Dough Samples Research Articles

Water mobility and microstructure of gluten network during dough mixing using TD NMR

This work aimed to establish the relationships between flour components, dough behaviour and changes in water distribution at mixing. TD NMR was used to track water distribution in dough during mixing for different mixing times and hydration levels. Four commercial wheat flours with distinct characteristics were expressly selected to exhibit various dough behaviours at mixing. TD NMR measurements of mixed dough samples revealed four to five water mobility domains depending on the flour type and the mixing modality. A classification tree procedure was used to identify characteristic patterns of water mobility in dough, called hydration states (HS). The HS changes with experimental conditions are highly dependent on flour characteristics, and HS were assigned to physical/chemical changes in the gluten network during dough formation. This study proposes an interpretation of the water distribution in dough based on gluten network development. This will help to adapt the mixing process to the flour characteristics.

Natural Alternative Curing Agent in Fermented Sucuk Production: Sugar beet (Beta vulgaris var. saccharifera L.) Molasses

In this study, sugar beet molasses was used as a natural curing agent in the production of fermented Turkish sucuk in two different forms (molasse and powdered molasse). Some quality characteristics were determined during the ripening (1st, 3rd and 5th days) period of the obtained sucuk dough (0. day) and sucuk samples. In order to compare the effects of molasses and powdered molasses used as natural curing agents in sucuk, a control (K) group containing sodium nitrate was formed. The application of the natural alternative curing process in sucuk production causes a decrease in the pH value and TBA content of the samples during the ripening period, whereas causes an increase in the nitrosomyoglobin and residual nitrate contents. As a result of microbiological analysis, it was determined that the natural alternative curing process increased (P<0.05) the number of LABs and there was no significant change in the total yeast-mold numbers during the ripening period (p>0.05). In addition, total Coliform group bacteria were not detected in sucuk dough and sucuk samples on the last day (5th day) of the ripening period. Consequently, it has been determined that it is possible to reduce the amount of chemical nitrate by using sugar beet molasses and powdered molasses as natural curing agents in sucuk formulation.

DEVELOPMENT OF TECHNOLOGY OF FROZEN SEMI-FINISHED PRODUCTS FROM YEAST DOUGH WITH STUFFING

Abstract. Today, food science knows many technologies for obtaining semi-finished products and readyto- go culinary products from yeast dough, along with comprehensive studies of their quality indicators. However, the vast majority of such developments concern dough products without stuffing. Also, for the most part, there is no review of ways to improve the quality of frozen ready-to-go products, especially aspects of the technology of re-freezing, thawing and cooking (warming) of ready-to-go products, in particular with stuffing, without changing the organoleptic properties of the finished products. Therefore, the technology of frozen semi-finished products from yeast dough with stuffing and the study of their quality indicators proposed in the work are appropriate, relevant and will be of scientific interest among specialists in the food industry. The purpose of the study is to develop the technology of frozen semi-finished products with stuffing and to study the influence of re-freezing, thawing and reheating on the quality indicators of finished products. The main results of the study. The influence of the introduction of dry wheat gluten on the quality of fibrin in the tested dough samples was determined experimentally, and its influence on the deliquescence of the fibrin ball was investigated. The recipe composition of the frozen semi-finished product from yeast dough with stuffing is presented, taking into account the mass fraction of added dry wheat gluten, as well as the technological scheme for the production of frozen semi-finished product from yeast dough with stuffing is developed. The optimal amount of adding gluten to the basic dough was found: it is advisable to replace no more than 4% of the mass of flour with fibrin. An analysis of the organoleptic quality indicators of the developed products with different contents of seaweed in the stuffing was carried out, which proved the relevance of adding algae as moisture-retaining agents. Prospects for further research in this direction. The analysis of the obtained data shows that the addition of kelp for no more than 3% and fucus for 5% of the weight of the stuffing is appropriate, improves and naturally enhances the taste properties of the products. Therefore, studies of the influence of kelp and fucus algae on quality indicators and storage of other flour and flour pastry products with stuffing will be promising.

