RESUMO
Coffee is widely consumed across the globe. The most sought out varieties are Arabica and Robusta which differ significantly in their aroma and taste. Furthermore, varieties cultivated in different regions are perceived to have distinct characteristics encouraging some producers to adopt the denomination of origin label. These differences arise from variations on metabolite content related to edaphoclimatic conditions and post-harvest management among other factors. Although sensory analysis is still standard for coffee brews, instrumental analysis of the roasted and green beans to assess the quality of the final product has been encouraged. Metabolomic profiling has risen as a promising approach not only for quality purposes but also for geographic origin assignment. Many techniques can be applied for sample analysis: chromatography, mass spectrometry, and NMR have been explored. The data collected is further sorted by multivariate analysis to identify similar characteristics among the samples, reduce dimensionality and/or even propose a model for predictive purposes. This review focuses on the evolution of metabolomic profiling for the geographic origin assessment of roasted and green coffee beans in the last 21 years, the techniques that are usually applied for sample analysis and also the most common approaches for the multivariate analysis of the collected data. The prospect of applying a wide range of analytical techniques is becoming an unbiased approach to determine the origin of different roasted and green coffee beans samples with great correlation. Predictive models worked accurately for the geographic assignment of unknown samples once the variety was known.
RESUMO
Forensic science is an emerging field driven by a number of factors, and the development of different methods of analyses, instruments, and techniques is of great help to experts in the field. Sampling and sample preparation in forensic cases are of utmost importance, and therefore, the methods for processing (or not) the samples are critical for acquiring accurate results. Some alternatives for attaining the minimalist concept, i.e. little or no sample treatment, are discussed in this review. For elemental analysis, analytical techniques, such as X-ray spectrometry, laser-ablation mass spectrometry, laser-induced breakdown spectrometry, inductively coupled plasma mass spectrometry and optical emission spectrometry, and Mössbauer spectrometry are overviewed. Molecular analysis, such as Raman spectroscopy, and ambient ionization mass spectrometry are discussed. Some representative examples are presented that involve in situ analysis, counterfeit bank notes and documents, post-mortem and bone analyses, and forensic analysis of drugs, glass, fingerprints, biological fluids and explosives.