Baking properties and microstructure of pseudocereal flours in gluten-free bread formulations

In the present study, the baking properties of the pseudocereals amaranth, quinoa and buckwheat as potential healthy and high-quality ingredients in gluten-free breads were investigated. Scanning electron micrographs were taken of each of the flours. The pasting properties of these flours were assessed using a rapid visco analyser. Standard baking tests and texture profile analysis were performed on the gluten-free control and pseudocereal-containing gluten-free breads. Confocal laser scanning microscopy (CLSM) images were also obtained from the baked breads and digital image analysis was conducted on the bread slices. Bread volumes were found to significantly increase for the buckwheat and quinoa breads in comparison with the control. In addition, the pseudocereal-containing breads were characterised by a significantly softer crumb texture effect that was attributed to the presence of natural emulsifiers in the pseudocereal flours and confirmed by the confocal images. No significant differences were obtained in the acceptability of the pseudocereal-containing gluten-free breads in comparison with the control.     

Effect of Different Raisin Juice Preparations on Selected Properties of Gluten-Free Bread

Incorporation of sucrose and raisin juice (in concentrated or in dried form) at 3 and 5% of flour weight to commercial wheat starch (Codex Alimentarius) gluten-free flour was carried out to examine the effects on baking, textural, and sensory properties of bread. Breads made with gluten-free flour are usually characterized by poor color and baking characteristics, as well as short shelf life. The current study was conducted to help solve these problems by using raisin juice, a natural sweetener that contains no preservatives, has lower caloric content than sucrose, and includes a number of important vitamins and minerals that are very important for the coeliac disease patients. The study showed that 3% raisin juice in concentrated form contributes to a great improvement in loaf volume, color, and hardness characteristics of gluten-free bread during the first day after baking but a higher staling rate because of its high moisture content. Dried raisin juice gave bread higher loaf volume and better color compared to the control gluten-free bread and also increased its shelf life because of its moisture absorption properties. Sensory analysis revealed a preference for breads containing concentrated raisin juice because of its fruity flavor, whereas all the samples that contained 5% raisin juice had very dark color.     

Improving the sensory and nutritional value of gluten-free bread

Bakery products, especially breads, are important part of everyday diet. Home-made breads are all the more crucial on the gluten-free diet, as commercially available breads without gluten are often unattractive. The study presents the recipe, nutritional characteristics (fat, protein, calcium, magnesium, sodium, potassium, copper, iron, zinc, manganese), costs and consumer acceptance of four easy to make home-made gluten-free breads. Partial substitution of bread-mix based on corn and rice (control bread) with teff flour, amaranth flour or quinoa flour significantly changed the content of the most of analysed nutrients, while their price was comparable. The highest nutritional benefits were found for protein, magnesium, potassium, calcium, zinc, iron and manganese in bread with teff and for magnesium, potassium, zinc and manganese in bread with amaranth. The highest consumer acceptance of people on gluten-free diet was noticed for breads with quinoa and teff.     

New opportunities for gluten-free diet:teff (Eragrostis tef) as fibre source in baking products

This study assessed physicochemical parameters of high fibre and gluten-free breads made with teff and associated flours. Four breads samples were developed: wheat flour (T1), teff flour (T2), teff flour + cassava starch + rice flour (T3 and T4). Hedonic evaluation of sensory attributes characterising the samples was performed by coeliac and non-coeliac subjects. Breads made with different percentages of teff flour showed huge amount of total and insoluble fibres. The wheat bread presented the highest values for pH and the texture parameters analysed, except for crumb hardness and elasticity. The sensory analysis showed that all samples made with teff were well accepted by coeliac and non-coeliac subjects. Purchase intention and the acceptability index suggested a potential market success for the developed products. Teff flour showed promising use for its technological and nutritional values as well as sensory properties, supporting the hypothesis that it is possible to develop new gluten-free bakery products without decreasing consumers’ satisfaction.     