Влияние ионизирующего облучения на пшеничную хлебопекарную муку

Radiation processing suppresses the development of microorganisms and pests in food products. This method is safe and does not affect nutritional value; however, it may change the properties of starch and proteins. The research objective was to define the effect of ionization on the baking properties and safety indicators of wheat flour.
 The study featured wheat flour subjected to gamma irradiation at 0–47.52 kGy, as well as dough and bread made from this flour. The flour samples were tested for the radioactivity of radionuclides; a set of experiments revealed their microbiological indicators and falling-number values. The dough samples were studied on an Alveograph and a Mixolab analyzer to define their structural and mechanical properties. The quality of bread was evaluated by its specific volume, shape stability, and sensory profile.
 The flour proved safe in terms of residual gamma radiation after 24 and 72 h. At the maximal dose of gamma radiation, the total viable count of mesophyll aerobic and optional-anaerobic microorganisms decreased by fifteen times, whereas the amount of mold decreased by five times. The total strain energy, elastic properties, and elasticity index of the dough declined by more than 50%. The dough had a lower stability during kneading. Its gelatinization onset started earlier by 2.3–3.3°C. The falling number decreased by more than four times, probably, due to the changes in the state of wheat starch. The bread samples had a smaller specific volume and a lower dimensional stability. They also demonstrated signs of darkening, stickiness, and crumb crushing at the maximal irradiation dose (47.52 kGy).
 The microbiological safety indicators of wheat flour increased at the maximal irradiation dose. However, the baking properties of flour decreased. The sensory and physicochemical parameters of bread quality started to deteriorate at ≥ 23 kGy. Therefore, ionization cannot be recommended as a disinfection method for baking wheat flour production.

Microbiological characteristics of bread dough and nutritional quality of “Tabnen-naow,” ethnic artisan bread in Burkina Faso

AbstractThis study aimed to evaluate the microbiological characteristics of bread dough and the nutritional quality of “Tabnen-naow,” an ethnic artisan bread consumed mainly in Burkina Faso. Originating in Boussé, this bread is spreading to the outskirts of Ouagadougou for several reasons, such as the increase in the price of industrial bread and especially the supposed low glycemic index of artisan bread. However, there is insufficient information in the literature about the nutritional quality and technology of artisan bread in Burkina Faso. For this purpose, surveys were conducted among artisan bakers in five artisan bread production units in Ouagadougou, using survey forms to draw the production diagram. The microbiological characteristics of bread dough were evaluated using standard microbiology methods. Lastly, the nutritional quality of ethnic artisan bread was determined using standard techniques. All the bakers were male, between 22 and 34 years old, with an average age of 27.8 ± 5.1 years. They all used wheat flour, mainly (80%) from the Grand Moulin du Faso (GMF). The Baker’s dough fermentation was done at room temperature using dry or lyophilized yeast. The interesting microorganisms (yeasts, lactic acid bacteria) were present in all the bread dough samples. The yeast (2.5 108 CFU/g) and lactic acid bacteria (2.27 107 CFU/g) were abundant apart from the one bread dough, which had a low lactic acid bacterial load. The ethnic artisan bread contains carbohydrates (88.20–89.05%), proteins (9.60–10.60%), and minerals such as iron (11.56 to 89.27 mg/kg), calcium (00.00–290.03 mg/kg), and zinc (69.18 ± 36.74 to 389.10 ± 32.89 mg/kg). The nutritional composition revealed that ethnic artisan bread could contribute significantly to a healthy diet and food security.

