Comparison of different sample preparation techniques for NIR screening and their influence on the geographical origin determination of almonds (Prunus dulcis MILL.)

Arndt, Maike; Rurik, Marc; Drees, Alissa; Bigdowski, Katharina; Kohlbacher, Oliver; Fischer, Markus

doi:10.1016/j.foodcont.2020.107302

Cited by 36 publications

(30 citation statements)

References 24 publications

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“…The truffles were freeze-dried because of two reasons, which are more discussed in Section 3.1: (i) FT-NIR spectra of fresh truffles showed unspecific spectra with large water bands. (ii) It was known from the literature that such a freeze-drying step can enhance the accuracy of the classification models [35]. Freeze-dried material was crushed using a mortar and a pestle to obtain a fine homogeneous powder.…”

Section: Sample Preparationmentioning

confidence: 99%

“…The analysis of fresh truffle samples has shown that a drying step is necessary, as otherwise large water bands and unspecific spectra are obtained which superimpose the information beneath. Thus, the truffle samples were freeze-dried because such a sample preparation can enhance the accuracy of the classification models [35]. Due to the freeze-drying step, the water content in the samples can be seen as negligibly small and in the same range, so it should have no impact on the differentiation with chemometric models in the following steps.…”

Section: Spectra Investigationmentioning

confidence: 99%

“…Regarding the determination of the geographical origin, however, DNA analysis cannot provide reasonable answers since the origin rather affects the phenotype. Here, FT-NIR analysis can be a tool for differentiating the origin [35] and the possibilities for the truffle differentiation by origin are examined in the following chapter.…”

Section: Evaluation Of Pre-processing and The Suitability For The Spementioning

confidence: 99%

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Food Authentication: Truffle (Tuber spp.) Species Differentiation by FT-NIR and Chemometrics

Segelke

Schelm

Ahlers

et al. 2020

Foods

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Truffles are certainly the most expensive mushrooms; the price depends primarily on the species and secondly on the origin. Because of the price differences for the truffle species, food fraud is likely to occur, and the visual differentiation is difficult within the group of white and within the group of black truffles. Thus, the aim of this study was to develop a reliable method for the authentication of five commercially relevant truffle species via Fourier transform near-infrared (FT-NIR) spectroscopy as an easy to handle approach combined with chemometrics. NIR-data from 75 freeze-dried fruiting bodies were recorded. Various spectra pre-processing techniques and classification methods were compared and validated using nested cross-validation. For the white truffle species, the most expensive Tuber magnatum could be differentiated with an accuracy of 100% from Tuber borchii. Regarding the black truffle species, the relatively expensive Tuber melanosporum could be distinguished from Tuber aestivum and the Chinese truffles with an accuracy of 99%. Since the most expensive Italian Tuber magnatum is highly prone to fraud, the origin was investigated and Italian T. magnatum truffles could be differentiated from non-Italian T. magnatum truffles by 83%. Our results demonstrate the potential of FT-NIR spectroscopy for the authentication of truffle species.

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Section: Sample Preparationmentioning

confidence: 99%

Section: Spectra Investigationmentioning

confidence: 99%

Section: Evaluation Of Pre-processing and The Suitability For The Spementioning

confidence: 99%

See 1 more Smart Citation

Food Authentication: Truffle (Tuber spp.) Species Differentiation by FT-NIR and Chemometrics

Segelke

Schelm

Ahlers

et al. 2020

Foods

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“…In a previous comparison of different sample preparation techniques, which were applied to almonds prior to NIR measurement, grounding combined with freeze-drying achieved the highest classification accuracies [ 27 ]. Due to the similarity of the matrices, the analyzed walnuts were ground and lyophilized for further analysis.…”

Section: Methodsmentioning

confidence: 99%

Determination of the Geographical Origin of Walnuts (Juglans regia L.) Using Near-Infrared Spectroscopy and Chemometrics

Arndt

Drees

Ahlers

et al. 2020

Foods

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The prices of walnuts vary according to their geographical origin and, therefore, offer a financial incentive for adulteration. A reliable analysis method is required to quickly detect possible misdeclarations and thus prevent food fraud. In this study, a method to distinguish between seven geographical origins of walnuts using Fourier transform near-infrared (FT-NIR) spectroscopy combined with chemometrics as a fast, versatile, and easy to handle analytical tool was developed. NIR spectra of 212 ground and afterwards freeze-dried walnut samples, harvested in three consecutive years (2017–2019), were collected. We optimized the data pre-processing by applying and evaluating 50,545 different pre-processing combinations, followed by linear discriminant analysis (LDA) which was confirmed by nested cross-validation. The results show that in the scope of our research minimal pre-processing led to the best results: By applying just multiplicative scatter correction (MSC) and median centering, a classification accuracy of 77.00% ± 1.60% was achieved. Consequently, this complex model can be used to answer economically relevant questions e.g., to distinguish between European and Chinese walnuts. Furthermore, the great influence of the applied pre-processing methods, e.g., the selected wavenumber range, on the achieved classification accuracy is shown which underlines the importance of optimization of the pre-processing strategy.

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“…In this study we will focus on the evaluation of MS data, even if some of the procedures are also suitable for NMR or alternative spectroscopic analyses [ 22 , 23 , 24 , 25 , 26 ]. The common feature of all these procedures is the fact that very complex extracts are measured in metabolome analysis.…”

Section: Introductionmentioning

confidence: 99%

Food Phenotyping: Recording and Processing of Non-Targeted Liquid Chromatography Mass Spectrometry Data for Verifying Food Authenticity

Creydt

Fischer

2020

Molecules

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Experiments based on metabolomics represent powerful approaches to the experimental verification of the integrity of food. In particular, high-resolution non-targeted analyses, which are carried out by means of liquid chromatography-mass spectrometry systems (LC-MS), offer a variety of options. However, an enormous amount of data is recorded, which must be processed in a correspondingly complex manner. The evaluation of LC-MS based non-targeted data is not entirely trivial and a wide variety of strategies have been developed that can be used in this regard. In this paper, an overview of the mandatory steps regarding data acquisition is given first, followed by a presentation of the required preprocessing steps for data evaluation. Then some multivariate analysis methods are discussed, which have proven to be particularly suitable in this context in recent years. The publication closes with information on the identification of marker compounds.

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Comparison of different sample preparation techniques for NIR screening and their influence on the geographical origin determination of almonds (Prunus dulcis MILL.)

Cited by 36 publications

References 24 publications

Food Authentication: Truffle (Tuber spp.) Species Differentiation by FT-NIR and Chemometrics

Food Authentication: Truffle (Tuber spp.) Species Differentiation by FT-NIR and Chemometrics

Determination of the Geographical Origin of Walnuts (Juglans regia L.) Using Near-Infrared Spectroscopy and Chemometrics

Food Phenotyping: Recording and Processing of Non-Targeted Liquid Chromatography Mass Spectrometry Data for Verifying Food Authenticity

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