Physicochemical and sensory attributes of gluten-free sourdough breads produced from underutilised African cereal flours and flour blends

To seek potential alternative(s) for imported wheat in the African baking industry, the physicochemical parameters and sensory attributes of sourdough breads developed from locally sourced underutilised cereals and their blends were assessed. Processed sorghum (Sorghum bicolour), finger millet (Eleusine coracana) and pearl millet (Pennisetum glaucum) and their composites (50:50) were used to produce sourdough. Sourdough and flour-sourdough blends (30% sourdough) were used in making gluten-free breads. The protein content of the breads ranged from 16.29% to 39.26%, whereas the fat, crude fibre, ash and carbohydrate contents fell between 14.02–18.80%, 0.55–1.22%, 1.90–3.32% and 42.16–65.61%, respectively. The calculated energy value of the gluten-free breads (405.99–446.39 Kcal per 100 g) exceeded that of wheat bread (396.43 Kcal per 100 g), while the specific loaf volume varied from 1.46 to 1.80 cm³ g⁻¹. Although the produced gluten-free breads have improved nutritional content compared to conventional wheat bread, they were at best moderately liked. This is perhaps due to the non-cohesive nature of the crumbs and psychological preference for known products. Further research targeted at improving the organoleptic properties of these sourdough breads is recommended.     

Impact of sourdough fermented with Lactobacillus plantarum FST 1.7 on baking and sensory properties of gluten-free breads

Sourdoughs were produced from buckwheat, oat, quinoa, sorghum, teff and wheat flour using the heterofermentative lactic acid bacteria Lactobacillus plantarum FST 1.7 and added to a basic bread formulation of flour from the same grain type (20 % addition level). Dough rheology, textural (crumb hardness, specific volume) and structural bread characteristics (crumb porosity, cell volume, brightness) of sourdough-containing breads were compared to non-sourdough-containing breads (control). Changes in protein profiles as analysed with capillary electrophoresis were observed in all sourdoughs. Furthermore, sourdough addition led to decreased dough strength resulting in softer dough. No influences on specific volume and hardness on day of baking were found for gluten-free sourdough breads. The staling rate was reduced in buckwheat (from 8 ± 2 to 6 ± 2 N/day) and teff sourdough bread (13 ± 1 to 10 ± 4 N/day), however, not significantly in comparison with the control breads. On the contrary, in wheat sourdough bread, the staling rate was significantly reduced (2 ± 1 N/day) in comparison with control bread (5 ± 1 N/day). Sourdough addition increased the cell volume significantly in sorghum (+61 %), teff (+92 %) and wheat sourdough breads (+78 %). Therefore, crumb porosity was significantly increased in all gluten-free and wheat sourdough breads. Shelf life for sourdough breads was one (teff and oat), two (buckwheat, quinoa and sorghum) and 3 days (wheat) and was not prolonged by sourdough addition. The inferior aroma of breads prepared from the gluten-free flours was also not improved by sourdough addition.     

BAKING PERFORMANCE AND CONSUMER ACCEPTABILITY OF RAW AND EXTRUDED COWPEA FLOUR BREADS

Cowpea flour was used to partially replace wheat flour in yeast bread, using automatic household‐type bread machines for mixing, proofing and baking. Loaves containing 15 or 30% extruded cowpea flour weighed more (683.4 g) than loaves from other treatments (641.1–652.6 g). The 100% wheat had the highest loaf volume (2.58 L) and the 30% extruded cowpea the lowest (1.64 L). Cowpea flour breads contained more protein (13.9–15.4%) than the 100% wheat (4.1% fat, 12.5% protein). Bread made with 15% extruded cowpea flour was not different (P < 0.05) from the all‐wheat control in sensory quality and acceptability. Hedonic ratings for the control and 15% extruded cowpea flour ranged from 6.6 (like slightly) to 7.4 (like moderately) for all sensory attributes. The least liked samples contained either 30% raw or 30% extruded cowpea flour, receiving ratings for all attributes ranging from 4.8 (disliked slightly) to 6.2 (liked slightly). Overall, 15% extruded cowpea flour demonstrated successful bread making performance without compromising sensory quality.     