Functional properties of rice flour and its effect on conformation changes in the structure of wheat dough and bread

Situation in food industry in Ukraine and in the world has undergone significant changes during the last decade, especially the last year, which was caused by the military aggression of the russian federation. Diseases, particularly of the gastrointestinal tract, such as inflammatory bowel di-sease, have developed rapidly. In this regard, it is worth looking for approaches to diet therapy, which involves reducing dietary fiber in the diet. A promising raw material for inclusion in the recipe of bakery products is rice flour. The water absorbing capacity of rice flour was 60% hig-her compared to wheat flour. The study of the water holding capacity indicator showed the redistribution in the interaction of flours with water. For rice flour, this indicator increa¬ed by 27% compared to wheat flour. Fat absorbing capacity is higher for wheat flour than for rice flour by 7%, the increase in the ability to hold fat was by 35% for rice flour. The advantages of wheat flour over rice flour in terms of the ability to form constant emulsions were shown: the emulsifying ability index of wheat flour was higher by 80% than of rice flour, emulsifying stability — by 210%. The analysis of the spectra of the control sample of do-ugh and the dough samples with 10% and 20% replacement of wheat flour with rice flour showed that the control sample of the dough and sample with 10% and 20% rice flour after kneading have practically the same spectra. The spectra of the dough control sample after 3.5 hours of fermentation and sample with 10% and 20% replacement have lover value of the relative reflection coefficient. But dependence that spectra of control samples are lover persists. Spectra of bread samples regardless of the presence of rice flour overlap but aspire to the spectrum of control sample of the dough after 3.5 hours of fermentation.

Effects of HMW-GSs at Glu-B1 locus on starch-protein interaction and starch digestibility during thermomechanical processing of wheat dough.

The composition of glutenin protein significantly affects protein-starch interactions and starch digestion characteristics in wheat dough matrices. To elucidate the effects of high molecular weight glutenin subunits at the Glu-B1 locus on dough processing quality, the detailed structural changes of protein, starch, and their complexes were compared in Mixolab dough samples of two near isogenic lines 7 + 8 and 7 + 9. The results showed that the degree of protein aggregation increased continuously during dough processing, as did the destruction and rearrangement of the gluten network. Compared to 7 + 8, the stronger and more stable protein network formed in 7 + 9 dough induced intensive interactions between protein and starch, primarily through hydrogen bonds and isomeric glycosidic bonds. In 7 + 9 dough, the more compact and extensive protein-starch network significantly inhibited starch gelatinization during dough pasting, while during the dough cooling stage [from C4 (82.8 °C) to C5 (52.8 °C)], more protein-starch complexes composed of monomeric proteins and short-chain starch were generated, which remarkably inhibited starch retrogradation. All protein-starch interactions in the 7 + 9 dough improved the starch digestion resistance, as reflected by the high content of resistant starch. The more extensive and intensive protein-starch interactions in the 7 + 9 dough inhibited the gelatinization and enzymatic hydrolysis of starch, thereby producing more slowly digestible starch and resistant starch. These findings demonstrate the feasibility of optimizing the texture and digestibility of wheat-based food products by regulating the behavior and interactions of proteins and starch during dough processing. © 2022 Society of Chemical Industry.

Use of rice flour in wheat bread technology

Last decade is characterized by the increase in the incidence of inflammatory bowel diseases all over the world. Diet therapy, which includes reducing the amount of dietary fiber and including phospholipids in it, is effective in maintaining a sTable condition in case of these diseases. A promising raw material with a low dietary fiber content is rice flour, which may be added to the recipe of bakery products to replace part of wheat flour. The aim of the work was to determine the influence of rice flour on the course of the technological process and the characteristics of the dough in bakery products manufacturing, as well as on the quality indicators of bread made from wheat flour, which contains lecithin. Rice flour contains 1.8 times less protein than wheat flour, but this protein is more complete in amino acid composition. The content of dietary fibers in rice flour is 8.5 times lower. The gas-forming capacity of the dough with lecithin separately and in a mixture with rice flour increases by 8.4−18.7 % when replacing 10−40 % of wheat flour. It was established that in the dough sample with lecithin, the amount of formed and fermented sugars increased by 1.2 % and 12.1 %, respectively, compared to the control sample without additives. With an increase in the percentage of replacement of wheat flour with rice flour, the amount of formed sugars increased by 35.2−39.0 %. The amount of fermented sugars also increased by 19.6−31.8 % with an increase in the percentage of replacement. The shape stability of bread slightly improved with the addition of lecithin. However, when adding rice flour, the shape stability of the products decreased by 7.1−26.8 %, as well as the specific volume and porosity of bread

