{ "id": "melanoidins", "url": "https://coffearium.org/entries/melanoidins/", "license": "CC-BY-4.0", "title": "Melanoidins", "summary": "The brown, high-molecular-weight compounds that form late in roasting and give roasted coffee its colour – built on polysaccharides and protein, with chlorogenic acids worked in, and still without a known structure.", "domain": "roasting", "kind": "Concept", "stage": "roast", "topics": [ "science" ], "topicSections": {}, "lang": "en", "status": "verified", "reviewer": "Coffearium verification pass", "lastVerified": "2026-10-20T00:00:00.000Z", "updated": "2026-10-20T00:00:00.000Z", "added": "2026-10-20T00:00:00.000Z", "brief": [ "Melanoidins are high-molecular-weight, nitrogen-containing brown compounds formed in roasting; polysaccharides, proteins and chlorogenic acids are involved in their formation in coffee.1", "A 2002 study reported that melanoidins make up to 25% of the dry matter of coffee beverages.3", "Darker roasts give more melanoidins in the brew; studies disagree on whether their molecular weight rises or falls as roasting goes on.3,4,7", "In model studies, coffee melanoidins bound odour-active thiols such as 2-furfurylthiol, which lowered their concentration in the brew.9,10", "Their exact structures and formation routes were described as far from elucidated in a 2012 review.1" ], "quickFacts": [ { "label": "What they are", "value": "Brown, nitrogen-containing compounds of high molecular weight, formed by browning reactions" }, { "label": "Built from", "value": "Polysaccharides (mainly arabinogalactans and galactomannans), proteins, chlorogenic acids" }, { "label": "Share of brew dry matter", "value": "Up to 25% (one 2002 study)" }, { "label": "In roasted coffee", "value": "36–115 g/kg in eight brew studies; mean 7.2 g per 100 g (same eight studies, medium roasts where available)" }, { "label": "With darker roasts", "value": "More melanoidins in the brew" }, { "label": "Charge at brew pH", "value": "Negative" }, { "label": "Isolated by", "value": "Ultrafiltration, diafiltration, dialysis, gel filtration" }, { "label": "Structure", "value": "Not established" } ], "aka": [ "Coffee melanoidins" ], "linkTerms": [ "melanoidin", "brown polymers", "brown pigments" ], "related": [ "maillard-reaction", "caramelisation", "strecker-degradation", "chlorogenic-acids", "carbohydrates-and-body", "green-coffee-composition", "roast-degree-and-colour", "browning-phase", "body-and-mouthfeel", "acids-in-coffee", "the-aroma-of-coffee", "freshness-and-storage", "bioactive-compounds" ], "contested": [ "Molecular weight with roast degree: a 2002 study found that melanoidins in the brew had a lower molecular weight as roasting intensified3; a 2008 study found that light roasting mainly formed intermediate-weight melanoidins and that prolonged roasting mainly formed high-weight ones.7 The 2002 study separated melanoidins by gel filtration3; the 2008 study compared brew fractions of different molecular weight.7 No source opened for this entry explains the difference.", "How much of coffee is melanoidin: the amount depends on how the material is isolated. In a survey of eight filter-brew studies, it ranged from 36 to 115 g per kg of roasted coffee.4 In one 2006 study, the dialysis retentate of the whole brew was about twice the diafiltration retentate.5" ], "corrections": [ { "date": "2026-10-20T00:00:00.000Z", "change": "The mean of 7.2 g per 100 g roasted coffee is now described as the mean of all eight filter-brew studies (medium roasts where available), not an ultrafiltration value.", "reason": "Fogliano & Morales 2011 derive the mean from their Table 2, which covers gel filtration, dialysis and ultrafiltration (min 36, max 115 g/kg)." }, { "date": "2026-10-20T00:00:00.000Z", "change": "The statement that most polysaccharides change only slightly in roasting was replaced by the chapter's own account of partial breakdown, mainly of arabinogalactan side chains, more in dark roasts.", "reason": "The same roasting chemistry chapter reports 12–24% (light) and 35–40% (dark) polysaccharide degradation a few pages earlier; the short sentence alone misrepresented it and conflicted with Carbohydrates and body." }, { "date": "2026-10-20T00:00:00.000Z", "change": "The dialysis yield of 7.4% is now identified as the dialysis retentate of the whole brew, compared with the 3.6% diafiltration retentate.", "reason": "Bekedam et al. 2006 (thesis chapter 2); the two figures are not like-for-like