Influence of extraction process on antioxidant capacity of spent coffee

Abstract

Spent coffee that is produced in tons by restaurants and cafeterias, and consumers at domestic levels, could be a good opportunity to have an important source of natural antioxidants. The main aim of this work was to study the influence of several process factors on the antioxidant capacity extraction from spent coffee. Total phenolic compounds, radical scavenging activity (ABTS and DPPH) and browned compounds (Abs 420nm) of spent coffee extracts obtained with continuous (soxhlet 1h and 3h) and discontinuous methods (solid-liquid extraction and filter coffeemaker), several solvents (water, ethanol, methanol and their mixtures), successive extractions, and water with different pHs (4.5, 7.0 and 9.5) were carried out. Spent coffee extracts with the highest antioxidant capacity were obtained after one extraction with neutral water (pH 7.0) in a filter coffeemaker (24 g spent coffee per 400mL water). Furthermore, spent coffee defatting and extracts lyophilization allowed us to obtain spent coffee extracts powder with high antioxidant capacity that can be used as an ingredient or additive in food industry with potential preservation and functional properties.

Influence of Extraction Conditions on the Recovery of Phenolic Antioxidants From Spent Coffee Grounds

“…This value is in line with those reported in the few published studies on SCG (Ramalakshmi et al, 2009;Murthy and Naidu, 2012;Bravo et al, 2013). A comparison with the values found for other agro-industrial wastes, such as grape pomace (Louli et al, 2004), carrot peel waste (Chantaro et al, 2008), kiwi and apple peel wastes (Wijngaard et al, 2009), shows that SCG have a higher amount of phenolic compounds.…”

Evaluation of Spent Coffee Obtained from the Most Common Coffeemakers as a Source of Hydrophilic Bioactive Compounds

“…Antioxidant activity has been also reported by other authors in extracts of spent coffee grounds from the soluble coffee production, 2,8,46 from espresso coffee 17,18 and from filter coffee in a previous work of our group. 19 However, to our knowledge, the antioxidant capacity of spent coffee grounds obtained from other different coffeemakers (plunger and mocha) using an Arabica and a Robusta coffee has not been reported previously. For those reasons, the antioxidant capacity was evaluated using three different colorimetric assays (Folin Ciocalteau, ABTS and DPPH) in spent coffee obtained from different coffeemakers (filter, espresso, plunger and mocha) and in their respective coffee brews.…”

“…[13][14][15][16] Currently, to our best knowledge, only few studies about the presence of phenolics in spent coffee grounds from espresso coffee, 17,18 and the preparation of extracts with antioxidant capacity from spent coffee grounds obtained by filter coffee brewing have been found. 19 On the other hand, the increasing demand for foodstuffs free of artificial additives or with nutritional or healthy added values, induces to food industry (and also to the pharmaceutical one) to find new sources of antioxidants and bioactive compounds. For that reason, the knowledge of the main bioactive compounds extracted from spent coffee grounds would give them a higher value.…”

Phytochemical and microbiological stability of spent espresso coffee grounds in capsules

“…Currently, disposable espresso capsules are among the most popular ways to consume coffee brew and are an interesting and widely method adopted in homes or at offices (Parenti, Guerrini, Masella, Spinelli, Calamai, & Spugnoli, 2014). Spent coffee grounds have recently been characterized showing high quantities of water-soluble organic bioactive antioxidant compounds, such as caffeine, chlorogenic acids and melanoidins (Bravo et al, 2012;Bravo, Monente, Juániz, Paz De Peña, & Cid, 2013;Panusa, Zuorro, Lavecchia, Marrosu, & Petrucci, 2013;Ramalakshmi, Rao, Takano-Ishikawa, & Goto, 2009;Zuorro, & Lavecchia, 2012) and inorganic components, such as minerals (Cruz et al, 2012). Nevertheless, the studies mentioned above have been carried out on fresh spent coffee grounds analysed after stages of preparation such as drying, defatting and/or freeze-drying to preserve the original organic sample.…”