Improving the Technological and Nutritive Properties of Gluten-Free Bread by Fresh Curd Cheese Enrichment

Replacing wheat flour in the breadmaking process is a technology challenge since the absence of gluten has a strong influence on overall bread quality. Protein-rich source substitutes are often used to aid a formation of a protein network capable of mimicking gluten-like structure so that it would support the gas cells of the dough foaming. Apart from the protein structuring ability, the interaction with starch granules can perhaps be useful to make them less available for enzymatic degradation, becoming a nutritional advantage. When the bread matrix includes simultaneously proteins and lipids, the nutritional advantages can be further enhanced, since the lipids can form lipid-amylose complexes influencing the final dough consistency. Therefore, nutritional gains in terms of the glycemic response of gluten-free bread can be positively improved. This study aimed at evaluating the technological and nutritional functionality of curd cheese as a protein and lipid source, and as a promising alternative bakery ingredient in gluten-free breadmaking. The influence of curd cheese, based on its ability to strengthen gluten-free dough structure, by testing several levels of addition (5% up to 20%, weight/ weight) focused on: i) dough rheology properties, mainly flow and viscoelastic profile modifications, ii) starch physical behaviour by pasting properties measurements, was assessed in detail. The quality of the derived bread samples was evaluated by measuring the post-baking quality. Nutritional gains focused on the chemical composition and glycemic response were further assessed. Considering the highest level of curd cheese (20%) tested, improvements in bread quality were observed, leading to a considerable increase in bread volume (73%) and softness (65%), with a marked reduction in staling kinetic (70%), comparing with control bread. Additionally, an improvement in nutritional value in terms of proteins (80%) and minerals content, particularly P, Mg and Ca, covering more than 15% of the daily recommended doses, was obtained. As for the glycemic response, a considerable reduction of 40%, resulting in bread with an intermediate glycemic index, was achieved. Strong linear correlations (R2 > 0.902) were observed between dough rheology properties and bread quality attributes, pasting properties, in vitro starch digestibility, and glycemic index. The linear relations found can be used to support the hypothesis that the curd cheese addition had a markedly influence on the overall bread quality and nutritional value.

Dietary fibre is a common and important ingredient of a new generation of healthy food products demanded more each day by customers. Dietary fibre increases the nutritional value of bread but usually at the same time alters rheological properties of dough and, finally, the quality and sensorial properties of bread. The present work investigates the effect of some purified dietary fibres from different origins (orange, pea, cocoa, coffee, wheat and microcrystalline cellulose) on the rheological properties of wheat flour dough and the final quality of breads. The study of the rheological behaviour of the dough was performed by means of a consistograph and an alveograph. Bread quality was determined by means of texture, colour and specific volume measurements after baking under controlled conditions. The influence of fibre on bread sensory evaluation was established. Dietary fibre additions, in general, had pronounced effects on dough properties yielding higher water absorption, mixing tolerance and tenacity, and smaller extensibility in comparison with those obtained without fibre addition (in the control bread). Regarding the effect on bread properties, the fibre always enhanced the shelf life, as textural studies revealed. Sensory evaluations revealed that dietary fibres, with the exception of those from coffee and cocoa, can be added to flour at the level of 2% without deterioration of the bread palatability in comparison with white flour bread. Additions of 5% could imply the use of some additives to correct the rheological properties of dough.

Background and ObjectiveA direct relationship between dough rheology and bread quality has been clearly revealed to show remarkable significance of studying dough rheological properties throughout breadmaking processes. This review paper has presented the effects of basic ingredients and mixing conditions on dough rheological properties at large and small deformations.FindingsAt both large and small deformations, dough rheological parameters have indicated that the variation in dough strength is due to a manipulation of ingredients and mixing conditions. The rheological properties of doughs over a wide range of formulations and processing conditions have been well characterized using the basic rheological models varying in the degree of complexity. Particularly, a power‐law gel model with only two parameters has a good ability for describing the strength and linear viscoelastic behavior of dough.ConclusionsTo devise strategies for achieving a desirable product quality, a deep understanding of the effects of ingredients and mixing conditions on dough rheology is in great need.Significance and NoveltyDough rheology insights not only benefit the bakery industry by screening suitable wheat flours for breadmaking, but also provide knowledge of how to improve dough handling properties during bakery manufacturing.

