(the late) C. H. F. FULLER and A. V. BELL X-ray diffraction patterns and infra-red spectra have shown that although the lactose in spray-dried milk powder is normally in the amorphous state, it can sometimes be present as the crystalline a-monohydrate, or in an unusual crystalline form.Studies have been made of the absorption and subsequent loss of moisture in humid atmospheres by (a) spray-and freeze-dried milks, and ( b ) spray-and freeze-dried lactose prepared from lactose solutions. I t is shown that milk powders exposed to these conditions generally contain a-lactose monohydrate, but the spray and freeze-dried lactose produce a mixture of the a-monohydrate and the ,!?-anhydride.For identification purposes all the known crystalline forms of lactose have been prepared and studied by X-ray diffraction and infra-red methods, and it has been found that the above-mentioned unusual crystalline form of lactose found in some milk powders is the anhydrous molecular compound consisting of a-lactose and ,!?-lactose in a molar ratio of 5 : 3. This compound gives an X-ray diffraction pattern which is different from, but an infra-red spectrum similar to, those of the stable &-lactose anhydride.

The micro-baking of sponges, madeira and high-ratio cakes has been investigated by cine and television microscopy. The temperatures of significant events in baking have been estimated and gas bubble diameters have been measured as a function of time and temperature during baking. The implications of the results for cake baking have been discussed.

Published literature on the flow of powders through orifices is reviewed. A new powder flow meter is described, and results obtained with some powdered food products are given. The mass flow rate is found to be proportional to the bulk density and to the 2 *8th power of the orifice diameter.The flow meter permits comparison of the flow properties of powders and prediction of their behaviour in food machinery and plant.

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