Whipping test for the determination of foaming capacity of protein: a collaborative study

A standard whipping test, which involved preparing a 0.5% protein dispersion, whipping the dispersion in a Kenwood Chef food mixer and measuring the foaming properties (foam expansion, FE; foam volume stability, FVS; foam liquid stability, FLS) was collaboratively evaluated. A total of sixty determinations was made involving six laboratories, each of which analysed five samples in duplicate. The repeatability coefficient of variation ( CV ₀) in the estimation of FE and FVS properties of proteins was 6.25%. The reproducibility coefficient of variation ( CV _X) for FE and FVS was 9.8%, excluding the FE value (i.e. 20%) for spray-dried albumen. The CV ₀ and CV _X values for FLS properties of proteins ranged from 7.4 to 13.4% and 17.2 to 24.6%, respectively. Thus, FE, FVS and FLS properties can be used for intralaboratory comparisons (e.g. to determine batch-to-batch variation in commercial protein products), whereas FE and FVS values are more reliable for inter-laboratory comparisons of the foaming properties of proteins.