The current study was designed to enhance the functionality of white bread by replacement of wheat flour with different levels (1%, 2%, 5%, and 8%) of grape seeds micropowder (GSMP) with nanosized particles (10 µm). Chemical composition of GSMP, volume and sensory attributes, evaluated with the panel of evaluators and an electronic nose (e-nose) and an electronic eye (e-eye) were investigated in the tested breads. It has been found out that GSMP contained appreciable amounts of flavonoids including catechin, epicatechin, gallic acid and minerals especially, Ca, K and Mg. The data from rheological analysis showed that the addition of GSMP (mainly at 5% and 8% levels) to the wheat flour had a positive effect on dough manifesting with rheology by increased dough stability. The volume of the experimental breads (above 1% concentration) was demonstrably declined (P < 0.0001) in comparison with the control bread. Sensory rating revealed that the bread fortified with 1% GSMP was judged by the consumer panelists as the most acceptable with the highest scores for all quality attributes which was also confirmed by the data of e-nose and e-eye. Our results suggest for the first time that 1% GSMP addition appears to be a promising functional ingredient to improve bread with required qualitative and sensory properties.

A way to improve the nutritional value of refined wheat flour with enhanced dough rheology is by substituting wheat flour with quinoa flour (QF) at different addition levels and particle sizes (PS). Experimental variation prediction of the flour α-amylase activity, dough rheological properties, and bread characteristics were estimated using mathematical models. A decrease in the falling number index, water absorption, speed of protein weakening, gas retention coefficient in the dough, maximum creep-recovery compliance, and bread volume and firmness was achieved with the increase of PS. When the QF addition level rose, the values of the following parameters decreased: dough stability, starch retrogradation, dough extensibility and deformation energy, viscosity factor, maximum gelatinization temperature, creep-recovery compliance, and bread quality parameters. Dough rheological properties are important for showing the behavior during processing, which impacts the bread quality. For each quinoa flour PS has identified the optimal addition level in wheat flour for improving bread quality. The best composite flours, regarding dough rheology and bread characteristics, contain 9.13% for large, 10.57% for medium, and 10.25% for small PS. These results may help to improve the quality of refined wheat bread or to range diversify the bread making products.

Hemp protein (Cannabis sativa L.) was incorporated into wheat flour at concentrations of 5%, 10%, and 15% and its effects on the rheological properties of the dough and the quality characteristics of the resulted breads were investigated. Rheological analysis revealed that hemp protein-enriched doughs exhibited significantly higher Young’s modulus of elasticity and elongational viscosity values compared to the wheat flour dough, indicating that the incorporation of hemp protein affected the firmness of the doughs. Farinograph analysis showed that replacing wheat flour with hemp protein increased water absorption, dough development time, and stability, while extensiograph analysis showed increased dough resistance and decreased extensibility and energy with hemp protein addition. Statistical analysis revealed that hemp protein significantly affected the moisture content, specific volume and crumb color of breads. Bread fortified with hemp protein had a darker color compared to the control bread. The addition of hemp protein affected the texture of the breads. It is recommended that hemp protein could be utilized as an alternative protein source, potentially enhancing dough characteristics, texture, quality, and the nutritional value of protein-rich breads, biscuits, snacks, and other bakery products.

