Effect of Baking Absorption on Bread Yield, Crumb Moisture,

and Crumb Water Activity 1

D. P. PUHR and B. L. D'APPOLONIA 2

ABSTRACT Cereal Chem. 69(5):582-586

Three cultivars of hard red spring wheat with identical protein contents from the high-absorption flours were greater than weights from the low-
were milled on a Buhler mill. The farinograph absorptions of the flours absorption flours. Bread crumb moisture, as determined by the two-step
at the 500-BU line varied. Bread was baked from this flour using both oven method, decreased over a four-day storage period. Water activity
the straight dough and sponge and dough methods at five absorption values for the bread crumb ranged from 0.995 to 0.975 in the study.
levels with each system. From the two higher absorption flours, bread One of the cultivars was further milled to produce additional levels of
yield loss was greater with the sponge and dough procedure than with starch damage for different absorptions. Similar results were obtained
the straight dough method. As the absorption levels in the baking formula for bread crumb moisture and water activity for these samples and for
increased, an increased bread yield loss was noted. Total bread weights the three cultivars used initially.

Flours that require high absorption levels to produce doughs The purpose of this study was to determine the effect of adding
of a certain consistency are desirable for bread baking. The amount different amounts of water to different flours and to ascertain
of dough produced from a fixed amount of flour increases with the economic advantage in terms of the number of loaves of
an increase in water content or absorption. This is an important bread produced. Because bread is sold by weight, the study
factor from an economic standpoint. Because water is one of compared the loss in the dough weight after mixing to the final
the least expensive ingredients, bakers can increase bread yield baked loaf. To determine the advantage of high-absorption flours
by choosing a flour with a higher absorption flour and, thus, in baking, bread yield loss was examined as it related to the
increase profits. The bread quality desired and the dough machin- baking absorption required by the flours. A straight dough and
ability also would be factors in the type of flour required by sponge and dough methods were used. Total bread yield loss
the baker. Although dough yield increases as absorption increases, was determined from the weight of dough immediately after
a corresponding increase in bread yield may or may not occur. mixing compared to the final bread weight. Varying levels of
Greater water loss during the baking stage would necessitate using water from the optimum baking absorption also were added to
more dough weight for a resultant fixed bread weight. Tipples determine the change in the yield loss. The relationship of water
and Kilborn (1968) noted that farinograph absorption increased activity to total moisture content in the bread crumb was examined
almost linearly with an increase in starch and that bread yield immediately after baking and during storage.
increased proportionally with the baking absorption. Farrand
(1972) stated that satisfactory bread could be made from pin- MATERIALS AND METHODS
milled flour over a range of 18-30 Farrand starch damage units
using a straight dough method. Three hard red spring wheat cultivars were selected to obtain
The role of water during the bread-staling process was examined Buhler-milled flours (Buhler Miag, Minneapolis, MN) of varying
by Pisesookbunterng and D'Appolonia (1983). It was noted that water absorption but the same flour protein (15.6% dry-moisture
in bread not decrusted, a measurable moisture loss in the crumb basis [dmb]) and medium-strong to strong farinograph properties.
occurred because of the migration of moisture from the crumb The optimum baking absorption and mix time were estimated
to the crust. Decrusted bread crumb showed a constant crumb on the basis of farinogram curves and by an experienced experi-
moisture during four days of storage. Czuchajowska et al (1989) mental baker's estimation of dough machinability.
stated that there were large differences found in the bread crumb Two baking methods were used. The first was a straight dough
moistures in bread baked with various baking absorption levels. procedure that used a 3-hr fermentation with two punches at
In addition, they found little change in water activity between 95 and 145 min after mixing. The breadmaking formula was flour,
the I- and 24-hr-old bread crumb. The functional availability 100%; yeast, 3%; salt, 2%; sugar, 5%, shortening, 3%; and water
of water in cereal foods and the subsequent presence of strongly (variable). The second baking method was a sponge and dough
bound, unavailable water was researched by Multon et al (1980). procedure in which the sponge was fermented for 4 hr. The sponge
The relationship between water activity of a cereal food and its contained 70% of the flour, 2% yeast, 0.5% yeast food, and 70%
moisture content was defined using sorption isotherm curves. of the water. The remaining ingredients (flour, 30%; salt, 2%;
Rogers et al (1988) stated that bread moisture content influenced sugar, 5%; shortening, 3%; and water, which was 30% of the
the firming rate and starch retrogradation. Firming rate was total water used) were added at the dough stage and mixed to
retarded in the higher moisture bread in the study. They further optimum development. The dough was returned to the fermenta-
noted that the fastest firming bread, which had the lowest mois- tion cabinet and allowed to rest for 40 min before dividing,
ture, also had the slowest starch retrogradation, similar to the rounding, and panning.
effect found in starch gels. Zeleznak and Hoseney (1986) also The optimum absorption for both baking procedures was de-
noted that the retrogradation of wheat starch gels was affected termined as 3.5% less than the farinograph absorption. Adjust-
by the amount of water present during bread storage and that ments were made in the baking formula to include ±4.0 or ±2.0%
starch recrystallization of starch gel and bread was affected by water from the optimum absorption. All doughs were mixed in
the moisture content. batch form on a Hobart D 300-T mixer (Hobart Corporation,
Troy, OH) with enough flour to produce a minimum of five 500-g
loaves. A minimum of two batches were mixed for each flour
'Published with the approval of the director of the Agricultural Experiment Station, formulation except for one batch of the low-absorption Marshall
2
North Dakota State University, as journal series 2019. flour. A National fermentation (National Manufacturing Co.,
Food technologist and professor and chairman, North Dakota State University Lincoln, NE) cabinet held at 30 ± 1°C with 80 ± 5% rh was
Department of Cereal Science and Food Technology, Fargo, ND 58105. used for the fermentation periods. All batches were divided into
This article is in the public domain and not copyrightable. It may be freely
500-g pieces, rounded, allowed to rest 10 min, molded using a
reprinted with customary crediting of the source. American Association of Moline experimental molder (Moline Co., Duluth, MN), and
Cereal Chemists, Inc., 1992. placed into pans. Panned doughs were proofed for 55 min in

