Frozen Sangak dough and bread properties: Impact of pre-fermentation and freezing rate

The impact of pre-fermentation time and freezing rate on Sangak frozen dough and bread quality were studied. The pre-fermented doughs for 0, 30, 60, 90, or 120 min were frozen under –20, –25, or –30°C in air blast freezer. After 24 h storage at –18°C, dough samples were baked after final fermentation. The yeast viability, gassing power, and dough development for fresh and frozen Sangak doughs were determined. Crust color, density, and shear stress of bread obtained from fresh and frozen Sangak dough were evaluated. The results showed that yeast survival initially increased and then decreased with increasing freezing rate. The maximum yeast survival was observed at short pre-fermentation (30 min). A direct relationship was observed between gassing power, dough development, and yeast viability. From bread quality point-of-view, short pre-fermentation and higher freezing rate led to a more desirable bread.     

Influence of vegetable shortening and emulsifiers on the unfrozen water content and textural properties of frozen French bread dough

The influence of vegetable shortening (VS) and emulsifiers (calcium stearoyl-2-lactylate (CSL) and polysorbate 80 (PS80)) on frozen French bread dough has been studied. Eight formulations without yeast were used with different quantities of VS, CSL and PS80. Dough was prepared by mixing all ingredients in a dough mixer at two speeds. The fresh dough was divided into 60 g pieces and molded. Fresh dough samples were also collected for water content and textural analyses. The dough pieces were packed, frozen in a freezer at −30°C and stored at −18°C up to 56 days. After 2, 7, 21, 28 and 56 days of frozen storage, samples were removed from the freezer, thawed at ambient temperature and textural analyses were conducted.The enthalpy of freezable water on fresh bread dough was determined by Differential Scanning Calorimetry (DSC) at the heating rate of 3°C/min, temperature range of −40°C to 20°C. The value of unfrozen water was 0.30–0.34 g H₂O/g solids and additives used during the storage up to 56 days significantly affected the textural properties of frozen dough.     

Effect of sourdough processing and baking on the content of enniatins and beauvericin in wheat and rye bread

The occurrence of the emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) has been reported in Fusarium-infected cereals. To study the effect of sourdough processing and baking on ENN B, ENN B1, and BEA concentrations, a recently developed stable isotope dilution assay for these mycotoxins was used. After milling of wheat and rye grains naturally contaminated with ENN B and ENN B1, approximately 70–82 % of the two ENNs were found in the bran fraction and the rest remained in flour. BEA was added to flour before sourdough fermentation. In an experiment on a microscale, dough was fermented for 24 h at 30 or 40 °C, which reduced part of the ENNs and BEA in particular at 40 °C. On a standard scale, mixing, resting, and proofing of the bread dough resulted in 13–19 % reduction of the ENNs compared with flour, but in no significant change of BEA. The final baking at 200 °C for 25 min led to a further decrease of the ENNs and BEA, ranging from 9 to 28 % compared with fermented dough. In case of rye sourdough bread, greater reductions of ENNs were found in crust than in crumb. For both wheat and rye flours, overall 25–41 % of ENN B, ENN B1, and BEA were reduced during the whole sourdough bread-making process.     

Effects of hydrothermal processing on rutin retention and physicochemical properties of Tartary buckwheat enriched dough and Chinese steamed bread

Effects of hydrothermal processing on content changes of rutin, quercetin and total flavonoids and physicochemical properties of Tartary buckwheat (TB) enriched dough and Chinese steamed bread (CSB) were investigated. Rutin loss and bitterness in CSB made from mixed wheat flour and hydrothermally processed TB flour decreased markedly compared with control. Total flavonoids were increased in dough after fermentation but decreased afterwards in CSB significantly (P < 0.05). The development time, stability time, extensibility, storage and loss moduli and tan δ of TB enriched dough, along with the volume, textural properties, sensory evaluation and bitterness of derived CSB, were significantly affected by hydrothermal processing temperature and time. Hydrothermal processing of TB flour at 100 °C for 20 min, compared with 100 °C for 10 min, 30 min or 121 °C for 10 min, 20 min, 30 min, was suggested to be a relatively better pretreatment condition for the present TB enriched CSB.     