Manufacture of gluten-free products requires the use of preselected raw materials. The number of such ingredients is limited; therefore, the portfolio of gluten-free bread is less variable and attractive in terms of their appearance, taste and nutritional value in comparison with traditional bread. The aim of the study was to apply debittered acorn flour as a natural nutritional enrichment of gluten-free bakery products and to check its effects on rheological properties of the dough and quality and staling of the bread. The analysis of rheological properties of gluten-free dough supplemented with acorn flour exhibited significant increase in the moduli G′ and G″ and a decrease in phase shift tangent, which denotes firming of dough structure. Introduction of limited amounts of acorn flour caused an increase in bread volume and improved crumb characteristics. In consequence of a diminished starch retrogradation, the respective loaves exhibited slower staling. Bread supplemented with acorn flour exhibited improved sensory acceptance. The obtained results signify that the application of debittered acorn flour in gluten-free baking could be useful for nutritional reasons, as it enriches bread with protein, minerals and dietary fiber, but also because of its technological effects, including structure strengthening, and sensory improvement.

Green coffee extract, GCE (Coffee canephora) was used at 1.0, 1.5 and 2.0% levels for making bioactive rich bread. The processed GCE from the green coffee beans had 21.42% gallic acid equivalents (GAE) total polyphenols (TPP), 37.28% chlorogenic acid (CGA) and 92.73% radical scavenging activity (RSA), at 100ppm concentration of GCE and caffeine content (1.75%). Rheological, physico-sensory and antioxidant properties of GCE incorporated breads were analysed and compared with control bread. The results revealed not much significant change in the rheological characteristics of dough up to 1.5% level; an increase in bread volume; greenness of bread crumb and mostly unchanged textural characteristics of the bread with increased addition of GCE from 0 to 2.0%. Sensory evaluation showed that maximum level of incorporation of GCE without adverse effect on the overall quality of bread (especially taste) was at 1.5% level. The contents of TPP, RSA and CGA increased by 12, 6 and 42 times when compared to control bread and had the highest amount of 4-5 caffeoylquinic acid.

Gluten-free products are on today’s agenda since they represent the most hastily growing segments in the market, representing an opportunity for food companies. Nevertheless, it is well-known that gluten is a crucial network structure in the wheat dough systems, which accounts for the overall desired technological features of the final bakery goods. Therefore, the absence of gluten negatively affects the characteristics of gluten-free bread, triggering a technological challenge in the manufacturing of products with resembled characteristics of wheat-derived counterparts. The search for new protein sources has been studied as an approach to circumvent the technological drawbacks of gluten removal. Dairy proteins are functional molecules that can likely be capable of building up a protein-network structure so that it would improve the technological properties of gluten-free products. In the present work, different levels of dairy product addition (10 and 20%, w/w) were used to supplement the gluten-free bread formulas, and the impact on dough rheology properties was well correlated to the bread technological quality parameters obtained. Linear correlations (R2 > 0.904) between steady shear (viscosity) and oscillatory (elastic and viscous moduli) values of the dough rheology with bread quality parameters (volume and firmness) were obtained, suggesting that the bread quality improvements are proportional to the levels of dairies added. Likewise, strong linear correlations (R2 > −0.910) between pasting properties parameters and bread staling rate supported the hypothesis that the dairies tested have a high potential to generate bread with a low staling rate, which is an advantage to extending the shelf-life. In short, results confirmed that the addition of both dairy products, as bakery ingredients, can constitute a technological advantage to improve the overall gluten-free bread quality.

SummaryThe formula and preparation of steamed bread are different from those of western bread. The extensional rheological behaviour plays a key role in the development of steamed bread dough. However, there are inadequate studies on the rheological properties of mixed dough with yeast. In this study, the relationship between properties of dough in the presence or absence of yeast was elucidated. Besides, the flour characteristics and quality of steamed bread prepared from different wheat varieties were evaluated. The uniaxial/biaxial extensional rheological properties of wheat dough were compared with traditional rheological test results. Large deformations in the extensional properties were measured by Extensograph and the Kieffer extensibility rig, while the biaxial extension was quantified using uniaxial compression. These characteristics of dough and flour correlated with each other in different ways. Correlation analysis illustrated that the uniaxial extensional rheological properties of dough with yeast better indicated the quality of the steamed bread. Moreover, the total work for breakage of the dough with yeast was the best predictor for specific volume of steamed bread. The texture‐based properties of steamed bread showed correlation with biaxial extension viscosity. The rheological tests provide useful information for evaluating wheat flour and steamed bread quality.

