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The Potential of Spent Coffee Grounds in Functional Food Development

School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia
Faculty of Health, Southern Cross University, Gold Coast, QLD 4225, Australia
School of Science, Western Sydney University, Richmond, NSW 2753, Australia
Author to whom correspondence should be addressed.
Nutrients 2023, 15(4), 994;
Submission received: 10 December 2022 / Revised: 9 February 2023 / Accepted: 12 February 2023 / Published: 16 February 2023
(This article belongs to the Section Nutrition and Public Health)


Coffee is a popular and widely consumed beverage worldwide, with epidemiological studies showing reduced risk of cardiovascular disease, cancers and non-alcoholic fatty liver disease. However, few studies have investigated the health effects of the post-brewing coffee product, spent coffee grounds (SCG), from either hot- or cold-brew coffee. SCG from hot-brew coffee improved metabolic parameters in rats with diet-induced metabolic syndrome and improved gut microbiome in these rats and in humans; further, SCG reduced energy consumption in humans. SCG contains similar bioactive compounds as the beverage including caffeine, chlorogenic acids, trigonelline, polyphenols and melanoidins, with established health benefits and safety for human consumption. Further, SCG utilisation could reduce the estimated 6–8 million tonnes of waste each year worldwide from production of coffee as a beverage. In this article, we explore SCG as a major by-product of coffee production and consumption, together with the potential economic impacts of health and non-health applications of SCG. The known bioactive compounds present in hot- and cold-brew coffee and SCG show potential effects in cardiovascular disease, cancer, liver disease and metabolic disorders. Based on these potential health benefits of SCG, it is expected that foods including SCG may moderate chronic human disease while reducing the environmental impact of waste otherwise dumped in landfill.

1. Coffee Waste Products—From Farm to Landfill

Spent coffee grounds (SCG) are the ultimate waste product in the consumption of coffee as a beverage. Coffee beverage consumption continues to have a remarkable economic, social and cultural impact across the globe [1,2]. Worldwide, the estimated coffee bean production in July 2020 to June 2021 was ~175 million 60-kg bags [3], approximately 10.5 million tonnes. Coffee production requires farming, harvesting, pulping of coffee cherry, fermentation and hulling in wet methods, roasting and brewing (Figure 1 and Figure 2) [4]. Significant wastage occurs during all stages of production, with the major impact being in developing countries, where most coffee is grown, such as Brazil, Vietnam, Colombia, Indonesia and Ethiopia. The economies of these countries rely heavily on coffee production. For example, in Brazil, more than 8 million people (around 4% of the population) are employed in coffee production by the coffee farms, excluding retail outlets, hospitality and other businesses involving commercialisation of coffee products [5]. Brazil’s coffee production constituted 5% of total export revenue at over USD 4.8 billion in 2019/2020 [6,7]. Therefore, the economic and environmental impacts of coffee farming are mainly observed in developing countries in tropical areas; these impacts include subsistence farming, heavy application of pesticides and fertilisers, destruction of complex tropical ecosystems, decreased soil fertility and contaminated water resources [8,9,10,11], which collectively can increase health risks for local communities [12,13]. The estimate of waste produced from coffee production worldwide is at least 6–8 million tonnes every year [14,15]. This value exclusively represents by-products of coffee production such as cascara, husk, mucilage, silverskin and post-brewing spent coffee grounds (SCG), and excludes contaminated soil and water [16].
The major coffee buyers are developed countries with large populations such as the USA, which imported about 29 million 60-kg bags (about 1.75 million tonnes) of coffee worth about USD 6.9 billion in 2021 [19]. The USA is one of many countries that produced very limited amounts of coffee, with production of 2270 tonnes in Hawaii and California in 2021 [20,21]. Post-consumption coffee waste includes SCG as well as increased slowly decaying microplastics [22] and nanoplastics [23] in the environment, with unknown long-term health risks. As an example, Planet Ark in 2016 in Sydney estimated that Australians use 1 billion coffee cups each year, producing 60,000 tonnes of plastic waste [24]. Therefore, unlike the waste products of coffee production, post-consumption pollution is mainly a problem of developed countries, the highest consumers. SCG production provides an increased 50–100% of the weight of the coffee beans as a standard double-shot espresso uses around 30 g of dry ground roasted coffee beans to yield 45–60 g of moist SCG [25]. The Planet Ark report in 2016 estimated that the 921 cafes in Sydney produced more than 3000 tonnes of SCG per year, with 93% ending up in landfill [24]. Thus, developing processes to use SCG in industrial or food production may be the more feasible approach to limiting the environmental and health damage from coffee waste, as these methods are more likely to be implemented in developed countries.
However, there are few studies investigating the health benefits of SCG, although there is a growing interest in its potential, due to the presence of many bioactive compounds that are also found in coffee beverages [26,27]. Our aim in this review is firstly to explore the production and identification of waste products in coffee production and consumption. Secondly, we will evaluate the potential health benefits of SCG, mainly using studies on coffee as a beverage and the compounds found in SCG. Thirdly, understanding the health benefits could allow the development of functional foods at affordable costs using SCG as an easily available product rather than complete purification of individual bioactive compounds. Functional foods provide health benefits beyond their nutritional values and thus have the potential to reduce the risk of chronic diseases. As an additional benefit, use of SCG in functional foods could reduce environmental damage by post-consumption coffee waste.

2. Bioactive Ingredients of SCG

The first step in value-adding to a complex mixture such as SCG is an understanding of the compounds present in the mixture, including the chemical changes during the process of roasting. By definition, the compounds present in SCG from roasted coffee powder are the compounds that have not been extracted during the production of the beverage. Low-molecular-weight bioactive compounds extracted into coffee as a beverage include caffeine, chlorogenic acids (CGA), trigonelline, tryptophan alkaloids and diterpenes such as cafestol and kahweol [28]. Further, coffee as a beverage produced by hot-brew processes contains approximately 1000 volatile organic compounds, which vary on growing and post-harvest conditions [29]. Cold-brew coffee differs from hot-brew coffee in the extent of compounds extracted during brewing rather than in the compounds that are present [30]. Roasting leads to the production of melanoidins by the non-enzymatic Maillard reaction which make up about 13–25% of the dry weight of the roasted coffee powder [31,32]. The chemical structures of the many melanoidins are only partly known, but the compounds include polysaccharides such as galactomannans and arabinogalactans, denatured proteins and CGA [31]. After roasting, coffee powder also contains carbohydrates (38–42%), proteins (8–14%), phenolic compounds (3–4%), lipids (11–17%), minerals (5%), fatty acids (3%), caffeine (1–2%) and trigonelline (1%) [29]. Degradation products during roasting include the carcinogen, acrylamide; practical solutions to reduce acrylamide production were proposed [33]. The SCG remaining after production of hot-brew coffee include carbohydrates such as 8–15% celluloses and 30–40% hemicelluloses, 20–30% lignins, 7–21% lipids and minerals, and 13–17% proteins, together with phenolic compounds (12 mg/g), caffeine (14.5 µg/g) and CGA (31.8 µg/g) [34]. Further, isolation and characterisation of these components were reviewed [34]. Similar information on SCG produced after cold-brew extraction processes is not available.
The chemical composition of coffee produced by either hot-brew or cold-brew processes will alter depending on factors including farming practices and extraction methods. The differences in concentrations between extraction processes implies that the content of bioactive compounds including caffeine and CGA remaining in SCG will depend on the extraction method used in the production of the beverage. The major compounds in coffee extracted by either hot-brew or cold-brew processes include caffeine, CGA, trigonelline and the diterpenes kahweol and cafestol [29,35,36,37]. Hot-brew processes with Ethiopian Arabica coffee showed highest caffeine and CGA concentrations in espresso coffees, up to 3–6 times higher than in Moka and filtered coffees [37]. The most efficient espresso methods used 14 g of fine powder and extraction for one minute at 93 °C and pressure of 9 bar [37]. The highest caffeine extraction from a 95% Robusta and 5% Arabica blend was in an espresso machine using 7.5 g of powder and 25 mL water at 92 °C and a pressure of 7 bar [35]. Unlike hot-brew coffee, cold-brew coffee extraction is a low-temperature, long-contact process, with different reported procedures to extract medium-roasted Arabica coffee under various conditions, such as using 50–100 g powder/L at 8 °C for 24 h [30] or 25 g powder/L for 282 min at 20 °C [35]. Extraction of caffeine and CGA by cold-brew procedures at room temperature reached a steady-state condition after around 400 min [36]. Further, per cup caffeine and CGA contents were greater in cold-brew processes than hot-brew espresso coffees [37]. The highest scores in sensory evaluation of cold-brew coffee, characterised by strong sweetness, fruity and floral flavours, medium bitterness and acidity, and a creamy body, were found after a 14 h extraction of coarse ground medium-roasted coffee at room temperature of 20 °C [38]. Cold-brew coffee showed increased floral flavour when compared to hot-brew coffee, and hot-brew coffee exhibited increased bitterness, sour taste and rubber flavour [39]. The differing results from different extraction procedures means that it is not possible to extrapolate the daily doses of caffeine and CGA from the number of cups of coffee consumed per day [37].

