(Dubois 1978, Shogren et al 1981) and introducing gritty textures GOULD, J. M., JASBERG, B. K., DEXTER, L.

G, B. K., DEXTER, L., HSU, J. T., LEWIS,

(Pomeranz et al 1976, Prentice and D'Appolonia 1977). This is in S. M., and FAHEY, G. C., Jr. 1989. High-fiber, noncaloric flour
contrast with the partially delignified, extensively hydrated substitute for baked foods. Properties of alkaline peroxide-treated wheat
straw. Cereal Chem. 66:201-205.
structure of AHP-treated lignocellulose that softens and integrates JASBERG, B. K., GOULD, J. M., WARNER, K., and NAVICKIS, L. L.
readily into the starch-gluten matrix with apparently minimal 1989a. High-fiber, noncaloric flour substitute for baked foods. Effects of
interruption of matrix continuity (Jasberg et al 1989a). alkaline peroxide-treated lignocellulose on dough properties. Cereal
Chem. 66:205-209.
LITERATURE CITED JASBERG, B. K., GOULD, J. M., and WARNER, K. 1989b. High-fiber,
noncaloric flour substitute for baked foods. Use of alkaline peroxide-
COTE, G. L., and ROBYT, J. F. 1983. The formation of alpha-D-(1-3) treated lignocellulose in chocolate cake. Cereal Chem. 66:209-213.
branch linkages by an exocellular glucansucrase from Leuconostoc POMERANZ, Y., SHOGREN, M. D., and FINNEY, K. F. 1976. White
mesenteroides NRRL B-742. Carbohydr. Res. 119:141-156. wheat bran and brewer's spent grains in high-fiber bread. Baker's Dig.
DeFOUW, D. F., ZABIK, M. E., UEBERSAX, M. A., AGUILERA, J. M., 50(6):35-38.
and LUSAS, E. 1982. Use of unheated and heat-treated navy bean hulls PRENTICE, N., and D'APPOLONIA, B. L. 1977. High-fiber bread
as a source of dietary fiber in spice-flavored layer cakes. Cereal Chem. containing brewer's spent grain. Cereal Chem. 54:1084-1095.
59:229-230. RAJCHEL, C. L., ZABIK, M. E., and EVERSON, E. 1975. Wheat bran
DUBOIS, D. 1978. The practical application of fiber materials in bread and middlings: A source of dietary fiber in banana, chocolate, nut, and
production. Baker's Dig. 52(2):30-33. spice cakes. Baker's Dig. 49(3):27-30.
DUBOIS, M., GILLES, K. A., HAMILTON, J. K., REBERS, P. A., and SATIN, M., McKEOWN, B., and FINDLAY, C. 1978. Design of a
SMITH, F. 1956. Colorimetric method for determination of sugars and commercial natural fiber white bread. Cereal Foods World 23:676-681.
related substances. Anal. Chem. 28:350-356. SHOGREN, M. D., POMERANZ, Y., and FINNEY, K. F. 1981. Counter-
GOULD, J. M. 1984. Alkaline peroxide delignification of agricultural acting the deleterious effects of fiber in breadmaking. Cereal Chem.
residues to enhance enzymatic saccharification. Biotechnol. Bioeng. 58:142-144.
26:46-52. SPRINGSTEEN, E., ZABIK, M. E., and SHAFER, M. A. 1977. Note on
GOULD, J. M. 1985a. Enhanced polysaccharide recovery from agricul- layer cakes containing 30 to 70% wheat bran. Cereal Chem. 54:193-198.
tural residues and perennial grasses treated with alkaline hydrogen TITCOMB, S. T., and JUERS, A. A. 1986. Reduced calorie, high fiber
peroxide. Biotechnol. Bioeng. 27:893-896. content breads and methods of making same. U.S. patent no. 4,590,076.
GOULD, J. M. 1985b. Studies on the mechanism of alkaline peroxide Patented May 20.
delignification of agricultural residues. Biotechnol. Bioeng. 27:225-231. VOLPE, T., and LEHMANN, T. 1977. Production and evaluation of a
GOULD, J. M. 1987. Alkaline peroxide treatment of nonwoody ligno- high-fiber bread. Baker's Dig. 51(2):24-26.
cellulosics. U.S. patent no. 4,649,113. Patented March 10. ZABIK, M. E., SHAFER, A. M., and KUKCROWSKI, B. W. 1977.
GOULD, J. M. 1989. Alkaline peroxide treatment of agricultural Dietary fiber sources for baked products. Comparison of cellulose types
byproducts. U.S. patent no. 4,806,475. Patented February 21. and coated products in layer cakes. J. Food Sci. 42: 1428-1431.

