Análise do teor de elementos traços e seu teor bioacessível em amostras de macroalgas do estado do Ceará-Brasil

Abstract

Macroalgae can have a variety of applications, including food and as a metabolite additive in industrial products. These organisms can accumulate various elements. Therefore, to evaluate their components and their absorption by the human body, brown (Sargassum vulgare), green (Ulva lactuca), and red (Gracilaria birdiae) macroalgae species were collected to conduct a study with a representative of each phylum. The total metal concentration in the samples was analyzed after decomposition in an acidic medium (3 ml HNO3 and 1 ml H2O2) with microwave-assisted heating. To study the absorption of these elements, bioaccessibility analysis was performed by simulating human digestion in vitro using gastric and intestinal solutions. Thus, both the total and bioaccessible concentrations were determined by ICP-OES. Sargassum vulgare showed the highest total concentrations of elements, such as Al (823±7 mg kg-1), Sr (768±20 mg kg-1) and V (4.86±0.37 mg kg-1). In Ulva lactuca and Gracilaria birdiae, lower and similar concentrations were observed with As (2.56±0.11 mg kg-1 and 5.04±0.34 mg kg-1), Ba (2.68±0.67 mg kg-1 and 0.983±0.034 mg kg-1), Sb (0.323±0.109 mg kg-1 and 0.274±0.042 mg kg-1) and V (1.13±0.05 mg kg-1 and 2.02±0.15 mg kg-1). For all elements analyzed, a reduced bioaccessible amount of them are capable of being absorbed by the brown macroalgae, with arsenic having the highest bioaccessible content for the sample (33.2%). In green and red macroalgae, elements such as Pb (90.79% and 81.98%, respectively) can be more readily absorbed through consumption, while other elements analyzed have lower levels, such as As (31.38% and 59.6%, respectively, for Ulva lactuca and Gracilaria birdiae). The lack of specific regulations for macroalgae in Brazil means there is no oversight, and consequently, the health of consumers of this organism is at risk.