抄録
It is shown that when packed powdered food is mechanically tapped, the relation between the strain γ and the number of consecutive tapping N is represented by an equation γ=abN/(1+bN) where a and b are the volume decrement from initial to final volume and the fluidity of the powder respectively. The value of a ranges from 0.9×10-1 to 3.3×10-1 and that of b from 2.3×10-2 to 17.5×10-2. a-value is varied with the magnitude of tapping impact; for whole milk powder, which is cohesive, it becomes constant above a certain magnitude of impact, however, for skimmed milk powder, which is not cohesive, it rises proportionally to the square of the magnitude of impact and becomes maximum at about the magnitude at which a-value of whole milk begins to become constant. Such is the case in which the separation phenomenon of tight packed powder occurs, a-value of skimmed milk powder decreases with increasing moisture content; at about 8% of the content, the fluidity becomes maximum owing to α transition of lactose in skimmed milk powder particles.
