Method for Characterising an Agri-Food Product and Device for Implementing Such a Method

• US 20130112895A1
• Filed: 06/15/2011
• Published: 05/09/2013
• Est. Priority Date: 06/16/2010
• Status: Abandoned Application

• Current Assignee: Spectralys Innovation, Co.
• Original Assignee: Spectralys Innovation, Co.
• Inventors: Birlouez-Aragon, Ins, Rizkallah, Jad
• Application Number:
  US13/704,433
• Publication Number:
  US 20130112895A1
• Time in Patent Office: Days
• US Class Current: 250/459.1
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 2021/6417 Spectrofluorimetric devices
• CPC Class Codes: G01N 2021/6419 Excitation at two or more wavelengths
• CPC Class Codes: G01N 2021/6421 Measuring at two or more wavelengths
• CPC Class Codes: G01N 2021/8466 Investigation of vegetal material, e.g. leaves, plants, fruits
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G01N 21/84 Systems specially adapted for particular applications
• CPC Class Codes: G01N 2201/1293 resolving multicomponent spectra
• CPC Class Codes: G01N 33/02 Food

Abstract

The invention relates to a method for characterising one or more samples of an agri-food product, in particular intended for determining the naturality, freshness and authenticity of such a product and/or the conformity of same with a target product. The method of the invention is characterised in that it comprises: acquiring a plurality of natural fluorescence spectra of the sample; applying a multivariate or multi-path analysis method to said spectra, wherein said method provides a limited number F of variables representing said or each sample, in order to enable the representation thereof by a point (PE) in a space having F dimensions; calculating a distance (D) between said point representing said or each sample and a target (C1) representing one or more reference samples; and determining a characteristic of said or each sample according to said distance (D).

Claims

1. A method for characterizing one or more samples of an agri-food product, characterized in that it comprises:

a) illuminating said or each sample to be analyzed with a plurality of excitation light radiations having respective wavelengths;

b) acquiring natural-fluorescence spectra of said or of each sample, each corresponding to a respective excitation light radiation;

c) applying a multi-way analysis method to said spectra, which provides a number F of variables representative of said or of each sample, such that said or each sample can be represented by a point in a space having F dimensions;

d) calculating a distance (D), in said space having F dimensions, between the point representing said or each sample and a target representing one or more reference samples; and

e) determining a characteristic of said or of each sample according to said distance.

2. The method as claimed in claim 1, in which said characteristic is chosen from a naturality indicator, a freshness indicator, an authenticity indicator and a conformity indicator.

3. The method as claimed in claim 1, in which the number F of variables representative of said or of each sample is between 1 and 10.

4. The method as claimed in claim 1, in which said multi-way analysis method is a PARAFAC decomposition.

5. The method as claimed in claim 4, in which said distance is chosen from a Euclidean distance, a Mahalanobis distance and a distance predicted by a regression model.

6. The method as claimed in claim 1, in which said step e) is carried out by application of a statistical test.

7. The method as claimed in claim 1, in which said step b) consists in acquiring front-face fluorescence spectra.

8. The method as claimed in claim 1, also comprising, between said steps b) and c), a step b′

) of preprocessing the acquired fluorescence spectra by subtraction of a contribution due to first-order Rayleigh scatter of the excitation light radiation, said contribution being calculated by means of a generalized linear model.

9. The method as claimed in claim 1, in which the number of excitation light radiations, and of corresponding fluorescence spectra for each sample, is between two and six.

10. The method as claimed in claim 1, in which the average spectral gap between said excitation light radiations is at least 20 nm, over a spectral range of at least 100 nm.

11. A device for spectroscopic analysis of at least one sample, comprising:

a set of light sources for illuminating said or each sample to be analyzed with respective excitation light radiations, having different wavelengths;

means for acquiring the front-face fluorescence spectra emitted by said or each sample when it is illuminated by said excitation light radiations; and

means for processing the acquired fluorescence spectra, suitable for implementing a method as claimed in claim 1.

12. The device for spectroscopic analysis as claimed in claim 11, comprising between two and six, of said light sources, with an average spectral gap of at least 20 nm over a spectral range of at least 100 nm.

13. The device as claimed in claim 12, comprising:

a first light source which emits a radiation having a wavelength between 270 and 300 nm;

a second light source which emits a radiation having a wavelength between 300 and 360 nm; and

a third light source which emits a radiation having a wavelength between 400 and 500 nm.

14. The method as claimed in claim 1, in which the number F of variables representative of said or of each sample is between 1 and 5.

15. The method as claimed in claim 1, in which the number of excitation light radiations, and of corresponding fluorescence spectra for each sample, is between 3 and 5.

16. The method as claimed in claim 1, in which the average spectral gap between said excitation light radiations is at least 50 nm, over a spectral range of at least 100 nm.

17. The device for spectroscopic analysis as claimed in claim 11, comprising between three and five, of said light sources, with an average spectral gap of at least 20 nm over a spectral range of at least 100 nm.