3. Value-Adding to SCG Outside the Health Industry

Utilisation of coffee by-products including SCG by industry has been a worldwide topic of research [14]. As a valuable industrial resource [27], industrial uses may provide the expertise in purifying compounds from SCG for therapeutic studies and also provide the financial support for these studies. This section will summarise some of the potential industrial uses of SCG including animal feed, biofuels, nutraceutical, cosmetic, fertilisers, composting and biopesticides [17,40,41].
Raw materials from coffee waste such as polysaccharide-rich fraction in SCG provide viscous and stable liquid solutions that are suitable for use as raw materials for biodegradable films or coating for packaging [42,43]. Such alternative materials for non-biodegradable fossil fuel-derived plastic packaging have been the target of research as many countries make the commitment to replace plastic packaging with environmentally friendly bioplastics by 2030 [44,45]. The biodegradable industry is growing, worth over USD 250 billion in 2020 and is expected to reach over USD 380 billion by 2028 [46].
SCG contain nitrogen and other important minerals required in both compost and fertilisers, and so could be used by the agriculture industry [4,14,27,47]. The current high costs of agricultural fertilisers, including nitrogen fertilisers, and compost prices at around 1320 AUD/tonne are expected to keep increasing [48]. Nutrient density increases in coffee plantations have been reported using SCG as part of fertilisers [49]. Potentially toxic responses to SCG to soil due to caffeine and high amounts of antioxidants [50] can be decreased by farming earthworms to decrease the caffeine content of SCG [51,52], making SCG then usable for the composting and fertilising industry.
Biofuels such as bioethanol, biogas and biodiesel can be produced from SCG, thus redirecting large amounts of coffee waste as a sustainable source of biofuel [53]. The commitment to reduce and eliminate fossil fuel use by generating renewable energy resources is the focus of almost the entire world [54]. The oil (10–30% of dry weight of SCG) extracted using ultrasound from SCG has the potential to be re-utilised to produce biodiesel [18,55,56]. Further, hydrothermal liquefaction of SCG has also been investigated as a viable option for producing crude bio-oil without the need of oil extraction [57]. In addition, fermenting the remaining oil-free SCG carbohydrate compounds showed the potential to use this waste to produce bioethanol [55]. Research findings are very promising, even though the methods to produce biofuels from SCG need improvements in scalability and efficiency [14].
SCG may be an efficient, low-cost and certainly environmentally friendly source of antioxidants, polyphenols and biomaterials for pharmaceutical products [26,58]. These compounds have been tested in cosmetics as anti-ageing and protective agents such as sunscreens, natural fillers and preservatives [58,59].
SCG, along with other coffee plant wastes, have been successfully used as a sustainable, cost-effective and healthy food additive in baked products, granolas, slow-cooked meals, seasoning for barbecues and desserts [60,61,62,63,64]. The production of food additives is a growing industry that turns over close to USD 45 billion a year [65]. SCG have been used in the preparation of baked products such as cookies and cakes as well as the production of beverages including alcoholic beverages [66]. Cookies prepared using SCG showed presence of caffeine, phenolic acids and polyphenols such as CGA [63]. Further, CGA extracts from coffee have been used in fried doughnuts, soymilk, wheat bread, liquid Khask, dark chocolate, yogurt and even instant coffee, which may increase the health benefits of these foods [67]. Increasing attention towards using coffee waste as a food additive will help to provide sustainable economic options to coffee farmers and reduce environmental impacts [66,68].
As SCG are a good source of caffeine, polyphenols such as CGA and melanoidins, it can be used as a raw material for the isolation of these compounds. The recovery of these compounds from SCG has used a range of methods of extraction [69,70]. Some of these methods include conventional solvent extraction, high hydrostatic pressure-assisted extraction, ultrasound-assisted extraction and microwave-assisted extraction [69,70,71,72]. Further, extraction methods have also been studied for coffee oil, which is a rich source of fatty acids and caffeine [73,74]. SCG after coffee oil extraction can be used for the extraction of galactomannan, diterpenes and mannose [74]. The leftover material can then be fermented into bioethanol [74]. This scheme, termed as biorefinery, can generate many valuable components from the SCG biomass that is generally being discarded in landfill, potentially generating many avenues for generating commercially viable components [41]. Thus, biorefinery using SCG can provide many valuable products including biodiesel, hydrocarbon fuel, bio-hydrogen, glycerine, many pharmaceutical-grade bioactive compounds, bioethanol, bio-oil, biochar, polymers and biogas [75].

4. Health Benefits of SCG

Although there are relatively few studies describing the physiological effects of SCG, they suggest that SCG intake may improve health and is safe. We have reported that modulation of gut microbiota by SCG from a hot-brew process, probably by melanoidins, reduced body weight, abdominal fat mass, systolic blood pressure and plasma triglycerides, improved glucose tolerance and improved the structure of the heart and liver in a rat model of diet-induced metabolic syndrome [76]. Coffee and SCG have been linked with changes in gut microbiota including increases in Bifidobacterium and decreases in Clostridium and Escherichia coli [77,78,79,80,81]. Further, CGA from coffee has shown non-polysaccharide-based prebiotic effects in an in vitro study through selective growth of human faecal microbiota [82]. These beneficial changes can help in improving the short-chain fatty acid profile produced by the gut microbiota and hence improve their composition and function. Pilot human studies found that consuming cookies enriched with SCG containing prebiotics promoted short-term satiety and reduced overall energy consumption even without other lifestyle changes [83]. Studies with SCG in humans include a small, randomised control single-blind parallel-group study and a pilot crossover randomised single-blind control study. Both studies observed better outcomes when participants ingested an extract of SCG antioxidant fibre. However, SCG (as a whole) also showed positive effects when compared to placebo [83,84]. An in vitro study suggested that SCG prebiotic fibre increased short-chain fatty acid production, resulting in gut microbiota modulation [85]. A small human clinical trial looking at chronotype and circadian locomotor activity in young adults found that the consumption of antioxidant fibre from SCG improved quality and length of sleep associated with an increased fermentation in the colon and short-chain fatty acids [84]. Furthermore, the inclusion of SCG with gluten-free flour (rice) in cookies improved sensory acceptance, with higher nutritional value as a source of fibre and polyphenols [86]. Figure 3 summarises the potential health benefits based on existing experimental evidence on SCG.

5. Health Benefits of Compounds in SCG

Bioactive compounds found in SCG have been researched for over 20 years, presenting evidence on the therapeutic effects when sourced from coffee [87,88]. Health benefits associated with the consumption of these compounds are directly associated with dose and frequency as well as source of compounds (for example, isolated pure compound vs. compound in coffee form). A summary of findings and types of studies is presented in Table 1. This section clarifies existing evidence on the compounds present in SCG concluding the health benefits associated with the consumption of SCG.

5.1. Chlorogenic Acids (CGA)

CGA is an abundant polyphenol found in plant foods. Coffee is the major source of CGA for humans, with amounts varying from 0.5–6 g to 100 g of dry coffee prior to the brewing process [36]. CGA is also present in SCG and preliminary experiments using SCG indicates compound activity [87,88].
When sourced from coffee, CGA affects cardiovascular health, glucose metabolism and obesity [36,89,92,93,96,98,112,113,114]. Similar findings from research using SCG are presented in Section 4. Overall, the main actions associated with CGA are antioxidant and anti-inflammatory.
Effects on cardiovascular health include potential benefits in regulating blood pressure, endothelial function and dyslipidaemia [36,89,92,93,112]. Specific mechanisms of action by which CGA may have a direct effect on blood pressure and endothelial function include increases in nitric oxide (NO) bioavailability by inhibiting reactive oxygen species (ROS), NADPH oxidase and superoxide anion generation [93]. Other mechanisms of action to improve cardiovascular risk factors such as dyslipidaemia include increased uptake of fatty acids in the liver and reduction in plasma low-density lipoprotein cholesterol in both animal and pilot human studies [93,115].
CGA effects on glucose metabolism may provide an alternative and non-invasive approach for the treatment and prevention of chronic metabolic diseases such as type 2 diabetes [112]. CGA reduced fasting blood glucose concentration in patients with impaired glucose tolerance at various doses and treatment duration [94,95]. CGA may act similarly to metformin, one of the most commonly prescribed pharmaceutical drugs for type 2 diabetes, as an insulin sensitiser [116]. Mechanisms of action for CGA to assist glucose metabolism include improving intestinal and adipocyte glucose absorption, potentially decreasing plasma glucose concentrations as well as influencing the glycaemic impact of foods and release of carbohydrate-specific digestive enzymes [95,117].
CGA decreased obesity, inhibited in vivo lipase enzymatic action and prevented lipid absorption [96,98,113,114]. In rats, CGA improved body weight, visceral fat accumulation and liver function, and decreased inflammatory cell infiltration in obese, hypertensive rats fed a high-fat and -carbohydrate diet [97]. In humans, a reduction in body weight and most markers associated with obesity, glucose and lipid metabolism were reported [114]. Further studies are needed to compare the difference in activity and concentration of CGA from different sources, including coffee (beverage), SCG, and their different methods of extractions (hot or cold brew), since temperature maybe relevant to this compound.

5.2. Caffeine

Caffeine is widely known for its mild stimulant effects, temporary energy boosts and sometimes changes in mood [118]. Caffeine absorption occurs 30–45 min after consumption and blood concentrations may take up to two hours to rise [119]. Caffeine is predominantly ingested as coffee in our diet, with an average double-shot coffee providing around 150 mg [118,120], and also found in SCG [88].
Similar to CGA, caffeine can impact cardiovascular health. The effect of caffeine in cardiovascular health depends on factors such as dose, time ingested, absorption variation and hepatic metabolism [121]. The mechanisms of action in which caffeine affects the cardiovascular system can include a reduction in cytoplasmic calcium concentrations in the vascular smooth muscle cells through cyclic adenosine monophosphate and an increase in the same in the endothelial cells favouring the endogenous synthesis of NO [121]. The main cardiovascular effect of caffeine is the increased concentration of NO, and, consequently, vasodilation.
The effects of caffeine in the nervous system are widely researched. One of the mechanisms of action in which caffeine affects the brain is by antagonising adenosine receptors, increasing the release of excitatory neurotransmitters such as glutamate and noradrenaline [122,123]. Caffeine potentially improves cognitive symptoms and has protective characteristics in neurodegenerative diseases such as Parkinson’s disease [99,123,124,125,126,127].
A widespread concern with caffeine is potential negative effects in those with existing cardiovascular conditions [128,129]. However, consumption of up to six cups of caffeinated coffee a day was not associated with an increased risk of cardiovascular outcomes, even with those who have history of hypertension and other cardiovascular diseases [120]. In addition, a meta-analysis showed those who consume three to five cups of caffeinated coffee a day have lower incidence of coronary artery disease, stroke and death due to cardiovascular causes [130]. However, longer-term or overconsumption of caffeine may cause addiction, insomnia, migraine and other adverse effects [131].

