Valorization of spent coffee grounds and their applications in food science

Abstract

Spent coffee grounds are generated in large quantities as a byproduct of coffee consumption. While often discarded as waste, spent coffee grounds still contain valuable bioactive compounds, including caffeine, chlorogenic acids, and polyphenols, along with dietary fiber, proteins, and essential minerals. Because of these nutritional properties, current research using spent coffee grounds includes fermented beverages, baked goods such as muffins and cookies, and ice cream cones. This graphical review explores the chemical composition and potential health benefits associated with spent coffee grounds. Additionally, the integration of spent coffee grounds in food products including fermented beverages and baked goods, food packaging, as well as food safety concerns, is explored. Utilizing spent coffee grounds as a functional ingredient in food not only contributes to sustainability by reducing waste but also enhances the nutritional profile of spent coffee grounds integrated products. Future research should not only focus on the effective utilization of spent coffee grounds but also address potential safety concerns, such as acrylamide formation and heavy metal contamination, to ensure food safety and consumer acceptability.

Keywords: Bioactive compounds; Food packaging; Functional foods; Spent coffee grounds; Valorization.

Fig. 1

Coffee consumption and facts. (A) the trend of increase in coffee consumption; (B) coffee as one of the most traded commodities in the world; (C) top ten coffee-consuming countries.

Fig. 2

Coffee processing and two different pathways from spent coffee grounds. (A) Coffee fruits in the tree; (B) harvested coffee fruits; (C) dehulled coffee beans; (D) roasted coffee beans; (E) coffee grinding; (F) coffee brewing; (G) spent coffee grounds; (H) landfilled spent coffee grounds generating methane and causing global warming; (I) reusing spent coffee bean grounds in foods, packaging, compost, biomass to protect the environment.

Fig. 3

Chemical compositions of spent coffee grounds. Spent coffee grounds include dietary fibers, proteins, lipids, minerals, and bioactive compounds.

Fig. 4

Potential health-beneficial properties of bioactive compounds from spent coffee grounds and recent potential health-beneficial research topics using spent coffee grounds. Bioactive compounds found in spent coffee grounds possess potential health-beneficial properties including (A) Antioxidant; (B) anti-inflammatory properties; (C) anti-bacterial properties. Recent potential health-beneficial research topics using spent coffee grounds include (D) protective effects on H₂O₂-induced oxidative stress in brain cells; (E) decreasing the F/B ratio in the gut; (F) controlling obesity by increasing satiety and reducing energy intake. F/B indicates Firmicutes/Bacteroidetes.

Fig. 5

Applications of spent coffee grounds in the food science and the possible aspects of future products. (A) Food products using spent coffee grounds; (B) biodegradable and BPA-free food packaging materials using spent coffee grounds; (C) suggested future research areas of spent coffee grounds including health benefits, toxicity assessment, large-scale processing, and storage.