Application of NIR Spectroscopy for the Valorisation of Cork By-Products: A Feasibility Study over the Screening and Discrimination of Chemical Compounds of Interest

Ricardo N M J Páscoa; Cláudia Pinto; Liliana Rego; Joana Rocha E Silva; Maria E Tiritan; Honorina Cidade; Isabel F Almeida

doi:10.3390/ph17020180

Application of NIR Spectroscopy for the Valorisation of Cork By-Products: A Feasibility Study over the Screening and Discrimination of Chemical Compounds of Interest

Pharmaceuticals (Basel). 2024 Jan 30;17(2):180. doi: 10.3390/ph17020180.

Authors

Ricardo N M J Páscoa¹, Cláudia Pinto^{2

3}, Liliana Rego^{4

5}, Joana Rocha E Silva⁶, Maria E Tiritan^{2

3

7}, Honorina Cidade^{2

3}, Isabel F Almeida^{4

5}

Affiliations

¹ Associated Laboratory for Green Chemistry/Network of Chemistry and Technology, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
² Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
³ Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal.
⁴ Applied Molecular Biosciences Unit, MedTech, Laboratory of Pharmaceutical Technology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
⁵ Associate Laboratory i4HB-Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
⁶ Dimas & Silva, Lda. Industry, Rua Central de Goda 345, 4535-167 Mozelos, Portugal.
⁷ Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116 Gandra, Portugal.

Abstract

Quercus suber is considered a sustainable tree mainly due to its outer layer (cork) capacity to regenerate after each harvesting cycle. Cork bark is explored for several application; however, its industrial transformation generates a significant amount of waste. Recently, cork by-products have been studied as a supplier of bioactive ingredients. This work aimed to explore whether near infrared spectroscopy (NIRS), a non-destructive analysis, can be employed as a screening device for selecting cork by-products with higher potential for bioactives extraction. A total of 29 samples of cork extracts were analysed regarding their qualitative composition. Partial least squares (PLS) models were developed for quantification purposes, and R²_P and RER values of 0.65 and above 4, respectively, were obtained. Discrimination models, performed through PLS-DA, yielded around 80% correct predictions, revealing that four out of five of samples were correctly discriminated, thus revealing that NIR can be successfully applied for screening purposes.

Keywords: NIR spectroscopy; PLS; PLS-DA; chemometrics; cork residues.

Grants and funding

This work was financed by national funds from the European Regional Development Fund (ERDF) through the Northern Regional Operational Programme (NORTE2020) under the project 47239—Cork2Cosmetic (NORTE-01-0247-FEDER-047239) in co-promotion with the company Dimas & Silva. This research was also supported by national funds from FCT-Fundação para a Ciência e a Tecnologia through the projects UIDB/04423/2020 and UIDP/04423/2020 (Group of Marine Natural Products and Medicinal Chemistry-CIIMAR), UIDP/04378/2020 and UIDB/04378/2020 (Research Unit on Applied Molecular Biosciences—UCIBIO), UIDB/50006/2020 and UIDP/50006/2020. It was also supported by the European Regional Development Fund (ERDF) through the COMPETE—Programa Operacional Fatores de Competitividade (POFC) program in the framework of the program, PT2020, and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. C. Pinto and L. Rego acknowledge their research fellowship (NORTE-01-0247-FEDER-047239), fully supported by national funding from project 47239-Cork2Cosmetic (NORTE-01-0247-FEDER-047239).