The effects of whey protein fibrils on the linear and non-linear rheological properties of a gluten-free dough

The increasing awareness of the celiac disease, an autoimmune disorder caused by the consumption of products containing gluten, has led to a growing interest in the development of gluten-free bakery products. In this study, whey protein fibrils (WPFs) were incorporated to mimic the fibrous network of gluten. The rheological properties and microstructure of the developed gluten-free doughs were evaluated and compared with gluten doughs. Protein fibrils were prepared by heating a whey protein isolate (WPI) solution at 80°C in an acidic environment with low salt concentration, and then the fibril lengths were adjusted by leveling up the solution pH to 3.5 and 7. The dimensions of the fibrils were measured by atomic force microscopy (AFM). Rice and potato starches were mixed with fibrils, WPI, gluten, or without protein, to form different doughs for further investigation. Shear tests, including stress sweep, frequency sweep, and creep recovery, were performed to study the viscoelastic properties of doughs under small or large deformation. The strain-hardening properties of doughs under biaxial extension were studied by the lubricated squeezing flow method. The microstructure of the doughs was characterized by cryo-scanning electron microscopy (cryo-SEM). Compared with doughs prepared with WPI and no proteins, doughs incorporating fibrils showed comparable linear viscoelasticity to gluten dough tested with stress sweep, frequency sweep, and creep recovery in the linear viscoelastic region. More differences between the protein fibril doughs were revealed in the rheological properties in the non-linear region. Creep recovery parameters, such as compliance, elastic moduli during the creep, and recovery stages of gluten dough, were like those of WPF pH7 dough, but significantly different from those of the WPF pH3.5 dough. Strain-hardening properties were found in the WPF pH7 dough, although not in WPF pH3.5 dough. Microstructural characterization showed that both fibrils prepared with the different conditions formed a continuous protein phase for the improvement of dough cohesiveness, but the structure of the phase was different between the two fibrils. To summarize, whey protein fibril at pH 7 seemed to have the potential of being used as an ingredient with similar functions to gluten in gluten-free bakery products.

Physicochemical Effects of Lactobacillus plantarum and Lactobacillus casei Cocultures on Soy-Wheat Flour Dough Fermentation

In contemporary food production, an important role is given to the increase in the nutritional quality of foodstuff. In the bakery industry, one of the main cereals used is wheat flour (WF), which creates bread with proper sensory evaluation but is nutritionally poor. Soy-flour (SF) has increased nutrient content, and its consumption is recommended due to several health benefits. Dough fermentation with lactic acid bacteria (LAB) increases bread shelf life, improves flavor, and its nutritional quality, mostly due to its high organic acid production capability. In the present study, the addition of SF to WF, through fermentation with the cocultures of Lactobacillus plantarum and Lactobacillus casei was analyzed. Three different batches were performed by using WF supplemented with SF, as follows: batch A consisting of 90% WF and 10% SF; batch B—95% WF and 5% SF; batch C—100% WF. The fermentation with these two LABs presented several positive effects, which, together with increased SF content, improved the dough’s rheological and physicochemical characteristics. The dynamic rheological analysis exhibited a more stable elastic-like behavior in doughs supplemented with SF (G′ 4936.2 ± 12.7, and G″ 2338.4 ± 9.1). Organic acid production changes were the most significant, especially for the lactic, citric, and tartaric content.

Go clean label: replacement of commercial dough strengtheners with hard red spring wheat flour in bread formulations

There is growing interest in the application of natural ingredients to replace chemical dough improvers in bread formulations in order to meet consumer demands of clean label products. The goal of this study was to evaluate the dough quality and baking quality of hard red spring (HRS) wheat flour blends to replace commercial dough improvers. Hard red winter (HRW) wheat flour is commonly used in bread and diner roll formulations. In this study, doughs were prepared by adding 10%, 20%, 30%, and 40% of HRS wheat flour to HRW wheat base-flour to compare the dough quality and baking quality relative to different levels of commercial improvers. Additional to commercial HRS flour, two commonly grown HRS wheat varieties (Glenn and Linkert) were included in the study. All of the HRS wheat flour blends had significantly (p < 0.05) higher farinograph stability and extensograph resistance at 135 min than doughs containing most of the commercial additives. Bread flour with 40% Glenn and 40% Linkert showed the highest loaf volumes of 920 cm3 and 950 cm3, respectively with the firmness of 1553.50 and 1525.50 mN, respectively. Baking quality of HRS wheat flour blends also showed significant (p < 0.05) correlation with dough rheology but commercial additives did not have the correlations. Therefore, HRS wheat flour may be used as a replacement for dough improvers, as it had better dough and bread properties compared to commercial additives and provides a great alternative for "clean-label" bread products.

