Proximates are the major components of the grain. For wheat, the NIR Proximate Analysis included Protein Content and Moisture Content. The test does not include ash content. This procedure is nondestructive to the wheat. Proximate Analysis is also available using wet chemistry methods for protein content and moisture content but the sample must be ground.
     Various end users have different demands for wheat composition; these will vary with the class of wheat as well. Hard wheat varieties are typically higher in protein (12-15%) than soft wheat (5-10%) and are usually used for breads, bagels, and other yeast-leavened products. The protein (gluten) develops a "stretchiness" during kneading that traps the gases produced by the yeast. Without this resilience, the bread would not rise and would not have the sponge-like texture. Very low protein contents (5-8%) are desired for cake flour. Flour for cookies, crackers and pastries is usually around 8-11% protein.
     Results (other than Moisture Content) are reported on a dry basis percentage (percent of non-water material). Moisture Content is reported "as is" (percent of total sample weight).

     Vomitoxin is a grain mycotoxin (fungal toxin) produced by the fungus Fusarium graminearium. Vomitoxin appears to affect swine to a larger degree than other animals. The most common effect of feeding wheat containing DON to swine is weight loss or reduced weight gain due to refusal of feed, reduced feed intake, or vomiting after eating. This has been observed at levels as low as 5 parts per million.
     For this test, a GIPSA-approved Enzyme-Liked Immunosorbent Assay (ELISA) is utilized to quantify the vomitoxin level of a sample. The U.S. Food and Drug Administration set maximum levels for vomitoxin contamination according to these guidelines: 1 part per million for wheat products for human consumption, 10 PPM for ruminating beef and feedlot cattle (not to exceed 50% of the diet), and 5 PPM in grain and grain products destined for swine and all other animals (not to exceed 20% of the diet).

Possible Values 0-20+ PPM; Typical Results 0-2 PPM

     The falling number test is a measure of wheat quality with respect to undesirable enzyme activity or sprout damage. Certain conditions, particularly large amounts of rainfall just prior to harvest, will prompt the mature wheat kernels to try to germinate. As part of the germination process, there is a spike in the activity of alpha-amylase enzyme. Alpha-amylase breaks down the starch in the kernel to create usable sugars, the nutrition source for the seedling until it begins photosynthesis.
     Sprout damage is detrimental to the quality of the wheat kernel for use as seed and for milling purposes. As the degree of sprout damage increases, the germination rate decreases. Severely sprout-damaged kernels may not grow if planted. The enzyme also affects the quality of flour (or more precisely batters and dough prepared from the flour) produced from the sprout-damaged wheat.
     The test is performed by making a paste from a ground wheat sample and water, heated, and mixed to "gelatinize" the starch. During gelatinization the starch granules swell and start to become solubilized. Samples with higher alpha-amylase activity will form a paste with a less viscous consistency as compared to undamaged samples.
     This phenomenon is measured using the Falling Number instrument. This device has a plunger which is allowed to fall through the heated paste. The time (in seconds) required for the plunger to travel a specific distance is measured. Undamaged wheat will typically have a Falling Number higher than 325 seconds. A Falling Number greater than 300 is desired in most applications.

Possible Values 150-500 seconds; Typical Results 250-350 seconds

     The Stenvert Hardness Test provides a measure of the hardness of the wheat grain.
     The Stenvert Hardness Test measures the time-to-grind a wheat sample to produce 17 ml of ground material using the Stenvert mirco-hammer cutter mill fitted with a 2 mm screen. Harder wheat will take longer to grind. The time required to grind the sample is reported.

Possible Values 4-25 seconds; Typical Results 5-15 seconds

     Moisture content is a critical factor for the long term storability of wheat. Wheat should be dried in the field or artificially to 14% moisture for storage up to 6 months and 13% for storage from six months to one year, and 12-13% for longer term storage. Over-drying of wheat wastes energy, money, and time. Overydrying grains will also lead to an increased risk of dust explosions.
   A reading is obtained from the meter which correlates to a specific moisture content at the testing temperature. The moisture content is reported as an "as is," or "wet basis," percentage.
     The ideal Moisture Content for further wheat testing is between 10 and 14%.