5.3. Trigonelline

Trigonelline is a pyridine alkaloid compound and a methylation product of vitamin B3, niacin [132], found in plant foods such as barley, cantaloupes, corn, onions, soybeans, tomatoes, peas, fenugreek seeds, coffee and SCG [133]. A 250 mL volume of brewed coffee provides 27 mg of trigonelline [134]. Higher concentrations of trigonelline are found in green coffee beans from the C. arabica species, and trigonelline changes into N-methylpyridinium and nicotinic acid during roasting [135,136].
In the nervous system, trigonelline improves the function of specific neurons, and sometimes the potential to regenerate certain neurons. Therefore, it is a possible intervention for neurovegetative diseases which are now incurable [102,103,107,137]. β-Amyloid peptide accumulation is a common risk factor and cause of Alzheimer’s disease [138]. The similarity of trigonelline to cotinine, an anti-Alzheimer’s drug, pushed studies that checked whether trigonelline had any affinity to interact with β-amyloid peptide, and results were promising [139]. Trigonelline was effective in suppressing oxidative stress, astrocyte activity and inflammation to prevent neuronal loss in the hippocampus to alleviate Alzheimer’s disease in mice [102]. Neuroinflammation is also a contributor to Alzheimer’s disease [140]. An animal study showed the anti-inflammatory effects and improvement of memory of trigonelline against liposaccharide-treated adult mice brains [104]. The positive results could be due to higher concentrations of brain-derived neurotrophic factor, lowered oxidative stress and decreased concentrations of tumour necrosis factor α, interleukin 6 and acetylcholinesterase [104]. Recently, a comprehensive animal study confirmed that trigonelline recovered memory function in a mouse model of Alzheimer’s disease [103]. The anti-Alzheimer’s disease effects of trigonelline in this study were confirmed by the reconstruction of neuronic networks after brain damage.

5.4. Cafestol and Kahweol

Cafestol and kahweol are the main diterpenes and their content is about 15% of total lipids in coffee [141]. Kahweol is largely found in C. arabica beans, whereas 16-O-methylcafestol ester is found mainly in C. robusta [142]. However, cafestol is found in both C. arabica and C. robusta [143]. Coffee consumption was associated with elevated serum cholesterol concentrations due to the presence of cafestol and kahweol esters [144,145]. Diterpenes are extracted from coffee during the brewing process, and when coffee is filtered, diterpenes are almost completely removed. In SCG, the presence of these compounds will also depend on the preparation method.
There are few data on the bioavailability and pharmacokinetics of cafestol and kahweol, especially in diseases, with most data from healthy individuals. An estimated 30% of cafestol is broken down in the stomach by gastric juices, with the remaining 70% absorbed in the duodenum at a rate of 84–93% [146]. Kahweol has a similar absorption rate and was absorbed in the small intestine at a higher rate of 91–95% [146].
Most of the evidence on these compounds’ health benefits is related to their ability to suppress activity, migration and proliferation of cancer cells. Kahweol acetate and cafestol inhibited proliferation and migration of prostate cancer cells, where other coffee compounds did not show the same effect [147]. The synergistic effects of both compounds may allow lower concentrations of these compounds to be effective in inhibiting prostate cancer progression. These findings could be important for those consuming unfiltered coffee, as concentrations of diterpenes are much higher than in filtered coffee. The mechanisms of actions were described as an ability to induce apoptosis and suppression of the epithelial–mesenchymal transition, and a reduction in androgen receptors and chemokine receptors CCR2 and CCR5, preventing cancer cell migration and proliferation [147].
Anti-angiogenesis activity from cafestol and kahweol has been published with experiments in vitro and protective effects in cancer proliferation and migration in endothelial cells. Angiogenesis plays an important role in cancer cell proliferation and migration [148].
Other health benefits of cafestol and kahweol include anti-diabetic and anti-inflammatory activity [149]. These compounds show anti-diabetic actions by increasing insulin secretion and glucose uptake by skeletal muscle, and AMP-activated protein kinase activation, which mimics metformin action [150,151]. Both compounds showed the ability to inhibit inflammatory mediators such as prostaglandin E2 and NO synthesis in lipopolysaccharide-activated macrophages, thus indicating their anti-inflammatory activity [152].

5.5. Melanoidins

Melanoidins are nitrogen-containing polymers produced during the non-enzymatic browning Maillard reaction, making these compounds a differentiation marker between green and roasted coffee beans present in coffee beverages and SCG. Melanoidins are not unique to coffee or SCG as other foods such as bread, roasted cocoa and beer undergo a Maillard reaction during preparation to produce melanoidins [153]. Hot-brewed coffee is likely to be the main source of melanoidins in the human diet [154]. Melanoidin concentrations in coffee may vary in roasted coffee beans, making around 25% of dry weight or slightly higher in a darker roasting process and around 29% in brewed coffee [155]. Melanoidins provide specific characteristics to foods such as flavour and brown colour [31]. Published biological activities of melanoidins include antioxidant, antimicrobial, ability to change xenobiotic enzymatic activity, prebiotic fibre and antihypertensive actions [153].
A recently published study concluded that melanoidins from coffee also undergo minor digestion in the upper gastrointestinal tract [156]. Melanoidins can be fermented by gut bacteria and produce short-chain fatty acids, modulating the bacterial population. This fermentation may also release phenolic compounds which can then be absorbed, increasing phenolic absorption from foods containing melanoidins. Modulation of gut bacteria by short-chain fatty acid production reduced symptoms of metabolic diseases [157,158].
The potential antioxidant activity of melanoidins on human health has been linked with protection against oxidative damages and it has been highly related to degrees of roasting [159]. Their ability to bind undesirable dietary metals also prevents oxidative damage [160]. High-molecular-weight fractions of coffee were able to completely inhibit lipid peroxidation in rat liver microsomes [161]. However, once isolated compounds were tested, they failed to duplicate the protective action alone, so two non-melanoidin compounds may be responsible to protective actions. In different in vitro methods, Maillard reaction products such as melanoidins may have similar antioxidant compounds to pre- or light-roasting polyphenol compounds found in coffee against oxidation from human low-density lipoproteins [155]. There are limited data published on in vivo antioxidant effects of coffee consumption, which is not specifically linked to melanoidins’ individual effect as it would also include polyphenols in coffee such as CGA. The antioxidant effects of roasted and brewed coffee were mainly attributed to melanoidins, as other antioxidant compounds in coffee are decreased by heat from roasting and brewing processes [162]. Other applications for melanoidins originating from foods other than coffee such as antioxidant and modulator of Phase I and II enzymes for detoxification were briefly described in a review, which could be applicable to coffee [162].
Although there is robust evidence on these compounds when sourced from coffee, studies to analyse each compound and their biological activity when sourced as part of SCG are needed. Understanding the biological responses of the compounds including caffeine, CGA, trigonelline, polyphenols, melanoidins and other antioxidants when sourced from SCG, rather than coffee (beverage), may provide options to test for therapeutic benefits as these compounds. SCG may be a sustainable resource for bioactive compounds with established health benefits and safety and efficacy for human consumption [18,27,88]. However, SCG are currently not utilised to the full potential.

6. Conclusions, Challenges and Future Directions

SCG can contribute to a wide variety of sustainable products, including animal feed, biofuels, fertilisers, compost and biopesticides. However, SCG applications can go beyond non-health-related purposes due to the presence of bioactive compounds in potentially therapeutic doses, such as CGA, caffeine, trigonelline, cafestol, kahweol and melanoidins. SCG, similar to hot-brew coffee, containing these compounds has potential to attenuate well-known metabolic disorders, including NAFLD, type 2 diabetes and cardiovascular disease.
This review shows that the literature on responses to SCG as a functional food component is often preliminary, so many more studies are required to understand what other compounds are present in coffee by-products, especially SCG, and how these could benefit human health. Moreover, it is important to elucidate the precise mechanisms by which the bioactive compounds obtained from SCG support health-related effects. As with other functional foods, SCG may experience challenges in clinical studies [163]. Some of these challenges may include limited industry funding to support the study, unsuitable placebos, maintaining food products and their safety, and limited opportunities to check compliance [163]. Thus, more focus on food by-products such as SCG from industries and funding bodies will help in making initial steps towards obtaining suitable clinical data that can be used for appropriate translation of the clinical outcomes.
As studies on SCG are limited regarding their health benefits, it is important to understand the differences between hot or cold extraction methods as well as differences in responses of these compounds when consumed in coffee beverages and SCG. Ultimately, more scientific investigations can promote economic and health benefits worldwide. The change from considering SCG as a waste product to one with widespread health and industrial uses could benefit both coffee producers and consumers. Finally, SCG as a low-cost raw material can provided affordable functional food products when used directly. However, purified nutraceutical product development can dramatically increase the cost of the process and hence the product, thus suggesting SCG as the most viable and affordable functional food option.
Limitations of current studies include the precise characterisation of the components of cold-brew coffee and SCG as well as longer and larger clinical trials in patients with chronic diseases. Further, limited attempts have been made to extract bioactive compounds from SCG for developing nutraceuticals. These nutraceuticals can serve as a viable option for the longer-term option for human consumption as supplements. Large-scale epidemiological or clinical studies in people consuming these supplements from SCG will be important in confirming any reduction in disease risk.

Author Contributions

Conceptualisation, E.B., V.C. and L.B.; resources, V.C., L.B. and S.K.P.; writing—original draft preparation, E.B.; writing—review and editing V.C., L.B., S.K.P., I.S. and R.B.R.; supervision, V.C., L.B. and R.B.R. All authors have read and agreed to the published version of the manuscript.


This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.