Temperature-induced changes in dough elasticity as a useful tool in defining the firmness of cooked pasta

Semolina with high protein content and strong gluten is recognized as the best raw-material for pasta-products with a good cooking quality, while little consideration has been given to semolina dough elasticity when heating is applied. In this research, a new technique was developed by adapting the Glutograph (Brabender GmbH&Co., Duisburg, Germany) to measure the changes in elasticity induced by heating on a sheeted dough. The information obtained by this procedure was related to the firmness of cooked pasta. Starting from semolina of four durum wheat varieties with differences in protein quantity and quality, dough samples were prepared in a Farinograph at a hydration level of 35 %. Each dough was sheeted by a home-made pasta machine, obtaining disks of 5 cm diameter and 2.1 mm thickness. Stretching (10 s) and relaxation (30 s) cycles were applied repeatedly during the test time, while dough temperature was increased from 30 to 90 °C at 1.2 °C/min. For each peak recorded, stretching and recovery values were calculated and plotted against sample temperature. Both stretching and recovery curves were integrated and the loss of elasticity was calculated. Results showed as high elasticity loss during heating is related to low firmness of the related cooked pasta.     

Overall and Local Bread Expansion,Mechanical Properties,and Molecular Structure During Bread Baking: Effect of Emulsifying Starches

In order to determine the relationship between molecular structure of wheat bread dough, its mechanical properties, total and local bread expansion during baking and final bread quality, different methods (rheological, nuclear magnetic resonance, magnetic resonance imaging and general bread characterisation) were employed. The study was extended on wheat dough with starch modified by octenyl succinic anhydride (OSA) in order to generalise the results. The interest of investigating multi-scale changes occurring in dough at different phases of baking process by considering overall results was demonstrated. It was found that OSA starch improved the baking performance during the first phase of baking. This feature was due to a higher absorption of water by OSA starch granules occurring at temperatures below that of starch gelatinization, as confirmed by NMR, and consecutive higher resistance to deformation for OSA dough in this temperature range (20–60 °C). This was explained by a delayed collapse of cell walls in the bottom of the OSA dough. In the second phase of baking (60–80 °C), the mechanism of shrinkage reduced the volume gained by OSA dough during the first phase of baking due to higher rigidity of OSA dough and its higher resistance to deformation. MRI monitoring of the inflation during baking made it possible to distinguish the qualities and defaults coming from the addition of OSA starch as well as to suggest the possible mechanisms at the origin of such dough behaviour.     

Effect of temperature and consistency on wheat dough performance

The effects of the dough consistency (DC; 300–700 BU), temperature of mixing (16–32 °C) and temperature along fermentation (15–35 °C) on the wheat bread dough performance during mixing, proofing, cooking and cooling have been studied through a central composite experimental design. Farinograph responses revealed the significant role of DC (α < 0.001) and mixing temperature (MT) (α < 0.001) on wheat bread dough elasticity. Fermentation responses obtained from the rheofermentometer showed that the DC induces a significant positive linear effect on dough development, whereas gas development was mainly governed by the fermentation temperature. The wheat bread dough behaviour subjected to a dual mechanical shear stress and temperature constraint showed that DC had a significant linear and positive effect on the starch gelatinisation and gelling process. Therefore, breadmaking is highly governed for DC, namely dough hydration, which has a direct consequence on the mixing, fermenting, cooking and cooling performance of the wheat bread dough.     

Bacilli Spoilage in Part-baked and Rebaked Brown Soda Bread

Brown soda bread had a pH of 7-9 depending on the sodium bicarbonate concentration. Part-baked bread developed ropiness after two days at room temperature. Bacillus subtilis, B. pumilus and B. licheniformis were isolated and their spores displayed D-values in bread dough of 14, 10 and 56 min at 100°C. Germination and growth was examined in broth at pH 6-10 and at 4°, 20°, 30° and 37°C. No growth was observed at 4°C and at pH 10. Rebaking of the part-baked bread heat activated particularly B. licheniformis spores.     

