Aplicação integrada de técnicas cromatográficas, espectroscópicas e quimiométricas na caracterização de chocolates artesanais
Carregando...
Data
2025-12-18
Autores
Altissimo, Joseline
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
The chemical characterization of artisanal chocolates has proven essential to ensuring quality, authenticity, and understanding sensory attributes related to cocoa content. In this work, different analytical approaches were employed to examine organic and inorganic constituents of chocolates produced in Brazil, with cocoa contents ranging from 36 % to 100 %. The chromatographic stage comprised the analysis of 45 samples, of which 17 representative ones were evaluated by HS SPME/GC-MS for the identification of volatile compounds. In total, 72 compounds were identified, including acids, esters, pyrazines, and aldehydes, associated with descriptors such as roasted, nutty, floral, and fruity. Methylxanthines were quantified by HPLC-DAD after the optimization of a US-LLE procedure, which resulted in recoveries of 91,7 % ± 11,3 % for theobromine and 94,7 % ± 2,7 % for caffeine. The obtained concentrations, ranging from 1.158 to 21.033 g kg-1 for theobromine and from 0.058 to 1.998 g kg-1 for caffeine, exhibited a positive correlation with the declared cocoa content. Principal component analysis revealed separation between low- and high-cocoa samples, with theobromine being the variable with the highest discriminant weight. These results reinforced the potential of methylxanthines as useful organic markers for classification and authenticity verification of artisanal chocolates. The spectroscopic investigation involved the application of Laser-Induced Breakdown Spectroscopy (LIBS) to 45 samples. Instrumental conditions were optimized using a 24 factorial design, considering spot diameter, laser energy, delay time, and the emission lines of C, Ca, Mg, and K. The function of desirability enabled the identification of variables with the greatest influence on analytical performance. Multiple Linear Regression (MLR) modeling provided strong correlation between predicted and declared cocoa content, with RMSEC of 4.5 % w/w and RMSEP of 4.0 % w/w. Validation samples showed trueness values between 90 % and 110 %, meeting the established criteria. Principal component analysis showed clear distinction between conventional chocolates (30–65 % cocoa) and higher-content chocolates (70–100 % cocoa), highlighting the contribution of elemental markers such as Ca, Mg, and K. Convergence between chromatographic and spectroscopic methods became evident when comparing monitored organic compounds and elements. Samples with higher concentrations of theobromine and caffeine also exhibited greater Mg and K intensity in LIBS, elements naturally associated with the solid fraction of cocoa. This alignment between organic and inorganic profiles highlighted the direct relationship between chemical composition and cocoa content, reinforcing the integrated use of these techniques for authentication and quality control purposes. The results demonstrate that the combined application of GC-MS, HPLC-DAD, and LIBS, together with chemometric tools, offers an efficient approach to examining the composition of artisanal chocolates, contributing to traceability practices, authenticity verification, and quality enhancement in the sector
Descrição
Palavras-chave
Chocolate artesanal , Compostos voláteis , Metilxantinas , Quimiometria , Teor de cacau , Artisanal chocolate , Volatile compounds , Methylxanthines , Chemometrics , Cocoa content