FoodNet

Experimental cookery

1932

Page 323

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Flour has been considered adulterated w^ith water, under the federal standards of the United States, if the moisture content exceeded 13.5 per cent. Recently this standard has been changed to 15 per cent. It has been found by careful experiments that, when the moisture is determined by the water-oven method, 13.5 per cent is equivalent to 15 per cent by the new vacuum method. Sanderson, in determining the variations in moisture content of flour during storage, decided that the moisture loss of flour varies less with 11.0 per cent of moisture. From different reports 11 to 13 per cent of moisture seems to be a normal content of flour over a large section of the United States. Bailey states that flour responds more readily to changes in humidity than the wheat kernel, because of its fineness of division of particles and the greater exposure in handling it in sacks. FAT CONTENT OF FLOUR 399 Hygroscopic property of flour. The starch of flour takes up and lets go of moisture very quickly. This affects the proportion of moisture needed for baked products such as bread and cake. Browne in determining the hygroscopic moisture of carbohydrates has reported that anhydrous starch ranked first in the amount of moisture absorbed at 60 per cent humidity in 1 hour. Over longer periods the starch did not absorb as much moisture as some of the sugars. Kent-Jones states that English flour has a moisture content ^ to 1 per cent higher than American flour on account of the higher humidity of the English climate. The Fat Content of Flour The percentage of fat in vrhite flour is low, since most of the fat is found in the germ which is removed during milling. But though present in a small quantity, the lipoid content of flour is important. Some lipoid constituents improve, whereas others injure the baking quality of flour. Working has reported that "The gluten of low grade flour increased in tenacity when the phosphatide was removed by washing. The addition of phosphatides to flour in small quantities injured the gluten as determined by the feel of the hand washed gluten, the viscosity as measured by the viscometer, and by baking tests." Working suggests that the effect of phosphatides on gluten is similar to that of oil on rope. Lubrication of the strands of the rope lessens its strength and tenacity. In a later paper Working reported that a small amount of phosphatide, such as the normal amount present in a good patent flour, may improve the baking quality. Sullivan, Near, and Foley report that it is well known that increasing percentages of wheat germ in flour harm the baking quality of the flour. They investigated the effect of fat from wheat germ and of each fat fraction and its hydrolytic products on normal sound patent flour as judged by gluten washing and baking tests as well as by the Farinograph and Fer- mcntograph. Fat from the fresh germ was not found to be deleterious to the baking quality. They say: "The only germ-fat constituents which were found to be injurious were the unsaturated fatty acids which develop upon aging due to hydrolysis of the triglycerides and, what is much more important, the subsequent oxidation products of these unsaturated acids.