Dragičević et al. 2025 — Essential minerals and bioavailability in popcorn kernels and flakes (Serbia)

This Chilean Journal of Agricultural Research paper measured Ca, Mg, Fe, Cu, Mn, Zn and phytic phosphorus in kernels and microwave-popped flakes of 12 popcorn (Zea mays subsp. everta) hybrids grown 2021-2022 at the Maize Research Institute Zemun Polje, Serbia. The study is a bio-fortification and nutritional-bioavailability investigation; HMI-scope heavy metals (Pb, Cd, iAs, tAs, MeHg, tHg, Ni, Al, Cr, Cr-VI, Sn, Sb, U) are NOT measured in the present work — Cd, As, Pb, and Ni appear only in the literature-review framing, citing Abebe et al. 2017 and Dada & Kutu 2022 on lower accumulation of potentially toxic elements in popcorn maize. Microwave popping decreased phytic acid concentration up to 11.8% in flakes of six hybrids (541/1k, ZP 542/1k, ZP 657/1k, ZP 644/1k, ZP 557/1k, ZP 686/1k), improving potential bioavailability of essential elements.

Key numbers

• Hybrids/sampling: 12 popcorn hybrids (H1-H12); 4 field replicates per hybrid; field-trial soil characteristics (slightly calcareous Chernozem; 51.0% sand, 31.0% silt, 18.0% clay, 3.5% organic matter, pH 7.0 KCl / 7.5 H₂O); concentrations expressed on dry-weight basis after drying at 105 °C to constant weight (4 h) (p. 278-279).
• Essential mineral concentrations across 12 hybrids (Table 4, µg/g dry weight; authors report identical kernel and flake values on a DW basis): Ca 103.3 ± 0.5 (H12) to 425.2 ± 24.1 (H5); Mg 1620.4 ± 51.6 (H12) to 2094.7 ± 66.8 (H11); Fe 31.03 ± 0.86 (H5) to 55.75 ± 0.81 (H10); Cu 6.79 ± 0.19 (H11) to 37.32 ± 2.95 (H1); Mn 9.57 ± 1.40 (H12) to 15.62 ± 0.56 (H7); Zn 32.40 ± 1.14 (H9) to 69.15 ± 0.29 (H10) (Table 4, p. 281).
• Phytic P (Pphy): kernels 2.94 ± 0.07 (H1) to 3.50 ± 0.04 (H6) mg/g; flakes 2.78 ± 0.01 (H10) to 3.46 ± 0.02 (H7) mg/g. Microwave popping reduced Pphy “up to 11.8%” in flakes of 541/1k, ZP 542/1k, ZP 657/1k, ZP 644/1k, ZP 557/1k, ZP 686/1k (Abstract; Table 3, p. 281).
• Molar ratios (Table 6, p. 283): lowest Phy/Mg in H10 kernels (0.190 ± 0.027) and H10 flakes (0.176 ± 0.007); lowest Phy/Fe in H10 kernels (7.06 ± 0.22) and H10 flakes (6.51 ± 0.26); lowest Phy/Zn in H10 kernels (5.69 ± 0.15) and H10 flakes (5.25 ± 0.34); lowest Phy/Mn in H7 kernels (25.54 ± 0.52) and H10 flakes (24.85 ± 0.64); lowest Phy/Cu in H1 kernels (23.29 ± 0.14) and H1 flakes (26.12 ± 0.27); lowest Phy/Ca in H5 kernels (1.580 ± 0.150) and H5 flakes (1.466 ± 0.164).
• Kernel yield 4.99 ± 0.19 (H10) to 6.77 ± 0.14 (H1) t/ha; popping volume 29.00 ± 1.41 (H3) to 40.09 ± 0.12 (H7) cm³/g; kernel size 60.00 ± 2.52 (H6) to 82.00 ± 3.76 (H3) kernels per 10 g; un-popped kernels 0.66 ± 0.03% (H12) to 4.57 ± 0.21% (H3) (Table 3, p. 281).
• Heavy-metal context (literature-review only, NOT measured in this study): authors cite Abebe et al. 2017 and Dada & Kutu 2022 reporting that accumulation of potentially toxic elements (Cd, As, Pb, Ni) is lower in popcorn maize even when grown on municipal-solid-waste-compost-fertilized soil, and that popping decreases K, Mg, Cr, Mn, Fe, Co, Pb concentrations while increasing Na, Ca, Cu, Zn (p. 277-278). These are cited prior-literature observations, not original measurements of the present paper.