582 CEREAL CHEMISTRY

a Despatch experimental proofing cabinet (Despatch Oven Co., The remaining loaves were sliced, placed in polyethylene bags,
Minneapolis, MN) at 43 ± 1PC with a relative humidity of 90 and kept at room temperature, 24 ± 20C. Bread crumb moisture
± 5%. Baking was done in a Despatch rotating oven for 25 min and water activity were determined two and four days after re-
at 2040 C. moval from the oven.
Dough yield loss was determined by comparing batch dough In one experiment, the cultivar that produced the lowest water
weight after mixing with dough weight before the dough was absorption flour was milled on a Miag mill (Buhler Miag), and
divided into 500-g pieces. In addition, yield loss also was deter- an aliquot of this flour was further damaged using the reduction
mined by comparing dough weight (500 g) at dividing with the rolls of an Allis mill (Allis-Chalmers Manufacturing Co., Mil-
dough weight before placing in the oven and with the final bread waukee, WI) to produce flours with starch damage values of 16.8
weight. Bread yield losses reported in this study include the entire and 24.3%. This resulted in two flours with different optimum
baking process from the weight of the dough at mixing to final baking absorption requirements. A minimum of two batches was
bread weight. The loaves were weighed 1 hr after removal from made, resulting in three 500-g loaves per batch. Starch damage
the oven, and loaf volume was determined by the rapeseed dis- was measured according to the method proposed by Farrand
placement method. (1964).
Bread crumb moisture was determined according to AACC Farinograms were determined with a 50-g bowl using AACC
(1983) procedure 44-15A. Water activity in the bread crumb was (1983) procedure 54-21. Amylographs were performed on 100 g
determined using the microcrystalline cellulose method proposed of flour (14% moisture basis) in 460 ml of water containing 46
by Vos and Labuza (1974). This procedure involved a standard ml of amylograph buffer (AACC 1983, method 22-10). Flour mois-
sorption isotherm curve for the microcrystalline cellulose estab- ture, ash, and protein content were measured by AACC (1983)
lished using standard sulfuric acid solutions. Fifty grams of bread methods 44-15A, 08-01, and 46-11, respectively.
crumb was placed in a desiccator with weighing bottles of dry Analytical determinations were performed at least twice and
microcrystalline cellulose for 24 hr. The water activity of the crumb all results were averaged unless otherwise indicated on the table.
was determined by measuring the weight gain of the microcrystal- The results were subjected to analysis of variance and evaluated
line cellulose and referring to the standard curve. Bread crumb by Duncan's multiple range test. Statistically significant differ-
moisture and water activity were done 2 hr after removal from ences at the 5% level are presented.
the oven using the following procedure. The bread was sliced
and 10 g of bread crumb was removed for bread crumb moisture RESULTS AND DISCUSSION
determination by cutting a central plug from one center slice
and from a slice off each end of the loaf. Fifty grams of crumb The ash contents of the Buhler-milled Butte 86, Len, and
were obtained in a similar fashion for water activity determination. Marshall cultivars were 0.48, 0.50, and 0.51 dmb, respectively.
Protein content on a dry-moisture basis for all three flours was
15.6%. Starch damage for the Butte 86, Len, and Marshall flours
TABLE I was 49.6, 60.4, and 39.8 Farrand units, respectively. Ash and
Farinograph Data for All Flours protein content of the original Miag-milled Marshall flour and
Absorptiona Peak Time Stability MTIb the second Marshall flour further starch damaged on the reduction
Variety (%) (min) (min) (BU) rolls of the Allis mill were 0.42 and 15.7% dmb, respectively.
Buhler milled Starch damage for these two flours were 16.8 and 24.3 Farrand
Butte 86 72.6 9.5 9.0 20 units, respectively. Farinograph data of the five flours are shown
Len 69.8 11.5 14.0 20 in Table I and indicated medium-strong to strong mixing prop-
Marshall 60.4 7.5 10.5 20 erties.
Miag milled Bread weights and volumes for the Buhler-milled Butte 86,
Marshall a 57.9 8.0 12.0 30 Len, and Marshall flours are shown in Table II. All three varieties,
b 60.2 8.0 11.0 30 except Marshall using the sponge and dough method, showed
a Absorption at 500 BU, 14.0% moisture basis. a decrease in final bread weight as more water was added to
bMixing tolerance index. the formula. Butte 86, Marshall, and, to a lesser extent, Len

TABLE II
Weight and Volume of Bread Loaves of the Buhler-Milled Flours Obtained
from 500-g Flour Doughs Baked with Different Absorption Levels

Baking Weight,a g Volume, cm

Absorption Straight Sponge Straight Sponge and
Variety (%) Dough and Dough Dough Dough
Butte 86 +4% (73.1) 419.3 cb 412.8 c 2,275 ab 2,539 a
+2%(71.1) 422.6bc 417.0b 2,319a 2,441 a
Optimum (69.1) 423.0 b 417.4 b 2,231 bc 2,469 a
-2% (67.1) 425.3 ab 418.5 b 2,203 c 2,469 a
-4% (65.1) 427.6 a 422.2 a 2,117 d 2,525 a
SD 0.33-1.97 0.63-4.56 12.5-66.1 0.0-75.0
Len +4% (70.3) 423.8 c 422.7 b 2,247 a 2,178 b
+2% (68.3) 424.7 bc 424.2 ab 2,200 b 2,292 a
Optimum (66.3) 425.8 b 424.5 ab 2,200 b 2,214 ab
-2% (64.3) 426.2 b 425.9 a 2,186 b 2,240 ab
-4% (62.3) 431.3 a 425.7 a 2,169 b 2,240 ab
SD 0.44-1.61 1.10-3.70 24.3-57.7 28.5-62.5
Marshall +4% (61.9) 422.0 c 436.5 a 2,475 a 2,290 a
+2% (59.9) 421.4 c 434.8 a 2,519 a 2,345 a
Optimum (57.9) 424.2 c 429.5 b 2,400 b 2,385 a
-2% (55.9) 427.1 b 429.1 b 2,270 c 2,462 a
-4% (53.9) 433.0 a 431.2 b 2,275 c 2,281 a
SD 0.92-2.38 1.24-1.97 20.41-46.8 23.9-248.4
a One hour after baking.
bValues followed by different letters indicate statistically significant differences at the 5% level.

