mg of dry sample, 5 mL of HNO3 9 mol L-1, 3 hours of decomposition at 135 °C, followed by the addition of 2 mL of H2O2 35% (v/v), plus heating for 1 hour at 120 °C), analyte concentrations were determined by MIP OES. The accuracy was evaluated through the analysis of tomato pulp powder CRM and recovery tests that ranged from 82 to 107% for CRM, 87 to 108% for the mixture between CRM and sample, and from 81 to 110% for analyte addition tests. The concentrations obtained in the peach parts ranged from 0.38 to 7.20 mg kg-1 for Al; 2.06 to 8.55 mg kg-1 for B; 0.49 to 1.98 mg kg-1 for Ba; 25 to 109 mg kg-1 for Ca; 0.23 to 1.72 mg kg-1 for Cu; 1.15 to 7.03 mg kg-1 for Fe; 1027 to 2558 mg kg-1 for K; 63 to 119 mg kg-1 for Mg; 0.59 to 2.75 mg kg-1 for Mn; 2.68 to 33 mg kg-1 for Na and 0.44 to 2.68 mg kg-1 for Zn, with the highest concentrations found for K and the lowest for Cu. Regarding the parts of the fruit, the skin has higher total concentrations of elements, with the exception of K with higher contents in the pulp. Bioaccessibility was determined through the simulation of the gastrointestinal system, with accuracy evaluated through the mass balance, obtaining recoveries in the range 80 to 119%. In peeled and unpeeled peaches, the highest bioaccessible fractions (> 50%) were obtained for K, Mg, Mn and B; and the smallest for Fe and Cu. The non-essential elements Al and Ba exhibited total and bioaccessible concentrations below the maximum allowed values. The PCA analysis revealed the presence of distinct groups of elements in relation to the total concentration, which was attributed to the origin of each cultivar. For the bioaccessible fractions, the PCA analysis showed that the characteristics that stand out are no longer linked to its origin, but to the way in which each element binds to the organic compounds of the fruit. Pearson's analysis showed negative correlations between polyphenols and bioaccessible fractions for most elements, especially for Al, Ba and Mn in the pulp without skin. The total and bioaccessible concentrations of minerals in peach cultivars do not meet the recommended daily needs, requiring the consumption of other fruits and vegetables to complement the diet.