Testing of cement stone modified with an additive based on industrial waste

Nowadays under the conditions of intensively developing construction production, hardening time and strength of Portland cement are becoming more and more relevant research issues of this type of binder. The basic requirements to the cement stated in the normative industry documents are considered. The strength limits of Portland cement of normal and fast-hardening are given. Raw materials for the production of fast-hardening and high-strength cement must be homogeneous and provide a high degree of fineness of the binder to increase its surface area. The production of cement with the addition of microsilica will make it possible to obtain concretes with the given characteristics without additional costs. To describe the methodology of testing cement recommendations of the main regulatory documents operating in Kazakhstan are used. Necessary means and equipment used in the testing laboratory and satisfying the existing standards are listed in a sequential manner. The procedure of preparing standard samples of cement dough is described step by step. The prepared specimens were kept in water at the required temperature regime. Determination of bending and compressive strength was carried out on accredited equipment. Processing of test results of cement samples with and without additives is given. Setting times of cement samples of two compositions were carried out according to the requirements. The dependence of the activity of the cement setting process on its temperature has been determined.

Chinese traditional sourdough steamed bread made by retarded sponge-dough method: Microbial dynamics, metabolites changes and bread quality during continuous propagation

Continuous propagation of Chinese traditional sourdough (CTS) was adopted to simulate the industrial production of sourdough steamed bread made by retarded sponge-dough method (SSB). Establishment of a stable microbial ecosystem occurred in mature sourdough within four days of continuous propagation, as revealed by both microbial and metabolic analyses. Lactobacillus sanfranciscensis and Kazachstania humilis were the predominant bacterial and fungal species in mature sourdoughs. Their relative abundances changed significantly from the first to third day of continuous propagation while exhibited relatively constant from the fourth day onwards despite the use of flour/water for each back-slopping step. Major changes in the metabolites and fermentative characteristics were observed during the initial three days and dough samples showed little temporal metabolic and fermentative variations from the fourth days onwards. Consequently, volumetric and textural properties as well as the volatile flavor compounds of SSB displayed rather high stability from the fourth day onwards.

Improvement of cupcake technology with the addition of dried beet pomace

The object is de-sugared beet pomace, which contains a large amount of dietary fiber in its composition, as well as the technology of cupcakes with its addition. The task of enriching cupcakes with useful substances is tackled. A production technique of dried powdered beet pomace has been substantiated, which is characterized by low-temperature concentration modes in the rotary evaporator and post-drying in the roller IR dryer, which could contribute to the preservation of physiologically functional ingredients. The rheological characteristics of concentrated beet pomace in the rotary evaporator in the temperature range of 65–75 °C were determined. The established indicators revealed a tendency to reduce the effective viscosity depending on the temperature in the range of 42 to 27 Pa·s. For the speed of the rotary evaporator agitator of 200–300 min–1, the maximum level of effective viscosity of beet pomace of 3–5 Pa·s was established. Studies of the rheological characteristics of the dough with the introduction of dried beet pomace have made it possible to establish an increase in its elastic-viscous properties with an increase in the amount of additive. The highest indicator of effective viscosity ηef (Pa∙s) of the studied dough samples for cupcakes with the addition of an additive of 10 % is 347; 15 % – 384; 20 % – 442; and control – 287, respectively. The compression of the crumb of finished cupcakes was also determined, which increases by 10.2–22.4 % with an increase in the amount of beet pomace powder. The organoleptic and physical-chemical indicators of the quality of cupcakes revealed the optimal amount of application of dried beet pomace – 15 %. The selected sample contains physiologically functional ingredients, namely dietary fiber, low molecular weight phenolic compounds, minerals. The technology can be introduced into the confectionery industry