Investigation of product quality, sensory profile and ultrastructure of breads made from a range of commercial gluten-free flours compared to their wheat counterparts

Bread is a major staple food consumed daily in all parts of the world. A significant part of the human population cannot tolerate gluten, a storage protein found in wheat, rye and barley, and therefore, products made from alternative cereals are required. During this study, the bread-making potential of seven gluten-free flours, wheat and wholemeal wheat flour was compared. Fermentation potential of the different flours was determined, showing that dough development height of gluten-free and wholemeal wheat samples was lower than for wheat and oat flour. Apart from standard bread quality parameters such as loaf-specific volume and physical crumb texture, also water activity and shelf life have been determined. The shelf life of gluten-free breads was reduced compared to wheat bread. Aroma profiles were evaluated by a trained panel. Wheat, oat and wholemeal wheat breads were liked moderately, while the remaining samples had lower liking scores. Crumb grain characteristics were investigated using image analysis, and microstructure was observed by scanning electron microscopy. Overall, only breads produced from oat flour were of similar quality to wheat bread, and the utilization of buckwheat, rice, maize, quinoa, sorghum and teff flours resulted in breads of inferior quality.     

Improving Carob Flour Performance for Making Gluten-Free Breads by Particle Size Fractionation and Jet Milling

Many different raw materials have been proposed for producing nutritious gluten-free breads, but rarely, there is a parallel analysis of the effect of physical treatment on those ingredients. The aim of this study was to incorporate carob flour fractions of varying particle size on rice gluten-free breads prepared with carob/rice (15:85) flour blends. Carob flour particle size was controlled by fractionation or jet milling application. Quality features of gluten-free breads containing carob flour and commercially available gluten-free breads were compared. Carob flour addition led to breads with improved colour parameters, crumb structure, retarded firming and lower moisture loss compared to rice bread. Further improvement in specific volume, crumb hardness, protein and ash content and estimated glycaemic index (eGI) could be obtained by a careful selection of the particle size distribution of the carob flour. Carob breads prepared either with the coarsest or the finest fraction prepared using jet milling led to end products with the highest specific volume (≈2.2 g/cm³) and the lowest crumb hardness (≈5.5 N), although they had lower specific volume and harder crumbs than breads from commercial blends (≈3–4 g/cm³, 0.6–3.8 N). Nevertheless, rice-based bread made with the finest carob flour was superior considering its slower firming, protein content and lower eGI. The incorporation of carob flour obtained by jet milling in rice-based gluten-free breads led to end products with quality characteristics and sensory acceptance resembling commercial breads and high nutritional value.     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.     

Total phenolic and total flavonoid content,antioxidant activity and sensory evaluation of pseudocereal breads

The aim of the study was to investigate the effect of adding (in two different doses 15% and 30%) pseudocereal (buckwheat, amaranth and quinoa) flour on the antioxidant properties and sensory value of breads. Buckwheat flour had the highest phenolic content (7.25 ± 0.23 mg/g dw). The content of total flavonoids in flours was about 2–4 fold higher when compared to breads. The addition of buckwheat flour to wheat bread, particularly in higher dose, was more effective in enhancing antioxidant activity, as evaluated by means of FRAP and DPPH, which increased by 2.36 fold, and 3.64 fold respectively, in comparison with other pseudocereal flours (amaranth, quinoa), which caused, in higher doses, the changes of above parameters within the ranges 1.20–1.79 fold, and 0.60–1.71 fold. Analysis of sensory results of breads showed that addition of buckwheat flour to the dough might improve subjective properties of bread and increase acceptable quality attributes such as taste, colour or odour. All these observations suggest that addition of buckwheat flour into bread can improve antioxidant as well as sensory properties of bread. Bread fortified with pseudocereal flours, and especially with buckwheat flour, may be placed on the market as a functional food.     

Potentials of Lactobacillus plantarum and Pichia kudriavzevii in co-fermentation of sourdough from millet

The use of millet in the production of gluten-free sourdough has significant benefits such as its suitability for individuals with gluten sensitivity. Lactic acid bacteria and yeasts were screened for functional properties from unmalted and malted millet for sourdough preparation. Lactobacillus plantarum MLd27 and Pichia kudriavzevii MYd23 were selected, used individually and mixed starter cultures to produce sourdough. The specific volume (3.07 ± 0.06 cm³ g⁻¹) of the bread made with unmalted flour and Pichia kudriavzevii MYd23 was significantly higher (P < 0.05) compared to all the other samples. The protein, ash and fibre contents of the bread samples ranged from 10.1 to 11.4, 2.2 to 4.5 and 1.45 to 1.74 g/100 g, respectively. The sourdough bread samples were generally acceptable, while spontaneously fermented bread from malted flour showed the significantly highest (P < 0.05) overall acceptability of (7.90). The production of gluten-free millet sourdough bread can aid in food security.     

