K-STATE GRAIN QUALITY RESEARCH PROGRAM STANDARD OPERATING PROCEDURES

Transcription

1 K-STATE GRAIN QUALITY RESEARCH PROGRAM STANDARD OPERATING PROCEDURES Date: March 3, 2005 Principal Investigator: Jane Lingenfelser Building and Rooms: Waters Rm. 001, Shellenberger Rm 316 Evaluation 1: Test Weight 1. Grain is poured to fill a Winchester bushel cup to overflow and leveled with three slanting strokes. 2. The measurement in bushels in determined from the hanging weight of the cup and grain from a calibrated scale. 3. Two replications are evaluated. A third evaluation is done if the difference between the first and second replication is greater than 0.5%. 4. The average of two replications is adjusted to 15% moisture and reported as the test weight. Potential Hazards and Protective Equipment: None 1

2 Evaluation 2: Kernel Size Distribution g of a representative sample of corn is placed on a Strand Sizer Shaker equipped with a 17/64 round-hole sieve and agitated for 20 complete shakes. 2. The amount of corn remaining on top of the 17/64 sieve is recorded and expressed as a percentage of kernels out of 250g. Potential Hazards and Protective Equipment: Special attention should be used to ensure that the spring is securely fastened across the sieve and pan; otherwise they can fly off during shaking. 2

3 Evaluation 3: Stenvert Hardness Tests 1. The starting moisture of the corn should be determined by the Grainspec. The target moisture for testing is 12.6% +/- 0.8%. Corn that is above this moisture range is spread out to air-dry. Corn that is below the target moisture is tempered to 12.6 using the dry weight formula: (100-original moisture) -1*weight of corn ( ) Samples that are dried or tempered are placed in air-tight plastic bags and allowed to equilibrate for 24 hours. 2. The Stenvert Hammer Mill (Glen Mills, Inc) should be fitted with a 2-mm aperature screen and a plastic tube calibrated to a volume of 17 ml to the mill exit. 3. Place 20 grams of corn of known moisture content in the hopper, with the slide shut. 4. Turn the speed control to 3600 rpm (tachometer will read 360). Pull out the slide to admit the grain to the milling chamber and simultaneously start a stopwatch. 5. Turn the tube gently as it fills with ground corn and stop the stopwatch when the base or the ground material reaches the calibration mark on the tube. Continue to collect the remainder of the ground material. 6. Stop the mill when the tachometer reads 340 and clean out the milling chamber with a brush and vacuum. Clear the holes in the grid between samples. 7. Measure the total column height of freshly ground grain. The total column height is an index of packing 8. The ratio of coarse to fine particles by volume. Measure the column height of the fine particles and to obtain the coarse subtract the fine particle column height from the total column height. The ratio is expressed in Vol. C/F. 9. The ratio of coarse to fine particles as determined by weight with the coarse particles larger than 700-microns (US 25) and fine particles smaller than 500-microns (US 35). The ratio is expressed in Wt. C/F. Potential Hazards and Protective Equipment: The blades of the hammer mill are designed to stop when the cover is removed, however care should be used to make certain that the blades are completely stopped before cleaning. Hearing protection is recommended for repeated use of the vacuum. 3

4 Evaluation 4: Pycnometer density 1. Turn on the multi-pycnometer (Quantachrome model MVP1) and open the helium tank valve 5 minutes prior to testing. The gas in and gas out valves should be opened and adjusted to a cell value of approximately 1.00 to clean out the system. 2. Weigh 60g of corn that has already been equilibrated at the /- 0.8% moisture range for the Stenvert Hardness Test and place in the cell cup. Place the cup in the pycnometer cylinder and tighten the cap, aligning the white marks to ensure an air-tight seal. 3. Close the gas out valve and slowly toggle the gas in valve to approximately 17 psi. while on the cell setting. Record the pressure reading once it has stabilized. 4. Switch to the reference setting and wait for the reading to stabilize. Record the final value. 5. Slowly toggle the gas out valve until the helium has been removed and the pressure reading is at 0. Switch back to the cell setting and repeat the process. Once the second trial has been completed, slowly release the cap and empty the cell cup for the next sample. 6. Re-calibrate the pycnometer according to the Quantachrome manual every time the helium tank is changed. Record the revised cell and reference values for calculation of density. The formula to calculate density is: weight of sample cell volume-reference volume*(p1/p2)-1 where cell volume and reference volume are established during calibration and P1 is the pressure reading at the cell setting and P2 the reading at the reference setting. 7. High purity (HP) grade helium should only be used. Potential Hazards and Protective Equipment: Long-term exposure to helium in poorly ventilated areas may cause headaches and irritation to the respiratory system. Extreme care should be used when transporting and installing replacement helium tanks. 4

