An untargeted metabolomics approach combined with sensory analysis was used to depict the impact of different traditional Italian extraction methods (i.e., Espresso, Neapolitan, Moka) along with Filter, on Coffea arabica and Coffea canephora var. robusta beverages. To this aim, polyphenols, Maillard reaction products, and coffee metabolites were screened by high resolution mass spectrometry and elaborated through both unsupervised and supervised multivariate statistical approaches. Multivariate statistics showed a distinctive chemical profile for Espresso preparation, while Moka and Neapolitan were very similar. The orthogonal projection to latent structures and discriminant analysis allowed the identification of 86 compounds showing a high VIP discrimination score (i.e., > 0.8). The 2,5-dimethyl-3-(methyldithio)-furan was a marker for the Filter preparation, while 1,2-disinapoylgentiobiose characterized both Filter and Neapolitan extractions. Caffeine (known to be a bitter compound) accumulated highly in Filter vs. Espresso, although at the sensory profile, bitterness was more perceived in Espresso. Vegetal aroma carried by pyrazines, pyridines, and phenolic acids were markers of Espresso, with Robusta showing higher values than Arabica. Notwithstanding, our findings showed that the extraction process played a hierarchically higher role in driving the chemical composition of the beverages when compared to coffee species.

Specialty coffee (SC) has been showing an increasing interest from the consumers which appreciate its traceability and the peculiar flavours from each single origin. Additionally, the processes to which coffee fruits underwent to get green coffee characterise the beans in terms of macromolecules acting as substrates during the roasting. This work evaluates via sensory analysed eight SC, roasted at light, medium, and dark level, submitted to Italian espresso extraction, to assess how different roasting levels exalt the expected cup profile obtained by the suppliers via cupping in origin countries. Finally, roasted beans were characterised for physico-chemical features (pH, titratable acidity, caffeine, melanoidins, polyphenols and acrylamide). Sensory analysis demonstrated that the intermediate roasting level and espresso extraction match better attributes from in-origin cupping. Melanoidins (mmol g À1 coffee d.b.) was able to discriminate among roasting levels (light 0.12 AE 0.01; medium 0.13 AE 0.003; dark 0.14 AE 0.01; a = 0.05). Acrylamide analyses ensured compliance with the food safety standards (light 301.9 AE 37.2 ppb; medium 126.1AE19ppb; dark 107.9 AE 22.5ppb). Physico-chemical features were able to cluster samples from different origins within the same roasting level (a = 0.05). Results showed correlations (a = 0.01) between sensory analysis and physico-chemical values: direct for caffeine and astringency, reverse for perceived acidity in relation to astringency, roasted, dried fruits and nutty notes.

BACKGROUND: This study aimed to establish the elemental profiling and origin combined with the genetic asset of coffee samples collected from major coffee-producing countries. A total of 76 samples were analysed for 41 elements using inductively coupled plasma-optical emission spectroscopy (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), and inductively coupled plasma-triple quadrupole mass spectrometry (ICP-MS/MS). The mineral composition of the silver skin detachment during the roasting process was also evaluated to verify the loss of minerals during roasting, differences in composition with beans, and between species.RESULTS: Application of linear discriminant analysis provided models with an accuracy of 93.3% for continents, 97.8% for countries of cultivation, and 100% for species. Discrimination between Arabica, Canephora coffee, and Eugenoides, and different varieties of Arabica species were identified in both models with calcium (Ca), barium (Ba), cadmium (Cd), rubidium (Rb), and strontium (Sr) as significant discriminant elements. Rb, Sr, sulphur (S), and thulium (Tm) were significant discriminant elements in both models for geographical distinction at different scales. Most of the elements had significantly higher values in silver skin than those in roasted coffee at different magnitudes, with exceptions of P and Rb.CONCLUSION: In summary, determination of mineral elements, processed by multivariate statistical analysis, was demonstrated to be discriminant for different coffee species. Linear discriminant analysis of the elemental analysis of samples from the seven major producing countries provided a reliable prediction model. Elemental analysis of major and minor elements is relatively easy and can be used together with other traceability systems and sensory evaluations to authenticate the origin of roasted coffee, different species, and varieties.

The aroma of coffee is a complex mixture of more than 1000 compounds. The volatile compounds in green and roasted coffee were analyzed to detect several features related to quality, roasting level, origins, and the presence of specific defects. With respect to specialty coffee, the flavor profile and peculiarities of the aforementioned characteristics are even more relevant knowing the expectations of consumers to find, in a cup of coffee, unicity bestowed by its origin and post-harvesting processes. In this work, which dealt with 46 lots of specialty Arabica coffee, we used HS-SPME/GC–MS to detect the volatile compounds in green coffees together with those in the same coffees roasted at three different levels to identify whether differences in headspace composition were ascribable to the origin, the post-harvesting processes, and the roasting profiles. The main results are related to the discriminant power of the volatile compounds in green coffee, which are impacted by the origins more than the post-harvesting processes. Compounds such as linalool and 2,3-butanediol were more concentrated in natural coffees, while hexanal was more concentrated in washed varieties (p < 0.05). In roasted coffees, the differences in composition were due to roasting levels, countries of origin, and the post-harvesting processes, in descending order of significance.

Origin of coffee, precursors concentration, post-harvesting processes and commercial roasting degrees were evaluated for their impact on acrylamide content in roasted coffee. Forty Seven Specialty Arabica and 7 high-quality Robusta green coffee samples were analysed to determine sugars, asparagine and A w . Acrylamide was quantified on light, medium and dark roasted samples. In green coffee, glucose and fructose content resulted lower after wet and honey processes, no remarkable differences were found for sucrose and asparagine. In all samples, the content of asparagine was generally lower than what provided in previous works. Acrylamide concentration never exceeded the limit of 400 lg kg À1 in Arabica samples and it does once in Robusta, it peaked between light and medium roasting, and it was higher in Robusta. Moreover, it was lower in honey coffee than in others. Acrylamide correlated with asparagine in Robusta, while with monosaccharides and A w in dry and honey Arabica. Coffee Origin impacted on precursors and acrylamide.