The authors would like to acknowledge the Faculty of Health, Southern Cross University, Gold Coast, and the Faculty of Health, School of Pharmacy and Medical Sciences, Griffith University, for research support.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Maksud, H.; Ali Syahban, A. The function of a coffee shop as a social cultural entity. In Trends and Innovations in Food Science; Yehia, E.-S., Ed.; IntechOpen: London, UK, 2022; p. 103852. [Google Scholar] [CrossRef]
  2. Samper, L.F.; Quiñones-Ruiz, X.F. Towards a balanced sustainability vision for the coffee industry. Resources 2017, 6, 17. [Google Scholar] [CrossRef] [Green Version]
  3. Shahbandeh, M. Coffee Market: Worldwide Production 2003/04–2020/21. 2022. Available online: (accessed on 26 November 2022).
  4. Murthy, P.S.; Madhava Naidu, M. Sustainable management of coffee industry by-products and value addition—A review. Resour. Conserv. Recy. 2012, 66, 45–58. [Google Scholar] [CrossRef]
  5. Soloway, B. In Brazil’s Coffee Industry, Some Workers Face ‘Conditions Analogous to Slavery’. Foreign Policy 13 April 2016. Available online: (accessed on 26 November 2022).
  6. Pines, L. Brazil’s Economy: Foreign Trade Figures Reveal Why They’re a Major Global Player. 7 April 2021. Available online: (accessed on 26 November 2022).
  7. Ozbun, T. Brazil: Coffee Production 2010–2020. Statista: 2022. Available online: (accessed on 26 November 2022).
  8. United Nation Environment Programme. Coffee, Environmental Degradation and Smallholder Livelihoods. Available online: (accessed on 26 November 2022).
  9. Moore, V. The Environmental Impact of Coffee Production: What’s Your Coffee Costing the Planet? Available online: (accessed on 26 November 2022).
  10. Varcho, A.L. 2.2 A Bitter Brew-Coffee Production, Deforestation, Soil Erosion and Water Contamination. Available online: (accessed on 26 November 2022).
  11. Chanakya, H.N.; De Alwis, A.A.P. Environmental issues and management in primary coffee processing. Process Saf. Environ. Prot. 2004, 82, 291–300. [Google Scholar] [CrossRef]
  12. de Queiroz, V.T.; Azevedo, M.M.; da Silva Quadros, I.P.; Costa, A.V.; do Amaral, A.A.; dos Santos, G.M.A.D.A.; Juvanhol, R.S.; de Almeida Telles, L.A.; dos Santos, A.R. Environmental risk assessment for sustainable pesticide use in coffee production. J. Contam. Hydrol. 2018, 219, 18–27. [Google Scholar] [CrossRef]
  13. Fernandes, A.S.; Mello, F.V.C.; Thode Filho, S.; Carpes, R.M.; Honório, J.G.; Marques, M.R.C.; Felzenszwalb, I.; Ferraz, E.R.A. Impacts of discarded coffee waste on human and environmental health. Ecotoxicol. Environ. Saf. 2017, 141, 30–36. [Google Scholar] [CrossRef]
  14. Dattatraya Saratale, G.; Bhosale, R.; Shobana, S.; Banu, J.R.; Pugazhendhi, A.; Mahmoud, E.; Sirohi, R.; Kant Bhatia, S.; Atabani, A.E.; Mulone, V.; et al. A review on valorization of spent coffee grounds (SCG) towards biopolymers and biocatalysts production. Bioresour. Technol. 2020, 314, 123800. [Google Scholar] [CrossRef]
  15. Efthymiopoulos, I.; Hellier, P.; Ladommatos, N.; Kay, A.; Mills-Lamptey, B. Integrated strategies for water removal and lipid extraction from coffee industry residues. Sustain. Energy Technol. Assess. 2018, 29, 26–35. [Google Scholar] [CrossRef]
  16. Gemechu, G.E.; Mulualem, T. The blooming of coffee industry: Its waste problem and utilization through management option: A review. J. Biol. Chem. Res. 2020, 37, 36–46. [Google Scholar]
  17. de Melo Pereira, G.V.; de Carvalho Neto, D.P.; Magalhães Júnior, A.I.; do Prado, F.G.; Pagnoncelli, M.G.B.; Karp, S.G.; Soccol, C.R. Chapter Three—Chemical composition and health properties of coffee and coffee by-products. In Advances in Food and Nutrition Research; Toldrá, F., Ed.; Academic Press: Cambridge, MA, USA, 2020; Volume 91, pp. 65–96. [Google Scholar] [CrossRef]
  18. Durán-Aranguren, D.D.; Robledo, S.; Gomez-Restrepo, E.; Arboleda Valencia, J.W.; Tarazona, N.A. Scientometric overview of coffee by-products and their applications. Molecules 2021, 26, 7605. [Google Scholar] [CrossRef]
  19. Ridder, M. Major Coffee Importing Countries Worldwide 2020. Statista: 2022. Available online: (accessed on 26 November 2022).
  20. Misachi, J. Which States Grow Coffee? 2019. Available online: (accessed on 26 November 2022).
  21. Knoema DataHub. United States of America—Green Coffee Production Quantity. 2021. Available online: (accessed on 10 January 2023).
  22. Bai, C.L.; Liu, L.Y.; Guo, J.L.; Zeng, L.X.; Guo, Y. Microplastics in take-out food: Are we over taking it? Environ. Res. 2022, 215, 114390. [Google Scholar] [CrossRef]
  23. Ekvall, M.T.; Lundqvist, M.; Kelpsiene, E.; Šileikis, E.; Gunnarsson, S.B.; Cedervall, T. Nanoplastics formed during the mechanical breakdown of daily-use polystyrene products. Nanoscale Adv. 2019, 1, 1055–1061. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  24. PlanetArk. Coffee Go Ground; Planet Ark Environmental Foundation: Sydney, Australia, 2016; Available online: (accessed on 29 November 2022).
  25. Cervera-Mata, A.; Navarro-Alarcón, M.; Delgado, G.; Pastoriza, S.; Montilla-Gómez, J.; Llopis, J.; Sánchez-González, C.; Rufián-Henares, J. Spent coffee grounds improve the nutritional value in elements of lettuce (Lactuca sativa L.) and are an ecological alternative to inorganic fertilizers. Food Chem. 2019, 282, 1–8. [Google Scholar] [CrossRef]
  26. Iriondo-DeHond, A.; Iriondo-DeHond, M.; Del Castillo, M.D. Applications of compounds from coffee processing by-products. Biomolecules 2020, 10, 1219. [Google Scholar] [CrossRef]
  27. Stylianou, M.; Agapiou, A.; Omirou, M.; Vyrides, I.; Ioannides, I.M.; Maratheftis, G.; Fasoula, D. Converting environmental risks to benefits by using spent coffee grounds (SCG) as a valuable resource. Environ. Sci. Pollut. Res. Int. 2018, 25, 35776–35790. [Google Scholar] [CrossRef]
  28. Hu, G.L.; Wang, X.; Zhang, L.; Qiu, M.H. The sources and mechanisms of bioactive ingredients in coffee. Food Funct. 2019, 10, 3113–3126. [Google Scholar] [CrossRef]
  29. Wang, X.; Wang, Y.; Hu, G.; Hong, D.; Guo, T.; Li, J.; Li, Z.; Qiu, M. Review on factors affecting coffee volatiles: From seed to cup. J. Sci. Food Agric. 2022, 102, 1341–1352. [Google Scholar] [CrossRef]
  30. Claassen, L.; Rinderknecht, M.; Porth, T.; Röhnisch, J.; Seren, H.Y.; Scharinger, A.; Gottstein, V.; Noack, D.; Schwarz, S.; Winkler, G.; et al. Cold brew coffee—Pilot studies on definition, extraction, consumer preference, chemical characterization and microbiological hazards. Foods 2021, 10, 865. [Google Scholar] [CrossRef]
  31. Moreira, A.S.; Nunes, F.M.; Domingues, M.R.; Coimbra, M.A. Coffee melanoidins: Structures, mechanisms of formation and potential health impacts. Food Funct. 2012, 3, 903–915. [Google Scholar] [CrossRef] [PubMed]
  32. Iriondo-DeHond, A.; Rodríguez Casas, A.; Del Castillo, M.D. Interest of coffee melanoidins as sustainable healthier food ingredients. Front. Nutr. 2021, 8, 730343. [Google Scholar] [CrossRef] [PubMed]
  33. Schouten, M.A.; Tappi, S.; Romani, S. Acrylamide in coffee: Formation and possible mitigation strategies—A review. Crit. Rev. Food Sci. Nutr. 2020, 60, 3807–3821. [Google Scholar] [CrossRef] [PubMed]
  34. Bomfim, A.S.; de Oliveira, D.M.; Walling, E.; Babin, A.; Hersant, G.; Vaneeckhaute, C.; Dumont, M.-J.; Rodrigue, D. Spent coffee grounds characterization and reuse in composting and soil amendment. Waste 2022, 1, 2–20. [Google Scholar] [CrossRef]
  35. Olechno, E.; Puścion-Jakubik, A.; Zujko, M.E.; Socha, K. Influence of various factors on caffeine content in coffee brews. Foods 2021, 10, 1208. [Google Scholar] [CrossRef]
  36. Fuller, M.; Rao, N.Z. The effect of time, roasting temperature, and grind size on caffeine and chlorogenic acid concentrations in cold brew coffee. Sci. Rep. 2017, 7, 17979. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  37. Angeloni, G.; Guerrini, L.; Masella, P.; Bellumori, M.; Daluiso, S.; Parenti, A.; Innocenti, M. What kind of coffee do you drink? An investigation on effects of eight different extraction methods. Food Res. Int. 2019, 116, 1327–1335. [Google Scholar] [CrossRef] [PubMed]
  38. Cordoba, N.; Pataquiva, L.; Osorio, C.; Moreno, F.L.M.; Ruiz, R.Y. Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee. Sci. Rep. 2019, 9, 8440. [Google Scholar] [CrossRef] [Green Version]