fractions." }, { "date": "2026-10-20T00:00:00.000Z", "change": "The astringency finding is now stated as a detectable, subtle drying or astringent difference; the 30 °C condition for the thiol time course was removed.", "reason": "Linne et al. 2025 report discrimination tests and call the effect subtle; Hofmann et al. 2001 give 30 °C in the methods and 40 °C in the results, so the temperature is not certain." } ], "sources": [ { "id": "s1", "title": "Coffee melanoidins: structures, mechanisms of formation and potential health impacts", "authors": "Moreira, A. S. P.; Nunes, F. M.; Domingues, M. R.; Coimbra, M. A.", "year": 2012, "publisher": "Food & Function 3(9)", "url": "https://agris.fao.org/search/en/records/65de1e904c5aef494fd9fb20", "doi": "10.1039/c2fo30048f", "tier": "A", "quote": "However, exact structures of coffee melanoidins and mechanisms involved in their formation are far to be elucidated.", "abstractOnly": true, "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s2", "title": "The Chemistry of Roasting – Decoding Flavor Formation", "authors": "Poisson, L.; Blank, I.; Dunkel, A.; Hofmann, T.", "year": 2017, "publisher": "In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 12, pp. 273–309", "url": "https://doi.org/10.1016/B978-0-12-803520-7.00012-8", "doi": "10.1016/B978-0-12-803520-7.00012-8", "tier": "B", "quote": "Both, Maillard reaction and caramelization are the main routes to the formation of brown polymers (i.e., melanoidins).", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s3", "title": "Chemical characterization and antioxidant properties of coffee melanoidins", "authors": "Borrelli, R. C.; Visconti, A.; Mennella, C.; Anese, M.; Fogliano, V.", "year": 2002, "publisher": "Journal of Agricultural and Food Chemistry 50(22), 6527–6533", "url": "https://air.uniud.it/handle/11390/672441", "doi": "10.1021/jf025686o", "tier": "A", "quote": "the amount of melanoidins present in the brews increased as the intensity of the thermal treatment increased", "abstractOnly": true, "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s4", "title": "Estimation of dietary intake of melanoidins from coffee and bread", "authors": "Fogliano, V.; Morales, F. J.", "year": 2011, "publisher": "Food & Function 2(2), 117–123", "url": "https://pubs.rsc.org/en/content/articlehtml/2011/fo/c0fo00156b", "doi": "10.1039/c0fo00156b", "tier": "A", "quote": "It is known that the darker the roasting degree, the higher the amount of melanoidins", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s5", "title": "High Molecular Weight Melanoidins from Coffee Brew", "authors": "Bekedam, E. K.; Schols, H. A.; van Boekel, M. A. J. S.; Smit, G.", "year": 2006, "publisher": "Journal of Agricultural and Food Chemistry 54, 7658–7666", "url": "https://edepot.wur.nl/122022", "tier": "A", "tierNote": "Peer-reviewed paper, read in full as chapter 2 of the first author's 2008 doctoral thesis (source 6), which reprints it.", "quote": "the low molecular weight chlorogenic acid is incorporated into the HMw material", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s6", "title": "Coffee Brew Melanoidins: Structural and Functional Properties of Brown-Colored Coffee Compounds", "authors": "Bekedam, E. K.", "year": 2008, "publisher": "Wageningen University (doctoral thesis), ISBN 978-90-8504-951-7", "url": "https://edepot.wur.nl/122022", "tier": "B", "quote": "the chemical structures of melanoidins remain unknown", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s7", "title": "Roasting Effects on Formation Mechanisms of Coffee Brew Melanoidins", "authors": "Bekedam, E. K.; Loots, M. J.; Schols, H. A.; van Boekel, M. A. J. S.; Smit, G.", "year": 2008, "publisher": "Journal of Agricultural and Food Chemistry 56(16), 7138–7145", "url": "https://research.wur.nl/en/publications/roasting-effects-on-formation-mechanisms-of-coffee-brew-melanoidi/", "doi": "10.1021/jf800999a", "tier": "A", "quote": "prolonged roasting predominantly led to formation melanoidins with a high Mw", "abstractOnly": true, "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s8", "title": "Arabinogalactan Proteins Are Incorporated in Negatively Charged Coffee Brew Melanoidins", "authors": "Bekedam, E. K.; de Laat, M. P. F. C.; Schols, H. A.; van Boekel, M. A. J. S.; Smit, G.", "year": 2007, "publisher": "Journal of Agricultural and Food Chemistry 55(3), 761–768", "url": "https://research.wur.nl/en/publications/arabinogalactan-proteins-are-incorporated-in-negatively-charged-c/", "doi": "10.1021/jf063010d", "tier": "A", "quote": "coffee