Methods (brief)

Two-year field trial (2021, 2022) at Maize Research Institute Zemun Polje, Belgrade, Serbia (44°52’ N, 20°19’ E, 81 m a.s.l.), slightly calcareous Chernozem under rain-fed conditions; preceding crop winter wheat both years; 100 kg/ha mono-ammonium phosphate (MAP) incorporated each autumn (2020, 2021) plus 250 kg/ha urea (spring 2021) and 280 kg/ha urea (spring 2022). Twelve hybrids in 6.2 m² plots (40 plants, 70 cm inter-row, 22 cm intra-row), fully randomized block design, 4 replicates, sown first week of May.

After harvest, kernel moisture brought to 14% (drying at 40 °C), kernel yield calculated. Popping: 4 × 100 kernels per replicate in a paper bag, Samsung 1.1 cu. Ft 1000 W microwave oven, 5 min, no oil/salt/sugar. Kernels and flakes milled to <500 µm (Perten Laboratory Mill 120, PerkinElmer, Stockholm, Sweden) and dried to constant weight at 105 °C / 4 h (EUGE425 ventilation oven, EU Instruments, Novo Mesto, Slovenia) for dry-weight basis.

Phytic P determined by Wade reagent spectrophotometry (Dragičević et al. 2011 method; reagent containing 0.3 g FeCl₃·6H₂O and 3 g 5’-sulfosalicylic acid in 1 L) at λ = 500 nm on a Libra S22 UV/Vis spectrophotometer (Biochrom, Cambridge, UK). Essential mineral analysis (Ca, Mg, Fe, Mn, Cu, Zn) by inductively coupled plasma optical emission spectroscopy (ICP-OES, iCAP 7000 Series dual-view, Thermo Scientific, Waltham, Massachusetts, USA), following AOAC procedure (Helrich 1990). Popping volume measured by metric weight volume test on a Cretors 2300W official metric weight volume tester (Cretors, Wood Dale, Illinois, USA). Statistics: ANOVA with Fisher’s LSD at p < 0.05; PCA in MATLAB R2011a with PLS Toolbox v.6.2.1 (mean-centred, auto-scaled, SVD algorithm, 95% confidence level for Hotelling T² limits).

Limitation for HMI scope: HMI-scope toxic metals (Pb, Cd, iAs, tAs, MeHg, tHg, Ni, Al, Cr, Cr-VI, Sn, Sb, U) were NOT measured in this study. The paper does not report LODs/LOQs for any element. All numeric values are essential-nutrient concentrations, not contaminant occurrence data.

Implications

• Certification (HMTc): No direct contribution. The paper does not measure any of the 10 HMTc analytes (Pb, tAs, Cd, MeHg, tHg, iAs, Ni, Al, Cr-VI, Sn) or the broader HMI metal vocabulary (which adds Cr, Sb, U). It is useful as a methodology reference for ICP-OES on maize-grain matrices and as a citation pointer to Abebe et al. 2017 and Dada & Kutu 2022, which do report heavy metals in popcorn.
• Courses: Teachable contrast between bio-fortification literature (essential-element framing) and contamination literature (toxic-element framing), and how the wiki must distinguish essential trace elements (Cu, Mn, Zn, Fe) from toxic species (Pb, Cd, iAs, etc.) when they share analytical platforms.
• App: Does not advance any HMTc analyte sub-block on Corn or maize. The Ca, Mg, Fe, Cu, Mn, Zn data are out of scope for the contamination_profile schema.
• Routing fan-out: matrix popcorn maps to [[products/snacks-crackers-biscuits]] per data/evidence/matrix-to-product-map.json; the source contributes context (not occurrence evidence) to that product page.

