Method for the classification of maple syrup

1. A method for the detection of an off-flavor buddy maple sap or an off-flavor maple syrup made from buddy maple sap comprising contacting a sample of maple syrup or maple sap with a nanoparticle reactive with a buddy sample of maple syrup or maple sap having a size of from about 1 nm to about 250 nm, and measuring a spectrophotometric property of the nanoparticle in contact with the sample of maple syrup or maple sap,

wherein

a change in said spectrophotometric property relative to a same type of spectrophotometric property measurement made on a good flavor maple syrup or maple sap sample, is associated with an off-flavor maple syrup or sap sample, and

no change in said spectrophotometric property relative to a same type of spectrophotometric property measurement made on a good flavor maple syrup or maple sap sample, is associated with a good flavor maple syrup or maple sap sample.

2. The method of claim 1 , wherein said nanoparticle reactive with a buddy sample of maple syrup or maple sap is selected from the group consisting of a metallic nanoparticle, a metallic coated nanoparticle, a semi-conducting nanoparticle, or combinations thereof.

3. The method of claim 2 , wherein a metal of said metallic nanoparticle or said metallic coated nanoparticle is selected from the group consisting of gold, copper, iridium, platinum, rhodium, or an alloy thereof, and combinations thereof, or wherein said semi-conducting nanoparticle is selected from the group consisting of a quantum dot, a carbon dot, and combinations thereof.

4. The method of claim 2 , wherein said metallic nanoparticle is in the shape of a sphere, a rod, a rice-grain, a cube, a pyramid, a cage, a disk, or combinations thereof.

5. The method of claim 1 , wherein said nanoparticle reactive with a buddy sample of maple syrup or maple sap has a size of about 15 nm.

6. The method of claim 1 , wherein said nanoparticle reactive with a buddy sample of maple syrup or maple sap further comprises a coating.

7. The method of claim 6 , wherein said coating is an acidic compound.

8. The method of claim 7 , wherein said acidic compound is a citrate.

9. The method of claim 1 , wherein said sample of maple syrup or maple sap is contacted with a reducing agent prior to or during contact with said nanoparticle.

10. The method of claim 9 , wherein said reducing agent is selected from the group consisting of dithiobutylamine, 2-mercaptoetahnol, 2-mercaptoethylamine, cysteine, dithiothreitol (DTT), tris (2-carboxyethyl) phosphine (TCEP), or combinations thereof.

11. The method of claim 1 , wherein said change in said spectrophotometric property is a change of color, a change in absorbance, transmittance, diffusion, refractive index or a combination of these measurements.

12. The method of claim 11 , wherein said change of color is a change from red to blue.

13. The method of claim 11 , wherein said change in absorbance is any one of:

1. an increase in absorbance at a wavelength of about 400 nm to about 1000 nm, relative to an absorbance measurement made on a good flavor maple syrup or maple sap sample;

2. a differential absorbance from the absorbance at any wavelength superior to a maximum wavelength of absorption of said nanoparticle in a good flavor maple syrup or maple sap sample and the absorbance at said maximum wavelength of absorption of said nanoparticle in said maple syrup or maple sap sample;

3. a differential absorbance from a wavelength where absorbance remains stable in any said off-flavor or said good flavor maple syrup or maple sap sample and a wavelength where absorbance changes in said off-flavor maple syrup or maple sap sample;

4. a differential absorbance between any one wavelength ≥561 nm to 1000 nm and any one wavelength between about 5560 nm wavelength and below;

5. a differential absorbance between any one wavelength between ≥560 nm to about 1000 nm and absorbance at any one wavelength between about 490 nm to about 560 nm;

6. a differential absorbance between absorbance at 610 nm and absorbance at any one wavelength between about 490 nm to about 560 nm, and/or between absorbance at 630 nm and absorbance at any one wavelength between about 490 nm to about 560 nm, and/or between absorbance at 640 nm and absorbance at any one wavelength between about 490 nm to about 560 nm; and

7. a change of a wavelength of maximum absorption to a higher wavelength in the off-flavor maple syrup or maple sap sample, compared to a good tasting maple syrup or maple sap sample.

14. The method of claim 13 , wherein a positive differential absorbance is associated to an off-flavor maple syrup or maple sap sample.

15. The method of claim 13 , wherein a negative differential absorbance is associated to a good flavor maple syrup or maple sap sample.

16. The method of claim 1 , wherein said off-flavor buddy maple sap is a maple sap contaminated with buddy maple sap, buddy maple syrup or combinations thereof.

17. The method of claim 1 , wherein said sample of maple syrup or maple sap is a diluted maple syrup sample, a pure maple syrup sample, a diluted maple sap sample, a pure maple sap sample, a diluted maple sap concentrate sample, or a pure maple sap concentrate sample.

18. The method of claim 17 , wherein said diluted maple syrup sample, said diluted maple sap sample or said diluted maple sap concentrate sample is diluted from about 1:1 to 1:1000 in a solvent.

19. The method of claim 18 , wherein said solvent is water or an organic solvent, or combinations thereof.

20. The method of claim 1 , wherein concentration of said nanoparticle is from about 0.1 nM to about 100 nM.

21. The method of claim 1 , wherein contacting said sample of maple syrup or maple sap from about 1 second to about 30 minutes.