R. C. Hoseney

Glucose oxidase in breadmaking systems

ABSTRACT The mechanism of glucose oxidase action in breadmaking was investigated by studying the baking performance of glucose oxidase, the active ingredient that it produced, and its effect on the rheological properties of dough. Glucose oxidase improved the loaf volume of bread made by 45-, 70-, and 90-min fermentation processes. Although the increase in loaf volume was significant, it was less than that obtained with an optimum level of KBrO3. With the 90-min fermentation process, the crumb grain of bread was similar for loaves oxidized with optimum levels of glucose oxidase or KBrO3. The rheological properties of doughs containing glucose oxidase and doughs containing no oxidant were compared. Doughs made with glucose oxidase had higher G′ and G″ and lower tan δ values than doughs made without an oxidant. Hydrogen peroxide was responsible for a drying effect in doughs. This drying effect of glucose oxidase was reduced significantly by incorporation of free radical scavengers into the dough.

Factors in hard wheat flour responsible for reduced cookie spread

ABSTRACT Time-lapse photography showed that, during baking, the diameter of sugar-snap cookies increased linearly then suddenly became fixed. Therefore, cookie diameter was a function of spread rate and set time. Cookies made with soft wheat flour were significantly larger in diameter (184 mm) than those made with hard wheat flour (161 mm). Cookies made with soft wheat flour set later (5.8 min) during baking than those made with hard wheat flour (5.1 min). The differences in set time within cookies made with various hard wheat flours or within cookies made with various soft wheat flours appeared to be affected by flour protein content. However, other factors also affected the difference in set time between cookies made with hard wheat and soft wheat flours. Cookies made with soft wheat flour spread at a faster rate (7.8 mm/min) than those made with hard wheat flour (4.6 mm/min). The level of soluble starch in the flour appeared to cause the difference in spread rate between cookies made with hard wheat an...

Role of Salt in Baking

The general term salt in baking formulas refers to sodium chloride. Salt is one of the four essential ingredients in bread (flour, salt, yeast, and water). The functions of salt in baking include stabilizing yeast fermentation rate, strengthening the dough, enhancing the flavor of the final product, and increasing dough mixing time. The flavor-enhancing function of salt is well known. Omitting salt from the formula results in baked products that are quite tasteless. At the level used, salt does not impart a salty taste to the product but rather brings out the other flavors in the system. It is also known to increase sweetness and mask metallic, bitter, or other off flavors. The reasons and mechanism of this function of salt are outside the expertise of the authors and will not be discussed further in this manuscript. An important function of salt in breadmaking is its stabilizing effect on fermentation. In dough made without salt, the yeast ferments excessively resulting in gassy, sour dough and baked products with open grain and poor texture (14). Salt inhibits or “controls” fermentation rate by decreasing the rate of gas production (6), which results in longer proof times (18,25). This appears to be the result of increased osmotic pressure and the action of the sodium and chloride ions on the membrane of the yeast cells (14). Salt gives the baker a tool to control the production of carbon dioxide gas and the other products of fermentation, especially in the warm summer months if temperature control is a problem in the bakery. It is well known in the baking industry that salt lengthens the mixing time of dough (Fig. 1). This has been well documented by the farinograph (7,13,17, 21,22,27,29) and in the mixograph (4, 12,24). The longer mix time slows the rate of production in large bakeries that are on tight production schedules and increases the energy cost of mixing. Therefore it is common practice to delay salt addition until the dough has reached the clean-up stage (when the dough forms into a continuous mass and no longer sticks to the sides of the mixer). At this stage the dough is essentially hydrated and the added salt does not affect the time required to finish mixing. Farinograph studies have also shown that salt decreases water absorption (7,13, 21,22,27,29). This effect was not reported in mixograph or baking studies. It is well known that salt has a strengthening effect on dough. This has been documented in the farinograph (7,13,17,22, 27,29), mixograph (4,12,24), ex t ens ig r aph (21,27), and baking studies (5,6,9). FEATURE

Effect of formula water content on the spread of sugar-snap cookies

ABSTRACT Sugar-snap cookie doughs prepared with a commercial soft wheat flour and standard formula water (25%, fwb) produced baked cookies with a mean diameter of 186 mm. Increasing the formula water to 30% resulted in cookies with a mean diameter of 187 mm and decreasing the formula water to 20% resulted in cookies with a mean diameter of 185 mm. A similar effect was seen when the formula water in cookie doughs prepared with the pure hard red spring cultivar Butte 86 or the pure soft white winter club cultivar Paha was varied. Thus, varying the formula water in cookie dough appeared to have little or no effect on final cookie diameter. Formula water content, however, did affect cookie dough spread rate and set time during baking. Increasing the formula water caused the spread rate to increase but shortened the set time. As a result, final cookie diameter was essentially unchanged.