[Received December 3, 1987. Revision received December 19, 1988. Accepted December 21, 1988.]

Effects of Wheat Bran in Breadmaking'

C. S. LAI,4 R. C. HOSENEY, 2 and A. B. DAVIS23

ABSTRACT Cereal Chem. 66(3):217-219

Wheat bran, as distinct from shorts and other wheat milling by-products, and sodium stearoyl lactylate, and fine grinding of added wheat bran will
is more detrimental to loaf volume than would be expected from simple allow the baker to overcome the detrimental effect of adding wheat bran to
dilution of gluten protein. This effect appears to be a function of bran-water white pan bread dough.
interaction. A combination of increased absorption, addition of shortening

Wheat bran is a component of whole wheat flour that has been contradict each other as to the specific nature of the effect
identified as detrimental to loaf volume (Smith and Geddes 1942, (Pomeranz et al 1977, Finney 1979, Finney et al 1985). A possible
Pomeranz et al 1976, Pomeranz 1977, Birch and Finney 1980, explanation for this discrepancy is the definition of bran used in
Shogren et al 1981, Rogers and Hoseney 1982, Moder et al 1984, various studies. As detailed below, bran varies depending upon the
and Finney et al 1985). The effect of bran on loaf volume has been mill producing it. In the milling process the pericarp and aleurone
reported to vary with the source of the bran (Finney et al 1985). layer are removed from the wheat kernel. To a greater or lesser
Various effects of bran on flour absorption have been cited in the degree these anatomical structures are separated into the milling
literature (Pomeranz 1977, Shogren et al 1981, Moder et al 1984). fractions known as bran and shorts, respectively. The effects of the
There are also reports that the effects of bran on functional two fractions on the functional characteristics of flour are quite
properties of flour vary with the particle size of the bran. These different, as outlined in this and a companion paper (Lai et al
reports, while agreeing that bran does affect flour properties, 1989). These differences, when coupled with the inherent variation
in completeness of separation of the two fractions during the
'Contribution no. 88-123-J, Kansas Agricultural Experiment Station, Manhattan. milling process, may explain much of the variation in the reported
2Research assistant, professor, and associate professor, respectively, Department of
effects of bran. This is especially true of work done with undefined
Grain Science and Industry, Kansas State University, Manhattan 66506.
'Present address: Hershey Foods Corp., Hershey, PA bran which may have been a mixture of bran and shorts.
4
Present address: Entenmann's Inc., Bay Shore, NY. This study was intended to determine and overcome the effects
of a specific bran fraction (primarily pericarp) as separated in a
© 1989 American Association of Cereal Chemists, Inc. conventional milling process.
Vol. 66, No. 3,1989 217
 MATERIALS AND METHODS Calculation of Dilution Value
Our standard baking test involved the replacement of 14% of the
Bran formula flour with wheat bran. This dilution of gluten protein with
Bran was collected from the pilot flour mill in the Department an inert ingredient would be expected to reduce the loaf volume of
of Grain Science and Industry at Kansas State University. A blend the resulting bread. We calculated a potential loaf volume value for
of hard red winter wheat varieties was milled using the normal mill each of our flours based on this dilution and the known linear
flow. Bran was defined as the material that remained on a 1,050-pm relationship between protein and loaf volume. This value is
wire screen following the fifth break rolls and then passed as the referred to as the dilution value for a given trial. Our calculation of
overs of the bran duster. The bran was stored at 40 C after milling effect of various treatments was based on the difference between
