Analysis of Gravity-Filtration Preparation Methods’ Antioxidant Content, Capacity, and Coffee Beverage Acceptance

Most gravity-filtration coffee preparation methods constitute good alternatives for obtaining coffee with varying acidity, bitterness, and bodies. The present study identifies the composition of compounds with antioxidant capacities and cup profiles for coffee beverages prepared using eight gravity-filtration methods. UV-visible spectrophotometry and high-performance liquid chromatography  quantified antioxidants, hydroxycinnamic acids, and antioxidant activity. A qualitative descriptive analysis was performed using an expert panel to establish the sensory quality. The methods that yielded the highest total phenol and flavonoid concentrations were Chemex, Siphon, and Silvertone. The Silvertone, Siphon, and Neapolitan methods had the most condensed tannin content. The maximum hydroxycinnamic acid content was found with the Siphon and Neapolitan methods. Antioxidant capacity was evaluated by the ABTS (antioxidant capacity of the cationic radical 2,2-Azino-bis-3-ethylbenzthiazoline-6-sulfonic acid), ORAC (Oxygen Radical Absorption Capacity), and FRAP (Ferric Reducing Antioxidant Power) methods and found to be the highest with the Silvertone, Siphon, and Neapolitan methods. The preparation methods with the highest sensorial scores were Silvertone and Chemex, while the lowest sensorial acceptance level was found with the Cloth filter method. Beverages made with the Kalita and Drip methods showed the lowest antioxidant compound expressions. The most predominant hydroxycinnamic acid was chlorogenic acid in the eight preparations studied. We thus recommend that coffee be consumed following preparation with the Silvertone, Siphon, or Neapolitan methods to increase antioxidant consumption in the diet. Should the consumer prefer bitter notes, these may be found with the Silvertone preparation method; otherwise, one may enjoy acidic notes in coffee beverages with the Siphon and Neapolitan methods.