Glucose oxidase effects on gluten and water solubles

ABSTRACT Hydrogen peroxide was responsible for the improving the effect of glucose oxidase in breadmaking. The mechanism by which H2O2 has its effect is not known. The objective of this study was to determine whether the H2O2 produced by glucose oxidase affected the gluten proteins or the water-soluble fraction of flour. Glucose oxidase had no effect on gluten protein as measured by protein solubility or the relative viscosity of soluble protein (solubilized using 1.5% w/v SDS). However, glucose oxidase did affect the water-soluble fraction. The sulfhydryl content of the water-soluble fraction extracted from flour or dough decreased in the presence of glucose oxidase. Glucose oxidase also caused oxidative gelation of the water-soluble fraction extracted from flour. However, the viscosity of the water-soluble fraction extracted from fermented doughs containing glucose oxidase decreased when higher levels of glucose oxidase were used (≥5.0 units of glucose oxidase). Glucose oxidase appeared to have the same...

Bread crumb grain development during baking

ABSTRACT Scanning electron microscopy was used to study gas cell size, shape, and distribution throughout the breadmaking process. Flours that produced bread with a relatively good grain and a relatively poor grain were used. Micrographs of the dough samples were taken at mixing; before and after each of two punches; before and after panning; after proofing; and after 12, 18, and 24 min (complete) of baking. No differences were found between the two flours at any dough stage. However, after 12 min of baking, the cell distributions were different between the doughs. These results suggest that the crumb grain differentiates during the early stages of baking. The changes documented during this time, i.e., cells becoming larger and the cell walls thicker, indicate that some gas cells coalesce during the early stages of baking and that this is reflected in the crumb grain of the bread.

Dynamic rheological properties of wheat starch-gluten doughs

ABSTRACT Flour-water doughs made from strong and weak flours were tested using a dynamic rheometer with cone-and-plate geometry. Flour was fractionated to determine what component or components were responsible for the dynamic rheological properties (elastic modulus [G′], viscous modulus [G″], and tan δ [G′/G″]) values. Doughs made from strong flour had lower tan δ values than medium or weak flours. The isolated starch or gluten fraction was combined with vital wheat gluten or commercial wheat starch. Only Larned starch gave doughs that were significantly different in dynamic rheological properties from dough made with other starches. The gluten isolated from strong flours gave doughs that were significantly different from doughs made with gluten isolated from weak flours. Reconstituted flours containing starch, gluten, and various amounts of lyophilized water-solubles were tested. Addition of water solubles decreased the elastic modulus and dramatically shortened optimum mixing time of the reconstituted ...

Effects of (1→3)(1→4)-β-D-glucans of wheat flour on breadmaking

ABSTRACT Water-soluble nonstarch polysaccharides were extracted from commercial hard red winter wheat flour and separated into three fractions by graded ethanol precipitation. The three fractions, F15, F40, and F60, varied in polysaccharide composition. Fraction F15 was rich in watersoluble (1→3)(1→4)-β-d-glucans, and fractions F40 and F60 were rich in arabinoxylans. Addition of individual fractions to a bread formula did not affect bread loaf volume. Addition of fraction F15 to the formula improved bread crumb grain. Treatment of (1→3)(1→4)-β-D-glucan-rich fraction F15 with lichenase before its addition to the bread formula resulted in bread with poor crumb grain. Treatment of the F15 fraction with β-xylanase before its addition to the bread formula resulted in bread with slightly improved crumb grain. Presumably, the (1→3)(1→4)-β-D-glucans in fraction F15 improved crumb grain by stabilizing air cells in the bread dough and preventing coalescence of the cells. Addition of pentosan-rich fractions F40 and ...

Factors Affecting Expansion of Corn Meals with Poor and Good Expansion Properties

ABSTRACT Two corn meals, one with good and one with poor expansion properties, were used to study the critical factors responsible for poor expansion during corn curl extrusion. Screening tests revealed that the corn meal with poor expansion had a slightly larger particle size. This sample also had a larger proportion of opaque particles compared to the corn meal with good expansion. Extrusion of coarse corn grits showed that larger particle size alone could cause poor expansion. Water diffusion tests showed that the sample containing more opaque particles was more competitive for water. As a result, in corn that contained both opaque and vitreous particles less water was available to the vitreous particles. The underplastisized (dry) vitreous particles remained glassy (unmelted) during extrusion, resulting in reduced expansion of the extrudates. The results suggest that addition of water to the conditioning cylinder of the extruder would overcome poor expansion.

Factors controlling gas cell failure in bread dough

ABSTRACT Stress relaxation in the wall of a gas bubble, as measured by the alveograph, was used to study surface tension at the gas-dough interface of doughs from flours producing differing bread crumb grains. The surface tensions in the various wheat flour doughs were not different. Dough rheological properties, as measured by both dynamic oscillatory rheometry and lubricated uniaxial compression, were not different for doughs made from wheat flours that gave breads with different crumb grains. However, when the effect of starch granule size on gas cell wall stability was tested, the presence of a greater proportion of large starch granules in wheat flour dough was sufficient to result in gas cell coalescence and open crumb grain in the final baked product. This suggests that starch granule size is at least one of the factors that affects the crumb grain of bread.