Overview
Biondic Fuckar and colleagues evaluated coffee silverskin, the thin tegument removed during coffee roasting, for food-safety contaminants and nutritional composition. The source reports one homogenized coffee-silverskin by-product sample with six parallel analyses; Ni, Pb, total As, Cd, and Cr were measurable, but the matrix is a roasting by-product rather than brewed coffee or ground coffee as sold. The paper is useful for coffee by-product and potential nutraceutical/supplement routing, with a clear matrix firewall.
Key numbers
Table 4 reports the detected heavy metals in coffee silverskin as Ni 2.495 +/- 0.055 mg/kg, Pb 0.249 +/- 0.077 mg/kg, As 0.107 +/- 0.018 mg/kg, and Cd 0.106 +/- 0.002 mg/kg. The paper does not speciate arsenic, so this page treats it as total arsenic rather than inorganic arsenic.
Section 3.2 also reports nutritional and trace-element values in the same silverskin sample: K 24,311 +/- 764 mg/kg, Ca 10,569 +/- 210 mg/kg, Mg 4672.5 +/- 88.5 mg/kg, Na 329 +/- 79 mg/kg, Fe 567.50 +/- 12.50 mg/kg, Cu 74.90 +/- 0.60 mg/kg, Mn 37.55 +/- 0.45 mg/kg, Zn 16.80 +/- 0.70 mg/kg, and Cr 1.53 +/- 0.04 mg/kg.
The authors compare the measured Pb and Cd values to European contaminant limits for food additives and supplements. They state that Pb at 0.249 +/- 0.077 mg/kg is below a 3.0 mg/kg food-additive maximum and that Cd at 0.106 +/- 0.002 mg/kg is below a 1.0 mg/kg food-supplement maximum.
The abstract states that 265 pesticides were analyzed and three were detected at small quantities. Those pesticide results are outside the heavy-metal scope of this source page except as context for the authors’ broader health-safety framing.
Methods (brief)
The coffee-silverskin sample was ground and homogenized before analysis. For metals, 0.5 g of crushed homogenized sample was hydrated, digested with concentrated nitric acid and 30% hydrogen peroxide in microwave decomposition, transferred to 25 mL, and measured by ICP-MS. The paper reports calibration linearity of at least 0.999 for each element and use of Bi, Sc, Y, and Ge internal standards.
The reported heavy-metal results are averages of six parallel analyses. The sample combined Arabica and Robusta roasting by-products, so it should not be interpreted as a varietal comparison.
Implications
Certification: Values may support a coffee by-product or supplement-ingredient evidence route. They should not be pooled as brewed coffee, ground coffee, or coffee-bean occurrence values without an explicit matrix conversion decision.
Courses: The source is useful for by-product utilization training because it pairs nutraceutical interest with contaminant screening and shows why by-product matrices need their own evidence route.
App: If coffee silverskin appears as an ingredient or supplement input, the relevant heavy-metal facts are Ni about 2.5 mg/kg, Pb about 0.25 mg/kg, total As about 0.11 mg/kg, and Cd about 0.11 mg/kg in this one Croatian composite sample.
Wiki pages this source may touch
- Coffee
- Coffee
- Dietary Supplements
- Nickel
- Lead
- Arsenic, Total
- Cadmium
- Chromium
- Copper
- Zinc
- Manganese
- Iron
Verification notes
- DOI, title, authors, journal, license, and year were taken from the Foods PDF first page.
- Author names are ASCII-normalized in frontmatter and cite key because the PDF byline uses Croatian diacritics.
- The paper reports “arsenic” without speciation; this page routes it as total arsenic and does not infer inorganic arsenic.
- The named supplier is omitted from the wiki body under the brand firewall; the source design is represented as a Croatian coffee-roasting by-product composite.
- Product routing is matrix-limited: coffee silverskin is a by-product and potential nutraceutical/supplement input, not a brewed-coffee concentration.
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.