and used without further grinding unless otherwise specified. the dilution value, the value expected if the added bran were truly
inert, and the loaf volume value actually achieved.
Flours
Four flours, flour A (12.4% protein [N X 5.7], 12.9% moisture), RESULTS AND DISCUSSION
flour B (11.6% protein, 12.0% moisture), flour C (11.8% protein,
11.8% moisture), and flour D (11. 8% protein, 12.4% moisture) The initial trials clearly showed that wheat bran as separated in a
were used in this study. They were donated by Ross Mills, Wichita, conventional milling process had a far greater effect on loaf volume
KS. All flours were medium long mixing with good loaf volume than would be expected from an inert ingredient (Table I). The
potential. effect of bran was essentially linear, with a greater volume-
depressing effect on flours with a higher loaf volume potential
Pup Loaf Baking (Tables I and II). With this information, we are confident that
A straight dough procedure with optimum mixing time and 3 hr although absolute values may differ between flours, the actual
fermentation at 30.60C, 88% rh was used (Finney 1984). Doughs effects are the same and that valid comparisons between flours can
were mechanically punched at 105, 155, and 180 min, then molded be made.
and panned. Panned doughs were proofed 55 min and baked at Extraction of bran with either water or 80% isopropanol failed
218.30C for 24 min. The breadmaking formula, if not specified to produce an extract with a significant volume-depressing effect.
otherwise, included 100 g of flour, 1.5 g of salt, 6 g of sugar, 4 g of Beta-glucosidase digestion did not alter the effects of bran on loaf
nonfat dried milk, and 3 g of shortening. In certain cases, bran was volume. Heat treatment likewise had no effect. Steeping the bran in
used to replace part of the formulated flour. either K10 3 or alkali tended to increase the loaf volume-reducing
effect. The effects of K10 3 and alkali were not pursued in this
Resistance Oven Baking study.
Resistance oven baking was carried out as described by Moore
and Hoseney (1986). Shortening
Bran-containing doughs baked in the resistance oven (Fig. 1)
TABLE I showed expansion and setting characteristics similar to those
Effects of Bran and Extracted Bran on Breadmaking observed for doughs made without shortening (Moore and
Loaf Standard Hoseney 1986). If bran were in some way altering shortening
Volume Deviation Va availability to other dough ingredients, especially gluten, then
3 3
Treatment (cm 3 ) (cm ) (cm )
timing of the addition of bran during mixing should change the
Control (flour A) 900b 11.8 ... effect of bran on loaf volume. Also, if the above hypothesis were
Bran (14%) 720 7.1 80 true, additional increments of shortening should eventually restore
Control (flour B) 846 17.1 ... loaf volume to the dilution value. In our trials, the timing of bran
Bran (14%) 716 18.4 30 addition made no difference in the final loaf volume. Addition of
Bran plus 2% additional water 737 3.5 9 shortening improved loaf volume, but the effect was far greater for
Control (flour C) 884 14.9 the first 3% shortening added, with additional amounts having far
Bran (14%) 743 19.9 60 less effect (Fig. 2). Control doughs containing shortening levels
Bran (14% bran was added above 3% gave no further increases in volume. The shortening
to a sponge) 739 12.4 64 addition curve levels off significantly below the dilution value,
WVis the difference between the dilution value and the observed effect. which suggested that something other than shortening effects were
'Numbers are averages of six observations. LSDo9 5 = 28 cm .
3
responsible for a major part of the effect of bran on loaf volume.
Doughs formulated with the level of water indicated by
mixograph absorption appeared dry. An additional 2% water had
TABLE II
Loaf Volumes of Breads Containing Coarse and Fine Bran
6
Loaf Standard
Volume Deviation Va
3 3
Treatment (cm 3 ) (cm ) (cm ) 5
M:
Control (flour D) 878 10.6 ...
14% bran 698 9.6 180
14% bran + 10% additional water 794 22 84 H-

