Biodiverse Neltuma spp. pod flours from the Paraguayan Chaco as ancestral sources of mineral

Abstract

One of the main uses of carob pods ‘algarroba’ (Neltuma spp.) is flour for direct human consumption in indigenous and rural populations of the Gran Chaco. The flour contains antioxidant compounds such as anthocyanins, flavonoids and alkaloids, the concentrations of which can vary according to environmental and genetic factors of the species. This ancestral food is an excellent nutritional alternative as a gluten-free ingredient with antioxidant potential for various culinary preparations. Minerals have essential functions in the human body, so a balanced diet is key to ensuring adequate intake. The composition of carob beans from the Paraguayan Chaco has been little explored in terms of their mineral nutrient content. The aim of this study was to determine the Fe, Cu, Zn and Mn content of carob meal from different species of Neltuma spp. From the Paraguayan Chaco. The mineral elements were determined by atomic absorption spectrometry using official AOAC (2000) methods. Of the samples analysed, N. ruscifolia carob flour had the highest content of Zn (2.2 ± 0.8 mg/100 g), Mn (1.6 ± 0.1 mg/100 g) and Cu (1.5 ± 0.4 mg/100 g). N. nigra and N. alba flour showed higher Fe contents (4 ± 2 and 3 ± 2 mg/100 g, respectively). Consumption of 100 g of P. ruscifolia and P. nigra meal would cover up to 100% of the Recommended Daily Intake (RDI) for Cu and 55–72% of the RDI for Mn. This implies that carob-based foods from Paraguayan Chaco species could have a protective role against oxidative stress if incorporated as functional foods, as well as representing a natural and bioavailable source of antioxidant minerals, which is especially valuable in diets of vulnerable populations with deficiencies or increased requirements, such as in pregnancy, ageing, or chronic diseases.