  39. Batali, M.E.; Lim, L.X.; Liang, J.; Yeager, S.E.; Thompson, A.N.; Han, J.; Ristenpart, W.D.; Guinard, J.X. Sensory analysis of full immersion coffee: Cold brew is more floral, and less bitter, sour, and rubbery than hot brew. Foods 2022, 11, 2440. [Google Scholar] [CrossRef] [PubMed]
  40. Angeloni, S.; Scortichini, S.; Fiorini, D.; Sagratini, G.; Vittori, S.; Neiens, S.D.; Steinhaus, M.; Zheljazkov, V.D.; Maggi, F.; Caprioli, G. Characterization of odor-active compounds, polyphenols, and fatty acids in coffee silverskin. Molecules 2020, 25, 2993. [Google Scholar] [CrossRef]
  41. Karmee, S.K. A spent coffee grounds based biorefinery for the production of biofuels, biopolymers, antioxidants and biocomposites. Waste Manag. 2018, 72, 240–254. [Google Scholar] [CrossRef]
  42. Batista, M.; Ávila, A.F.; Franca, A.S.; Oliveira, L.S. Polysaccharide-rich fraction of spent coffee grounds as promising biomaterial for films fabrication. Carbohydr. Polym. 2020, 233, 115851. [Google Scholar] [CrossRef]
  43. Coelho, G.O.; Batista, M.J.A.; Ávila, A.F.; Franca, A.S.; Oliveira, L.S. Development and characterization of biopolymeric films of galactomannans recovered from spent coffee grounds. J. Food Eng. 2021, 289, 110083. [Google Scholar] [CrossRef]
  44. Australian Government. Plastics; Department of Agriculture, Water and the Environment: 2022. Available online: (accessed on 26 November 2022).
  45. European Commission. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions; COM 650 Final; European Commission: Comission Work Programme 2018. 2017. Available online: (accessed on 29 November 2022).
  46. Fortune Business Insights. The Global Green Packaging Market Size was USD 258.35 Billion in 2020. The Market is Projected to Grow from USD 267.83 Billion in 2021 to USD 385.34 Billion by 2028; Fortune Business Insight: 2022. Available online: (accessed on 29 November 2022).
  47. Gouws, S.; Muller, M. Valorization of products from grounded-coffee beans. Sci. Rep. 2021, 11, 20445. [Google Scholar] [CrossRef] [PubMed]
  48. Whiitelaw, A. Record-High Fertiliser Prices in Australia Could Disrupt Food Supplies. The Guardian 12 November 2021. Available online: (accessed on 29 November 2022).
  49. Cervera-Mata, A.; Delgado, G.; Fernández-Arteaga, A.; Fornasier, F.; Mondini, C. Spent coffee grounds by-products and their influence on soil C–N dynamics. J. Environ. Manag. 2022, 302, 114075. [Google Scholar] [CrossRef]
  50. Santos, C.; Fonseca, J.; Aires, A.; Coutinho, J.; Trindade, H. Effect of different rates of spent coffee grounds (SCG) on composting process, gaseous emissions and quality of end-product. Waste Manag. 2017, 59, 37–47. [Google Scholar] [CrossRef] [PubMed]
  51. Liu, K.; Price, G.W. Evaluation of three composting systems for the management of spent coffee grounds. Bioresour. Technol. 2011, 102, 7966–7974. [Google Scholar] [CrossRef] [PubMed]
  52. Hanc, A.; Hrebeckova, T.; Grasserova, A.; Cajthaml, T. Conversion of spent coffee grounds into vermicompost. Bioresour. Technol. 2021, 341, 125925. [Google Scholar] [CrossRef]
  53. Battista, F.; Barampouti, E.M.; Mai, S.; Bolzonella, D.; Malamis, D.; Moustakas, K.; Loizidou, M. Added-value molecules recovery and biofuels production from spent coffee grounds. Renew. Sustain. Energy Rev. 2020, 131, 110007. [Google Scholar] [CrossRef]
  54. United Nations Climate Change. The Paris Agreement; United Nations Climate Change: Bonn, Germany, 2022; Available online: (accessed on 26 November 2022).
  55. Rocha, M.V.; de Matos, L.J.; Lima, L.P.; Figueiredo, P.M.; Lucena, I.L.; Fernandes, F.A.; Gonçalves, L.R. Ultrasound-assisted production of biodiesel and ethanol from spent coffee grounds. Bioresour. Technol. 2014, 167, 343–348. [Google Scholar] [CrossRef]
  56. Massaya, J.; Prates Pereira, A.; Mills-Lamptey, B.; Benjamin, J.; Chuck, C.J. Conceptualization of a spent coffee grounds biorefinery: A review of existing valorisation approaches. Food Bioprod. Process. 2019, 118, 149–166. [Google Scholar] [CrossRef]
  57. Yang, L.; Mahmood, N.; Corscadden, K.; Xu, C.; He, Q. Production of crude bio-oil via direct liquefaction of spent K-Cups. Biomass Bioenergy 2016, 95, 354–363. [Google Scholar] [CrossRef]
  58. Ballesteros, L.F.; Ramirez, M.J.; Orrego, C.E.; Teixeira, J.A.; Mussatto, S.I. Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials. Food Chem. 2017, 237, 623–631. [Google Scholar] [CrossRef] [Green Version]
  59. Vu, D.C.; Vu, Q.T.; Huynh, L.; Lin, C.-H.; Alvarez, S.; Vo, X.T.; Nguyen, T.H.D. Evaluation of fatty acids, phenolics and bioactivities of spent coffee grounds prepared from Vietnamese coffee. Int. J. Food Prop. 2021, 24, 1548–1558. [Google Scholar] [CrossRef]
  60. Martinez-Saez, N.; García, A.T.; Pérez, I.D.; Rebollo-Hernanz, M.; Mesías, M.; Morales, F.J.; Martín-Cabrejas, M.A.; del Castillo, M.D. Use of spent coffee grounds as food ingredient in bakery products. Food Chem. 2017, 216, 114–122. [Google Scholar] [CrossRef]
  61. Klingel, T.; Kremer, J.I.; Gottstein, V.; Rajcic de Rezende, T.; Schwarz, S.; Lachenmeier, D.W. A review of coffee by-products including leaf, flower, cherry, husk, silver skin, and spent grounds as novel foods within the European Union. Foods 2020, 9, 665. [Google Scholar] [CrossRef]
  62. Gaston, S. 12 Delicious Food Recipes with Coffee Grouds in Them. 2021. Available online: (accessed on 26 November 2022).
  63. Castaldo, L.; Lombardi, S.; Gaspari, A.; Rubino, M.; Izzo, L.; Narváez, A.; Ritieni, A.; Grosso, M. In vitro bioaccessibility and antioxidant activity of polyphenolic compounds from spent coffee grounds-enriched cookies. Foods 2021, 10, 1837. [Google Scholar] [CrossRef]
  64. Pourfarzad, A.; Mahdavian-Mehr, H.; Sedaghat, N. Coffee silverskin as a source of dietary fiber in bread-making: Optimization of chemical treatment using response surface methodology. LWT Food Sci. Technol. 2013, 50, 599–606. [Google Scholar] [CrossRef]
  65. Gaille, B. 18 Food Additives Industry Statistics and Trends. 2018. Available online:,their%20foods%20be%20free%20of%20any%20artificial%20additives (accessed on 26 November 2022).
  66. Franca, A.S.; Oliveira, L.S. Potential uses of spent coffee grounds in the food industry. Foods 2022, 11, 2064. [Google Scholar] [CrossRef] [PubMed]
  67. Rojas-González, A.; Figueroa-Hernández, C.Y.; González-Rios, O.; Suárez-Quiroz, M.L.; González-Amaro, R.M.; Hernández-Estrada, Z.J.; Rayas-Duarte, P. Coffee chlorogenic acids incorporation for bioactivity enhancement of foods: A review. Molecules 2022, 27, 3400. [Google Scholar] [CrossRef]
  68. Arya, S.S.; Venkatram, R.; More, P.R.; Vijayan, P. The wastes of coffee bean processing for utilization in food: A review. J. Food Sci. Technol. 2022, 59, 429–444. [Google Scholar] [CrossRef] [PubMed]
  69. Okur, I.; Soyler, B.; Sezer, P.; Oztop, M.H.; Alpas, H. Improving the recovery of phenolic compounds from spent coffee grounds (SCG) by environmentally friendly extraction techniques. Molecules 2021, 26, 613. [Google Scholar] [CrossRef] [PubMed]
  70. Bouhlal, F.; Aqil, Y.; Chamkhi, I.; Belmaghraoui, W.; Labjar, N.; Hajjaji, S.E.; Benabdellah, G.A.; Aurag, J.; Lotfi, E.M.; Mahi, M.E. GC-MS analysis, phenolic compounds quantification, antioxidant, and antibacterial activities of the hydro-alcoholic extract of spent coffee grounds. J. Biol. Active Prod. Nat. 2020, 10, 325–337. [Google Scholar] [CrossRef]
  71. Coelho, J.P.; Robalo, M.P.; Boyadzhieva, S.; Stateva, R.P. Microwave-assisted extraction of phenolic compounds from spent coffee grounds. Process optimization applying design of experiments. Molecules 2021, 26, 7320. [Google Scholar] [CrossRef] [PubMed]
  72. Al-Dhabi, N.A.; Ponmurugan, K.; Maran Jeganathan, P. Development and validation of ultrasound-assisted solid-liquid extraction of phenolic compounds from waste spent coffee grounds. Ultrason. Sonochem. 2017, 34, 206–213. [Google Scholar] [CrossRef] [PubMed]
  73. Leow, Y.; Yew, P.Y.M.; Chee, P.L.; Loh, X.J.; Kai, D. Recycling of spent coffee grounds for useful extracts and green composites. RSC Adv. 2021, 11, 2682–2692. [Google Scholar] [CrossRef] [PubMed]
  74. Jin Cho, E.; Gyo Lee, Y.; Song, Y.; Nguyen, D.-T.; Bae, H.-J. An integrated process for conversion of spent coffee grounds into value-added materials. Bioresour. Technol. 2022, 346, 126618. [Google Scholar] [CrossRef]