Possible vales 0-25%; Typical Results 8-15%

     The Combustion (Dumas) Method can be used to measure the protein or nitrogen content in a wide range of substances. It has replaced the slow, dangerous, and environmentally unfriendly Kjeldahl procedure for most applications. The combustion method is an approved method and has become the most common reference ("wet chemistry") method for NIR calibrations for protein content. The combustion method is typically employed for samples for which no NIR calibration exists. The IPG lab does offer protein content using NIR. There are situations in which the combustion method may not be suitable.
     In this test, a 50-300 mg representative sample (liquid or ground solid) is burned at high temperature in a sealed system. The nitrogen in the sample is aonverted to nitrogen gas, separated from the other chemical components, and measured by thermal conductivity. The nitrogen content can be converted to protein content by using a conversion factor (typically 6.25 x nitrogen) to obtain "as is" protein percentage. This test is performed in duplicate, and the moisture content in the original sample is determined by the air oven method to convert the protein content to dry basis.

Protein contents measured by the combustion method can range from very low (0.1%) to 90+%.

    Ether extraction can be used to quantify the amount of fat or oil in a sample. The ether extraction method is an approved method and is a common reference ("wet chemistry") method for NIR calibration for oil content. The IPG lab does offer oil content using NIR for some crops. There are situations in which ether extraction may not be a suitable method for oil measurement.
    In this test, a representative sample is ground and extracted in refluxing petroleum ether. Extracted oil is captured in the boiling flask. The oil is sperated from the ether and weighed to determind the percentage of the original sample weight collected as oil to obtain the "as is" oil percentage. This test is performed in duplicate, and the moisture content in the original sample is determined by the air oven method to convert the protein content to dry basis.

    Oil contents measured by the ether extraction method can range from very low (0.2%) to 50+%.

     The Air Oven method can be used to quantify the amount of water in a sample. The air oven method is an approved method and is a common reference ("wet chemistry") method for NIR calibrations for moisture content. The air oven method is typically employed for samples for which no NIR calibration or other reliable rapid method (NIR or Moisture Meter) exists. There are situations in which the air oven method may not be a suitable method for moisture measurement.
     In this test, a representative sample (liquid or ground solid) is weighed into a tared cup and placed in an oven. Oven temperatures and residence times vary by substance. The dried sample is cooled in a dessicator and the weight of the remaining material is recorded. The weights may be used to determine the amount of water removed in the oven. Moisture content is reported as the amount of water removed from the original sample. Solids content is the weight of material remaining after drying divided by the original sample weight. Moisture content and solids content are reported as an "as is" or wet basis percentage. They are related by the equation:

Moisture Content ("as is") + Solids Content ("as is") = 100%

     The High Performance Liquid Chromatography (HPLC) method can be used to quantify the amount of various amino acids in a sample. The HPLC method is an approved method and is a common reference ("wet chemistry") method of NIR calibrations for amino acid contents. The HPLC method is typically employed for samples for which no NIR calibration exists. The IPG lab does offer amino acid profile for corn and soybeans using NIR.
     Various procedures must be employed depending on the amino acids of interest. The moisture content in the original sample is determined by the air oven method to convert the amino acid contents to dry basis. 

     The Gas Chromatography (GC) method can be used to quantify the amount of various fatty acids in a sample. The GC method is an approved method and is a common reference ("wet chemistry") method for samples for which no NIR calibration exists. The IPG lab does offer fatty acid profile for corn and soybeans using NIR.
     Various procedures may be employed depending on the fatty acids of interest. The moisture content in the original sample is determined by the air oven method to convert the fatty acid contents to dry basis.