Fermented Frozen Dough: Impact of Pre-fermentation Time and of Freezing Rate for a Pre-fermented Frozen Dough on Final Volume of the Bread

This paper proposes an original study on the impact of the process condition using pre-fermented frozen dough on the final bread volume. The impact of the degree of pre-fermentation before freezing and the impact of the freezing conditions have been considered with an experimental design procedure. The first fermentation step (pre-fermentation) was between 60 and 120 min and the corresponding second (or final) fermentation was between 60 and 0 min, respectively, resulting in a total fermentation time of 120 min. Freezing was performed between the first and the second fermentation at −20°C, −30°C or −40°C in blast air tunnel. The results show that the faster the freezing rate, the higher the final bread volume. Further work is needed to fully optimise this process, which is minimally present at the industrial bread market, whereas the technology is now adopted by many viennoiseries such as croissant and laminated puffing pastries.     

Experiments on dough rheology to improve screening of bread wheat cultivars

The bread‐making potential of flour may be roughly estimated by dough rheology, especially its tolerance to over‐mixing as determined with the farinograph. The objective of this study was to identify the relative effects of experimental conditions likely to affect dough mixing stability: mixer speed, temperature, salt, yeast and bread additives such as ascorbic acid and preservatives. The addition of 1–2% salt or ascorbic acid (50 mg kg^?1 flour) improved dough mixing stability and counteracted the negative effect of bread preservatives. Mixing salted dough at slow speed (63 rpm) and 25 °C might be a more realistic bread‐making procedure for performing dough rheology assays with equipment such as the farinograph, compared to official methods (only flour and water, no salt; 30 °C). Amongst five bread wheat cultivars, differences existed in dough strengthening response to both salt and ascorbic acid, a property that may find application in wheat breeding and screening.     

发酵工艺对马铃薯面包品质及消化特性的影响

为研究不同发酵工艺对马铃薯面包品质及消化特性的影响,分别采用快速发酵法、直接发酵法、中种发酵法、过夜种子面团法、低温过夜发酵法制作马铃薯粉占比20%的面包,测定不同发酵工艺得到的马铃薯面包的质构特性、比容、感官及体外消化特性。结果表明:快速发酵法的硬度和咀嚼度最高,与低温过夜发酵法制作的面包均存在黏附性高、硬度大的问题;直接发酵法与过夜种子面团法质构特性优于快速发酵法和低温过夜发酵法;中种发酵法制作的马铃薯面包硬度小、弹性大,比容(4.43)和感官评分(89.33)最佳,面包品质相对最高;发酵工艺可影响面包的血糖生成指数(GI)值,快速发酵制作的面包GI值最低(87.11),中种发酵制作的面包GI值最高(112.18),GI值与产品的感官评分呈负相关。     

Effect of Temperature on the Solubility of CO2 in Bread Dough

Dough expansion during fermentation is caused by CO₂ production by yeast, and its transfer from liquid state in the dough liquor to gaseous phase in the gas cells. The liquid-gas equilibrium is controlled by the solubility of CO₂ in the dough and by the Henry coefficient. The solubility of CO₂ in bread dough was measured for different temperatures with a specific device based on the evolution of the pressure during fermentation at constant volume. The measurements range from 15 to 40°C. Data obtained was extrapolated to 0 and 50°C. Values were found between 1.6 × 10^?5 and 5 × 10^?6 g CO₂ kPa^?1 g^?1 LPD, at 0 and 50°C, respectively (LPD: Liquid Phase of Dough).     

