Abstract
Coffee husks (Coffea arabica L.) are characterized by exhibiting secondary metabolites such as phenolic compounds, which can be used as raw material for obtaining bioactive compounds of interest in food. The objective of this study is to evaluate different methods for obtaining the raw material and extracting solutions of bioactive compounds from coffee husks. Water bath and ultrasound-assisted extraction methods were used, using water (100%) or ethanol (100%) or a mixture of both (1:1) as extracting solutions and the form of the raw material was in natura and dehydrated. The extracts were evaluated by their antioxidant potential using DPPH radicals, ABTS, and iron reduction (ferric reducing antioxidant power (FRAP)), and later total phenolic compounds, total flavonoids, and condensed tannins were quantified the phenolic majority compounds were identified. It was verified that the mixture of water and ethanol (1:1) showed better extraction capacity of the compounds with antioxidant activity and that both conventional (water bath) or unconventional (ultrasound) methods showed satisfactory results. Finally, a satisfactory amount of bioactive compounds was observed in evaluating the chemical composition (total phenolic compounds, total flavonoids, condensed tannins, as well as the analysis of the phenolic profile) of these extracts. Corroborating with the results of the antioxidant activities, the best extracting solution was generally the water and ethanol mixture (1:1) using a dehydrated husk and water bath as the best method, presenting higher levels of the bioactive compounds in question, with an emphasis on chlorogenic acid. Thus, it can be concluded that the use of coffee husk as raw material to obtain extracts of bioactive compounds is promising. Last, the conventional method (water bath) and the water and ethanol mixture (1:1) stood out among the methods and extracting solutions used for the dehydrated coffee husk.
Highlights
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Brazil is considered the world’s largest producer and exporter of coffee, and is the second largest consumer of the product
Coffee husks are characterized by secondary metabolites, such as caffeine and tannins, and phenolic acids such as chlorogenic acid, thereby being a potential source for obtaining bioactive compounds of interest to apply in food
In light of the above, the objective of this study was to evaluate different extraction methods—water bath (B) and ultrasound (U)—of bioactive compounds from coffee husks (Coffea arabica L.) in natura and after dehydration (D) using different extracting solutions— ethanol €, water (W), and mixture ethanol: water (M)—and evaluating the antioxidant activity of the extracts
Summary
Brazil is considered the world’s largest producer and exporter of coffee, and is the second largest consumer of the product. Coffee processing can be done by dry or wet routes, generating different types of residues [4]. According to Setter et al [5], the most used method in Brazil is dry processing, with the main residue generated being the husk obtained with a yield of approximately 50% of the weight of the coffee beans. Coffee husks are characterized by secondary metabolites, such as caffeine and tannins, and phenolic acids such as chlorogenic acid, thereby being a potential source for obtaining bioactive compounds of interest to apply in food. Chlorogenic acid is widely distributed in the plant kingdom, and coffee and its by-products are considered its greatest source. The biological function of this phenolic compound is linked to its antioxidant, antimicrobial, and anticarcinogenic activities [6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