Physicochemical Properties and Consumer Acceptance of Wheat-Germinated Brown Rice Bread during Storage Time

Abstract: Selected physicochemical properties and consumer acceptance of bread prepared from composite flour (wheat:germinated brown rice:germinated glutinous brown rice flours at 60:30:10 ratio) were evaluated during storage for 0, 3, and 5 d, and compared with wheat bread (0 d, control). During storage, color profiles and water activity (from 0.947 to 0.932) of crumbs of composite flour breads slightly changed, but moisture content drastically decreased along with increasing crumb hardness (from 4.16 N to 10.37 N). Higher retrogradation in bread crumb was observed particularly for 5-d stored bread (ΔH = 2.24 J/g) compared to that of the fresh composite bread and the control (ΔH = 0.70 and 0.51 J/g, respectively). Mean (n = 116) overall liking score of the fresh composite flour bread (0 d) was slightly lower than that of the control (7.1 compared with 7.6 based on a 9-point hedonic scale). At least 76% of consumers would purchase the fresh composite flour bread if commercially available. Breads were differentiated by textural (moistness, smoothness, and softness) acceptability with canonical correlation of 0.84 to 0.87. The signal-to-noise ratio values of the 5-d stored breads were lower than the control, due mainly to the non-JAR (not-enough) intensity responses for moistness, smoothness, and softness; the mean drop of liking scores for these attributes ranged from 2.42 to 2.98. Flavor acceptability and overall liking were factors influencing consumers’ purchase intent of composite flour breads based on logistic regression analysis. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. In the current U.S. market, this type of bread may be sold as frozen bread that would have a longer shelf life, or may be supplied as a food-service product that would be made-to-order or made fresh daily as currently practiced in some major grocery stores.     

Baking Studies with Winged Bean (Psophocarpus tetragonolobus L.DC) Flour-Wheat Flour Blends

Physical, rheological and baking properties of winged bean-wheat composite flours were studied and the acceptability of the bread was evaluated by sensory tests. The sponge-dough method (SPD) gave bread with significantly greater specific loaf volume (P<0.05) than the straight-dough method (STD). Incorporation of 1% sodium stearoyl 2-lactylate (SSL) significantly improved (P<0.05) the specific loaf volume at all concentrations of winged bean full-fat flour (WBFF) tested, except for 15 and 20% substitution, for both STD and SPD methods. Using the STD method, 5% to 8% substitution of WBFF without SSL and 10% substitution with SSL gave acceptable breads. Using the SPD method, WBFF substitution at 10% without SSL and 12% with SSL gave acceptable breads.     

EFFECT OF EMULSIFIERS AND FUNGAL α-AMYLASE ON RHEOLOGICAL CHARACTERISTICS OF WHEAT DOUGH AND QUALITY OF FLAT BREAD

Teftoon, a flat bread made of whole wheat flour, is prepared by hand sheeting of dough, followed by baking. Different emulsifiers, like lecithin, E471 (distilled monoglyceride) and E472 (diacetylated tartaric acid esters of mono- and digelycerid of fatty acids), were added to the flour at various levels ranging between 0.25 and 1.0% w/w, and it was observed that they improved the dough characteristics. Improvement in bread quality parameters, such as force to tear and sensory acceptability, were monitored. Fungal α -amylase was also incorporated into the flour at 5–20 g/100 kg flour basis alone and in combination with the emulsifier. The force required to tear the fresh bread was decreased with emulsifier and enzyme addition; however, E472 addition at 0.75% w/w of whole wheat flour gave the softest bread. The tear force of stored bread significantly increased with storage; however, bread containing E472 showed a less increase in tear force up to a period of 3 days. The sensory acceptability was found to be higher than that of the control bread for emulsifiers, and lower for enzyme at a concentration higher than 10 g/kg flour.

PRACTICAL APPLICATIONS

Flat bread is normally consumed fresh, but the staling phenomenon starts immediately after baking this kind of bread. Today, large-scale production and increased consumer demands for high-quality bread with long shelf life have created the need for functional food additives such as emulsifiers and α -amylase enzyme. Incorporation of emulsifiers and enzyme decreased the hardness of Taftoon bread. Emulsifiers and α -amylase enzyme enhanced the flat bread dough quality. The sensory acceptability also improved with the addition of emulsifiers. Optimizing the amount of emulsifiers and enzyme required for reduction of bread hardness is vital because the quality and price of the final product depend on this parameter.     

