The SRC-CHOPIN 2, Bringing Precision Where You Need It

There is no doubt that Solvent retention capacity tests (SRC) is a recognized and developing method for all soft flour product manufacturers. Additionally, every day more producers of hard wheat products are also using the SRC as a routine quality testing method. Hundreds of publications are available all evidencing the benefit of measuring SRC values of flours. It is therefore logical to see these values appearing in specification books. This is where standard methods enter. Currently there are only 2 official standards:

• The traditional Manual method (AACC 56-11.02)
• The new SRC-CHOPIN standards (ICC 186, AACC 56-15.01)

Referring to standard methods we can see that the New automated method bring much more precision in results, particularly on the reproducibility (comparing results of 2 different labs). This is a typical situation when comparing data from Seller/buyer.

There have been attempts to improve the precision of AACC 56-11.02 by adding different tools. Although this can have an impact on results, there is no official data supporting these results and thus, this cannot be considered as a standard method. Situations due to laboratories using manual or non-standardized (adapted) methods can have a disastrous impact when it comes to comparing results between 2 laboratories.

Some online information sources are interesting to look at. One study shows 11 different labs testing the same samples (Soft and hard wheats) over a period of 4 years (2016-2019). An example on SUC SRC shows that comparison between labs is far from perfect. Some labs do compare very well (Lab 10 & 5, 37 samples), 1 year), while others do not (Lab 1 & 3, 86 samples, 4 years). Overall, the average correlation between labs is 0.42…and CVR% is 7.4%.

The same observations can be done for other solvents. In all cases the observed value is higher than that of the Manual method. This observation is not strange for at least 3 reasons:

• The observed values integrate all data (no outlier removal).
• The number of samples are higher than in a standardization Collab
• It is a constant observation that results “in routine” are always a bit higher than those assessed during a collab study (People, training, material, maintenance…)

What does this mean for the SRC current and future users?

• Specification must be based on fair values. These are indicated by standard method, and everyone should refer to them.
• Make sure your SRC method supports the precision required from your product specifications.
• By automating the tests and removing most of the causes for human-based errors, the CHOPIN-SRC method creates an outstanding basis for commercial transactions.