Biondic Fuckar et al. 2023 - metals in coffee silverskin

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.

Page history

The five most recent substantive edits to this page. 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.