brew melanoidins were negatively charged", "abstractOnly": true, "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s9", "title": "Chemical interactions between odor-active thiols and melanoidins involved in the aroma staling of coffee beverages", "authors": "Hofmann, T.; Schieberle, P.", "year": 2002, "publisher": "Journal of Agricultural and Food Chemistry 50(2), 319–326", "url": "https://portal.fis.leibniz-lsb.tum.de/en/publications/chemical-interactions-between-odor-active-thiols-and-melanoidins--3/", "doi": "10.1021/jf010823n", "tier": "A", "quote": "its concentration decreased by a factor of 16 upon addition of melanoidins", "abstractOnly": true, "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s10", "title": "Model Studies on the Influence of Coffee Melanoidins on Flavor Volatiles of Coffee Beverages", "authors": "Hofmann, T.; Czerny, M.; Calligaris, S.; Schieberle, P.", "year": 2001, "publisher": "Journal of Agricultural and Food Chemistry 49(5), 2382–2386", "url": "https://pages.uoregon.edu/chendon/coffee_literature/old_literature/2001%20J.%20Agric.%20Food%20Chem.,%20Coffee%20melanoidin%20impact%20on%20flavor%20and%20odor.pdf", "doi": "10.1021/jf0012042", "tier": "A", "quote": "significantly reduced in the presence of melanoidins", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s11", "title": "Roasting Conditions and Coffee Flavor: A Multi-Study Empirical Investigation", "authors": "Münchow, M.; Alstrup, J.; Steen, I.; Giacalone, D.", "year": 2020, "publisher": "Beverages 6(2), 29", "url": "https://www.mdpi.com/2306-5710/6/2/29", "doi": "10.3390/beverages6020029", "tier": "A", "quote": "By contrast, the mouthfeel attribute “body” was not affected at all by either roasting phases, which is interesting as this goes against popular beliefs linking the Maillard reaction with texture.", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s12", "title": "Chemical characterization and sensory evaluation of a phenolic-rich melanoidin isolate contributing to coffee astringency", "authors": "Linne, B. M.; Tello, E.; Simons, C. T.; Peterson, D. G.", "year": 2025, "publisher": "Food & Function 16(7), 2870–2880 (Royal Society of Chemistry)", "url": "https://pubs.rsc.org/en/content/articlehtml/2025/fo/d4fo04934a", "doi": "10.1039/d4fo04934a", "tier": "A", "quote": "We hereby provide the first evidence of melanoidins contributing to the complex tactile flavor profile of coffee.", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s13", "title": "Comparison of Ultra-High-Pressure and Conventional Cold Brew Coffee at Different Roasting Degrees: Physicochemical Characteristics and Volatile and Non-Volatile Components", "authors": "Shi, Q.; Xiao, Y.; Zhou, Y.; Tang, W.; Jiang, F.; Zhou, X.; Lu, H.", "year": 2024, "publisher": "Foods 13(19), 3119", "url": "https://mdpi-res.com/d_attachment/foods/foods-13-03119/article_deploy/foods-13-03119.pdf", "doi": "10.3390/foods13193119", "tier": "A", "tierNote": "Melanoidin values taken from Table 1 (means ± SD as printed). The paper is internally inconsistent in places – the significance letters for the melanoidin column do not match the values in every case, the results text says roast degree affected the ultra-high-pressure brews less than conventional cold brew although Table 1 shows the larger spread for ultra-high pressure, and the abstract’s statement on chlorogenic acids differs from the results section. The entry uses only the printed means and the direction of change (light to dark), which agrees with sources 3 and 4; no significance claims or method comparisons are taken from it.", "quote": "The coffee was diluted to a concentration of 1:19 and its absorbance was determined using a microplate reader", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s14", "title": "A universal color curve for roasted arabica coffee", "authors": "Anokye-Bempah, L.; Styczynski, T.; Ristenpart, W. D.; Donis-González, I. R.", "year": 2025, "publisher": "Scientific Reports 15, 24192", "url": "https://www.nature.com/articles/s41598-025-06601-w", "doi": "10.1038/s41598-025-06601-w", "tier": "A", "quote": "melanoidin formation resulting from nonenzymatic browning reactions such as the Maillard reaction", "accessed": "2026-10-20T00:00:00.000Z" }, { "id": "s15", "title": "Cupping and Grading – Discovering Character and Quality", "authors": "Lingle, T. R.; Menon, S. N.", "year": 2017, "publisher": "In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 8, pp. 