Vol. 69, No. 5,1992 583

 TABLE III
Weight and Volume of Bread Loaves of the Marshall Flours with Different Starch Damage Levels Obtained
from 500-g Flour Doughs Baked with Different Absorption Levels -

3
Baking Weight,' g Volume,a cm
Absorption Straight Sponge Straight Sponge and
Variety (%) Dough and Dough Dough Dough
+4% (60.7) 418.4 cc 421.6 b 2,522 ab 2,719 a
Marshall, 2 4 .3 b
+2% (58.7) 421.6 bc 422.0 b 2,606 a 2,669 a
Optimum (56.7) 423.2 b 424.7 b 2,600 a 2,650 a
-2% (54.7) 426.9 a 428.5 a 2,556 ab 2,359 b
-4% (52.7) 430.1 a 429.9 a 2,478 b 2,278 b
SD 0.54-2.53 0.29-2.76 0.0-68.8 23.9-77.4
+4% (58.4) 422.0 d 424.8 c 2,534 a 2,643 ab
Marshall, 16 .8 b
+2% (56.4) 425.4 c 426.9 bc 2,534 a 2,659 a
Optimum (54.4) 428.7 b 427.5 bc 2,522 ab 2,625 ab
-2% (52.4) 431.4 b 429.6 b 2,438 b 2,572 b
-4% (50.4) 435.3 a 435.8 a 2,316 c 2,344 c
SD 0.57-3.08 0.24-1.84 12.5-85.1 14.4-73.6
a One hour after baking.
bPercent starch damage in Farrand units determined using Farrand method.
c Values followed by different letters indicate statistically significant differences at the 5% level.