  75. Lauberts, M.; Mierina, I.; Pals, M.; Latheef, M.A.; Shishkin, A. Spent coffee grounds valorization in biorefinery context to obtain valuable products using different extraction approaches and solvents. Plants 2023, 12, 30. [Google Scholar] [CrossRef]
  76. Bhandarkar, N.S.; Mouatt, P.; Goncalves, P.; Thomas, T.; Brown, L.; Panchal, S.K. Modulation of gut microbiota by spent coffee grounds attenuates diet-induced metabolic syndrome in rats. FASEB J. 2020, 34, 4783–4797. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  77. Jaquet, M.; Rochat, I.; Moulin, J.; Cavin, C.; Bibiloni, R. Impact of coffee consumption on the gut microbiota: A human volunteer study. Int. J. Food Microbiol. 2009, 130, 117–121. [Google Scholar] [CrossRef]
  78. Nakayama, T.; Oishi, K. Influence of coffee (Coffea arabica) and galacto-oligosaccharide consumption on intestinal microbiota and the host responses. FEMS Microbiol. Lett. 2013, 343, 161–168. [Google Scholar] [CrossRef] [Green Version]
  79. Nehlig, A. Effects of coffee on the gastro-intestinal tract: A narrative review and literature update. Nutrients 2022, 14, 399. [Google Scholar] [CrossRef]
  80. González, S.; Salazar, N.; Ruiz-Saavedra, S.; Gómez-Martín, M.; de Los Reyes-Gavilán, C.G.; Gueimonde, M. Long-term coffee consumption is associated with fecal microbial composition in humans. Nutrients 2020, 12, 1287. [Google Scholar] [CrossRef]
  81. Pérez-Burillo, S.; Pastoriza, S.; Fernández-Arteaga, A.; Luzón, G.; Jiménez-Hernández, N.; D’Auria, G.; Francino, M.P.; Rufián-Henares, J.Á. Spent coffee grounds extract, rich in mannooligosaccharides, promotes a healthier gut microbial community in a dose-dependent manner. J. Agric. Food Chem. 2019, 67, 2500–2509. [Google Scholar] [CrossRef] [PubMed]
  82. Mills, C.E.; Tzounis, X.; Oruna-Concha, M.J.; Mottram, D.S.; Gibson, G.R.; Spencer, J.P. In vitro colonic metabolism of coffee and chlorogenic acid results in selective changes in human faecal microbiota growth. Br. J. Nutr. 2015, 113, 1220–1227. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  83. Campos-Vega, R.; Arreguín-Campos, A.; Cruz-Medrano, M.A.; Del Castillo Bilbao, M.D. Spent coffee (Coffea arabica L.) grounds promote satiety and attenuate energy intake: A pilot study. J. Food Biochem. 2020, 44, e13204. [Google Scholar] [CrossRef] [PubMed]
  84. Oseguera-Castro, K.Y.; Madrid, J.A.; Martínez Madrid, M.J.; García, O.P.; Del Castillo, M.D.; Campos-Vega, R. Antioxidant dietary fiber isolated from spent coffee (Coffea arabica L.) grounds improves chronotype and circadian locomotor activity in young adults. Food Funct. 2019, 10, 4546–4556. [Google Scholar] [CrossRef]
  85. López-Barrera, D.M.; Vázquez-Sánchez, K.; Loarca-Piña, M.G.; Campos-Vega, R. Spent coffee grounds, an innovative source of colonic fermentable compounds, inhibit inflammatory mediators in vitro. Food Chem. 2016, 212, 282–290. [Google Scholar] [CrossRef]
  86. Oliveira Batista, J.; Car Cordeiro, C.; Klososki, S.J.; Mongruel Eleutério Dos Santos, C.; Leão, G.M.C.; Pimentel, T.C.; Rosset, M. Spent coffee grounds improve the nutritional value and technological properties of gluten-free cookies. J. Culin. Sci. Technol. 2022. [Google Scholar] [CrossRef]
  87. Ramón-Gonçalves, M.; Gómez-Mejía, E.; Rosales-Conrado, N.; León-González, M.E.; Madrid, Y. Extraction, identification and quantification of polyphenols from spent coffee grounds by chromatographic methods and chemometric analyses. Waste Manag. 2019, 96, 15–24. [Google Scholar] [CrossRef]
  88. Angeloni, S.; Nzekoue, F.K.; Navarini, L.; Sagratini, G.; Torregiani, E.; Vittori, S.; Caprioli, G. An analytical method for the simultaneous quantification of 30 bioactive compounds in spent coffee ground by HPLC-MS/MS. J. Mass Spectrom. 2020, 55, e4519. [Google Scholar] [CrossRef]
  89. Kozuma, K.; Tsuchiya, S.; Kohori, J.; Hase, T.; Tokimitsu, I. Antihypertensive effect of green coffee bean extract on mildly hypertensive subjects. Hypertens. Res. 2005, 28, 711–718. [Google Scholar] [CrossRef] [Green Version]
  90. Watanabe, T.; Arai, Y.; Mitsui, Y.; Kusaura, T.; Okawa, W.; Kajihara, Y.; Saito, I. The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension. Clin. Exp. Hypertens. 2006, 28, 439–449. [Google Scholar] [CrossRef]
  91. Johnston, K.L.; Clifford, M.N.; Morgan, L.M. Coffee acutely modifies gastrointestinal hormone secretion and glucose tolerance in humans: Glycemic effects of chlorogenic acid and caffeine. Am. J. Clin. Nutr. 2003, 78, 728–733. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  92. Lara-Guzmán, O.J.; Álvarez, R.; Muñoz-Durango, K. Changes in the plasma lipidome of healthy subjects after coffee consumption reveal potential cardiovascular benefits: A randomized controlled trial. Free Radic. Biol. Med. 2021, 176, 345–355. [Google Scholar] [CrossRef]
  93. Suzuki, A.; Nomura, T.; Jokura, H.; Kitamura, N.; Saiki, A.; Fujii, A. Chlorogenic acid-enriched green coffee bean extract affects arterial stiffness assessed by the cardio-ankle vascular index in healthy men: A pilot study. Int. J. Food Sci. Nutr. 2019, 70, 901–908. [Google Scholar] [CrossRef] [PubMed]
  94. Zuñiga, L.Y.; Aceves-de la Mora, M.C.A.; González-Ortiz, M.; Ramos-Núñez, J.L.; Martínez-Abundis, E. Effect of chlorogenic acid administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance. J. Med. Food 2018, 21, 469–473. [Google Scholar] [CrossRef] [PubMed]
  95. Roshan, H.; Nikpayam, O.; Sedaghat, M.; Sohrab, G. Effects of green coffee extract supplementation on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome: A randomised clinical trial. Br. J. Nutr. 2018, 119, 250–258. [Google Scholar] [CrossRef] [Green Version]
  96. Narita, Y.; Iwai, K.; Fukunaga, T.; Nakagiri, O. Inhibitory activity of chlorogenic acids in decaffeinated green coffee beans against porcine pancreas lipase and effect of a decaffeinated green coffee bean extract on an emulsion of olive oil. Biosci. Biotechnol. Biochem. 2012, 76, 2329–2331. [Google Scholar] [CrossRef] [Green Version]
  97. Bhandarkar, N.S.; Brown, L.; Panchal, S.K. Chlorogenic acid attenuates high-carbohydrate, high-fat diet-induced cardiovascular, liver, and metabolic changes in rats. Nutr. Res. 2019, 62, 78–88. [Google Scholar] [CrossRef]
  98. Zhong, Y.; Ding, Y.; Li, L.; Ge, M.; Ban, G.; Yang, H.; Dai, J.; Zhang, L. Effects and mechanism of chlorogenic acid on weight loss. Curr. Pharm. Biotechnol. 2020, 21, 1099–1106. [Google Scholar] [CrossRef]
  99. Postuma, R.B.; Anang, J.; Pelletier, A.; Joseph, L.; Moscovich, M.; Grimes, D.; Furtado, S.; Munhoz, R.P.; Appel-Cresswell, S.; Moro, A.; et al. Caffeine as symptomatic treatment for Parkinson disease (Café-PD): A randomized trial. Neurology 2017, 89, 1795–1803. [Google Scholar] [CrossRef]
  100. Walters, E.R.; Lesk, V.E. Time of day and caffeine influence some neuropsychological tests in the elderly. Psychol. Assess. 2015, 27, 161–168. [Google Scholar] [CrossRef] [Green Version]
  101. Sherman, S.M.; Buckley, T.P.; Baena, E.; Ryan, L. Caffeine enhances memory performance in young adults during their non-optimal time of day. Front. Psychol. 2016, 7, 1764. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  102. Fahanik-Babaei, J.; Baluchnejadmojarad, T.; Nikbakht, F.; Roghani, M. Trigonelline protects hippocampus against intracerebral Aβ(1-40) as a model of Alzheimer’s disease in the rat: Insights into underlying mechanisms. Metab. Brain Dis. 2019, 34, 191–201. [Google Scholar] [CrossRef] [PubMed]
  103. Farid, M.M.; Yang, X.; Kuboyama, T.; Tohda, C. Trigonelline recovers memory function in Alzheimer’s disease model mice: Evidence of brain penetration and target molecule. Sci. Rep. 2020, 10, 16424. [Google Scholar] [CrossRef]
  104. Chowdhury, A.A.; Gawali, N.B.; Munshi, R.; Juvekar, A.R. Trigonelline insulates against oxidative stress, proinflammatory cytokines and restores BDNF levels in lipopolysaccharide induced cognitive impairment in adult mice. Metab. Brain Dis. 2018, 33, 681–691. [Google Scholar] [CrossRef]
  105. Liu, L.; Du, X.; Zhang, Z.; Zhou, J. Trigonelline inhibits caspase 3 to protect β cells apoptosis in streptozotocin-induced type 1 diabetic mice. Eur. J. Pharmacol. 2018, 836, 115–121. [Google Scholar] [CrossRef] [PubMed]
  106. Hamadi, S.A. Effect of trigonelline and ethanol extract of Iraqi Fenugreek seeds on oxidative stress in alloxan diabetic rabbits. J. Assoc. Arab Univ. Basic Appl. Sci. 2012, 12, 23–26. [Google Scholar] [CrossRef] [Green Version]
