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![(a) Partial least squares discriminant analysis (PLS-DA) t[1]/t[2] scores plot for the monocultivar extra virgin olive oils (EVOOs) data sets. 6 components, R 2 X = 0.953; R 2 Y = 0.750; Q 2 = 0.711. (b) Line plot for the model, indicating the 1 H Nuclear Magnetic Resonance chemical shifts of the signals, characteristic of specific metabolites, discriminating the classes along t[1] and colored according to the correlation-scaled loading (*p(corr) ≥ |0.5|). w*c[1] axis represented the weighted correlation vector.](publication/347695468/figure/fig1/AS:993223099031555@1613814248849/a-Partial-least-squares-discriminant-analysis-PLS-DA-t1-t2-scores-plot-for-the.png)
(a) Partial least squares discriminant analysis (PLS-DA) t[1]/t[2] scores plot for the monocultivar extra virgin olive oils (EVOOs) data sets. 6 components, R 2 X = 0.953; R 2 Y = 0.750; Q 2 = 0.711. (b) Line plot for the model, indicating the 1 H Nuclear Magnetic Resonance chemical shifts of the signals, characteristic of specific metabolites, discriminating the classes along t[1] and colored according to the correlation-scaled loading (*p(corr) ≥ |0.5|). w*c[1] axis represented the weighted correlation vector.
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![Figure 5. (a) OPLS-DA t[1]/t[2] scores plot for the monocultivar EVOOs...](publication/347695468/figure/fig3/AS:993223099047939@1613814248926/a-OPLS-DA-t1-t2-scores-plot-for-the-monocultivar-EVOOs-data-sets-built-with-bucket_Q320.jpg)
During the last few years, the global demand for extra virgin olive oil (EVOO) is increased. Olive oil represents a significant percentage of world fat consumption determining an important development of its market. In this context, the problems related to counterfeiting and product fraud is becoming extremely relevant. Thus, the quality and authen...
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Citations
... First, a predicted UV-PLS-DA model ( Figure 5, I) between the two classes N and A was obtained with the training set, where samples (T) and (S) were considered together. The predicted Y-values (YpredPS) were generated and used to define class membership [35,36]. The non-adulterated samples (N) have YPredPS in the range of −0.06 to 0.27, while the YPredPS of the adulterated (A) samples is between 0.54 and 1.29 ( Figure 6A). ...
Recently, benchtop nuclear magnetic resonance (NMR) spectrometers utilizing permanent magnets have emerged as versatile tools with applications across various fields, including food and pharmaceuticals. Their efficacy is further enhanced when coupled with chemometric methods. This study presents an innovative approach to leveraging a compact benchtop NMR spectrometer coupled with chemometrics for screening honey-based food supplements adulterated with active pharmaceutical ingredients. Initially, fifty samples seized by French customs were analyzed using a 60 MHz benchtop spectrometer. The investigation unveiled the presence of tadalafil in 37 samples, sildenafil in 5 samples, and a combination of flibanserin with tadalafil in 1 sample. After conducting comprehensive qualitative and quantitative characterization of the samples, we propose a chemometric workflow to provide an efficient screening of honey samples using the NMR dataset. This pipeline, utilizing partial least squares discriminant analysis (PLS-DA) models, enables the classification of samples as either adulterated or non-adulterated, as well as the identification of the presence of tadalafil or sildenafil. Additionally, PLS regression models are employed to predict the quantitative content of these adulterants. Through blind analysis, this workflow allows for the detection and quantification of adulterants in these honey supplements.
... A non-targeted approach has been proposed to categorize over 200 samples of Italian blends of olive oil using 1H NMR coupled with chemometric analysis of the entire spectra. This involves comparing the samples to a database of 126 monocultivar oils obtained from specific geographical origins [66]. This approach proves to be a valuable tool for detecting adulterated blends. ...
... A simple PCA was performed to visualize any intrinsic variation of the dataset and the possible clustering of the samples or identifying outliers [25]. All the variables were previously Pareto scaled, which confers partially the same weight to each variable and allows for not giving so much importance to the regions with noise. ...
