Systems and methods for feedstock quality assessment
Assessing quality of feedstock is provided and may be useful for determining quality of feed (such as corn kernels). The assessment determines endogenous enzyme activity within the feedstock, which correlates with total ethanol yields in raw starch hydrolysis (non-cooked) systems. In some embodiments, a sample containing flour (ground feedstock) is provided. In some cases, flour is diluted in water and buffered with a phosphate buffered solution. The buffered flour solution is contacted with a molecule, or fluorescent dye, such as fluorescein diacetate and/or difluorofluorescein that is altered by enzymatic (esterase) activity in a detectable fashion. Enzyme activity may be facilitated using an incubator. The detectible alteration may be measured using a fluorometer. In some embodiments, two incubations and fluorescence measurements can be performed. By subtracting the difference between the measured fluorescence, a fluorescence index may be found, which correlates with the endogenous enzyme activity in the feedstock sample.
1. A method for assessing quality of feedstock comprising:
providing a sample containing a flour, wherein the flour is ground feedstock;
contacting the sample containing the flour with a molecule that is detectibly altered by enzymatic activity of endogenous enzymes within the flour, wherein the enzymatic activity is esterase activity;
detecting a total amount of enzymatically altered molecule by observing a change in fluorescence of the sample over a plurality of incubations; and
correlating the detected total amount of enzymatically altered molecule to a quality value for the feedstock for ethanol production.
2. The method of claim 1 , wherein the contacting comprises contacting the sample with a molecule that includes at least one of fluorescein diacetate and difluorofluorescein.
3. The method of claim 1 , wherein the detecting the total amount of enzymatically altered molecule is performed using a fluorometer.
4. The method according to claim 1 , wherein a first incubation from the plurality of incubations lasts about one minute and a second incubation from the plurality of incubations lasts about two minutes.
5. A method for assessing quality of feedstock by measuring a change in fluorescence over a plurality of incubations to determine levels of endogenous enzymes in the feedstock, the method comprising:
grinding the feedstock to a flour;
buffering the flour with a buffering solution to generate a buffered flour solution;
combining a test solution to the buffered flour solution to generate a sample solution, wherein the test solution is detectibly altered by esterase activity;
incubating the sample solution for a first time period;
measuring a first fluorescence value of the sample solution;
incubating the sample solution for a second time period;
measuring a second fluorescence value of the sample solution;
detecting a total amount of esterase activity by observing a change in fluorescence of the sample over the first time period and second time period; and
correlating the detected total amount of esterase activity to a quality value for the feedstock for ethanol production.
6. The method of claim 5 , further comprising diluting the flour after grinding.
7. The method of claim 6 , wherein diluting the flour comprises combining about 0.5 grams of flour with about 10 milliliters of water.
8. The method of claim 5 , wherein the grinding comprises grinding feedstock that includes corn kernels.
9. The method of claim 5 , wherein the grinding includes generating flour with greater than 90% fines.
10. The method of claim 5 , wherein the buffering comprises buffering the flour with a phosphate buffered solution.
11. The method of claim 5 , wherein the combining comprises combining to the buffered flour solution the test solution that includes fluorescein diacetate.
12. The method of claim 11 , wherein the test solution includes fluorescein diacetate in acetone in a concentration of about 30 milligrams of fluorescein diacetate in 10 milliliters of acetone.
13. The method of claim 5 , wherein the incubating includes incubating at approximately 30 degrees Celsius.
14. The method of claim 5 , wherein first time period is for about one minute.
15. The method of claim 5 , further comprising assigning a quality designation to the feedstock based upon a fluorescence index.
16. The method of claim 5 , further comprising:
generating a fluorescence index by taking a difference between the second fluorescence value and the first fluorescence value.
17. The method of claim 16 , wherein the second time period for about two minutes.
18. The method of claim 16 , wherein measuring the first fluorescence value and the second fluorescence value includes using a fluorometer for emitting an excitation wavelength of about 494 nm and detecting an emission wavelength of about 521 nm.