181–203", "url": "https://www.sciencedirect.com/book/9780128035207/the-craft-and-science-of-coffee", "doi": "10.1016/B978-0-12-803520-7.00008-6", "tier": "B", "quote": "beans, as well as microfine particles of the bean may play a role.", "accessed": "2026-10-20T00:00:00.000Z" } ], "markdown": "## What melanoidins are\n\nMelanoidins are the brown compounds that form when coffee is roasted. A 2012 review defines them as high-molecular-weight, nitrogen-containing brown compounds.1 They are large molecules, far larger than the aroma compounds that form alongside them.1,2 They dissolve into the brew and make up a large part of what is dissolved.3\n\nThey are the end products of browning. According to a roasting chemistry chapter, the Maillard reaction and caramelisation are the main routes to these brown polymers.2 The Maillard reaction joins sugars with amino compounds; caramelisation breaks down sugars alone.2 Both are covered in their own entries.\n\nMelanoidins are not one substance. They are a mixture of many molecules of different size and make-up.5,7 No one has yet drawn their full structure. A thesis on coffee brew melanoidins states that their chemical structures remain unknown.6\n\n## What they are made of\n\nIn coffee, melanoidins form from three groups of building blocks: polysaccharides, proteins and chlorogenic acids.1\n\n- **Polysaccharides.** These are long sugar chains from the bean’s cell walls. Arabinogalactans appear relatively more involved than galactomannans, according to a 2008 roasting study.7\n- **Proteins.** In the same study, the melanoidin level in every fraction rose with its nitrogen and protein content.7\n- **Chlorogenic acids.** These are phenolic acids of green coffee. A 2006 study found them built into the large brew molecules.5\n\nThe roasting chemistry chapter sums this up as a polymerisation of polysaccharides, proteins and polyphenols.2 Taken together, the studies opened for this entry picture a coffee melanoidin as a sugar backbone with protein and brown, phenolic pieces attached; this is a working picture, not an established structure.1,7,8\n\n
\n
\n
How coffee melanoidins are pictured from the studies opened for this entry: a polysaccharide backbone with protein, incorporated chlorogenic acids and brown Maillard-derived groups, negatively charged and able to bind thiols. Schematic only: no single structure has been established.1,5,6,7,8,9
\n
\n\n## How much there is\n\nMelanoidins are a large part of what dissolves into a brew. A 2002 study reported that they make up to 25% of the dry matter of coffee beverages.3\n\nMeasured amounts vary widely between studies, which isolated them in different ways. A 2011 survey collected values from eight studies of filter coffee. They ranged from 36 to 115 g of melanoidins per kg of roasted coffee.4 Across these studies, using medium-roast values where available, the survey obtained a mean of 7.2 g per 100 g of roasted coffee.4\n\n
\n
\n
Melanoidins in filter coffee brews, per kg of roasted coffee, as reported in eight studies collected in a 2011 survey; each bar is one study, labelled by its isolation method.4
\n
\n\n## How roast degree changes them\n\nDarker roasts give more melanoidins. A 2011 survey describes this as known: the darker the roast, the higher the amount.4 A 2002 study roasted one coffee to light, medium and dark. The amount of melanoidins in the brews rose with the intensity of the roast.3\n\nA 2024 study of cold brew found the same direction. It roasted one Ethiopian arabica coffee to three degrees, from Agtron 73 to 53.13 Melanoidins, estimated from the brew’s absorbance, rose from light to dark in both brewing methods tested.13\n\n
\n
\n
Melanoidins in cold brew from one Ethiopian arabica coffee at three roast degrees (Agtron 73, 62, 53), conventional 12-h cold brew and ultra-high-pressure extraction; spectrophotometric estimate at 420 nm, mean ± SD.13
\n