  107. Tohda, C.; Nakamura, N.; Komatsu, K.; Hattori, M. Trigonelline-induced neurite outgrowth in human neuroblastoma SK-N-SH cells. Biol. Pharm. Bull. 1999, 22, 679–682. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  108. Rufián-Henares, J.A.; Morales, F.J. Effect of in vitro enzymatic digestion on antioxidant activity of coffee melanoidins and fractions. J. Agric. Food Chem. 2007, 55, 10016–10021. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  109. Rufián-Henares, J.A.; de la Cueva, S.P. Antimicrobial activity of coffee melanoidins—A study of their metal-chelating properties. J. Agric. Food Chem. 2009, 57, 432–438. [Google Scholar] [CrossRef] [PubMed]
  110. Sauer, T.; Raithel, M.; Kressel, J.; Münch, G.; Pischetsrieder, M. Activation of the transcription factor Nrf2 in macrophages, Caco-2 cells and intact human gut tissue by Maillard reaction products and coffee. Amino Acids 2013, 44, 1427–1439. [Google Scholar] [CrossRef]
  111. Reichardt, N.; Gniechwitz, D.; Steinhart, H.; Bunzel, M.; Blaut, M. Characterization of high molecular weight coffee fractions and their fermentation by human intestinal microbiota. Mol. Nutr. Food Res. 2009, 53, 287–299. [Google Scholar] [CrossRef] [PubMed]
  112. Tajik, N.; Tajik, M.; Mack, I.; Enck, P. The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: A comprehensive review of the literature. Eur. J. Nutr. 2017, 56, 2215–2244. [Google Scholar] [CrossRef] [PubMed]
  113. Kong, L.; Xu, M.; Qiu, Y.; Liao, M.; Zhang, Q.; Yang, L.; Zheng, G. Chlorogenic acid and caffeine combination attenuates adipogenesis by regulating fat metabolism and inhibiting adipocyte differentiation in 3T3-L1 cells. J. Food Biochem. 2021, 45, e13795. [Google Scholar] [CrossRef] [PubMed]
  114. Pimpley, V.; Patil, S.; Srinivasan, K.; Desai, N.; Murthy, P.S. The chemistry of chlorogenic acid from green coffee and its role in attenuation of obesity and diabetes. Prep. Biochem. Biotechnol. 2020, 50, 969–978. [Google Scholar] [CrossRef] [PubMed]
  115. Wan, C.W.; Wong, C.N.; Pin, W.K.; Wong, M.H.; Kwok, C.Y.; Chan, R.Y.; Yu, P.H.; Chan, S.W. Chlorogenic acid exhibits cholesterol lowering and fatty liver attenuating properties by up-regulating the gene expression of PPAR-α in hypercholesterolemic rats induced with a high-cholesterol diet. Phytother. Res. 2013, 27, 545–551. [Google Scholar] [CrossRef] [PubMed]
  116. McCarty, M.F. A chlorogenic acid-induced increase in GLP-1 production may mediate the impact of heavy coffee consumption on diabetes risk. Med. Hypotheses 2005, 64, 848–853. [Google Scholar] [CrossRef]
  117. Pérez-Nájera, V.C.; Gutiérrez-Uribe, J.A.; Antunes-Ricardo, M.; Hidalgo-Figueroa, S.; Del-Toro-Sánchez, C.L.; Salazar-Olivo, L.A.; Lugo-Cervantes, E. Smilax aristolochiifolia root extract and its compounds chlorogenic acid and astilbin inhibit the activity of α-amylase and α-glucosidase enzymes. Evid. Based Complement. Alternat. Med. 2018, 2018, 6247306. [Google Scholar] [CrossRef] [Green Version]
  118. Cappelletti, S.; Piacentino, D.; Sani, G.; Aromatario, M. Caffeine: Cognitive and physical performance enhancer or psychoactive drug? Curr. Neuropharmacol. 2015, 13, 71–88. [Google Scholar] [CrossRef] [Green Version]
  119. Institute of Medicine (US) Committee on Military Nutrition Research. 2. Pharmacology of caffeine. In Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations; National Academies Press (US): Washington, DC, USA, 2001. Available online: (accessed on 29 November 2022).
  120. van Dam, R.M.; Hu, F.B.; Willett, W.C. Coffee, caffeine, and health. N. Engl. J. Med. 2020, 383, 369–378. [Google Scholar] [CrossRef]
  121. Echeverri, D.; Montes, F.R.; Cabrera, M.; Galán, A.; Prieto, A. Caffeine’s vascular mechanisms of action. Int. J. Vasc. Med. 2010, 2010, 834060. [Google Scholar] [CrossRef] [Green Version]
  122. Nehlig, A.; Daval, J.L.; Debry, G. Caffeine and the central nervous system: Mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Res. Brain Res. Rev. 1992, 17, 139–170. [Google Scholar] [CrossRef] [PubMed]
  123. Sharma, K.; Fallon, S.J.; Davis, T.; Ankrett, S.; Munro, G.; Christopher, G.; Coulthard, E. Caffeine and attentional control: Improved and impaired performance in healthy older adults and Parkinson’s disease according to task demands. Psychopharmacology 2022, 239, 605–619. [Google Scholar] [CrossRef]
  124. Munoz, D.G.; Fujioka, S. Caffeine and Parkinson disease: A possible diagnostic and pathogenic breakthrough. Neurology 2018, 90, 205–206. [Google Scholar] [CrossRef] [PubMed]
  125. Ren, X.; Chen, J.F. Caffeine and Parkinson’s disease: Multiple benefits and emerging mechanisms. Front. Neurosci. 2020, 14, 602697. [Google Scholar] [CrossRef] [PubMed]
  126. Ross, G.W.; Abbott, R.D.; Petrovitch, H.; Morens, D.M.; Grandinetti, A.; Tung, K.H.; Tanner, C.M.; Masaki, K.H.; Blanchette, P.L.; Curb, J.D.; et al. Association of coffee and caffeine intake with the risk of Parkinson disease. JAMA 2000, 283, 2674–2679. [Google Scholar] [CrossRef]
  127. Postuma, R.B.; Lang, A.E.; Munhoz, R.P.; Charland, K.; Pelletier, A.; Moscovich, M.; Filla, L.; Zanatta, D.; Rios Romenets, S.; Altman, R.; et al. Caffeine for treatment of Parkinson disease: A randomized controlled trial. Neurology 2012, 79, 651–658. [Google Scholar] [CrossRef] [Green Version]
  128. Wilson, P.W.; Bloom, H.L. Caffeine consumption and cardiovascular risks: Little cause for concern. J. Am. Heart Assoc. 2016, 5, e003089. [Google Scholar] [CrossRef] [Green Version]
  129. Zulli, A.; Smith, R.M.; Kubatka, P.; Novak, J.; Uehara, Y.; Loftus, H.; Qaradakhi, T.; Pohanka, M.; Kobyliak, N.; Zagatina, A.; et al. Caffeine and cardiovascular diseases: Critical review of current research. Eur. J. Nutr. 2016, 55, 1331–1343. [Google Scholar] [CrossRef]
  130. Ding, M.; Bhupathiraju, S.N.; Satija, A.; van Dam, R.M.; Hu, F.B. Long-term coffee consumption and risk of cardiovascular disease: A systematic review and a dose-response meta-analysis of prospective cohort studies. Circulation 2014, 129, 643–659. [Google Scholar] [CrossRef] [Green Version]
  131. Saimaiti, A.; Zhou, D.-D.; Li, J.; Xiong, R.-G.; Gan, R.-Y.; Huang, S.-Y.; Shang, A.; Zhao, C.-N.; Li, H.-Y.; Li, H.-B. Dietary sources, health benefits, and risks of caffeine. Crit. Rev. Food Sci. Nutr. 2022. [Google Scholar] [CrossRef]
  132. Zhou, J.; Chan, L.; Zhou, S. Trigonelline: A plant alkaloid with therapeutic potential for diabetes and central nervous system disease. Curr. Med. Chem. 2012, 19, 3523–3531. [Google Scholar] [CrossRef] [PubMed]
  133. Mohamadi, N.; Sharififar, F.; Pournamdari, M.; Ansari, M. A review on biosynthesis, analytical techniques, and pharmacological activities of trigonelline as a plant alkaloid. J. Diet. Suppl. 2018, 15, 207–222. [Google Scholar] [CrossRef]
  134. Belayneh, A.; Molla, F. The effect of coffee on pharmacokinetic properties of drugs: A review. Biomed. Res. Int. 2020, 2020, 7909703. [Google Scholar] [CrossRef] [PubMed]
  135. Garg, R.C. Chapter 44—Fenugreek: Multiple Health Benefits. In Nutraceuticals; Gupta, R.C., Ed.; Academic Press: Cambridge, MA, USA, 2016; pp. 599–617. [Google Scholar] [CrossRef]
  136. Koshiro, Y.; Zheng, X.-Q.; Wang, M.-L.; Nagai, C.; Ashihara, H. Changes in content and biosynthetic activity of caffeine and trigonelline during growth and ripening of Coffea arabica and Coffea canephora fruits. Plant Sci. 2006, 171, 242–250. [Google Scholar] [CrossRef]
  137. Socała, K.; Szopa, A.; Serefko, A.; Poleszak, E.; Wlaź, P. Neuroprotective effects of coffee bioactive compounds: A review. Int. J. Mol. Sci. 2020, 22, 107. [Google Scholar] [CrossRef] [PubMed]
  138. National Institute of Aging. What Causes Alzheimer’s Disease? National Institute of Health: Bethesda, MD, USA, 2019. Available online: (accessed on 27 November 2022).
  139. Makowska, J.; Szczesny, D.; Lichucka, A.; Giełdoń, A.; Chmurzyński, L.; Kaliszan, R. Preliminary studies on trigonelline as potential anti-Alzheimer disease agent: Determination by hydrophilic interaction liquid chromatography and modeling of interactions with β-amyloid. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 2014, 968, 101–104. [Google Scholar] [CrossRef] [PubMed]
  140. Heppner, F.L.; Ransohoff, R.M.; Becher, B. Immune attack: The role of inflammation in Alzheimer disease. Nat. Rev. Neurosci. 2015, 16, 358–372. [Google Scholar] [CrossRef]