TABLE IV TABLE V
Percent Bread Yield Loss in Weight of Dough During Percent Loss in Weight of Dough During the Entire Baking Process
the Entire Baking Process from Doughs of the Buhler-Milled Flours from Doughs that Varied in Starch Damage and
that Varied in Optimum Baking Absorption and Baked Baked with Different Absorption Levels
with Different Absorption Levels Baking Loss, %
AbsorptionLos%
Baking Absorption Loss, % Variety (%) Straight Dough Sponge and Dough
Variety (%) Straight Dough Sponge and Dough
Marshall, 24.3 a +4% (60.7) 17.49 ab 16.49 a
Butte 86 +4% (73.1) 17.23 aa 18.78 a +2% (58.7) 16.71 b 16.49 a
+2% (71.1) 16.58 ab 17.98 b Optimum (56.7) 16.22 bc 15.82 ab
Optimum (69.1) 16.39 b 17.88 b -2% (54.7) 15.46 c 15.06 bc
-2% (67.1) 15.96 bc 17.52 b -4% (52.7) 14.66 d 14.67 c
-4% (65.1) 15.37 c 16.88 b SD 0.104-0.452 0.057-0.565
SD 0.061-0.405 0.127-1.010
Marshall, 16.8 a +4% (58.4) 16.76 a 15.74 a
Len +4% (70.3) 16.71 aa 16.97 a +2% (56.4) 15.87 a 15.34 ab
+2% (68.3) 16.53 ab 16.39 b Optimum (54.4) 15.10 b 15.14 ab
Optimum (66.3) 15.80 b 16.40 b -2% (52.4) 14.57 b 14.69 b
-2% (64.3) 15.69 b 16.04 b -4% (50.4) 13.67 c 13.48 c
-4% (62.3) 14.55 c 16.12 b SD 0.111-0.624 0.053-0.358
SD 0.085-0.324 0.218-0.734
mPercent starch damage in Farrand units determined using Farrand
Marshall +4% (61.9) 16.71 aa 13.62 a method.
+2% (59.9) 16.71 a 13.91 a bValues followed by different letters indicate statistically significant
Optimum (57.9) 15.99 b 14.97 a differences at the 5% level.
-2% (55.9) 15.31 c 14.99 a
-4% (53.9) 14.04 d 14.53 a
SD 0.186-0.480 0.255-0.397 range test, the sponge and dough method showed a significantly
a Values followed by different letters indicate statistically significant different mean yield loss (16.48%) than the straight dough method
differences at the 5% level. (15.93%). The total bread yield loss for Butte 86, Len, and
Marshall, with means of 17.0, 16.0, and 15.0%, respectively, would
indicate statistically significant differences at the 5% level.
showed an increase in volume as more water was added to the The losses of weight from mixing to the final bread weight
baking formula when the straight dough method was used. The for bread made from the Miag-milled Marshall flours with differ-
sponge and dough method did not show this increase. ent levels of starch damage are shown in Table V. Both baking
Bread weights and volumes for the Miag-milled Marshall flours methods showed an increase in percent yield loss as more water
with two differing levels in starch damage are shown in Table was added to the baking formula. When the two baking methods
III. Both flours showed a decrease in final bread weight and were compared using Duncan's multiple range test, the mean yield
a general increase in bread volume as more water was added loss (15.33%) was the same for both methods. The Marshall flours
to the formula. The bread weights are based on 500-g dough with 24.3 and 16.8 Farrand starch damage units had a mean
pieces. The final bread weights indicate that an increase in the yield losses of 15.9 and 15.0%, respectively, and were significantly
water content in the formulation results in less bread weight per different at the 5% level. Tables IV and V indicate that when