Verification notes

This page was merge-enhanced on 2026-05-29 against the original PDF (raw/Manual Fetch Kimi /Essential minerals and their potential bioavailability in popcorn (Zea mays L. subsp. everta (Sturtev.) Zhuk.) kernels and flakes.pdf):

• metals: field corrected and completed. Prior listing was [Cu, Mn, Zn] which omitted the macro-minerals the paper actually quantified (Ca, Mg) and the Fe values prominently reported in Table 4 and the Implications. Replaced with [Ca, Mg, Fe, Cu, Mn, Zn], matching the sibling convention used for Abebe et al. 2017 popcorn (list all measured analytes regardless of HMI scope). None of these are HMI-scope toxic metals; the page remains EF-4 (Context only) for HMTc purposes.
• matrices: expanded from [cereal-grain] to [popcorn, cereal-grain]. The paper measures both raw kernels (cereal-grain matrix) and microwave-popped flakes (popcorn matrix). The popcorn matrix key is recognized in data/evidence/matrix-to-product-map.json and routes to [[products/snacks-crackers-biscuits]].
• products: populated from [] to ["[[products/snacks-crackers-biscuits]]"] per the matrix-to-product map (popcorn → snacks-crackers-biscuits). This clears the routing-malformed advisory entry that prior products: [] triggered. Did not propose any new product pages — Step 0 Lock is Karen’s separate workflow per Part 10.
• Mg upper-range typo corrected from 2094.9 to 2094.7 µg/g. The PDF Table 4 (p. 281) reports H11 Mg = 2094.7 ± 66.8 µg/g; the prior wiki value of 2094.9 was a single-digit transposition. Verified against Table 4 directly.
• Phytic P maxima attributed to correct hybrids. Prior page reported the kernel/flake Pphy ranges (2.94-3.50 / 2.78-3.46 mg/g) without naming the responsible hybrids. Added: kernel max in H6 (3.50 ± 0.04), flake max in H7 (3.46 ± 0.02). Verified against Table 3 (p. 281).
• Range-and-attribution detail added throughout ## Key numbers to make each min/max value individually re-derivable against Tables 3, 4, and 6.
• Limitation paragraph added to ## Methods (brief) explicitly noting which HMI-scope analytes are absent and that no LOD/LOQ data are reported for any element.
• Legacy ## Wiki pages this source may touch section removed. Per the 2026-05-17 cleanup of ## Wiki pages updated on ingest legacy headings (and the sibling Abebe 2017 popcorn merge-enhance on 2026-05-29), the routing layer (not the source page) is responsible for fan-out to metal and ingredient pages. The metals/copper, metals/manganese, metals/zinc, metals/iron pages do exist as wiki pages but are not HMI-scope; the source’s lack of HMI-scope metal measurements means it does not advance the contamination_profile for any ingredient page anyway.
• Frontmatter additions to align with current schema landed in the 2026-05-28 10-year architecture commit (10eef01): evidence_fitness: EF-4 (Context only — no HMI-scope metals measured), public_evidence_label: Context only, review_state: approved_for_internal, claim_classes: [] (no HMI-scope claims supported), access_url (DOI link), access_date: 2026-05-29, raw_sha256 (computed via shasum -a 256 against the source PDF), sampling_locations: ["Zemun Polje, Belgrade"], sampling_year_range: "2021-2022", ingest_method: manual_phase1_priority, created_by: claude_opus_47_session.
• Sample population expanded to include all twelve hybrid identifiers and the 4 × 100 kernels-per-replicate popping detail.
• Authors string updated to include the full author list (was previously truncated in authors: array order; now matches PDF p. 277 byline exactly).
• Publication string updated to “Chilean Journal of Agricultural Research 85(2): 277-286” (was 277-285; the article runs through p. 286 per the PDF page numbering).
• Brand-firewall scan: the paper does not name any consumer brand or producer. Genotype identifiers (ZP 611k, ZP 542/1k, etc.) are breeding-program designations from Maize Research Institute Zemun Polje, not consumer-product brand names; these are research-material identifiers and are retained. Methods-section vendor names (Samsung, Perten/PerkinElmer, Biochrom, Thermo Scientific, Cretors, EU Instruments) are scientific-reproducibility content retained per the Part 12 vendor-name exception.
• Direction-of-edit check (CLAUDE.md Part 2): all changes move toward the literature (correcting a transposed Mg digit, completing the measured-analyte list, populating routing fields per the matrix map, removing a legacy heading). No changes move toward HMTc convenience; the page remains explicit that no HMTc analyte sub-block is advanced.

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.