Effects of wheat sourdough process on the quality of mixed oat-wheat bread

The aim of this work was to study the effects of sourdough fermentation of wheat flour with Lactobacillus plantarum, on the quality attributes of mixed oat-wheat bread (51 g whole grain oat flour and 49 g/100 g white wheat flour). Emphasis was laid both on β-glucan stability as well as bread structure and sensory quality. The variables of the sourdough process were: dough yield (DY), fermentation time, fermentation temperature, and amount of sourdough added to the bread dough. The sourdough process was shown to be a feasible method for mixed oat-wheat bread, and, when optimized, provided bread quality equal to straight dough baking. A small amount (10g/100 g dough) of slack sourdough fermented at high temperature for a long time resulted in the most optimal sourdough bread with the highest specific volume (3.5 cm³/g), the lowest firmness after 3 days storage (0.31 kg), and low sensory sourness with high intensity of the crumb flavour. Wheat sourdough parameters did not affect the content of oat β-glucan in the bread. Additionally, both straight dough and sourdough bread contained 1.4-1.6 g β-glucan/100 g fresh bread. The average molecular weight of β-glucan was 5.5 × 10⁵ in both types of bread, while that of oat flour was 10 × 10⁵. This indicates that a slight degradation of β-glucan occurred during proofing and baking, and it was not affected by variation in the acidity of the bread between pH 4.9-5.8.     

Effects of hydrophilic hydrocolloids on dough and bread performance of samples made from frozen doughs

ABSTRACT:  The objective of this study was to determine the effects of hydrocolloids in dough (xanthan 0.02%, 0.06%, and 0.1%; κ-carrageenan and carboxymethylcellulose 0.2%, 0.6%, and 1.0%) and duration of frozen storage on the quality of finished bakery product. Doughs were prepared with different concentrations of gums, stored at −18 °C and analyzed after 0, 7, 14, and 30 d for fermentation activity of yeast and rising time of dough. At the end of each frozen storage interval, bread was prepared and characterized for specific volume, crumb firmness, and crumb structure. The addition of the gums had significant effects on dough performance and quality of the final product. Gums at all tested concentrations reduced fermentation activity of yeast and prolonged the rising time of dough, which was similar to the effects of frozen storage. However, specific volume of bread for the control sample significantly decreased on the 30th d of frozen storage. Addition of hydrocolloids resulted in higher specific volume of loaves compared to the specific volume of control sample loaves. With the increase of the duration of frozen storage the specific volume of bread decreases in all analyzed samples. This decrease is less in the samples with hydrocolloids compared to the decrease in the control sample. The addition of 0.1% xanthan accomplished the same or higher values for specific fermentation activity, specific volume, and penetrometric's number compared to the values accomplished by the addition of 1% carboxymethylcellulose and κ-carrageenan, respectively.     

Rheological Changes of Dough and Bread Quality Prepared from a Sweet Dough: Effect of Temperature and Mixing Time

Abstract

The effect of dough mixing time and temperature on the extensographic characteristics of yeast sweet dough was studied. Changes on bread structural characteristics were also evaluated. Mixing time was varied from 15 to 35 min. Temperature was worked out on four ranges: 16–19, 19–22, 22–25, and 25–29°C. Results showed that extensibility did not change at short mixing times (15 min). As temperature and mixing time increased, extensibility also increased, varying from 9.6 to 29 cm. Resistance to extension was a function of both temperature and mixing time, reaching a maximum value of 650 extensographic units (EU) and a minimum of 180 EU. As temperature increased, greater resistance to the extension values were observed at shorter mixing times. Bread apparent density was also affected by mixing time, whereas temperature did not affect. Firmness also increased with mixing time and temperature. Extensographic and bread characteristics showed an abrupt change depending on process conditions, indicating a limit of energy input to provoke this behavior. Although rheological results could be fitted to a mathematical model, there was not a single equation that fits all data.     