unit of dough. the loss of dough weight from mixing to panning also was included
Table IV summarizes the results of the loss in dough weights in the percent bread yield loss, there was a greater yield loss
from mixing to the final bread weight for the Buhler-milled flour as more water was added to the baking formula. If the bread
cultivars with varied optimum baking absorption levels. The three yield losses of the three cultivars used in the study were calculated
different flours showed an increase in percent yield loss as more with the mean baking absorptions, the amount of ingredients
water was added to the baking formula when the straight dough required to produce 100 456-g (1-lb) loaves could be determined.
method was used. When the sponge and dough method was used, Table VI summarizes these results. The calculations indicate that
Butte 86 and Len show an increase in bread yield loss only at a higher absorption flour would require less flour and other in-
the highest absorption level. When the total yield losses for Butte gredients, excluding water, to produce the same amount of loaves
86, Len, and Marshall were compared using Duncan's multiple as a lower absorption flour.

584 CEREAL CHEMISTRY

 The moisture contents present in the bread crumb baked from with the Marshall samples with different starch damage levels
the Buhler-milled Butte 86, Len, and Marshall flours are shown (Table VIII) also was shown to increase as absorption in the
in Table VII. In general, there was an increase in crumb moisture baking formula increased. In Tables VII and VIII, there is a
content as more water was added to the baking formula, except decrease over time in the crumb moisture content during the four-
for the Butte 86 baked with the straight dough method and day storage period.
measured after 2 hr. The standard deviation for this set of samples The water activity of the bread crumb from the Buhler-milled
also was high. Bread from the Marshall flour also showed an Butte 86, Len, and Marshall flours is summarized in Table IX.
increase in crumb moisture content as more water was added The Len flour, using the straight dough baking method, showed
to the baking formula. However, no statistics were possible as some statistical variation in water activity on the bread crumb
it was only baked once. The moisture content of the bread made after two days of storage. However, the range in water activity

TABLE VI
Cultivar Effect on Bread Yield at Various Absorptions
Mean Baking
Absorptiona Yield Loss Dough Weightb Dough Weight Waterc Water Flourd Flour
Variety (%) (%) (kg) (lb) (kg) (lb) (kg) (lb)
Butte 86 69.1 17.0 ae 53.35 117 21.80 47.81 31.55 69.19
Len 66.3 16.0 b 52.90 116 21.09 46.25 31.81 69.75
Marshall 57.9 15.0 c 52.44 115 19.23 42.17 33.21 72.83
aIncludes both baking methods and all baking absorptions used.
bDough weight required to produce 100 456-g (1-lb) loaves of bread.
c Water required to produce 100 456-g (l-lb) loaves of bread.
dFlour and other ingredients (constant) required to produce 100 456-g (1-lb) loaves of bread.
Values followed by different letters indicate statistically significant differences at the 5% level.

