Inorganic Contaminants in Rapadura from Latin America

Abstract

Non-centrifugal cane sugar (NCS) is an artisanal product, also known as rapadura or brown sugar, and it is consumed both as a dessert and as a substitute to refined sugar. Despite being a source of essential nutrients, inorganic contaminants may be found in rapadura composition. Thus, this study aimed to optimize and to apply a method for As, Cd, and Pb determination in 72 NCS samples commercialized in Latin America. The method consisted of acid extraction of the inorganic contaminants using an ultrasound bath, and the determination was conducted by inductively coupled plasma optical emission spectroscopy (ICP OES). The method optimization was performed using a 22 central composite design, considering time and oxidant mixture as key parameters, and the best conditions were verified by extracting the inorganic contaminants using a 15% oxidant mixture for 20 min. The acid extraction method using an ultrasound bath was considered adequate, with values for limits of detection and quantification between 0.005 and 0.039 mg kg−1, respectively, and trueness (spiked experiments and certified reference material) ranging from 93 to 108% for all analytes. Rapadura samples from Latin America presented low levels for As and Cd, <0.012 µg kg−1 and <0.005–0.045 mg kg−1, respectively. For Pb, all samples presented quantifiable levels, and 33% were not within the requirements established by the Brazilian and The Southern Common Market (MERCOSUR) regulations. Thus, monitoring the levels of inorganic contaminants in non-centrifugal cane sugar is fundamental to provide safety for consumers.