Protected Designation of Origin cheeses are products with high-quality standards that can claim higher prices on the market. For this reason, non-PDO cheeses with lower quality can be mislabeled as PDO or mixed with it for economic gain especially when the product is in a shredded form. Luckily, the production of PDO cheese is subjected to strict procedural specification rules that result in a product with a defined profile of its metabolites, which can be used for authentication purposes. In this study, an NMR metabolomic approach combined with multivariate analysis was implemented to build a classification model able to discriminate PDO Grana Padano cheese from a large dataset of competitors. The great advantage of the proposed approach is a simple sample preparation, obtaining a holistic overview of the analyzed samples. The untargeted approach highlighted a “typical profile” of Grana Padano samples, which could be used for protection purposes. In parallel, the targeted results allowed us to identify potential chemicals, such as lactate, some amino acids and lipids. These initial results could open the road to a potential new additional tool to check the authenticity of PDO cheeses in the future.
... Świadczą o tym liczne doniesienia naukowe pojawiające się na przestrzeni ostatnich lat, opisujące zastosowanie techniki 1 H NMR w badaniach EVOO. Obecnie wykorzystuje się analizę 1 H NMR do badania mieszanek oliwy z oliwek [7,15], oceny pochodzenia geograficznego [21], badania profilu związków występujących w niewielkich ilościach w oliwie (steroli, skwalenu, alkoholi tłuszczowych, wosków, polifenoli) [30,38] czy badania stabilności oliwy podczas przechowywania [1]. ...
Background. Vegetable oils play an important role in the food, pharmaceutical and cosmetic indus tries. They are not only a source of nutrients, but also a carrier of bioactive substances as an ingredient of creams or emulsions. Some oils, like extra virgin olive oil or argan oil, due to high consumer demand and high prices, may be subject to adulteration by using cheaper and easily accessible oils. Hence, the need to develop new research methods enabling the quick identification of such adulterations, but also enabling the assessment of oil quality, e.g. in variable storage conditions. Typically, gas chromatography (GC) is used to assess the profile of fatty acids. Oil parameters such as acid number, peroxide value and iodine number are also assessed to determine oil quality. Nevertheless, instead of performing all the above mentioned tests, these parameters can also be determined directly from 1H NMR spectra. Hence, there is great potential for using this method in quick screening of oil quality. The 1H NMR technique has been growing in importance in recent years in researching the quality and composition of food, including vege table oils. Multidimensional NMR techniques and analysis of other nuclei (13C NMR) are also used in the study of oils. The aim of this work is to present the applications of the most commonly used 1H NMR technique. Results and Conclusions. The article contains examples of the application of this method in testing the composition, quality and authenticity of olive oil, hemp oil and argan oil as oils used (both in the food, medical or cosmetic context) and becoming more and more popular among consumers.
... Coratina EVOOs are well-known for the significant bitterness and pungency attributed to the high polyphenols content. 12,45,46 On the other hand, Oteri et al. 41 reported a similar TG composition between Coratina and Frantoio varieties, spread at positive values of LD1. Such a clusterization was quite similar to statistical analyses achieved with the iKnife approach, where two distinct monovarietal models were obtained by using analyses acquired in negative and positive mode. ...
Background
Following our previous research on the differentiation of Italian extra virgin olive oils (EVOOs) by rapid evaporative ionization mass spectrometry coupled to a tandem high resolution mass analyser, the present study deals with the evaluation of another direct mass spectrometry (direct‐MS) approach for the rapid and automatic discrimination of EVOOs. In particular, direct analysis in real time (DART‐MS) was explored as an ambient MS (AMS) source for the building of a top‐quality Italian EVOOs database and fast identification of unknown samples. A single quadrupole detector (QDa) was coupled with DART, taking advantage of a cost‐saving, user‐friendly and less sophisticated instrumental setup. Particularly, quickstrip cards, located on a moving rail holder, were employed, allowing for the direct analysis of 12 EVOO spots in a total analysis time of 6 min. The aim was to develop a reliable statistical model by applying principal component and linear discriminant analyses to clusterize and classify EVOOs according to geographical origin and cultivar, as main factors determining their nutritional and sensory profiles.
Results
Satisfactory results were achieved in terms of identification reliability of unknown EVOOs, as well as false positive risk, thus confirming that the use of AMS combined with chemometrics is a powerful tool against fraudulent activities, without the need for mass accuracy data, which would increase the analysis cost.