  141. Oestreich-Janzen, S. 3.25—Chemistry of Coffee. In Comprehensive Natural Products II; Liu, H.-W., Mander, L., Eds.; Elsevier: Oxford, UK, 2010; pp. 1085–1117. [Google Scholar] [CrossRef]
  142. Finotello, C.; Forzato, C.; Gasparini, A.; Mammi, S.; Navarini, L.; Schievano, E. NMR quantification of 16-O-methylcafestol and kahweol in Coffea canephora var. robusta beans from different geographical origins. Food Cont. 2017, 75, 62–69. [Google Scholar] [CrossRef] [Green Version]
  143. Gunning, Y.; Defernez, M.; Watson, A.D.; Beadman, N.; Colquhoun, I.J.; Le Gall, G.; Philo, M.; Garwood, H.; Williamson, D.; Davis, A.P.; et al. 16-O-methylcafestol is present in ground roast Arabica coffees: Implications for authenticity testing. Food Chem. 2018, 248, 52–60. [Google Scholar] [CrossRef]
  144. Urgert, R.; Katan, M.B. The cholesterol-raising factor from coffee beans. Annu. Rev. Nutr. 1997, 17, 305–324. [Google Scholar] [CrossRef] [Green Version]
  145. Thelle, D.S.; Arnesen, E.; Førde, O.H. The Tromsø heart study. Does coffee raise serum cholesterol? N. Engl. J. Med. 1983, 308, 1454–1457. [Google Scholar] [CrossRef]
  146. De Roos, B.; Meyboom, S.; Kosmeijer-Schuil, T.G.; Katan, M.B. Absorption and urinary excretion of the coffee diterpenes cafestol and kahweol in healthy ileostomy volunteers. J. Intern. Med. 1998, 244, 451–460. [Google Scholar] [CrossRef] [PubMed]
  147. Iwamoto, H.; Izumi, K.; Natsagdorj, A.; Naito, R.; Makino, T.; Kadomoto, S.; Hiratsuka, K.; Shigehara, K.; Kadono, Y.; Narimoto, K.; et al. Coffee diterpenes kahweol acetate and cafestol synergistically inhibit the proliferation and migration of prostate cancer cells. Prostate 2019, 79, 468–479. [Google Scholar] [CrossRef] [PubMed]
  148. Okubo, Y.; Motohashi, O.; Nakayama, N.; Nishimura, K.; Kasajima, R.; Miyagi, Y.; Shiozawa, M.; Yoshioka, E.; Suzuki, M.; Washimi, K.; et al. The clinicopathological significance of angiogenesis in hindgut neuroendocrine tumors obtained via an endoscopic procedure. Diagn. Pathol. 2016, 11, 128. [Google Scholar] [CrossRef] [Green Version]
  149. Ren, Y.; Wang, C.; Xu, J.; Wang, S. Cafestol and kahweol: A review on their bioactivities and pharmacological properties. Int. J. Mol. Sci. 2019, 20, 4238. [Google Scholar] [CrossRef] [Green Version]
  150. Mellbye, F.B.; Jeppesen, P.B.; Hermansen, K.; Gregersen, S. Cafestol, a bioactive substance in coffee, stimulates insulin secretion and increases glucose uptake in muscle cells: Studies in vitro. J. Nat. Prod. 2015, 78, 2447–2451. [Google Scholar] [CrossRef]
  151. Zhang, B.B.; Zhou, G.; Li, C. AMPK: An emerging drug target for diabetes and the metabolic syndrome. Cell Metab. 2009, 9, 407–416. [Google Scholar] [CrossRef] [Green Version]
  152. Kim, J.Y.; Jung, K.S.; Jeong, H.G. Suppressive effects of the kahweol and cafestol on cyclooxygenase-2 expression in macrophages. FEBS Lett. 2004, 569, 321–326. [Google Scholar] [CrossRef] [Green Version]
  153. Wang, H.-Y.; Qian, H.; Yao, W.-R. Melanoidins produced by the Maillard reaction: Structure and biological activity. Food Chem. 2011, 128, 573–584. [Google Scholar] [CrossRef]
  154. Fogliano, V.; Morales, F.J. Estimation of dietary intake of melanoidins from coffee and bread. Food Funct. 2011, 2, 117–123. [Google Scholar] [CrossRef] [Green Version]
  155. Bekedam, E.K.; Loots, M.J.; Schols, H.A.; Van Boekel, M.A.; Smit, G. Roasting effects on formation mechanisms of coffee brew melanoidins. J. Agric. Food Chem. 2008, 56, 7138–7145. [Google Scholar] [CrossRef] [PubMed]
  156. Pérez-Burillo, S.; Rajakaruna, S.; Pastoriza, S.; Paliy, O.; Ángel Rufián-Henares, J. Bioactivity of food melanoidins is mediated by gut microbiota. Food Chem. 2020, 316, 126309. [Google Scholar] [CrossRef] [PubMed]
  157. Blaak, E.E.; Canfora, E.E.; Theis, S.; Frost, G.; Groen, A.K.; Mithieux, G.; Nauta, A.; Scott, K.; Stahl, B.; van Harsselaar, J.; et al. Short chain fatty acids in human gut and metabolic health. Benef. Microbes 2020, 11, 411–455. [Google Scholar] [CrossRef] [PubMed]
  158. Zhao, L.; Zhang, F.; Ding, X.; Wu, G.; Lam, Y.Y.; Wang, X.; Fu, H.; Xue, X.; Lu, C.; Ma, J.; et al. Gut bacteria selectively promoted by dietary fibers alleviate type 2 diabetes. Science 2018, 359, 1151–1156. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  159. Gómez-Ruiz, J.Á.; Ames, J.M.; Leake, D.S. Antioxidant activity and protective effects of green and dark coffee components against human low density lipoprotein oxidation. Eur. Food Res. Technol. 2008, 227, 1017–1024. [Google Scholar] [CrossRef]
  160. O’Brien, J.; Morrissey, P.A. Metal ion complexation by products of the Maillard reaction. Food Chem. 1997, 58, 17–27. [Google Scholar] [CrossRef]
  161. Daglia, M.; Papetti, A.; Aceti, C.; Sordelli, B.; Gregotti, C.; Gazzani, G. Isolation of high molecular weight components and contribution to the protective activity of coffee against lipid peroxidation in a rat liver microsome system. J. Agric. Food Chem. 2008, 56, 11653–11660. [Google Scholar] [CrossRef]
  162. Morales, F.J.; Somoza, V.; Fogliano, V. Physiological relevance of dietary melanoidins. Amino Acids 2012, 42, 1097–1109. [Google Scholar] [CrossRef]
  163. Brown, L.; Caligiuri, S.P.B.; Brown, D.; Pierce, G.N. Clinical trials using functional foods provide unique challenges. J. Funct. Foods 2018, 45, 233–238. [Google Scholar] [CrossRef]
Figure 1. Coffee production generating waste. Data sourced from [14,17,18].
Figure 1. Coffee production generating waste. Data sourced from [14,17,18].
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Figure 2. Coffee by-products and their potential applications. Data sourced from [14,17,18].
Figure 2. Coffee by-products and their potential applications. Data sourced from [14,17,18].
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Figure 3. Potential health benefits of spent coffee grounds.
Figure 3. Potential health benefits of spent coffee grounds.
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Table 1. Studies analysing the components of spent coffee grounds and their benefits.
Table 1. Studies analysing the components of spent coffee grounds and their benefits.
CompoundType of StudyFindings
Chlorogenic acidHumanRegulated blood pressure [89,90]; improved insulin secretion, uptake of glucose by intestinal cells [91]; improved insulin secretion [91]; improved dyslipidaemia and endothelial function [92,93]; improved fasting glucose in patients with impaired glucose tolerance [94,95]; body weight reduction and waist circumference reduction [95]
In vitroImproved lipase reaction [96]
AnimalReduced accumulation of fat in the liver and reduced blood lipids [97,98]; improved body weight and reduced visceral fat [97]
CaffeineHumanImproved cognitive health in patients with degenerative disease [99]; better performance in tests in age-related cognitive impairment [100]; enhanced memory and cognitive performance in young adults [101]
TrigonellineAnimalImproved specific neuron function [102]; improved memory in Alzheimer-induced mice [103]; suppressed oxidative stress and inflammation in the brain [102,104]; reduced blood glucose and improved lipid in metabolically ill animals [105,106]
In vitroPromoted regeneration of neuronal network by neurite outgrowth [107]
MelanoidinsIn vitroAntioxidant activity [108]; antibacterial activity against Gram-negative and Gram-positive bacteria [109]; antioxidant activity and activation of other gene-protective mechanisms in different cell lines [110]
Ex vivoAntioxidant activity and activation of other gene-protective mechanisms in human gut tissue [110]; fermentation of gut bacteria, activation of antioxidant pathways and modulation of gut bacteria population [111]
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Bevilacqua, E.; Cruzat, V.; Singh, I.; Rose’Meyer, R.B.; Panchal, S.K.; Brown, L. The Potential of Spent Coffee Grounds in Functional Food Development. Nutrients 2023, 15, 994.

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Bevilacqua E, Cruzat V, Singh I, Rose’Meyer RB, Panchal SK, Brown L. The Potential of Spent Coffee Grounds in Functional Food Development. Nutrients. 2023; 15(4):994.

Chicago/Turabian Style

Bevilacqua, Elza, Vinicius Cruzat, Indu Singh, Roselyn B. Rose’Meyer, Sunil K. Panchal, and Lindsay Brown. 2023. "The Potential of Spent Coffee Grounds in Functional Food Development" Nutrients 15, no. 4: 994.

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