EFFECT OF DIFFERENT FOOD ENZYMES AS LEAVENING AGENT ON WHEAT FLOUR PROTEIN DURING FERMENTATION

The present study was undertaken for the characterization of wheat flour on the basis of protein content and dough quality and to evaluate the rheological changes of the dough after fermentation with a-amylase, protease, sodium acid pyrophosphate (SAPP) and yeast. In this experiment, three types of wheat flour (hard, soft and mixed) were used and the resulted gluten percentage were 1575, 10.14 and 5.78, respectively. Four types of dough samples were made. During fermentation of the dough, the temperature and pH of the dough mass using different leavening agents viz. a-amylase, protease, SAPP and yeast have been found optimum 24 to 25 °C at pH 5.9- 6.3; 25 to 26 °C at pH 6.2; 26 °C at pH 5.2 to 5.4 and 28 to 30 °C at pH 4.9 to 5.3, respectively. After fermentation, the content of gluten in different processed dough samples were estimated as 8.32 %, 0.11%, 6.5% and 3.15 %, respectively. The use of a-amylase resulted crispiness crumb, protease resulted very small yellowish crumb product, SAPP resulted very good crumb mass with increased volume and yeast showed more elastic crumb texture with gas cell at desirable stage. The results of the study indicate that, soft wheat flour can be used for quality biscuit dough preparation and the use of particular leavening agents can bring desirable rheological changes during fermentation. The particular leavening agents can also help to produce well structured crumb texture, sufficient gas cell (porosity) and color which are few of the requirements for standard biscuit production.

Physical and Sensory Qualities of Hydrocolloid Treated 80:20 Wheat-Cassava Composite Breads

The objective of this study was to determine the physical and sensory qualities of hydrocolloid treated 80:20 wheat-cassava composite bread. The study was limited to the use of various ratios of these hydrocolloids; carboxymethyl cellulose (CMC), gelatin and egg white. The dough samples from the various wheat-cassava composite flour, treated with egg white, gelatin and CMC respectively and in combination were baked using the straight dough method. The physical parameters- loaf weight were carried out 20 mins after baking using laboratory scale and the readings recorded in grams, then the loaf volumes were determined using seed displacement methods and the loaf samples weighed in a laboratory balance. Sensory evaluations were conducted using forty member trained panelists who were drawn from usual bread consumers to evaluate the quality attributes of the loaves for crumb texture, taste, color, appearance and overall acceptance. All analyses were carried out in triplicate and the results were subjected to statistical analysis using analysis of variance (ANOVA). Regression analyses of the data were conducted. Significance differences among the means were established at 5% level of using Duncan’s multiple range tests. The results obtained showed significant differences (P<0.05) among some of the parameters analyzed; loaf weights, loaf volumes and sensory attributes. Thus, 80:20 wheat cassava composite flour bread samples treated singly with egg white, gelatin and carboxymethyl cellulose or their combinations as hydrocolloids had different degrees of acceptability. The 80:20 wheat-cassava composite flour treated with a combination of egg white, gelatin and carboxymethyl cellulose (EGCm) in respective ratio of 1:2:1 or 1:1:2, yielded breads with similar volumes (4.17-5.27cm3/g) as reference 90:10 (W-C) and control (100% wheat) flour.

Elucidation of rheological properties of frozen non-fermented dough with different thawing treatments: The view from protein structure and water mobility

The objective of this study was to elucidate the rheology differences between the dough with different thawing methods in terms of protein structure and water mobility. The frozen dough samples were thawed by three methods: refrigerator (4 °C), proofer (25 °C, 85% RH), and microwave (1000W), respectively. Results showed that the rheological properties of doughs produced by refrigerator and proofer-thawing were closer to untreated dough than that produced by microwave thawing. Contrastingly, microwave-thawing produced doughs with a harder and less elastic texture. Besides, refrigerator and microwave thawing tended to have highest and lowest percentage of large polymeric proteins (LPP), respectively. A significant decrease in the proportion of α-helices, accompanied with the increased β-sheets and random coils was obtained from the microwave thawing group (P＜0.05). Furthermore, microwave-thawing had the biggest impact on water mobility and distribution, followed by proofer and refrigerator-thawing. The refrigerator-thawing produced dough samples with a more intact inner structure, indicating less damage and impact on the quality of dough.