Conclusion
A DART ionization source with a compact and reliable QDa MS analyser allowed for rapid fingerprinting analysis. Furthermore, MS spectra provided quali‐quantitative information successfully related to EVOO differentiation. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... Chemical shifts were reported with respect to TMS signals set as 0.0 ppm, obtaining peak alignment. The olive oil profile and phenolic molecules assignments were performed based on 1D NMR spectral analysis and by comparison with published data [35]. ...
This study aims to evaluate the Proton Nuclear Magnetic Resonance (1H-NMR)-based metabolomic profiles of monovarietal olive oils obtained from Arbequina and Koroneiki, which are typically present in the Mediterranean basin and grown in Spain and Greece, respectively. Micro-milled oils were obtained from olives harvested both in their cultivar home countries (Spain and Greece) and in Italy. Investigations by 1H NMR metabolic profiling were carried out to develop a strategy for the correct interpretation of differences based on geographical origins. The NMR Spectroscopy and multivariate statistical analysis (MVA) revealed significant differences in fatty acids profile as well as the unsaponifiable fraction, not only according to the cultivars but also to the specific geographical origin of the olives used. In particular, the oils from Spain were higher in polyunsaturated fatty acids (PUFAs) content than those from Italy. Conversely, the Italian oils of Koroneiki showed higher content of monounsaturated fatty acids (MUFAs) than Greek oils. Regarding the Extra Virgin Olive Oils (EVOOs) minor fraction, for both cultivars, the olive oils obtained using olives harvested in Italy were characterized by higher relative content of phenolic compounds. It was found that each of the investigated cultivars (Arbequina and Koroneiki), very popular in super high density (SHD) planting systems, assumed a specific well-characterized metabolic EVOO profile when the olives are harvested in Italy. These results may contribute to extending and enforcing available literature data on 1H NMR-based chemometric models as powerful tools for EVOOs geographical origin discrimination.
... Multivariate statistics (PCA) of NMR spectrum-derived variables enabled authors to clearly distinguish the three fractions and the whole-grain flour samples. The NMR profiling approach has been largely used to study the same food aspects described for the untargeted NMR analysis: pedoclimatic factors (olive oil [99,100]), geographical origin (wines [101,102], olive oils [103][104][105], cocoa beans [106], coffee [41], saffron [107], asparagus [108], walnuts [109], hazelnut [110], honey [111]), botanical origin (honey [112]), ripening (tomatoes (64), passion fruit (69)), post-harvesting (peaches, tomatoes, and plums [113]), and the manufacturer (beer [114], coffee [44]). Food authenticity (seeds [115], olive oil [116], beer [117], honey [118], avocado oil [119]) has been also studied with the described untargeted approach. ...
In this review, the three different NMR-based approaches usually used to study foodstuffs are described, reporting specific examples. The first approach starts with the food of interest that can be investigated using different complementary NMR methodologies to obtain a comprehensive picture of food composition and structure; another approach starts with the specific problem related to a given food (frauds, safety, traceability, geographical and botanical origin, farming methods, food processing, maturation and ageing, etc.) that can be addressed by choosing the most suitable NMR methodology; finally, it is possible to start from a single NMR methodology, developing a broad range of applications to tackle common food-related challenges and different aspects related to foods.
... As an untargeted method, recently Girelli et al. (2020) proposed 1 H NMR and chemometric analysis of the entire spectra to classify over 200 samples of commercial 100% Italian blends of olive oil by comparison to a database of 126 monocultivar oils from specific geographical origins, making this a useful tool for the fight against adulterated blends. Another untargeted study (Girelli et al., 2017) determined the origin of Italian/Tunisian blends in the range 10%-90% w/w by building an ad hoc NMR database and multivariate statistical analysis. ...
Extra virgin olive oil (EVOO) is a high‐quality product that has become one of the stars in the food fraud context in recent years. EVOO can encounter different types of fraud, from adulteration with cheaper oils to mislabeling, and for this reason, the assessment of its authenticity and traceability can be challenging. There are several officially recognized analytical methods for its authentication, but they are not able to unambiguously trace the geographical and botanical origin of EVOOs. The application of nuclear magnetic resonance (NMR) spectroscopy to EVOO is reviewed here as a reliable and rapid tool to verify different aspects of its adulteration, such as undeclared blends with cheaper oils and cultivar and geographical origin mislabeling. This technique makes it possible to use both targeted and untargeted approaches and to determine the olive oil metabolomic profile and the quantification of its constituents.
