Effect of relative humidity on milling and air classification explained by particle dispersion and flowability.

Dry fractionation of legumes is used to produce protein and starch-rich fractions with a clean label and lower environmental impact than conventional wet fractionation. Dry fractionation relies on the use of ambient air that varies in humidity. This study assessed the effect of relative humidity (RH) on milling and air classification of yellow pea and chickpea. Particle size analysis and powder rheology were used to assess the particle dispersibility and flowability of the flours. The RH has limited effect on milling and air classification between 30% and 70%. However, upon storage of fine milled chickpea flour at a RH of 70% and storage of fine milled yellow pea flour at a RH of 90% the air classification performance decreased. This was linked to a poorer dispersibility and flowability. Concluding, a relative humidity above 70% should be prevented to perform robust air classification. • Humidity between 30% and 70% has limited effect on direct milling and air classification. • Particle dispersibility and flowability decreased after storage at higher humidity. • Relative humidity above 70% should be prevented to perform robust air classification. • Lower flowability and agglomerated particles were detrimental for air classification. • Yellow pea flour has better flowability than chickpea flour under similar conditions. [ABSTRACT FROM AUTHOR]