TABLE VII
Moisture (%) Content in Crumb of Bread Baked From Flours that Varied in Optimum Baking Absorption
and Baked with Different Absorption Levels
Baking Straight Dougha Sponge and Dougha
Absorption
Variety (%) After 2 Hr After 2 Days After 4 Days After 2 Hr After 2 Days After 4 Days
Butte 86 +4% (73.1) 51.2 ab 51.3 a 50.0 a 51.1 a 51.2 a 50.0 a
+2% (71.1) 50.5 a 50.7 ab 50.0 a 50.2 b 50.4 ab 49.8 a
Optimum (69.1) 49.8 a 50.0 bc 49.0 ab 49.5 c 49.4 bc 48.5 ab
-2% (67.1) 49.4 a 49.4 c 48.7 ab 49.4 c 48.8 cd 48.7 ab
-4% (65.1) 49.0 a 49.0 c 47.8 b 48.2 d 47.8 d 47.7 b
SD 0.92-1.48 0.14-0.71 0.07-0.85 0.0-0.35 0.07-0.71 0.07-0.85
Len +4% (70.3) 50.0 a 49.6 a 49.2 a 50.2 a 49.8 a 49.6 a
+2% (68.3) 49.4 a 49.4 a 48.2 b 50.0 a 49.4 ab 49.1
Optimum (66.3) 48.2 c 48.5 ab 47.5 bc 48.8 b 48.8 b 48.2 c
-2% (64.3) 47.8 c 47.5 ab 46.9 cd 48.2 bc 48.0 c 47.6 d
-4% (62.3) 47.2 d 46.6 b 46.4 d 47.4 c 47.1 d 47.0 e
SD 0.07-0.28 0.71-1.06 0.0-0.64 0.0-0.56 0.07-0.35 0.0-0.28
Marshallc +4% (61.9) 47.2 47.0 45.9 47.3 47.4 46.8
+2% (59.9) 46.7 46.2 45.7 46.7 46.7 46.0
Optimum (57.9) 45.7 45.1 44.5 45.6 45.9 45.2
-2% (55.9) 45.3 45.2 44.7 45.2 45.0 44.3
-4% (53.9) 44.4 44.4 43.8 44.2 44.3 43.2
aMoistures done by two-step air oven method, done after removal from the oven at the times indicated.
bValues followed by different letters indicate statistically significant differences at the 5% level.
c Standard deviation not applicable. Marshall was baked only once and moisture determination was done only once for each observation listed.

TABLE VIII
Moisture (%) Content in Crumb of Bread From Dough that Varied in Starch Damage and Baked with Different Absorption Levels
Baking Straight Dough' Sponge and Dough'
Absorption
Variety (%) After 2 Hr After 2 Days After 4 Days After 2 Hr After 2 Days After 4 Days
Marshall 2 4 .3b +4% (60.7) 48.6 ac 48.4 a 47.0 a 47.8 a 47.5 a 45.8 a
+2% (58.7) 48.1 ab 47.6 b 46.1 a 46.9 ab 46.8 ab 45.6 a
Optimum (56.7) 46.8 bc 46.4 c 44.5 b 46.3 ab 45.8 bc 44.6 ab
-2% (54.7) 46.4 cd 46.2 c 44.2 b 45.9 ab 45.4 bc 44.2 ab
-4% (52.7) 45.4 d 45.5 d 43.6 b 44.9 b 44.7 c 43.0 b
SD 0.14-0.92 0.07-0.35 0.14-0.85 0.85-1.13 0.35-0.99 0.35-1.20
Marshall, 16.8 +4% (58.4) 48.0 a 47.4 a 46.6 a 47.6 a 46.4 a 45.8 a
+2% (56.4) 47.6 ab 46.8 b 46.0 a 46.9 a 46.3 a 45.2 a
Optimum (54.4) 46.4 bc 45.6 c 44.6 b 45.7 b 44.9 ab 43.8 b
-2% (52.4) 45.6 cd 45.0 d 44.0 b 45.0 bc 44.2 ab 43.6 b
-4% (50.4) 44.4 d 44.2 e 43.0 c 44.4 c 43.6 b 42.2 c
SD 0.07-1.06 0.0-0.28 0.07-0.56 0.00-0.71 0.71 0.92 0.07-0.64
a Moistures done by two-step air oven method, done after removal from the oven at the times indicated.
bPercent starch damage in Farrand units determined using Farrand method.
c Values followed by different letters indicate statistically significant differences at the 5% level.