Biological Activation of Baker's Yeast and the Possibility of Enrichment of Bakery Products with Peptides

Introduction. The stimulation of the fermentation activity of baker's yeast in baking and giving additional nutritional value to mass consumption food products is an important area of ​​scientific research.Purpose. The purpose of the study is to evaluate the effect of partial replacement of a salt solution with an enzymatic hydrolyzate of cow colostrum on the activation of baking yeast Saccharomyces cerevisiae when kneading the dough and to study the possibility of enriching bakery products with biologically active peptides.Materials and Methods. The research materials were model dough samples prepared without yeast activation and on activated yeast using enzymatic hydrolyzate of bovine colostrum. The presence of peptides in the dough samples was determined on a MALDI-TOF mass spectrometer, decryption was performed using the Mascot database, the Peptide Fingerprint option (Matrix Science, USA) using the Protein NCBI database.Results. It has been established that the replacement of the sodium chloride solution used in the dough formulation with the enzymatic hydrolyzate of bovine colostrum has a positive effect on the activation of metabolic processes in the yeast cells of Saccharomyces cerevisiae. The results obtained indicate that, compared with the control, the lifting force of pressed baker's yeast with a complete replacement of the salt solution with the enzymatic hydrolyzate of cow colostrum increased by 26%, for dried yeast, the lifting force increased by 20% compared to the control sample. In model dough samples, a biologically active peptide present in the used enzymatic hydrolyzate of bovine colostrum was identified, the amino acid sequence and molecular weight of the isolated peptide were determined.Conclusions. The use of enzymatic hydrolyzate of bovine colostrum in the technology of bakery products will speed up the production process and enrich the bread with biologically active peptides. But at the same time, it is necessary to conduct additional studies on the effect of activated yeast on the quality and shelf life of biologically active peptides in finished bread.

Assessment of the concentrations of ochratoxin A, zearalenone, and deoxynivalenol during cracker production

Flour samples spiked with ochratoxin A (OTA) (3,10 and 20 μg kg–1), zearalenone (ZEA) (75, 100, and 200 μg kg–1), and deoxynivalenol (DON) (500, 750, and 1000 μg kg–1), and combined mycotoxins (OTA, ZEA and DON at 20, 200 and 1000 μg kg–1) were split into two parts, one used immediately for cracker production, and the other kept at −80 °C for 18 h before the manufacture of crackers. The changes in mycotoxin concentrations in the control flour (without any mycotoxins), spiked flour, dough, and cracker samples produced from the normal and frozen flours were assessed using ultra-performance liquid chromatography. The reduction during fermentation ranked as OTA (21.16–25.92%) > DON (18.08–9.29%) > ZEA (0.02–7.01%), while during baking an increase in OTA (22.56–24.96%) and DON (11.80–21.9%) in contrast with a reduction in ZEA (1.07–3.28%) was noted. The thermal process used in the cracker production and the fermentation procedure used in dough preparation caused a significant decrease in the DON and ZEA concentrations in the final cracker products. The freezing of flour can be introduced as a new method to reduce the contamination by mycotoxins of cereal-based products.

Valorization of the under-utilized apricot kernels protein based on the rheology and texture properties of dough

As an under-utilized resource of the apricot kernel by-product, the apricot kernel flour (AKF) and its derivatives were analyzed and partially substituted for the wheat flour of the bread ingredients so as to explore it reutilization. The effects of AKF derivatives addition on the rheological and textural properties of the dough samples were investigated using confocal laser scanning microscopy, rheometer and texture analyzer, respectively. The results indicate that the protein is the main component in AKF derivative flours, and the texture and rheological properties of the dough samples were greatly influenced with the nutritional flours added in bread formula. The use of AKF derivatives leads to dough with higher hardness and weaker interaction between the starch and gluten than that of the control group. Moreover, the partial replacement with 10% of medium-fat apricot kernel flours is an effective way to improve the texture of dough samples. In a word, AKF derivatives could be well reused by partially replacing the wheat flour in the bread ingredients and improve the added-value of the under-utilized by-products.