5 Evaluation 5: Tangential Abrasive Dehulling Device (TADD) 1. Weigh out 40g of corn at the target moisture of 12.6+/-0.8% moisture. 2. Place in one of the eight bottomless cells located on top of the rotating disc on the TADD. 3. Place the hose of the Shop-Vac in the exit spout on the side of the TADD. 4. Turn on Shop-Vac, set the timer of the TADD for 10 minutes, and start the instrument. 5. After 10 minutes wait until the disc comes to a complete stop before opening the cover. Attach a tared plastic container to the vacuum aspirating device to collect the corn. Record the weight after abrasion. 6. Run a control sample each day the TADD is used and record in the log to measure the wear of the emery disc. Apply the necessary correction factor to the hardness calculation: Weight 2/Weight1 *100 Potential Hazards and Protective Equipment: Hearing protection should be used when operating the Shop-Vac. 5

6 Evaluation 6: Water Absorption Index 1. A representative sample of corn is ground with a Perten laboratory mill and separated with #60 mesh sieve for 2 minutes g of ground material that passes through the #60 sieve is placed in a weighed, highspeed centrifuge tube 3. Distilled water is added in unmeasured amounts until a paste is formed 4. Tube and paste are placed in a centrifuge for 10 minutes at 4,000rpm 5. After centrifuge the supernatant is poured off and the tube and gel are re-weighed 6. Calculation of WAI: (tube+gel)- tube 2.5g Potential Hazards and Protective Equipment: None 6

7 Evaluation 7: Pericarp Removal 1. Mix solution of May-Gruenwald dye under fume hood wearing protective gloves. Dissolve 1g of eosine Y and 1 g methylene blue in 200 ml of methanol. Refrigerate the dye if it is to be used the following day. 2. Mix 3.33g reactive lime with 1 L distilled water in a beaker and bring to a boil on the hot plate. 3. Place 10-15g of corn in perforated nylon bags and submerge in lime mixture for 20 minutes, stirring every 4-5 minutes. 4. After 20 minutes, place nylon bags in bucket of running tap water to wash away removed pericarp. 5. Place cooked kernels in a wire basket and dip in dye for 15 seconds. Any remaining pericarp should be stained purple. 6. Rinse away the excess dye by dipping the basket into 3 beakers of methanol. 7. Evaluate the amount of pericarp removal with the following visual scale: 1=pericarp completely removed; kernel is yellow (or white) 2= 75% of pericarp removed 3= 50% of pericarp removed 4= 25% removed 5=all the pericarp remains on the kernel 8. Do three evaluations of the same hybrid on different kernels. Potential Hazards and Protective Equipment: Protective latex gloves and the fume hood MUST be used during the pericarp removal test. Used methanol should be discarded in the Hazardous Waste container. 7

8 Evaluation 8: Experimental Dry Milling 1. Determine the moisture of a 1000g sample of corn with the Grainspec. 2. Calculate the amount of water needed to temper the sample to 16% moisture. 100-original moisture -1* Place corn in a plastic bag, add water to temper, shake vigorously; set aside for 30 minutes. 4. Again determine the moisture of the corn, calculate the amount of water needed to raise the sample to 18% moisture, shake vigorously; set aside for 15 minutes. 5. Verify that the moisture is 18+/-0.5% after 15 minutes. 6. Set gaps and differential of according to the specified mill flow. Use Lifeline flow for AgraMarke samples and Long Flow #1 for all other samples. 7. Record product weights after each sifting step. 8. Record final product weights for calculation of yield percentages. Potential Hazards and Protective Equipment: Extreme care should be exercised when operating the roll stands. Never put hands or feeler gauge in the rolls when the machine is running. When adjusting the differentials be aware of the moving belts nearby. 8

9 Evaluation 9: 100 kernel weight 1. Moisture of the grain is recorded with a Grainspec Whole Grain Analyzer 2. A 200g representative corn sample is placed in a vibratory kernel counter. 3. The counter is stopped after 100 kernels. 4. The weight of the 100 kernels is adjusted to 15% moisture/ 9