Vol. 69, No. 5,1992 585

 TABLE IX
Water Activity (a,) in Crumb of Bread Baked from Flours That Varied in Optimum Baking Absorption and Baked With Different Absorption Levels
Baking Straight Dougha Sponge and Dougha
Absorption (aw) (aw)
Variety (%) After 2 Hr After 2 Days After 4 Days After 2 Hr After 2 Days After 4 Days
Butte 86 +4% (73.1) 0.990 ab 0.995 a 0.994 a 0.995 a 0.995 a 0.995 a
+2% (71.1) 0.995 a 0.995 a 0.995 a 0.995 a 0.994 a 0.995 a
Optimum (69.1) 0.991 a 0.995 a 0.991 a 0.995 a 0.992 a 0.987 a
-2% (67.1) 0.986 a 0.995 a 0.995 a 0.995 a 0.995 a 0.988 a
-4% (65.1) 0.984 a 0.995 a 0.994 a 0.995 a 0.995 a 0.989 a
SD 0.0-0.0156 0.0 0.0-0.0056 0.0 0.0-0.035 0.0-0.0106

Len +4% (70.3) 0.979 a 0.992 ab 0.995 a 0.988 a 0.995 a 0.995 a

+2% (68.3) 0.995 a 0.995 a 0.995 a 0.992 a 0.995 a 0.995 a
Optimum (66.3) 0.992 a 0.986 b 0.995 a 0.983 a 0.995 a 0.995 a
-2% (64.3) 0.982 a 0.989 ab 0.994 a 0.981 a 0.986 b 0.986 b
-4% (62.3) 0.995 a 0.987 b 0.988 a 0.992 a 0.995 a 0.995 a
SD 0.0-0.0155 0.0-0.0049 0.0-0.0106 0.0035-0.0162 0.0-0.0007 0.0-0.0035

Marshall' +4% (61.9) 0.990 0.995 0.980 0.995 0.992 0.995

+2% (59.9) 0.987 0.995 0.985 0.995 0.995 0.995
Optimum (57.9) 0.995 0.980 0.988 0.995 0.995 0.995
-2% (55.9) 0.995 0.995 0.995 0.977 0.995 0.995
-4% (53.9) 0.975 0.995 0.975 0.995 0.980 0.995
'Water activity measured using microcrystalline cellulose method.
bValues followed by different letters indicate statistically significant differences at the 5% level.
Marshall was baked only once.

TABLE X
Water Activity (a,) in Crumb of Bread Baked from Doughs That Varied Starch Damage and Baked with Different Absorption Levels

Baking Straight Dougha Sponge and Dough'

