Effect of oil content on pin-milling of soybean

Abstract

Milling is a critical step to prepare plant-based food ingredients by dry fractionation. It should provide a dispersible flour of finely milled particles composed of different cellular substructures. Especially, for raw materials with higher oil content such as soybean, this is challenging. We present an investigation on the effect of oil content on milling yield, particle size, energy use and flour dispersibility upon pin-milling of soybean. Soybean (20 g oil/100 g dry solids) and mechanically de-oiled soybeans (9–17 g oil/100 g dry solids) were subjected to pin-milling experiments. Increasing soybean oil content limited milling to smaller particles and lowered the overall milling yield. Particle size reduction can be described with an adapted Bond's model with oil content as an input parameter. The produced soy flours were well dispersible. • Particle size reduction was described with an oil-independent Bond's constant. • All pin-milled soy flours had a low degree of de-agglomeration. • Dispersion of fine particles showed an optimum for soy with high oil content. • All milled soy flours were dispersible and may be used for dry fractionation.