\n\nTheir make-up changes too. A 2008 study found that light roasting mainly formed melanoidins of intermediate size. Prolonged roasting mainly formed large ones.7 A 2002 study found the opposite trend in molecular weight (see Contested).3\n\n## What they do in the cup\n\n- **Colour.** Melanoidins are the brown pigments of roasted coffee. A 2025 colour study attributes the darkening of beans during roasting to their formation.14 The roasting chemistry chapter says the same.2 Roast colour measurement is covered in Roast degree and colour.\n- **Aroma.** Melanoidins bind some aroma compounds. In a 2002 study, adding coffee melanoidins lowered 2-furfurylthiol, a key roasty odorant, by a factor of 16.9 The authors link this to the loss of roasty, sulphury aroma soon after brewing.9\n- **Bitterness.** A 2020 sensory paper names melanoidins among the main sources of bitterness in coffee, citing earlier work.11\n- **Mouthfeel.** In one 2025 study, tasters could detect a phenolic-rich melanoidin fraction added to coffee, as a subtle drying or astringent sensation.12 A link between melanoidins and body is often assumed, but a 2020 analysis of eight roasting studies found no evidence supporting it.11\n- **Acidity.** Melanoidins in brewed coffee carry a negative charge.8 No study opened for this entry measured how much they add to measured or perceived acidity. Acids are covered in Acids in coffee.\n\n\n\n## Structure and formation\n\n**Definition.** A thesis on coffee brew melanoidins defines them as macromolecular, nitrogenous, brown Maillard reaction end-products.6 A 2012 review keeps the same three features: high molecular weight, nitrogen and brown colour.1 In practice, each study measures the brown material that its membrane or column retains.4,5\n\n**Polysaccharide backbone.** According to the roasting chemistry chapter, the green bean’s arabinogalactans are highly branched and covalently linked to proteins as arabinogalactan proteins (AGPs).2 Roasting breaks their main and side chains and releases free arabinose. The chapter states that most of this arabinose is involved in melanoidin formation.2 A 2007 study isolated an AGP-containing fraction from brew that was brown, where the same material is white in green beans; the authors concluded that the AGPs had undergone the Maillard reaction.8 A 2008 study found that arabinogalactans seem to be relatively more involved than galactomannans.7\n\n**Protein and nitrogen.** In a 2006 study of brew, the high-molecular-weight fraction showed a strong correlation between melanoidin content, protein and non-protein nitrogen.5 The 2008 roasting study found that the melanoidin level in all fractions correlated with nitrogen and protein, and suggested that proteins and chlorogenic acids are primarily involved in melanoidin formation.7\n\n**Chlorogenic acids.** In the 2006 study, the low-molecular-weight chlorogenic acid was incorporated into the high-molecular-weight material.5 The thesis summary states that intact chlorogenic acids are incorporated through their phenolic acid part by non-ester bonds.6 For light roasts, the 2008 study proposed incorporation reactions between chlorogenic acids, sucrose and amino acids or protein fragments.7 A separate entry on chlorogenic acids covers their breakdown in roasting.\n\n**Charge.** Ion-exchange experiments showed brew melanoidins to be negatively charged, with no positive charge at the pH of a coffee brew.8 For the AGP part, the authors suggest the charge probably comes from uronic acids; for melanoidins in general, they hypothesise that acidic groups form or are taken up during roasting.8\n\n**In-bean studies.** According to the roasting chemistry chapter, the bean itself has been used as the reaction vessel to study how coffee melanoidins form, by changing its content of precursors before roasting.2 The chapter notes that free sugars and free amino acids are almost used up in roasting, while crude protein changes only slightly.2 The polysaccharides are partly broken down, more in dark than in light roasts: mainly the arabinogalactan side chains, while cellulose and mannans stay almost intact.2 How much is degraded is covered in Carbohydrates and body.\n\n## Isolation and measurement\n\nThere is no single standard method. Melanoidins are separated from the rest of the brew by size, then weighed or measured by colour.4,5\n\n- **Ultrafiltration and diafiltration.** A membrane holds back the large molecules. In the 2011 survey’s own measurements, the content was determined by weighing the freeze-dried product after ultrafiltration.4 The 2006 study used diafiltration with a 3 kDa cut-off.5\n- **Dialysis.** A dialysis membrane also separates by size. In the 2006 study, dialysis of the whole brew retained 7.4% of the dry, defatted beans, against 3.6% for the diafiltration retentate; the authors attribute the difference to the separation technique.5\n- **Gel filtration.** A column separates molecules by size. The 2002 study used it, followed by MALDI-TOF mass spectrometry.3 The 2001 aroma study used a Sephadex G-25 column and collected four fractions from about 1,500 to 60,000 Da.10\n- **Colour.