Absorption (aw) (aw)
Variety (%) After 2 Hr After 2 Days After 4 Days After 2 Hr After 2 Days After 4 Days
+4% (60.7) 0.995 a' 0.994 a 0.995 a 0.995 a 0.995 a 0.995 a
Marshall 2 4 .3b
+2% (58.7) 0.986 b 0.980 b 0.990 a 0.995 a 0.980 b 0.975 a
Optimum (56.7) 0.995 a 0.995 a 0.995 a 0.995 a 0.995 a 0.995 a
-2% (54.7) 0.994 a 0.995 a 0.995 a 0.995 a 0.995 a 0.995 a
-4% (52.7) 0.995 a 0.995 a 0.995 a 0.995 a 0.970 c 0.995 a
SD 0.0-0.0057 0.0-0.0035 0.0-0.0071 0.0 0.0-0.0042 0.0-0.0035
Marshall, 16.8 +4% (58.4) 0.986 a 0.990 a 0.982 a 0.995 a 0.982 a 0.995 a
+2% (56.4) 0.989 a 0.995 a 0.993 a 0.988 a 0.992 a 0.995 a
Optimum (54.4) 0.995 a 0.995 a 0.994 a 0.995 a 0.995 a 0.995 a
-2% (52.4) 0.986 a 0.988 a 0.985 a 0.995 a 0.991 a 0.995 a
-4% (50.4) 0.995 a 0.995 a 0.995 a 0.995 a 0.995 a 0.995 a
SD 0.0-0.0120 0.0-0.0091 0.0-0.0141 0.0-0.0106 0.0-0.0177 0.0
'Water activity measured using microcrystalline cellulose method.
bPercent starch damage in Farrand units determined using Farrand method.
c Values followed by different letters indicate statistically significant differences at the 5% level.

values was very small (0.995-0.975) during the four-day storage 66: 128.
period for all samples presented in Table IX. The water activity FARRAND, E. A. 1964. Flour properties in relation to the modern bread
of the bread made from the Marshall flours with different levels processes in the United Kingdom, with special reference to a-amylase
and starch damage. Cereal Chem. 41:98.
of starch damage is presented in Table X. The water activity
FARRAND, E. A. 1972. Controlled levels of starch damage in a com-
range for these samples was 0.995-0.970. Statistically significant mercial United Kingdom bread flour and effects on absorption,
differences at the 5% level also are indicated in the table. The sedimentation value, and loaf quality. Cereal Chem. 49:479.
Marshall flour (24.3 Farrand units of starch damage) baked using MULTON, J., BIZOT, H., and SAVET, B. 1980. Water absorption in
the sponge and dough method showed the lowest water activity cereal foods and water activity measurement. Pages 97-117 in: Cereals
level when baked at 52.7% absorption. In general, the water for Foods and Beverages. G. E. Inglett and L. Munch, eds. Academic
activity remained in the 0.995-0.970 range for all samples used Press, Inc.: New York.
in the study, but there was a reduction in bread crumb moisture PISESOOKBUNTERNG, W., and D'APPOLONIA, B. L. 1983. Bread
during the same four-day storage period. staling studies. I. Effect of surfactants on moisture migration from
crumb to crust and firmness value of bread crumb. Cereal Chem. 60:298.
LITERATURE CITED ROGERS, D. E., ZELEZNAK, K. J., LAI, C. S., and HOSENEY, R. C.
1988. Effect of native lipids, shortening, and bread moisture on bread
AMERICAN ASSOCIATION OF CEREAL CHEMISTS. 1983. Ap- firming. Cereal Chem. 65:398.
proved Methods of the AACC. Method 08-01, approved April 1961, TIPPLES, K. H., and KILBORN, R. H. 1968. Effect of pin-milling on
revised October 1981; Method 22-10, approved May 1960, revised the baking quality of flour in various baking methods. Cereal Sci.
October 1982; Method 44-1SA, approved October 1975, revised October Today 13:331.
1981; Method 46-1 lA, approved October 1976, revised October 1982; VOS, P. T., and LABUZA, T. P. 1974. Technique for measurement of
and Method 54-21, approved April 1961, revised October 1982. The water activity in the high Aw range. J. Agric. Food Chem. 22:326.
Association: St. Paul, MN. ZELEZNAK, K., and HOSENEY, R. C. 1986. The role of water in the
CZUCHAJOWSKA, Z, POMERANZ, Y., and JEFFERS, H. C. 1989. retrogradation of wheat starch gels and bread crumb. Cereal Chem.
Water activity and moisture content of dough and bread. Cereal Chem. 63:407.

[Received April 15, 1991. Revision received March 3, 1992. Accepted March 4, 1992.]

586 CEREAL CHEMISTRY