Influence of defatted mango kernel seed flour addition on the rheological characteristics and cookie making quality of wheat flour

Defatted mango kernel seed flour was added to wheat flour for the production of cookies. The protein contents of the wheat-mango kernel flour blend were optimized using optimal mixture design of response surface methodology. The farinograph analysis had acceptable mixing profile at 25%-defatted mango kernel flour incorporation, after which the mixing profile was adversely affected. The pasting temperature was between 65.8 and 75.6°C; peak viscosity ranged between 448 and 521 BU while the final viscosity ranged between 594 and 709 BU. The flour blends had promising dynamic rheological characteristics; at 15% incorporation of defatted mango kernel flour, G' was greater than G'' while a stage was reached when G' was equal to G'' at 25% incorporation. At 50% incorporation, G'' was greater than G'. The cookies produced showed high (>70%) quality in terms of physical properties, color, and sensory evaluation at 25% incorporation of defatted mango flour.

Taguchi-generalized regression neural network micro-screening for physical and sensory characteristics of bread

Generalized regression neural networks (GRNN) may act as crowdsourcing cognitive agents to screen small, dense and complex datasets. The concurrent screening and optimization of several complex physical and sensory traits of bread is developed using a structured Taguchi-type micro-mining technique. A novel product outlook is offered to industrial operations to cover separate aspects of smart product design, engineering and marketing. Four controlling factors were selected to be modulated directly on a modern production line: 1) the dough weight, 2) the proofing time, 3) the baking time, and 4) the oven zone temperatures. Concentrated experimental recipes were programmed using the Taguchi-type L9(34) OA-sampler to detect potentially non-linear multi-response tendencies. The fused behavior of the master-ranked bread characteristics behavior was smart sampled with GRNN-crowdsourcing and robust analysis. It was found that the combination of the oven zone temperatures to play a highly influential role in all investigated scenarios. Moreover, the oven zone temperatures and the dough weight appeared to be instrumental when attempting to synchronously adjusting all four physical characteristics. The optimal oven-zone temperature setting for concurrent screening-and-optimization was found to be 270-240 °C. The optimized (median) responses for loaf weight, moisture, height, width, color, flavor, crumb structure, softness, and elasticity are: 782 g, 34.8 %, 9.36 cm, 10.41 cm, 6.6, 7.2, 7.6, 7.3, and 7.0, respectively.

Optimization of mold wheat bread fortified with soy flour, pea flour and whey protein concentrate

The objective of this work was to study the effect of replacing a selected wheat flour for defatted soy flour, pea flour and whey protein concentrate on both dough rheological characteristics and the performance and nutritional quality of bread. A mixture design was used to analyze the combination of the ingredients. The optimization process suggested that a mixture containing 88.8% of wheat flour, 8.2% of defatted soy flour, 0.0% of pea flour and 3.0% of whey protein concentrate could be a good combination to achieve the best fortified-bread nutritional quality. The fortified bread resulted in high protein concentration, with an increase in dietary fiber content and higher calcium levels compared with those of control (wheat flour 100%). Regarding protein quality, available lysine content was significantly higher, thus contributing with the essential amino acid requirement.

Wheat dough microstructure: the relation between visual structure and mechanical behavior

The microstructure of food matrixes, and specifically that of wheat-flour dough, determines mechanical behavior. Consequently, the analysis of such microstructure is both necessary and useful for understanding the physico-chemical and mechanical alterations during the production of cereal-based products such as breads. Confocal laser scanning microscopy (CLSM) is an established tool for the investigation of these matrix properties due to its methodical advantages such as easy preparation and handling, and the high depth resolution due to the optical sectioning of probes. This review focuses on the microstructure of wheat-flour dough from a mechanical and visual point of view. It provides an overview of the dependencies between the visibly detectable microstructural elements achieved by CLSM and the physical determined rheological properties. Current findings in this field, especially on numerical microstructure features, are described and discussed, and possibilities for enhancing the analytical methodology are presented.

Effect of addition of thermally modified cowpea protein on sensory acceptability and textural properties of wheat bread and sponge cake

This paper investigates the sensory acceptability and textural properties of leavened wheat bread and sponge cake fortified with cow protein isolates that had been denatured and glycated by thermal treatment. Defatted cowpea flour was prepared from cow pea beans and the protein isolate was prepared (CPI) and thermally denatured (DCPI). To prepare glycated cowpea protein isolate (GCPI) the cowpea flour slurry was heat treated before isolation of the protein. CPI was more susceptible to thermal denaturation than GCPI as determined by turbidity and sulphydryl groups resulting in greater loss of solubility. This is attributed to the higher glycation degree and higher carbohydrate content of GCPI as demonstrated by glycoprotein staining of SDS PAGE gels. Water absorption of bread dough was significantly enhanced by DCPI and to a larger extent GCPI compared to the control, resulting in softer texture. CPI resulted in significantly increased crumb hardness in baked bread than the control whereas DCPI or GCPI resulted in significantly softer crumb. Bread fortified with 4% DCPI or GCPI was similar to control as regards sensory and textural properties whereas 4% CPI was significantly different, limiting its inclusion level to 2%. There was a trend for higher sensory acceptability scores for GCPI containing bread compared DCPI. Whole egg was replaced by 20% by GCPI (3.5%) in sponge cake without affecting the sensory acceptability, whereas CPI and DCPI supplemented cakes were significantly different than the control.