** Brown colour is read as absorbance, for example as a specific extinction coefficient at 405 nm5 or as absorbance at 420 nm of the diluted brew.13 The 2024 cold brew study read its values from absorbance against a standard curve, not by weighing.13\n\nThe choice of method changes the result. In the 2011 survey, values per kg of roasted coffee differed about threefold between studies (see the chart above).4\n\n## Binding of aroma compounds\n\n**Thiols.** In a 2001 model study, coffee melanoidins added to a mixture of odorants reduced the headspace of three thiols: 2-furfurylthiol, 3-methyl-2-butene-1-thiol and 3-mercapto-3-methylbutyl formate.10 Half of the 2-furfurylthiol was lost from the headspace after 20 min, and almost all after 30 min.10 The fraction of 1,500–3,000 Da was the most effective against 2-furfurylthiol.10 The authors proposed that thiols add to double bonds or carbonyl groups in the melanoidins, but did not prove it.10\n\nA 2002 follow-up found a drastic decrease of odorous thiols when melanoidins were added. Spectroscopic evidence pointed to covalent binding through pyrazinium intermediates from the Maillard reaction.9 According to the roasting chemistry chapter, chlorogenic acids and their breakdown products also form low-molecular-weight thiol-binding sites.2 Losses of aroma in the cup are covered in The aroma of coffee and Freshness and storage.\n\n## Metal chelation, antioxidant activity and health\n\n**Metals.** The thesis on brew melanoidins lists metal chelation among their reported properties.6 No study of metal binding by coffee melanoidins was opened in full for this entry, so no values are given.\n\n**Antioxidant activity in vitro.** In the 2002 study, the radical-scavenging activity of brew melanoidins fell as roasting intensified. Their ability to prevent linoleic acid peroxidation was higher in dark-roasted samples.3 These are laboratory assays, not measurements in people.\n\n**Health.** A 2012 review lists antioxidant, antimicrobial, anticariogenic, anti-inflammatory, antihypertensive and antiglycative activities that have been attributed to coffee melanoidins, and names coffee brew as one of the main sources of melanoidins in the diet.1 The 2011 survey estimated melanoidin intake from coffee at an order of magnitude of 1 g per day.4 No health authority opened for this entry has assessed coffee melanoidins. This entry makes no health claim.\n\n## Melanoidins and sensory attributes\n\n**Bitterness and aftertaste.** A 2020 analysis of eight roasting studies names melanoidins as one of two main sources of bitterness, citing earlier work. It also describes most of the lingering aftertaste as due to heavy, poorly water-soluble bitter melanoidins.11 Both are background statements in the paper, not its own measurements.\n\n**Body.** The same analysis discussed the belief that more melanoidins mean higher molecular weight, more viscosity and more body. Body was not affected by roasting time in either phase, and the authors found no evidence supporting the link.11 A cupping chapter lists melanoidins, with fibres, lipids and fine particles, among factors that may play a role in body, and states that exact correlations are not known.15 More is in Body and mouthfeel.\n\n**Astringency.** A 2025 study split a high-body drip coffee into fractions and tasted each. Added to water, or to a low-body coffee, a phenolic-rich melanoidin fraction was perceptibly different, described as drying or astringent; the authors call the effect subtle. They present this as the first evidence of melanoidins in coffee’s tactile profile.12\n\n## Reference values\n\nThe values below are those reported in the sources. Each describes the coffees and methods of one study or survey; they are not targets.\n\n| Parameter | Value reported | Basis and method | Source |\n|---|---|---|---|\n| Share of beverage dry matter | Up to 25% | Coffee beverages | Borrelli et al.3 |\n| Content per kg roasted coffee, filter brews | 36–115 g/kg: ultrafiltration 115, 90, 81 and 36; dialysis 76 and 51; gel filtration 70 and 53 | Coffee-to-water ratio 0.070 or 0.050, as listed in the survey | Fogliano & Morales4 |\n| Content used for medium roasts | 7.2 g per 100 g roasted coffee (SD 2.97) | Mean of the eight filter-brew studies, medium roasts where available | Fogliano & Morales4 |\n| Content per 100 mL filter brew | 0.25–0.81 g | Same eight studies | Fogliano & Morales4 |\n| Estimated intake from coffee | Order of magnitude 