This paper provides, for the first time, an overview of different aspects related to the quality of coffee beans and their volatile fractions: species/cultivars, geographic origins, bean defects, and types of beverages, processing, roasting, and storage. In other words, it concerns the complex relation between the quality of coffee seeds and their volatile components. It is an overview of 48 articles and considering 6 different aspects related to the quality of coffee and its aromatic fraction. The greatest numbers of published papers concerned "species and cultivars" and "defective seeds," both with 11 articles cited, followed by "storage" with 10 articles. Many aspects still require greater clarification, including the effects of geographical origin, processing, and roasting. Other issues that are better understood include the effects of species type, defective seeds, and storage conditions. Another topic that has received very little attention is the question of the existence of many different coffee cultivars within each species, which we believe should be further investigated, given that this can significantly affect the quality of the final beverage. Meanwhile, with the growing technological development in the areas of science and agriculture, there are many other aspects to be studied (or revisited), and the field of the aromatic quality of coffee provides ample opportunity for scientific investigation.

Coffee quality is highly dependent on geographical factors. Based on the chemical characterization of 25 coffee samples from worldwide provenances and same roasting degree, Discriminant Analysis (DA) was employed to develop models that are able to identify the continental or country (Brazil) provenance of blind coffee samples. These models are based on coffee composition, particularly on several key compounds either with or without significant impact on aroma, such as 2,3-butanedione, 2,3-pentanedione, 2-methylbutanal and 2-ethyl-6-methylpyrazine. All models were validated with new and independent data from literature, and also through cross validation and permutation tests. Furthermore, the robustness of the proposed models in case of incomplete characterization data was also tested, being concluded that missing data is supportable by the models. In the whole, this article provides compelling arguments for the development of DA-based tools with the purpose of controlling the quality of coffee in terms of their continental and/or national origins.

With globalization, it has become necessary to adopt policies to regulate the coffee market, addressing problems including the authenticity and traceability of products. It is therefore important to establish methodologies that can help to safeguard the interests of producer countries and add value to products. For this purpose, the use of NMR combined with multivariate statistical procedures can be an attractive option. The aim of this study was to develop a fast and effective technique, using H NMR coupled with multivariate statistics, to create a fingerprint of roasted coffees, distinguishing them according to the main Brazilian producer regions. Several compounds suitable for differentiating roasted coffees were identified in the fingerprint. Discriminant analysis revealed good distinction among the samples. The compounds catechol, trigonelline, caffeine, and-methylpyridine were most important for the differentiation. The findings should assist coffee-producing countries in adopting measures to protect their markets and to add value to coffee products.

Compliance with ethics requirements This article does not contain any studies with human or animal subjects.