Oil Seed Processing
Near Infrared Spectroscopy (NIR) is a widely accepted tool for quality control in the soy processing industry. Routine NIR analyses are conducted on soybean meal, soybean hulls, and soybean “white flakes” to monitor milling and oil extraction processes. Another product of interest to the soybean processors is soy protein concentrate (SPC). Soy protein concentrate is produced by immobilizing the soy proteins in the defatted flakes while extracting the soluble carbohydrates during this process. The resulting product is approximately 70% protein. Other methods that can be used are wet chemistry and image analysis but may not be as affective.
Soy protein concentrate is used as an ingredient in baked foods, breakfast cereals, and some meat products. The function of SPC in meat and poultry is to increase water and fat retention as well as improving the nutrition values by adding more protein. SPC is very digestible and is well suited for children, pregnant women, and the elderly. It is also used in pet foods and as a milk substitute for calves and pigs.
Protein and moisture in SPC are monitored by the soybean processors to assess the carbohydrate extraction and protein concentration. SPC should contain a minimum of 65% protein on a dry moisture basis.
The SpectraStar is capable of measuring protein and moisture in SPC. Approved wet chemistry methods are labor intensive and can take up to several hours. Soybean processors rely on the speed of NIR technology to monitor their process at increased time intervals.
Approximately 600 samples currently reside in the SpectraStar 2400 SPC database for protein. The samples were collected over five months and incorporate harvest and production variation. The protocol at the data collection site required SPC to be “reground” on a hammer mill with a 1 mm screen. However, a preliminary experiment shows this additional grinding step may not be necessary. The powder cup was used to analyze all the samples on the SpectraStar 2400. The resulting calibrations have proved to be accurate and reliable since inception.
SpectraStar 2400 SPC Statistics
Parameter |
Range % |
R2 |
SECV |
Protein |
63.7-70.1 |
0.81 |
0.69 |
Moisture |
4.7-8.3 |
0.94 |
0.23 |