Effect of cold pre‐treatment duration before freezing on frozen bread dough quality

The effect of cold pre‐treatment (CT) duration prior to freezing on the quality of a standard bread dough was investigated. Doughs held at 0 °C or 10 °C for 1 h or 3 h before air‐blast freezing were compared with standard dough frozen after 0.5 h at 0 °C (0 °C/0.5 h) and fresh (unfrozen) dough. Cumulative gas production measured in a risograph was used to quantify the dough quality after storage at ?18 ± 0.1 °C for 1, 7 or 17 days. Relative to fresh dough, gas production significantly reduced after freezing for all treatments. The doughs with CT at 0 °C for 1 or 3 h or 10 °C for 1 h had significantly higher gas production after freezing and less rapid decline in gas production during frozen storage than the doughs with the 0 °C/0.5 h CT. The 10 °C/3 h CT gave no gas production benefit after freezing and had the most rapid decline in gas production during frozen storage.     

DIFFERENTIAL SCANNING CALORIMETRY OF STARCH12

At high water-to-starch (2:1) ratios a single endotherm was obtained for starch gelatinization. As the water-to-starch ratio was decreased the endotherm area decreased and the peak developed a trailing shoulder. At high water-to-starch ratios birefringence is lost over a temperature range of about 7°C. That narrow range increases to about 30°C at a low water-to-starch ratio. Starch and flour gave essentially the same endotherm initiation temperatures. In low-water systems the second DSC peak is much smaller with starch than with flour. It appears that in a starch system, water migrates during gelatinization. In dough, gluten limits that migration. As the level of sucrose was increased in a dough, the transition temperature increased and the gelatinization temperature range decreased. At the levels found in bread doughs both sugar and salt increase starch gelatinization temperatures.     

Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processes

Two different green tea extracts (GTE‐A and ‐B) as a rich source of tea catechins were incorporated into a no‐time bread‐making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE‐A and ‐B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE‐A with higher content of tea catechins (73%) at a level of 1.5 g kg^?1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 °C). GTE‐B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg^?1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at ?20 °C. Copyright © 2006 Society of Chemical Industry     

Effect of fermentation on naturally occurring deoxynivalenol (DON) in Argentinean bread processing technology.

The stability of naturally occurring DON was evaluated during the fermentation stage of the bread-making process on a pilot scale. Two different products, French bread and Vienna bread, were prepared with naturally contaminated wheat flour (150 mg kg(-1)) under controlled experimental conditions. Dough was fermented at 30, 40 and 50 degrees C according to standard procedures employed in Argentinean low-technology bakeries. When the dough was fermented at 50 degrees C, the maximum reduction was 56% for the Vienna bread, with French bread being reduced by 41%. DON reduction during bread-making occurs not only in the baker due to thermal decomposition, but also during the fermentation step. The Argentinean traditional bread-making process might reduce DON levels during the fermentation stages if the dough is leavened at temperatures > 30 degrees C.     

The effects of wheat sourdough on glutenin patterns, dough rheology and bread properties

Sourdough was prepared with cellular suspension containing 10⁹ cfu of each strain mL⁻¹ and incubated at 28 °C for 24 h and at 37 °C for 4 h. Two different sourdough levels (20 and 40%) were used in bread dough preparation. The bread doughs were proofed at 30 °C and 85% relative humidity for 60/120/180 min. When glutenin changes that occurred in samples 17, 18, 19, and 20 (40% SD 28) are compared with those that appeared in controls, it is obvious that, the relative intensities of some of the protein bands slightly decreased and a few fainter protein bands appeared (which did not exist in controls). A few fainter protein bands corresponding to the MM ≈ 25 kDa (high-mobility region) and the MM ≈ 66 kDa (low-mobility region) were appeared in the same samples. In the samples prepared with 20% sourdoughs incubated at 28 or 37 °C, the bands were still evident after 180 min of proof. This can be explained that glutenin fractions were not hydrolysed in these applications due to the delay in pH drop. The use of 40% sourdough incubated at 28 °C for 24 h resulted in sticky doughs and breads with lower volume, harder texture, unsatisfactory crumb grain and unpleasant flavour than the rest of the samples. The use of sourdoughs incubated at 37 °C for 4 h caused positive effect on loaf volumes, specific loaf volumes and crumb structure.