How is the whiteness of edible corn starch measured? What are the whiteness standards for premium, first-grade, and second-grade products?
How to judge the whiteness of edible corn starch? By sight, some are whiter and some are yellower, making it impossible to distinguish the grade. Traditional visual comparison has large errors and does not meet the standards. During random inspections, we often encounter problems, which not only loses costs but also delays the construction period.
Today, this article, based on the national standard GB/T 8885-2017, thoroughly explains the whiteness grading standards, measurement methods, and TS8520 testing tutorial for edible corn starch , making it easy for beginners to get started quickly!
Grading standards for the whiteness of edible corn starch
According to China's current national standard GB/T 8885-2017, the whiteness of edible corn starch specifically refers to the reflectivity of the starch powder surface to blue light at a wavelength of 457nm. A higher value indicates a whiter and purer starch color , meaning that impurities such as protein, fat, and fiber have been removed more thoroughly, and the processing technology is more refined.
Edible corn starch is clearly divided into three grades based on indicators such as whiteness (457nm blue light reflectance):
GB/T 8885-2017
✅ Premium grade : Whiteness ≥ 88.0%
✅ Grade 1 : Whiteness ≥ 87.0%
✅ Grade II : Whiteness ≥ 85.0%
These seemingly minor differences actually reflect the overall level of raw material quality, processing precision, and production control. Higher whiteness usually means higher starch purity and fewer impurities, making it more suitable for high-end foods with extremely high color requirements, such as crystal dumplings, high-end pastries, and transparent sauces.
Measurement standards for the whiteness of edible corn starch
How can we ensure that global edible starch producers, quality inspection agencies, and traders have a unified understanding and reproducible measurement results when discussing whiteness values?
The key lies in a national standard: GB/T 22427.6-2008 Determination of Starch Whiteness . This standard is a general method for determining the whiteness of starch, and it is also the whiteness testing method recommended in GB/T 8885-2017 Edible Corn Starch.
GB/T 8885-2017
This standard specifies the authoritative method for determining the whiteness of starch: using a qualified whiteness meter, under blue light at a wavelength of 457 nm, the reflectance of the sample relative to a standard white plate is measured, and the result is expressed as a whiteness value.
GB/T 8885-2017
This method is scientific and objective, effectively avoiding the subjectivity and instability of traditional visual colorimetry, and providing a unified technical standard for fair trade and quality control in the starch industry.
Methods for measuring the whiteness of edible corn starch
1 Measuring instrument – TS852 0
Faced with stringent national standards and meticulous quality control requirements, choosing a high-precision, high-efficiency measuring instrument is crucial. The Sanenshi TS8520 benchtop spectrophotometer is an excellent choice, offering significant advantages in measuring the whiteness of corn starch.
R457 whiteness index, national standard level accuracy.
The instrument can be configured with R457 whiteness , enabling precise measurement of 457nm blue light whiteness. Furthermore, it exhibits high repeatability of reflectance chromaticity values, fully meeting the stringent requirements of GB/T 22427.6 for measurement repeatability (absolute difference between parallel measurement results ≤ 0.2).
Intelligent and simple operation, improving detection efficiency
Equipped with a 7-inch independent rotatable capacitive touchscreen , the interface is intuitive and wizard-driven, allowing even beginners to quickly get started. The camera viewfinder positioning function provides clear observation of the measurement area, ensuring accurate measurements every time.
Specialized optical systems to meet powder challenges
The instrument is equipped with measuring fixtures and test boxes (cuvettes), enabling a more comprehensive evaluation of the surface appearance of powder samples. Its stable optical structure effectively reduces measurement errors, addressing the inherent inhomogeneity of powder samples.
2 Measurement Procedure – TS852 0
3nh colorimeter manufacturer
2.1 Preparation
Prepare a bag of edible corn starch and process the sample according to GB/T 22427.6-2008. Put the mixed starch into a measuring dish, press the power button, and wait for the instrument to start.
Sample processing
Instrument power-on
2.2 Instrument calibration
To enter the "Black and White Calibration" interface: First, place the black tube into the measurement port as instructed on the screen, and then click the screen to complete the "Black Calibration" ; then remove the black tube, place the standard white plate in the port, and click "White Calibration" .
Black Calibration
White Calibration
2.3 Parameter selection
Select the appropriate parameters , such as light source, observer angle, and color index (whiteness). The selection method is "Color Options -- Reflectance Color Index -- Whiteness -- WI (R457)" .
2.4 Sample measurement
Place the prepared measuring dish in the instrument's reflective measuring port, clamp it in place to ensure complete coverage, and click the "Measure" button.
According to GB/T 22427.6-2008, the same sample should be subjected to two or more parallel determinations . If the absolute difference between the parallel determinations does not exceed 0.2 (meeting the national standard's repeatability requirements), the arithmetic mean should be taken as the final whiteness value, rounded to one decimal place. By comparing this result with the standard of GB/T 8885-2017, it is possible to quickly and objectively determine whether the batch of corn starch belongs to superior, first-grade, or second-grade products.
Place the sample
Measurement ①
Measurement ②
As shown in the figure, the screen displays whiteness values of 88.31% and 88.30% , with a difference of 0.01. Therefore, the final whiteness value of the corn starch is 88.3%, which meets the whiteness requirements for superior grade products in GB/T 8885-2017.
2.5 Data Analysis
After measurement, the data can be saved and printed. If needed, it can also be connected to the SQCX host computer software for in-depth data analysis. Download and installation instructions are below. Welcome to use and experience it!
SQCX