... Over the last decade, NMR has merged as a very attractive technique to record information about the origin and authenticity of food products [131,132], particularly olive oil traceability [133][134][135], showing high resolution and fidelity. However, it requires the use of isotopes such as 13 C [136,137], 31 P [138] and 1 H [132,139,140], and is rather dedicated to the organic matrix of the non-volatile components of olive oil [133]. Moreover, NMR often needs to be coupled with other technique [140] and combined with chemometric methods and strong statistical analyses [141], which make it more a complementary approach than a real alternative for olive oil traceability and authentication [134]. ...
Several socio-economic problems have been hidden by the COVID-19 pandemic crisis. Particularly, the agricultural and food industrial sectors have been harshly affected by this devastating disease. Moreover, with the worldwide population increase and the agricultural production technologies being inefficient or obsolete, there is a great need to find new and successful ways to fulfill the increasing food demand. A new era of agriculture and food industry is forthcoming, with revolutionary concepts, processes and technologies, referred to as Agri-food 4.0, which enables the next level of agri-food production and trade. In addition, consumers are becoming more and more aware about the origin, traceability, healthy and high-quality of agri-food products. The integration of new process of production and data management is a mandatory step to meet consumer and market requirements. DNA traceability may provide strong approach to certify and authenticate healthy food products, particularly for olive oil. With this approach, the origin and authenticity of products are confirmed by the means of unique nucleic acid sequences. Selected tools, methods and technologies involved in and contributing to the advance of the agri-food sector are presented and discussed in this paper. Moreover, the application of DNA traceability as an innovative approach to authenticate olive products is reported in this paper as an application and promising case of smart agriculture.
... The input variables used as descriptors for each sample in chemometric analyses are the buckets. The description of statistical analyses refers to Pareto-scaled data obtained by dividing the mean-centered bucket values by the square root of the standard deviation [37,38]. The two bucket tables (BUCKET-1 and BUCKET-2), obtained by alignment (using TMS for calibration at δ 0.00 ppm) and successive bucket row reduction in the spectra, were separately submitted to MVDA. ...
... MVDA was performed by using Simca-14 software (Sartorius Stedim Biotech, Umeå, Sweden). In particular, PCA (Principal Component Analysis) and OPLS-DA (Orthogonal Partial Least Squares Discriminant Analyses, respectively) analyses were applied to the data [37,38]. PCA is at the basis of the multivariate analysis [37,39] and usually performed to extract and display the systematic variation in a data matrix X formed by rows (the considered observations) and columns (the variables) of the buckets from each NMR spectrum. ...
... The further improvements made by the OPLS-DA in MVDA resides in the ability to separate the portion of the variance useful for predictive purposes from the not predictive variance (which is made orthogonal) [37]. Statistical models were validated using the internal cross-validation default method (seven-fold) and further evaluated with a permutation test, all available in the SIMCA-14 software [37,38]. The quality of the models was described by R 2 and Q 2 parameters [37]. ...
The agricultural sector is facing a decrease in water supply and water quality at a global level and this is a problem that strictly affects all the Mediterranean olive growing areas. The aim of this work was to evaluate, for the first time, by NMR Spectroscopy and multivariate data analysis the metabolic profiling of the oils produced under different irrigation schemes. Arbosana olive oils were obtained from the use of saline reclaimed water (RW) and treated municipal wastewater (DW), combined with: full irrigation (FI) and regulated deficit irrigation (RDI). The results show a higher relative content of saturated fatty acids in EVOOs obtained from RDI strategy, regardless of the water source. Moreover, an increase in unsaturated fatty acids, a ω6/ω3 ratio content was observed in EVOOs obtained from RW when compared with DW water. Furthermore, the RW–RDI showed an increase in secoiridoid derivatives and hydroperoxides with respect to DW–RDI. A sustainable irrigation management, by combining a deficit irrigation strategy and saline reclaimed water source, could be crucial in order to overcome the problem of water scarcity and to guarantee the olive oil nutraceutical properties. The 1H NMR-based metabolomic approach proved a powerful and versatile tool for this specific investigation.