Response Surface Methodology in the Development of Rice Flour Yeast Breads: Sensory Evaluation

Yeast breads were developed from rice flour (80%) and potato starch (20%). Using sensory measurement from a trained panel, response surface methodology (RSM) was applied to find carboxymethylcel-lulose (CMC), hydroxypropylmethylcellulose (HPMC), and water level combinations for gluten-free breads from three different rice flours. Formulations resulted in rice breads that met wheat bread reference standards for moistness, cohesiveness, yeasty flavor, adhesiveness, aftertaste, top crust and crumb color, cell size uniformity and predominant cell size. Medium grain rice flour breads met more sensory reference standards than long grain rice flour breads.     

A Study on Staling Characteristics of Gluten-Free Breads Prepared with Chestnut and Rice Flours

The effects of chestnut flour and a xanthan–guar gum blend–DATEM mixture on staling of gluten-free rice breads baked in conventional and infrared–microwave combination ovens were studied. Staling properties of the bread were assessed using mechanical compression (TA), differential scanning calorimetry, X-ray diffraction, and fourier transform infrared spectroscopy (FT-IR). Hardness, moisture loss, and retrogradation enthalpy values for all bread samples increased significantly during storage. FT-IR spectra showed that the integrated area of peaks around 1,041 and 1,150 cm^?1 wave lengths, which are related to the structure of starch retrogradation, increased with storage time. The X-ray diffractograms of aged breads indicated a B-type structure with the appearance of peaks at around 17°, 19.5°, and 22°. An additional peak at 24° was observed in breads stored for longer periods. Higher values of hardness and lower moisture contents were obtained for breads baked in an infrared–microwave combination oven, but the use of infrared–microwave combination oven did not result in excessive hardness after storage. Retrogradation enthalpies and total crystallinity values of breads did not show significant differences with baking type.The replacement of rice flour with chestnut flour and addition of xanthan–guar gum blend–DATEM mixture in formulations significantly delayed staling of gluten-free breads by decreasing moisture loss, hardness, retrogradation enthalpy, and total mass crystallinity.     

Gluten-Free Bread Making Trials from Cassava (Manihot Esculenta Crantz) Flour and Sensory Evaluation of the Final Product

The aim of this work was to evaluate the effectiveness of the use of cassava flour in bread making, and the sensory acceptability of the final product. Different baking trials were carried out by using egg white and extra-virgin olive oil, in consideration of their high nutritional value with respect to other food additives (i.e., hydrocolloids). Significant (p < 0.05) improvements of loaf specific volume (from 2.24 to 3.93 mL/g) and crumb firmness (from 9.14 to 4.67 N) were achieved by contemporarily including egg white and extra-virgin olive oil in the formulation. Cassava breads containing both these ingredients obtained the best scores from panelists for all the test breads examined and resulted attractive as the wheat bread prepared as reference.     

Towards the development of peanut–wheat flour composite dough: Influence of reduced‐fat peanut flour on bread quality

The effect of partial substitution of wheat flour with reduced‐fat peanut flour at different levels (10, 20, 30, 40, and 50%) on physical parameters, proximate composition, sensory profile, and shelf stability of bread were investigated. Loaf volume, specific volume, and crumb density were significantly (p ≤ .05) reduced with increasing level of substitution with the peanut flour. Peanut flour had significant (p ≤ .05) improvement on the protein content and reduction in carbohydrate content of loaves. Consumers preferred the taste aroma and color of the peanut–wheat flour composite loaves at ≥20% peanut flour inclusion. Freshly baked composite peanut–wheat bread loaves with 10% level of peanut substitution had higher overall acceptability than 100% wheat flour formulation but less microbial stability during storage. Reduced fat‐peanut has potential application for improving the nutritional quality and shelf stability of wheat flour bread.

Practical applications

The demand for convenient alternative to conventional foods is on the increase with the dynamics of the world's social values, lifestyles, and demographic trends. Having peanut incorporated into dough (as one food system) will offer convenience to consumer and therefore add value to bread variety on market shelves. Assessing the influence of the peanut flour on bread quality provides first‐hand information that can facilitate optimization of the baking process toward commercial production of peanut–wheat flour bread.