In this research, the effects of a low mixing temperature on dough rheology and the quality of bread were investigated. In the experiments, strong flour samples (Type 550), 1.5% salt, 3% of yeast and 1% additive mixture were used and dough samples were mixed at 17 °C (low temperature), 23 °C (control) and 30 °C (high temperature). Five different periods (0, 30, 60, 90 and 120 min) were applied at the bulk fermentation stage. At the final proofing stage, the dough was fermented until it reached a constant height. It was determined that almost every bread from dough samples mixed at 17 °C resulted in not only the highest bread volume and bread weight, but also the best texture, elasticity and crumb structure. The results of dough samples mixed at 23 °C were worse than those of dough samples mixed at 17 °C. The worst results were obtained from dough samples mixed at 30 °C (high temperature). As a result, it may be concluded that the quality of bread from dough samples mixed at low temperature (17 °C) is superior to those from dough samples mixed at the higher temperatures. Besides these findings, it may also be stated that prolonging the period of bulk fermentation in dough samples mixed at 17 °C positively develops baking performances.

Chapter 12 - Rheological Properties of Gluten-Free Bread Doughs: Relationship With Bread Quality

Effects of ingredient and processing conditions on the rheological properties of whole wheat flour dough during breadmaking - A review

Germinated soybean flour has been proposed for use in bread making as a product to improve bread quality when small amounts are added to wheat flour. However, it is not clear which soybean components promote this action, and how these components may influence bread quality. The aim of this work was to evaluate the effect of the addition of soybean 7S protein fraction obtained from germinated and nongerminated seeds in dough rheological properties (farinographic and extensographic) and bread quality, including loaf volume, texture (firmness, compression force, resilience), colour (L*, a*, b*), crumb grain structure (cell density, mean cell area, shape factor), and consumer acceptance (sensory analysis). Results showed that this protein fraction just slightly affects bread quality, since no significant changes (P > 0.05) on bread volume and texture were obtained. Only crust and crumb colour were affected in a small amount, and a coarser crumb structure was also observed when adding 7S protein obtained from germinated soybean at its highest concentration. As the proportion of protein increased in the flour, both kinds of 7S fraction (germinated and nongerminated) were related to the increment in water absorption, as well as to the increment in extensographic maximum resistance to extension, specifically when adding 7S protein obtained from nongerminated soybean seeds. These results showed that the 7S soybean protein, as obtained in this work, is not related to the reported loaf bread quality improving effect of this legume when it is added in small quantities.

Absence of gluten in bakery goods is a technological challenge, generating gluten-free breads with low functional and nutritional properties. However, these issues can be minimized using new protein sources, by the addition of nutritional added-value products. Fresh yogurt represents an interesting approach since it is a source of protein, polysaccharides, and minerals, with potential to mimic the gluten network, while improving the nutritional value of gluten-free products. In the present work, different levels of yogurt addition (5% up to 20% weight/weight) were incorporated into gluten-free bread formulations, and the impact on dough rheology properties and bread quality parameters were assessed. Linear correlations (R2 > 0.9041) between steady shear (viscosity) and oscillatory (elastic modulus, at 1 Hz) values of the dough rheology with bread quality parameters (volume and firmness) were obtained. Results confirmed that the yogurt addition led to a significant improvement on bread quality properties, increasing the volume and crumb softness and lowering the staling rate, with a good nutritional contribution in terms of proteins and minerals, to improve the daily diet of celiac people.