Particle size, powder properties and the breakage behaviour of infant milk formula

Dairy powder breakage occurs in many processes and causes deterioration in powder properties but there is currently no research presented in the literature on dairy powder breakage behaviour. The breakage behaviour and the effect of powder properties of an infant milk formula and its sieved size fractions were investigated during three processing methods (powder venturi feeder, lab-scale dilute phase pneumatic conveyor, and laboratory high-speed mixer) based on the changes of particle size distributions (PSD) before and after breakage. Particle size influenced other properties and the breakage behaviour of powders. Four breakage mechanisms were found, dispersion, chipping, disintegration, and splitting, corresponding to the increasing degree of breakage. More intense processing conditions were needed to cause the same breakage mechanism for smaller-sized particles because of their higher powder strength. The breakage of samples with wide PSD often displayed a combination of breakage mechanisms due to the influence of particle size on breakage behaviour.