Detection and Quantification of Adulteration in Krill Oil with Raman and Infrared Spectroscopic Methods

Fatema Ahmmed; Keith C Gordon; Daniel P Killeen; Sara J Fraser-Miller

doi:10.3390/molecules28093695

Detection and Quantification of Adulteration in Krill Oil with Raman and Infrared Spectroscopic Methods

Molecules. 2023 Apr 25;28(9):3695. doi: 10.3390/molecules28093695.

Authors

Fatema Ahmmed¹, Keith C Gordon¹, Daniel P Killeen², Sara J Fraser-Miller¹

Affiliations

¹ Te Whai Ao-Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, New Zealand.
² The New Zealand Institute for Plant and Food Research Limited, P.O. Box 5114, Port Nelson, Nelson 7043, New Zealand.

Abstract

Raman and infrared spectroscopy, used as individual and low-level fused datasets, were evaluated to identify and quantify the presence of adulterants (palm oil, PO; ω-3 concentrates in ethyl ester, O3C and fish oil, FO) in krill oil. These datasets were qualitatively analysed with principal component analysis (PCA) and classified as adulterated or unadulterated using support vector machines (SVM). Using partial least squares regression (PLSR), it was possible to identify and quantify the adulterant present in the KO mixture. Raman spectroscopy performed better (r² = 0.98; RMSEP = 2.3%) than IR spectroscopy (r² = 0.91; RMSEP = 4.2%) for quantification of O3C in KO. A data fusion approach further improved the analysis with model performance for quantification of PO (r² = 0.98; RMSEP = 2.7%) and FO (r² = 0.76; RMSEP = 9.1%). This study demonstrates the potential use of Raman and IR spectroscopy to quantify adulterants present in KO.

Keywords: PCA; PLSR; Raman spectroscopy; SVM; adulteration; chemometrics; infrared spectroscopy; low level data fusion; marine lipid; omega-3 fatty acids; vibrational spectroscopy.

MeSH terms

Animals
Euphausiacea*
Food Contamination / analysis
Least-Squares Analysis
Spectrophotometry, Infrared
Spectrum Analysis, Raman

Grants and funding

F.A. acknowledges the University of Otago for her PhD scholarship. The New Zealand (NZ) Ministry for Business, Innovation, and Employment (MBIE) is acknowledged for an Endeavour funding grant (grant number C11X2001, D.P.K. and K.C.G.). S.J.F.-M. is supported by a Royal society Te Apārangi, Marsden fast-start (grant number 19-UOO-210) and a MBIE smart idea (grant number UOOX1907). S.J.F.-M. and K.C.G. are funded by Te Whai Ao-Dodd-Walls Centre for photonic and quantum technologies (a NZ Centre of Research Excellence).