Brown bread

Abstract: Present-day interest in fiber stems from the middle of the nineteenth century when the preoccupation of the Victorians with their bowel habits led many physicians to declaim the virtues of bran. John Burne,1 writing in 1840 in A Treatise on the Causes and Consequences of Habitual Constipation, recommends that “coarse brown and bran bread is very efficacious, the bran acting as a salutory stimulus to the peristaltic action of the intestines.” There was little need to convince Burne and his generation that bran stimulated colonic movement and increased fecal output. Nevertheless, each generation of medical scientists seems to have to rediscover this fact for itself, and medical and nutritional literature in the 1970s contained many papers in which little else but the laxative properties of bran were reported. By 1909, Sir Arthur Hertz (later Sir Arthur Hurst)2 was writing, “One of the most valuable foods for constipation in whole-meal bread ... white bread, which is made of the endosperm alone and those varieties of brown bread, such as Hovis, which are made from the endosperm and germ, contain only about one-fifth of the cellulose present in whole-meal bread. It is clear, therefore, that the substitution of whole-meal bread for white bread is a very important part of the dietetic treatment of constipation.” Thus, 75 years ago fiber was being singled out as the principal component of bran responsible for its colonic effects. In 1936, Dimock,3 in his M.D. thesis for the University of Cambridge entitled “Treatment of Habitual Constipation by the Bran Method,” was able to review over 50 papers reporting clinical, biochemical, radiological, and physiological studies of the use of fiber in constipation. He discussed various current ideas about the way bran produces its laxative effect, such as the presence of undigestible fiber, its content of vitamin B, phytin, hemicellulose, inorganic salts, and the production of volatile fatty acids from decomposition of cellulose and hemicellulose. As a result of his own observations, he concluded, “My view is that bran exerts a mechanical laxative action due to its fibre content. The fibre mixes intimately with the food residues in the colon, even when bran is taken only once a day. I believe that by so doing, it not only retains moisture itself but enables the other residues in the colon to resist dehydration.” The 1930s were a time of vigorous investigation of the laxative properties of dietary fiber. Purified forms of fiber such as ispaghula, various celluloses, agar, karaya, sterculia, and psyllium

Abstract: We compared the effects of spontaneous fermentation of the bran fraction and fermentation with added yeast or added yeast and lactic acid bacteria (Lactobacillus brevis) on the quality of wheat bread supplemented with bran. Prefermentation of wheat bran with yeast or with yeast and lactic acid bacteria improved the loaf volume, crumb structure, and shelf life of bread supplemented with bran. The bread also had added flavor and good and homogenous crumb structure. Elasticity of the crumb was excellent. Spontaneous fermentation of the bran fraction did not have the same positive effects on bread quality. The microstructure of the breads was characterized by light microscopy. The positive effect of fermentation of bran on bread quality was evident when comparing the well-developed protein network structure of the breads baked with fermented bran with the control bread. Prefermentation of the bran with yeast and lactic acid bacteria had the greatest effect on the structure of starch. The starch granu...

Abstract: Brown bread was produced by adding bran (all of the same nominal particle size range) from 10 widely differing wheat samples to a common base white flour The different brans caused different levels of loaf volume depression In all cases, dry heat-treatment of the brans decreased total reducing substances, inactivated lipase and increased loaf volume and height However, the loaves still differed somewhat in volume A similar study was conducted with three bran fractions of different sizes (Pollard 075 mm 18 mm), from the same grist, to a common base white flour Smallest loaf volumes were obtained with Pollard and largest with Digestive Subjecting the brans to the heat-treatment, increased loaf volume However, smallest volumes were still obtained with Pollard Brans were also milled to a common maximum particle size (