Supplemental material

Comparison of different sample preparation techniques for NIR screening and

their influence on the geographical origin determination of almonds

(Prunus dulcis MILL.)

Maike Arndt1,‡, Marc Rurik2,6,‡, Alissa Drees1, Katharina Bigdowski1, Oliver

Kohlbacher2,3,4,5,6, Markus Fischer1,*

1 Hamburg School of Food Science, Institute of Food Chemistry, University of

Hamburg, Grindelallee 117, 20146 Hamburg, Germany

2 Applied Bioinformatics, Center for Bioinformatics, Sand 14, 72076 Tübingen,

Germany

3 Quantitative Biology Center, University of Tübingen, Auf der Morgenstelle 10, 72076

Tübingen, Germany

4 Biomolecular Interactions, Max Planck Institute for Developmental Biology, Max-

Planck-Ring 5, 72076 Tübingen, Germany

5 Translational Bioinformatics, University Medical Center Tübingen, Sand 14, 72076

Tübingen, Germany

6 Institute for Bioinformatics and Medical Informatics, University of Tübingen, Sand

14, 72076 Tübingen, Germany

‡ These authors contributed equally to this work.

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Table S1: Overview of all almond samples with country of origin, harvest year and

variety; SNA: sweet, not available, BNA: bitter, not available, USA: United States of

America.

Sample ID Harvest year Country of origin Variety19-AU-001 2019 Australia Padre19-AU-002 2019 Australia Monterey19-AU-003 2019 Australia Carmel19-AU-004 2019 Australia Butte19-AU-005 2019 Australia Non Pareil19-AU-006 2019 Australia Desmayo19-AU-007 2019 Australia Marcona19-AU-008 2019 Australia Ferragnès19-AU-009 2019 Australia SNA18-IR-001 2018 Iran BNA18-IR-002 2018 Iran BNA18-IR-003 2018 Iran BNA18-IR-004 2018 Iran BNA18-IR-005 2018 Iran BNA18-IR-006 2018 Iran BNA18-IT-001 2018 Italy SNA18-IT-003 2018 Italy Tuono18-IT-004 2018 Italy Tuono18-IT-005 2018 Italy SNA18-IT-006 2018 Italy Fascionello18-IT-007 2018 Italy Romana18-IT-008 2018 Italy Pizzuta d'Avola18-IT-009 2018 Italy SNA18-IT-010 2018 Italy SNA18-IT-011 2018 Italy Tuono18-IT-012 2018 Italy Genco18-IT-013 2018 Italy Tuono18-IT-014 2018 Italy Ferragnès18-IT-015 2018 Italy Pizzuta d'Avola18-IT-016 2018 Italy Tuono18-IT-017 2018 Italy Lauranne18-IT-019 2018 Italy Genco18-IT-020 2018 Italy SNA18-IT-021 2018 Italy SNA18-IT-022 2018 Italy Juno18-IT-024 2018 Italy Filippo Cea18-IT-025 2018 Italy Filippo Cea18-MA-001 2018 Morocco BNA18-MA-002 2018 Morocco BNA18-MA-003 2018 Morocco BNA18-MA-005 2018 Morocco BNA18-MA-006 2018 Morocco BNA

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Sample ID Harvest year Country of origin Variety18-ES-002 2018 Spain SNA18-ES-003 2018 Spain SNA18-ES-004 2018 Spain SNA18-ES-005 2018 Spain SNA18-ES-006 2018 Spain SNA18-ES-007 2018 Spain SNA18-ES-008 2018 Spain SNA18-ES-009 2018 Spain SNA18-ES-010 2018 Spain SNA18-ES-011 2018 Spain SNA18-ES-014 2018 Spain SNA18-ES-015 2018 Spain SNA18-ES-018 2018 Spain SNA18-ES-019 2018 Spain SNA18-ES-020 2018 Spain SNA18-US-001 2018 USA Fritz18-US-002 2018 USA Monterey18-US-003 2018 USA Non Pareil18-US-004 2018 USA SNA18-US-005 2018 USA SNA18-US-007 2018 USA SNA18-US-009 2018 USA SNA

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Table S2: Mean confusion matrix across all 20 repeats of the nested cross-validation

of whole almonds with the reduced wavenumber range of 6,500–5,500 cm−1.

Confusion values are given as count values.

PredictedAU ES IR IT MA US

Act

ual

AU 2.30 2.95 0.15 1.85 0.00 1.75ES 0.85 8.60 0.30 4.25 0.95 0.05IR 2.00 0.95 1.35 0.90 0.35 0.45IT 0.00 2.70 0.00 19.30 0.00 0.00MA 0.60 3.20 1.15 0.00 0.05 0.00US 2.80 2.50 1.05 0.00 0.00 0.65

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Figure S1: Uncorrected full FT-NIR spectra, median for every wavenumber over

each sample preparation technique.

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Figure S2: FT-NIR spectra of one almond sample, recorded from a whole almond, a

blanched (1 min, 95–100 °C) almond and from an almonds’ tegument (separated

after blanching). The highlighted wavenumber range of 4,960–4,510 cm−1 refers to

the

O–H bending and C–O stretching combination of polymers like cellulose or lignin

(Blackwell, 1977).

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Figure S3: PCA score plots of the FT-NIR analysis of whole almonds, possible combinations for PC 1–4.

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Figure S4: PCA score plots of the FT-NIR analysis of bisected almonds, possible combinations for PC 1–4.

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Figure S5: PCA score plots of the FT-NIR analysis of ground almonds, possible combinations for PC 1–4.

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Figure S6: PCA score plots of the FT-NIR analysis of freeze-dried almonds (after grinding), possible combinations for PC 1–4.

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