1 g per day | Survey estimate | Fogliano & Morales4 |\n| High-molecular-weight brew fraction | 3.6% of dry, defatted beans (diafiltration retentate, 3 kDa); 7.4% (dialysis retentate of the whole brew) | One roast, 16.4% weight loss | Bekedam et al. 20065 |\n| Cold brew, Agtron 73 / 62 / 53 | 4.33 / 5.17 / 5.92 mg/mL (12 h, 4 °C); 4.21 / 5.23 / 6.35 mg/mL (ultra-high pressure, 300 MPa, 20 min) | Absorbance at 420 nm; one Ethiopian arabica coffee | Shi et al.13 |\n| 2-Furfurylthiol with melanoidins added | Fell by a factor of 16 | Model study | Hofmann & Schieberle9 |\n| 2-Furfurylthiol loss over time | ≈50% after 20 min; nearly absent after 30 min | Headspace, model study | Hofmann et al. 200110 |\n| Most thiol-active fraction | 1,500–3,000 Da | Sephadex G-25 gel filtration | Hofmann et al. 200110 |\n| Astringent melanoidin-rich fraction | 15.7 mg/L (high-body drip coffee); 7.9 mg/L (low-body) | Below 5 kDa; LC-MS/MS standard addition (high-body), gravimetric estimate (low-body) | Linne et al.12 |\n\n## Open questions\n\n- **Structure.** No full structure of a coffee melanoidin has been established. A 2012 review described exact structures and formation mechanisms as far from elucidated.1,6\n- **Method dependence.** Amounts differ about threefold between the studies collected in one survey.4 No agreed reference method was found among the sources opened.\n- **Molecular weight and roast.** Studies disagree on whether molecular weight rises or falls with roast degree (see Contested).3,7\n- **Acidity.** Brew melanoidins are negatively charged8, but no study opened for this entry measured their contribution to titratable acidity or to perceived acidity.\n- **Body.** A role in body is assumed in a cupping chapter15 but was not supported in a multi-study sensory analysis.11\n- **Roast profile.** No study opened for this entry compared melanoidin content between fast and slow roasts to the same colour.\n\n## Key studies\n\n
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Borrelli et al., 2002 – Melanoidins at three roast degrees. One coffee was roasted light, medium and dark, and the brew melanoidins were isolated by gel filtration. Darker roasting gave more melanoidins of lower molecular weight; their radical-scavenging activity fell, while protection against lipid peroxidation was higher in the dark roast.

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Journal of Agricultural and Food Chemistry 50(22), 6527–6533 · doi:10.1021/jf025686o

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Hofmann & Schieberle, 2002 – Thiols bound by melanoidins. Adding coffee melanoidins sharply lowered odour-active thiols, with 2-furfurylthiol down by a factor of 16. Spectroscopy pointed to covalent binding through Maillard-derived pyrazinium intermediates, offered as a cause of aroma staling after brewing.

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Journal of Agricultural and Food Chemistry 50(2), 319–326 · doi:10.1021/jf010823n

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Bekedam et al., 2008 – Roast degree and formation routes. Molecular-weight fractions from green, light, medium and dark roasts were analysed for nitrogen, protein, phenolics and sugars. Melanoidin levels followed nitrogen and protein; light roasting formed mainly intermediate-weight melanoidins, prolonged roasting mainly high-weight ones, with arabinogalactans more involved than galactomannans.

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Journal of Agricultural and Food Chemistry 56(16), 7138–7145 · doi:10.1021/jf800999a

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Fogliano & Morales, 2011 – How much melanoidin people drink. Collects melanoidin values from coffee studies that used gel filtration, dialysis or ultrafiltration. Filter brews ranged from 36 to 115 g per kg of roasted coffee, and daily intake from coffee was estimated at around 1 g.

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Food & Function 2(2), 117–123 · doi:10.1039/c0fo00156b

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Moreira et al., 2012 – Review of coffee melanoidins. Reviews what is known about their structure, formation and possible health effects. Concludes that polysaccharides, proteins and chlorogenic acids take part, but that exact structures and mechanisms remain unresolved.

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Food & Function 3(9), 903–915 · doi:10.1039/c2fo30048f

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