Effects of Germinated Lentil Flour on Dough Rheological Behavior and Bread Quality.

The present study analyzed the effects of germinated lentil flour (LGF) addition at different levels in wheat flour (2.5%, 5%, 7.5%, and 10%), on dough rheological behavior, dough microstructure, and bread quality. Creep-recovery tests showed that the dough samples with high levels of LGF addition presented a higher resistance to flow deformability of the dough. Dough microstructure as analyzed using EFLM showed an increase in the protein area (red color) and a decrease in the starch (green color) amount with the increased level of LGF addition in the wheat flour. It was found that the LGF addition led to the improvement of the porosity, specific volume, and elasticity of the bread samples. The breads with LGF addition were darker and had a slightly reddish and yellowish tint. The bread textural parameters highlighted significant (p < 0.05) higher values for firmness and gumminess and significant (p < 0.05) lower ones for cohesiveness and resilience for the bread with LGF addition when compared with the control. The bread samples with a 2.5% and 5% addition had a more dense structure of the crumb pores. Regarding sensory evaluation, the bread samples with LGF addition in the wheat flour were well appreciated by the consumers. The addition also was desirable due to the fact that it supplemented bread with a greater amount of protein and minerals due to the composition of lentil grains. Therefore, LGF could be successfully used as an ingredient for bread making in order to obtain bread with an improved quality.

Zein and gluten interactions: A rheological and confocal Raman microscopy study

Zein has the unique ability to form a viscoelastic protein network, similar to gluten, upon hydration and shearing above its glass transition temperature. In the present work, confocal Raman microscopy, and small and large deformation rheological tests were used to study the interactions and structures driving zein and gluten network formation. Starch (80% w/w), protein (20% w/w) (composed of different proportions of zein and gluten) and water were mixed into a viscoelastic dough mass at 40 °C. Results showed that, although, the zein-rich dough samples exhibited higher extensibility and resistance to deformation, these samples had undesirable weaker elastic behavior (low G’ and G*, and low creep recovery percentage) according to rheological tests. The high resistance to extension of zein-rich dough samples was attributed to the β-sheet-rich fibrils that are stabilized by extensive hydrogen bonding. Confocal Raman microscopy also confirmed the described fibrillar network structure of zein. In addition, strong positive correlations were found between the tyrosine doublet intensity ratio (Raman), intermolecular β-sheets, and elastic properties of the dough samples. Based on the data obtained at different length scales, a model was proposed for the zein structure in a viscoelastic dough system.

The influence of varying levels of molecular oxygen on the functionality of azodicarbonamide and ascorbic acid during wheat bread making

Air, and thus also molecular oxygen (O2), is incorporated in wheat flour dough during mixing. O2 participates in several (enzymatic) reactions, including those resulting in the oxidation of free sulfhydryl groups, thereby increasing dough strength and bread volume. We here incorporated different O2 levels in dough by mixing dough samples for a fixed time under different modified atmospheres which led to significant changes in dough free sulfhydryl contents and bread volumes. Although altering the mixing time not only impacted how much O2 was incorporated in dough but also the mechanical input, the changes in dough and bread properties when using different mixing times, largely depended on differences in O2 uptake. When used in bread recipes, redox agents such as azodicarbonamide (ADA) and ascorbic acid (AH2) impact the dough sulfhydryl contents and bread volumes. The effect of different levels of O2 incorporation on dough samples which contained ADA or AH2 was studied by altering the mixing time or the O2 content in the mixing atmosphere. Lower ADA levels were needed when dough was mixed under an atmosphere enriched in O2. As AH2 requires O2 to be converted to dehydroascorbic acid (DHA) to exert its improver effect, it came as a surprise that when it was included in a dough which was prepared under O2 enriched conditions, no additional impact was obtained and that, even under reduced O2 conditions, its use still resulted in an increased bread volume. These findings suggest that AH2 oxidase very effectively uses O2 to form DHA.