A review on the application of chromatographic methods, coupled to chemometrics, for food authentication

Food Control, 93, 165-182, 2018

DOI: 10.1016/j.foodcont.2018.06.015

The increase of food adulteration, inducing losing a large amount of money as well as of the confidence of consumers, has become an urgent issue for producers, researchers, governments and consumers. Chromatographic methods, in combination with chemometrics, are usually developed and applied throughout the food chain to verify the nature or origin of food, with both targeted (metabolomics) and non-targeted (profiling) approaches. Their operation, together with their advantages and drawbacks, will be discussed in this review to show strategies to solve food authentication issues.

Assessment of polar phenolic compounds of virgin olive oil by NIR and mid-IR spectroscopy and their impact on quality

European Journal of Lipid Science and Technology

DOI: 10.1002/ejlt.201600099

Chemometric analyses of near- (NIR) and middle-infrared (mid-IR) spectroscopy spectral data (12 500–4000 cm−1 and 4000–400 cm−1) by Partial Least Square (PLS) regression combined with analytical determination of polar phenolic compounds measured by HPLC in different varieties, geographical origin and marketplace categories olive oils—Protected Denomination of Origin (PDO) “Montes de Toledo”; Galician; high quality extra virgin (“Gourmet”/“Premium”); and commercial extra virgin and olive oils—were used to generate calibration and validation models in order to be able to predict the content and profile of these minor compounds, and thereby the quality of the product. Satisfactory multivariate test set validation algorithms were obtained for virgin olive oil (VOO)'s total polar phenolic (TPP) compounds (r = 0.91), hydroxytyrosol and tyrosol secoiridoid derivatives (HtyrSec, TyrSec; r = 0.91 and 0.92, respectively). Contrary to NIRS, the chemometric analysis of the mid-IR spectra gave no satisfactory validation models (r = 0.43, 0.54, and 0.66 for HtyrSec, TyrSec, and TPP), despite that the calibration algorithms gave even higher correlation than NIRS (r > 0.96 for all the polar phenolics studied).

The results establish that NIRS is a very useful technique that allows rapid screening of VOO samples to estimate polar phenolic profile, and thereby their quality and commercial grade. Furthermore, it may give real time information about olive oil composition during processing in order to automatically control technological parameters.

High-throughput HPLC–MS/MS determination of the persistence of neonicotinoid insecticide residues of regulatory interest in dietary bee pollen

Analytical and Bioanalytical Chemistry

DOI 10.1007/s00216-015-8870-4

The aim of this work is the development of a simple, fast, quantitative, and economic method for the determination of neonicotinoid insecticide residues in dietary bee pollen. Several parameters of the method, such as extraction solvent, extraction time, and solid-phase extraction sorbents for purification [silica, C18, primary–secondary amine (PSA), and Envi-Carb II/PSA], were studied. The final proposed method based on solid–liquid extraction with hexane, cleanup with Supelclean™ Envi-Carb II/PSA cartridges, and subsequent analysis by high-performance liquid chromatography with tandem mass spectrometry was validated and applied to the analysis of commercial bee pollen samples from different geographical zones. Method performance was assessed by the evaluation of several quality parameters of the method, such as recovery values, repeatability, reproducibility, linearity, and limits of detection and quantification. Matrix effects on the chromatographic signal were also studied. The quality parameters of the method were equivalent to or better than those obtained with previously published methods, with recoveries between 81 and 99 % and repeatabilities lower than 8.8 %. The detection and quantification limits were in the ranges 0.2-2.2 μg kg-1 and 0.4-4.3 μg kg-1, respectively.

Liquid chromatography–mass spectrometry method development for monitoring stress-related corticosteroids levels in pig saliva

Journal of Chromatography B

Volume 990, 15 May 2015, Pages 158–163

doi:10.1016/j.jchromb.2015.03.021

Biochemical response stressors results in an increase of adrenocortical activity. Before knowing the corticosteroid levels in saliva in a stressful situation, baselines salivary levels should be established. A method for simultaneous determination of five corticosteroids was developed, validated and applied to pig saliva at farms. The method employs solid-phase extraction (SPE) coupled with clean-up extraction step using silica cartridge in the same step followed by liquid chromatography/tandem mass spectrometry (LC–MS/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 0.050 to 0.30 μg/L for the enrichment of 1.0 mL saliva samples and analyte recoveries are between 60 and 90% (RSD < 11%). Some factors studied were: pig sex, breeds, and time at farm. The analytical method clearly shows that CRL and CRS levels of, respectively, 3.0 and 4.0 μg/L in saliva can be indicative of maxima non-stress levels in different pig breeds at farm.

Effect of Beer Marinades on Formation of Polycyclic Aromatic Hydrocarbons in Charcoal-Grilled Pork

J. Agric. Food Chem., 2014, 62 (12), pp 2638–2643

DOI: 10.1021/jf404966w

The effect of marinating meat with Pilsner beer, nonalcoholic Pilsner beer, and Black beer (coded respectively PB, P0B, and BB) on the formation of polycyclic aromatic hydrocarbons (PAHs) in charcoal-grilled pork was evaluated and compared with the formation of these compounds in unmarinated meat. Antiradical activity of marinades (DPPH assay) was assayed. BB exhibited the strongest scavenging activity (68.0%), followed by P0B (36.5%) and PB (29.5%). Control and marinated meat samples contained the eight PAHs named PAH8 by the EFSA and classified as suitable indicators for carcinogenic potency of PAHs in food. BB showed the highest inhibitory effect in the formation of PAH8 (53%), followed by P0B (25%) and PB (13%). The inhibitory effect of beer marinades on PAH8 increased with the increase of their radical-scavenging activity. BB marinade was the most efficient on reduction of PAH formation, providing a proper mitigation strategy.

Development of an improved extraction and HPLC method for the measurement of ascorbic acid in cows' milk from processing plants and retail outlets

International Journal of Food Science & Technology

Volume 49, Issue 3, pages 679–688, March 2014

DOI: 10.1111/ijfs.12350

An improved extraction (2.5% HPO3, 5 mm dithiothreitol) and HPLC quantification methodology using a C–18 column at 35 °C and 0.1 m acetic acid (98%) and acetonitrile (2%) mobile phase was developed to quantify total ascorbic acid (AA) in commercial whole/semi-skim/skim raw/pasteurised/UHT milk packaged in opaque bags, transparent plastic, cardboard and Tetra Brik™. AA content ranged from 0.21 to 10 and from 3.4 to 16 mg L−1 in milk from retail outlets and processing plants, respectively, and was higher in organic milk. For same processor/lot samples, pasteurised milk showed higher AA content than UHT milk. This was not true for retail outlets samples. AA content was similar for whole/semi-skim and semi-skim/skim milk, but not for whole/skim comparisons. Among UHT samples, the AA content trend was whole<semi-skim<skim and lower for UHT milk in opaque plastic and Tetra Brik™ container. After 14 days at 4 °C in the dark, AA losses ranged 35–83% depending on milk type and preservation method with a higher AA retention in unopened containers.