Optical method and apparatus for determining status of agricultural products

• US 20040130714A1
• Filed: 02/05/2004
• Published: 07/08/2004
• Est. Priority Date: 03/22/2001
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Gellerman, Werner, McClane, Robert, Bernstein, Paul S.
• Granted Patent: US 7,215,420 B2
• Time in Patent Office: Days
• US Class Current: 356/300
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 2021/1797 in landscape, e.g. crops
• CPC Class Codes: G01N 2030/027 Liquid chromatography
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 33/025 Fruits or vegetables

Abstract

A spectroscopic method, preferably Raman scattering, is used to rapidly determine the general health or stress status of living plants and plant products, including agricultural crops, forests, and harvested fruits and vegetables. In the preferred embodiments, carotenoid levels are used to provide an indication of oxidative deterioration. Based upon the results of the analysis, further action may or may not be taken, for example, in terms of choosing, picking, harvesting or sorting the agricultural product in accordance with the carotenoid level. Concentration levels of an analyte substance can be determined relative to an external standard, to each other, or relative to another substance in the item being analyzed. Carotenoids such as lycopene, beta-carotene, lutein, violaxanthin, neoxanthin, antheraxanthin, and zeaxanthin are determined according to the invention, through other plant components may be analyzed such as other terpenes, polyenes, chlorophyll, proteins, starches, sugars, overall nitrogen levels, flavonoids, and vitamins. The hardware associated with the invention may be field portable or mounted on a piece of equipment such as a harvester or sorter.

Claims

1. A method of evaluating an agricultural product as a prerequisite to further action, comprising the steps of:

exposing the agricultural product to a laser beam having a nominal wavelength;

collecting light scattered by the product;

analyzing the light scattered by the product to identify a wavelength shift characteristic of a carotenoid; and

determining the concentration level of the carotenoid within the agricultural product.

2. The method of claim 1, further including the step of choosing, picking, harvesting or sorting the agricultural product in accordance with the carotenoid level.

3. The method of claim 1, wherein the wavelength shift is representative of Raman scattering.

4. The method of claim 1, wherein the agricultural product is an item of produce.

5. The method of claim 1, wherein the item of produce is a post-harvest fruit or vegetable.

6. The method of claim 1, wherein the agricultural product is a processed food product made from post-harvest fruits or vegetables.

7. The method of claim 1, wherein the agricultural product is being processed into a food product made from post-harvest fruits or vegetables.

8. The method of claim 1, wherein the agricultural product is a packaged food product.

9. The method of claim 1, wherein the agricultural product is within a crop or forest.

10. The method of claim 1, wherein the level of the carotenoid is used to determine plant heath or stress.

11. The method of claim 1, wherein the carotenoid is beta-carotene, lutein, violaxanthin, neoxanthin, antheraxanthin or zeaxanthin.

12. The method of claim 1, further including the step of analyzing the light scattered by the product to identify a wavelength shift characteristic of terpenes, polyenes, chlorophyll, proteins, starches, sugars, overall nitrogen levels, flavonoids, or vitamins.

13. The method of claim 1, wherein the concentration level of the carotenoid is determined through comparison with an external standard.

14. The method of claim 1, wherein the concentration level of the carotenoid is determined through comparison with another substance present in the agricultural product.

15. The method of claim 1, wherein the concentration level of one carotenoid is determined through comparison with another cartenoid.

16. The method of claim 1, wherein:

the agricultural product is a leafy plant, and the method includes the steps of;

determining a level of chlorophyll; and

determining the stress of the plant from a leaf carotenoid to chlorophyll ratio.

17. The method of claim 1, further including the steps of:

determining a level of the cartenoid violaxanthin;

determining a level of the cartenoid antheraxanthin or zeaxanthin; and

assessing one or more environmental effects by comparing the level of violaxanthin to the level of antheraxanthin or zeaxanthin.

18. The method of claim 1, including the step of:

exposing the agricultural product to multiple laser beams; and

wherein some or all of the nominal wavelengths are different.

19. The method of claim 1, wherein the step of exposing the agricultural product to a laser beam having a nominal wavelength includes the step of modulating or pulsing the beam.

20. The method of claim 1, further including the step of performing a time-dependent analysis on the detected scattered light.

21. The method of claim 1, further including the step of providing portable apparatus operative to generate the laser beam and collect the light scattered by the agricultural product.

22. The method of claim 1, further including the step of taking remedial action in conjunction with the determined concentration level of the carotenoid.

23. The method of claim 22, wherein the remedial action includes watering, fertilizing or the application of a herbicide or insectide.

24. The method of claim 1, further including the step of using the level of the carotenoid as part of a plant breeding or genetic engineering program.

25. The method of claim 1, further including the step of determining the geographic position of the agricultural product.

26. The method of claim 1, further including the step of determining the distance to the agricultural product.

27. The method of claim 1, wherein the step of analyzing the light scattered by the product is analyzed in conjunction with another remote sensing technique.

28. The method of claim 27, wherein the multiple remote sensing technique includes one or more of the following:

Raman spectroscopy, fluorescence, ultraviolet spectra, infrared spectra or emission, ultrasound, visual appearance, or smell.

29. The method of claim 1, wherein the step of analyzing the light scattered by the product is analyzed in conjunction with an invasive analysis technique.

30. The method of claim 29, wherein the invasive analysis technique includes one or more of the following:

touch, HPLC or other chromatography, or consumption by a human, animal or bacteria.

31. The method of claim 1, further including the steps of:

removing a portion of an outer covering of the agricultural product; and

exposing the removed portion or the vacancy left by the removed portion of the agricultural product to the laser beam.

32. The method of claim 31, wherein the removed portion is a rind, bark or skin.

33. The method of claim 1, wherein the step of determining the concentration level of the carotenoid forms part of a freshness evaluation method associated with a produce display.

34. The method of claim 1, further including the step of characterizing one or more neutraceuticals within the product.

35. The method of claim 1, wherein the product is a processed or functional food.

36. The method of claim 35, wherein the processed or functional food is a jam, preserve, pet food, baby food, vitamin product, tomato product or dietary supplements.