Composição Multielementar das Plantas Alimentícias Não Convencionais no Amazonas: Pereskia aculeata Mill. e Xanthosoma sagittifolium (L.) Schott.

Abstract

In recent years, the growing demand for healthy, accessible, and environmentally sustainable food alternatives has driven interest in Unconventional Food Plants (UFPs), especially in regions of high biodiversity such as the Amazon. In this context, the present study investigated the multielemental composition of Xanthosoma sagittifolium (taro) and Pereskia aculeata (Barbados gooseberry), aiming to evaluate their nutritional potential and viability as bioindicators of environmental contamination. Collections were carried out in five municipalities of Amazonas state (Manaus, Novo Airão, Tabatinga, Humaitá, and Itacoatiara), which present distinct edaphoclimatic and socioeconomic characteristics, as well as different levels of urbanization. A total of 54 samples of leaves and rhizospheric soils from both species were collected. Analyses involved physical processing of samples and determination of elemental concentration by Total Reflection X-ray Fluorescence spectrometry (TXRF), a technique that allowed simultaneous quantification of macro and micronutrients (Ca, Cl, Mg, Fe, Zn, P, K, S, Na, Si, Al, Cu, I, Mn, Rb, Se, Ti, Y) and trace elements classified as heavy metals (As, Ba, Br, Ce, Cd, Co, Cr, Hf, Hg, Ni, Pb, Sn, Sr, Te, Yb). Multivariate statistical analyses were employed, including hierarchical clustering (UPGMA), principal component analysis (PCA), non-metric multidimensional scaling (nMDS), and Pearson correlation, which made it possible to identify chemical patterns between genotypes and correlations between foliar and edaphic elements. The results indicated that X. sagittifolium presents high chemical variability among genotypes and locations, with emphasis on the concentration of essential elements such as Ca, Mg, P, and Mn, in addition to morphophysiological sensitivity to environmental variations, reinforcing its applicability as a bioindicator. For P. aculeata, a more consistent and mineral-enriched chemical profile was identified. Comparative analyses between plants and soils showed significant correlations between nutrients and heavy metals, indicating potential routes of bioaccumulation and physiological implications. In some leaf samples, high concentrations of trace elements were detected, possibly associated with urbanized or anthropized environments, reinforcing the bioindicator role of these species. From an environmental and nutritional perspective, the results reinforce the importance of UFPs in promoting food security, especially in regions marked by socioeconomic inequalities and limitations in access to diversified food. The species X. sagittifolium and P. aculeata have high nutritional value and potential as environmental indicators. The chemical variability observed between locations results from genetic and edaphic factors, as well as cultivation practices. The species Xanthosoma sagittifolium and Pereskia aculeata presented profiles enriched in essential macro and micronutrients, standing out for their high content of Ca, Mg, P, K, Mn, Fe, and Zn. The application of the TXRF technique proved efficient in multielemental characterization, providing relevant information for future research, public policies for the use of local plant resources, and strategies for sustainable management of Amazonian biodiversity.