Bioactive Micronutrients in Coffee: Recent Analytical Approaches for Characterization and Quantification

Production of coffee beans is an important lifeline for the economy of several countries in Latin America, Africa, and Asia. The brew from this well sought for cash crop is readily consumed due to its good sensory qualities owing to the presence of many micronutrients. Some of these chemical compounds possess biological activities, including antiproliferative, antioxidant, and antimicrobial effects. Four representative groups of these micronutrients, namely, caffeine, chlorogenic acid, diterpenes, and trigonelline, play key roles in these bioactive effects of coffee. In order to guarantee the quality of coffee products and to protect consumer interest and safeguard their well-being, it is extremely important to employ sensitive and accurate analytical methods in the characterization and quantitative determination of these bioactive constituents. This review aims to present recent applications in this regard. 1. Introduction Coffee is a popular beverage that is widely consumed around the world [1, 2]. Since its introduction into Arabia from Ethiopia many centuries ago [3], its cultivation has continued to blossom in three regions of our globe, namely, Africa, Latin America and Asia, [4–6]. Coffee is often produced from the roasted beans of a great variety of coffee crops [7]. However, Coffea canephora and Coffea arabica are the two most economically important species [8, 9]. It can now be found in both organic and conventional types [10]. Presently, the largest coffee bean producing region is Latin America [11], leading to an immense boost in the economy of the respective countries by bringing in the much needed foreign exchange. Unfortunately, market shocks, extreme weather conditions, and pests are an enormous challenge to this reality [12, 13]. World prices of coffee beans vary reasonably with their geographical source, as this affects the physical presentation of these beans and their nutritive components, two factors that are important in determination of coffee quality [14–17]. There are many nutritive substances in coffee brews which vary with the types of techniques employed in brewing processes [18]. Coffee contains mineral ingredients such as Ca, K, Fe, P, Ni, Mg, and Cr [19], polyphenols, caffeine, melanoidins, and carbohydrates [20, 21] among others. Since the variability of these chemical constituents affects price of coffee commodities by determining their qualities, there must be sensitive, precise, and accurate analytical means for their determination. It is, therefore, the aim of this paper to present a review on the recent analytical