Control (flour D) 855 13.2 *- CD

14% soaked bran 3
w
(in 21 ml of water) 830 7.1 25
I
Control (flour D) 868 7.6 -- 2
22% soaked fine bran CD
(soaked in 35 ml of water) 855 18.3 13 0
0 I
22% soaked coarse bran
(soaked in 31 ml of water) 822 2.9 46
Control (flour D) 866 8.5 ...
+34 30 40 50 60 70 80 90 100
22% soaked fine bran 910 4.1
22% fine bran (driest addition) 884 14.4 +17.8 DOUGH TEMPERATURE ( C )
aV is the difference between the dilution value and the observed effect. Fig. 1. Dough height versus dough temperature of doughs with and without
3
bNumbers are averages of six observations. LSDo.9 5 = 28 cm . bran.

218 CEREAL CHEMISTRY

 900 unable to maintain a manageable dough when sufficient water was
control
added to overcome the effect of the bran. Assuming that the rate of
water uptake by bran was relatively slow, we tried presoaking the
800
bran in an appropriate amount of water, then adding it to the
o /bran
dough during mixing (Table II). With this system we were able to
produce loaves of near dilution volume with 14% bran.
0) 700-
In a further attempt to increase the rate of water absorption by
E bran, we tried fine grinding the bran with a Udy mill. Doughs
.5
> 600 -
containing the finely ground bran were much superior to those
with coarse bran (Table II). Presoaking the fine ground bran
0 improved loaf volumes even further. Finally, we were able to add
500 22% presoaked, fine ground bran to a dough, have the dough
remain manageable, and produce a loaf with a volume significantly
above not only the dilution value but also significantly above the
volume of a control loaf that did not contain bran.
I 3 5 7 9 i From this work, it appears that the effects of bran on loaf
% OF SHORTENING ADDED volume, which are greater than would be expected from a totally
Fig. 2. Effects of shortening on the loaf volume of breads with or without inert ingredient, can be overcome. A combination of grinding and
added bran. presoaking the bran and additional water and SSL will produce a
dough that can be handled and will produce an acceptable loaf
900
volume.

850 LITERATURE CITED

0
EU) BIRCH, R. E. W., and FINNEY, P. L. 1980. Note on fresh egg yolk in 50%
0 whole wheat bread. Cereal Chem. 57:448.
800
FINNEY, K.F. 1984. An optimized, straight-dough bread-making method
after 44 years. Cereal Chem. 61:20.
750 FINNEY, P. L. 1979. Germinated wheat and soybeans in human nutrition.
-co Adv. Exp. Med. 105:681.
0r FINNEY, P. L., HENRY, S., and JEFFERS, H. 1985. Effect of wheat
O~~~~ILUTION VALUE
1 variety, flour grinding, and egg yolk on whole wheat bread quality.
700
Cereal Chem. 62:170.
LAI, C. S., and HOSENEY, R. C. 1989. Functional effects of shorts in
I - -. I - 1, - - 1-- -
breadmaking. Cereal Chem. 66:220.
MODER, G. J., FINNEY, K. F., BRUINSMA, B. L., PONTE, J.G., JR.,
0 2
and BOLTE, L. C. 1984. Bread-making potential of straight-grade and
% OF SSL ADDED whole-wheat flours of Triumph and Eagle-Plainsman V hard red winter
Fig. 3. Loaf volume of breads containing bran plus various amounts of wheats. Cereal Chem. 61:269.
additional water (numbers on graph are additional water in percentages) MOORE, W., and HOSENEY, R. C. 1986. The effect of flour lipids on the
and sodium stearoyl lactylate (SSL). expansion rate and volume of bread baked in a resistance oven. Cereal
Chem. 63:172.
POMERANZ, Y. 1977. Fiber in breadmaking: A review of recent studies.
Baker's Dig. 51(10):94.
a beneficial effect on loaf volume (Fig. 3). Additional water in the POMERANZ, Y., SHOGREN, M., and FINNEY, K. F. 1976. White
absence of sodium stearoyl lactylate (SSL) had little effect. With wheat bran and brewer's spent grains in high-fiber bread. Baker's Dig.
the addition of SSL the effect of added water was marked. Even 50(12):35.
without additional water the addition of 2% SSL resulted in loaf POMERANZ, Y., SHOGREN, M., and FINNEY, K.F., and BECHTEL,
volumes at or slightly above the dilution value (Fig. 3). Loaves with D. B. 1977. Fiber in breadmaking-Effects of functional properties.
6% additional water and 2% SSL were nearly equal to the nonbran Cereal Chem. 54:25.
containing control. These doughs were wet, sticky, and difficult to ROGERS, D., and HOSENEY, R.C. 1982. Problems associated with
handle. They had pitted bottoms and sides, but their internal producing whole wheat bread. Cereal Foods World 27:451.
structure was normal. SHOGREN, M. D., POMERANZ, Y., and FINNEY, K. F. 1981. Counter-
acting the effects of fiber in breadmaking. Cereal Chem. 58:142.
The addition of water in excess of that expected from the SMITH, D. E., and GEDDES, W. F. 1942. Yeast fermentation and
mixogram curve could produce a manageable, though sticky, potassium bromate as factors influencing the harmful effects of wheat
dough with up to 10% bran. With bran in excess of 10%, we were germ on baking quality. Cereal Chem. 19:785.

[Received March 11, 1988. Accepted January 9, 1989.]

Vol. 66, No. 3, 1989 219