EFFECT OF MILLING PROCEDURE ON THE MEASUREMENT OF DIETARY FIBER BY A GRAVIMETRIC METHOD

Samples of white potato, sweet potato, hard red spring wheat, soft whi te winter wheat, and soft wheat bran were ground in a Wiley mill or a Cyclotec mill. A significantly (p <0.0001) larger proportion of coarse material (>75 mu) resulted from the Wiley mill, and a significantly ( p <0.0001) larger proportion of fine material (<45 mu) was produced by the Cyclotec mill. The effect of particle size on the determination o f soluble, insoluble, and total dietary fiber was less well defined, I n 4 of 5 commodities tested, samples from the Cyclotec mill showed a g reater amount of soluble fiber, while the reverse was true for insolub le and total fiber. The difference in total dietary fiber, with respec t to the mill used in sample preparation, varied from 0.24% on a total 9.10% for potatoes to 1.00% on a total of 14.05% for hard red spring wheat.