Metallic elements in chocolate drink powder: total contents and bioaccessible and bioavailable fractions

Author(s)

Rafaella Regina Alves Peixoto

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2015-08-25

Examining board members

Solange Cadore; Marcelo Antônio Morgano; Joaquim de Araujo Nobrega; Celio Pasquini; Ivo Milton Raimundo Júnior

• Advisor: Solange Cadore

Abstract

Chocolate drink powder is a cocoa-derived product of wide consumption in Brazil, mainly due its sensorial and nutritional characteristics. This type of food is considered as a good source of several essential elements in the diet. However, the presence of some potentially toxic elements for the human being at trace levels can also be relevant. Considering the lack of information about the presence of metallic elements in chocolate drink powder, the total contents and their bioaccessible and bioavailable fractions were studied. For the determination of the total contents, a method of sample preparation was evaluated and analytical methods were optimized using Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) for the determination of Al, Ba, Co, Cu, Fe, K, Mg, Mn, Mo, Na, P and Zn and Graphite Furnace Atomic Absorption Spectrometry (GF AAS) for Cd and Cr. The optimized analytical methods were applied to the analysis of 34 samples of chocolate drink powder, acquired in the local market of Campinas-SP. Generally, the results indicated that diet and light products presented the highest concentrations for most elements. The bioaccessible fractions of Al, Ba, Cd, Cr, Cu, Fe, Mg, Mn and Zn in chocolate drink powder were also studied. Two in vitro digestion methods were evaluated for selecting the most adequate. The results showed that in most cases, the internal exposure is lower than the external (ingestion of the element). In addition, the bioaccessibility was studied according to the type of chocolate drink powder (traditional, light, diet and organic) and the different factors that may affect it, including physical-chemical parameters of the human gastrointestinal tract (gastric pH, concentration of bile salts and presence of lipase) and the presence of dietary components (phytate, pectin, cellulose and tannin). The bioaccessibility varied greatly according to the sample type (5-12% for Al, 74-120% for Ba, 3-11% for Cd, 5-19% for Cr, 22-74% for Cu, 1-30% for Fe, 47-98% for Mg, 19-59% for Mn, 19-115% for P and 15-31% for Zn). The bile concentration and the presence of dietary components also significantly affected the bioaccessibility of the majority of elements. Considering the bioaccessible fractions, there is a significant reduction in the contribution of chocolate drink powder consumption to the Recommended Daily Intakes (RDI) of essential elements and the Provisional Tolerable Weekly Intake (PTWI) of Al and Cd. Studies aiming to estimate the bioavailable fractions of elements were also conducted, using human epithelial cell lines (Caco-2 and HT29-MTX) for the in vitro simulation of the intestinal barrier. The results showed that, in general, a small fraction of the elements B, Ba, Co, Mn, Ni and Se was able to cross the cell monolayers, suggesting that these elements, when ingested from chocolate drink powder, would be absorbed in a low to moderate extension by human intestinal epithelium (AU)

• FAPESP's process: 11/21023-3 - Determination of inorganic composition and metallic species bioavailable fraction in cocoa-based food
• Grantee: Rafaella Regina Alves Peixoto
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)