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.     

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.     

Effect of quinoa,chia and millet addition on consumer acceptability of gluten-free bread

There is an increasing demand for gluten-free foods; however, standard gluten-free foods are deficient in nutrients. This study investigated the use of alternative grains (chia, millet and quinoa) in gluten-free breads to evaluate their sensory properties (fresh and following a partial bake method). A sensory trial (n = 98) asked participants to consider six fresh bread samples made from chia, millet and quinoa, using 9-point hedonic scales and check-all-that-apply. A second sensory trial (n = 89) was then completed using par-baked bread samples of the different formulations. The sensory properties and the acceptability of the bread were significantly affected by the chia and quinoa flour. The millet flour did not change the acceptability of the bread. Furthermore, the partial baking method (after 90 days of frozen storage) did not significantly affect the acceptability of the breads made with chia, millet and quinoa, but it did affect the acceptability of the control bread prepared with brown rice flour. Overall, millet flour could be incorporated into gluten-free breads made following a partial baking method without affecting consumer acceptability. Future studies should use a trained panel to evaluate how the breads differ based on the partial baking method.     

Sourdough on quinoa and buckwheat gluten-free breads: Evaluation of autochthonous starter fermentation on bread nutritional and technological properties

The aim of this work was to evaluate the effect of two autochthonous strains of lactic acid bacteria as sourdough (SD) starters on gluten-free bread technological quality and in vitro starch hydrolysis and antioxidant activity. Two strains of Limosilactobacillus fermentum isolated from buckwheat (BW) and quinoa flours were used. SDs were prepared from wholegrain quinoa or BW flours. Bread technological properties, total polyphenol content and in vitro antioxidant activity and starch hydrolysis and dialysability were assessed. Specific bread volumes were between 2.61 and 2.76 cm³ g⁻¹. Breads with quinoa-based SD had overall higher technological quality than breads made with BW SDs, shown by a softer, well-aerated crumb, with an opener crumb structure and larger air area. Crumb firming during storage was reduced up to 29% when quinoa SD was used, and up to 42% when BW SD was added. Quinoa breads showed higher polyphenols and FRAP values, whereas BW breads had significantly higher ABTS values. Total starch hydrolysis and dialysability were significantly reduced when SD was used. Starch hydrolysis was reduced up to 42% and 25% when quinoa and BW SD were used, respectively. SD application produced breads with higher technological quality and modified in vitro starch hydrolysis and antioxidant capacity. Even though these effects seemed to be influenced by pH, a biological effect was also observed.     

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.     

Polyphenol composition and in vitro antioxidant activity of amaranth,quinoa buckwheat and wheat as affected by sprouting and baking

This study examined the polyphenol composition and antioxidant properties of methanolic extracts from amaranth, quinoa, buckwheat and wheat, and evaluated how these properties were affected following two types of processing: sprouting and baking. The total phenol content amongst the seed extracts were significantly higher in buckwheat (323.4 mgGAE/100 g) and decreased in the following order: buckwheat > quinoa > wheat > amaranth. Antioxidant capacity, measured by the radical 2,2-diphenyl-1-picylhydrazyl scavenging capacity and the ferric ion reducing antioxidant power assays was also highest for buckwheat seed extract (p < 0.01). Total phenol content and antioxidant activity was generally found to increase with sprouting, and a decrease in levels was observed following breadmaking. Analysis by liquid chromatography coupled with diode array detector revealed the presence of phenolic acids, catechins, flavanol, flavone and flavonol glycosides. Overall, quinoa and buckwheat seeds and sprouts represent potential rich sources of polyphenol compounds for enhancing the nutritive properties of foods such as gluten-free breads.     

Low folate content in gluten-free cereal products and their main ingredients

Folate content in some gluten-free cereal products and their main ingredients was determined using a validated method based on reversed-phase high performance liquid chromatography (HPLC) with fluorescence and diode array detection. The main folate forms found in gluten-free products were 5-methyl-tetrahydrofolate and tetrahydrofolate. Starches and low protein flours commonly used as main components in gluten-free products appeared to be poor folate sources with folate content ?6 μg/100 g fresh weight. Folate content in gluten-free breads was higher (15.1–35.9 μg folate/100 g fresh weight) due to use of bakery yeast which is a rich folate source. Overall, folate content in gluten-free products was lower than in their gluten-containing counterparts. Therefore, fortification of gluten-free products with folic acid or enrichment of these products with nutrient-dense fractions of cereals naturally free from gluten (such as buckwheat, quinoa, amaranth or millet) can be of interest.     

Cricket powder (Gryllus assimilis) as a new alternative protein source for gluten-free breads

Gluten elimination in bakery goods is a technological challenge since the absence of gluten generates breads with poor capacity to retain gas during leavening, which can be minimised with the use of gluten-free proteins in combination with hydrocolloids and/or enzymes. Due to the increasing world population and scarce land resources to expand current food production, it is necessary to find alternative and sustainable ways of growing food. This study aimed to characterise cricket (Gryllus assimilis) powder as a new protein source for gluten-free breads in comparison with the use of lentil and buckwheat flours. Cricket powder presented high water and oil holding capacities and appropriate microbiological features for human consumption. Results confirm that the enrichment with cricket powder can lead to the production of gluten-free bread with acceptable technological properties and high protein content. As the addition of cricket powder increases lipid contents, for better nutritional and functional results, the use of oil-free formulations is recommended.Industrial relevanceConsidering the rising world population and the scarce water and land resources, it is extremely important to find new and sustainable ways to produce food. Edible insects are particularly interesting due to its high protein content and lower environmental impacts compared to traditional livestock. This study evaluated the use of cricket powder as protein source for the production of gluten-free bread in comparison with two other protein sources: buckwheat and lentil flours. Results confirm that the enrichment with cricket powder can lead to the production of gluten free bread with acceptable technological properties and high protein content.     

Effects of oxidase and protease treatments on the breadmaking functionality of a range of gluten-free flours

In this study, the application of glucose oxidase and protease commercial preparations was investigated in order to evaluate their impact on the breadmaking performance of four different gluten-free flours (buckwheat, corn, sorghum and teff). Bread formulas were developed without addition of hydrocolloids in order to avoid synergistic effects. Glucose oxidase improved corn (CR) and sorghum (SG) bread quality by increasing specific volume (P < 0.05) and reducing collapsing at the top. The improvements could be related to protein polymerization which resulted in enhanced continuity of the protein phase and elastic-like behavior of CR and SG batters. No significant effects were detected on buckwheat (BW) and teff breads. On the other hand, protease treatment had detrimental effects on the textural quality of BW and SG breads. The effects were related to protein degradation resulting in increased liquid-like behaviour of BW and SG batters. Overall, the results of this study suggest that protein polymerisation can improve the breadmaking performance of gluten-free flours by enhancing elastic-like behaviour of batters. However, the protein source is a key element determining the impact of the enzymes. In the absence of hydrocolloids, protein structures are important to ensure the textural quality of these types of breads.     

Analysis of volatile compounds in polished-graded wheat flour bread using headspace sorptive extraction

Flavor compounds are one of the very important factors for the taste of commercial breads, and then the volatile flavor compounds in the present novel polished-wheat-flour breads were determined by headspace sorptive extraction method to develop the baking properties, comparing two baking procedures of straight-common- and sourdough-methods. The polished flours of outermost, middle and innermost fractions, and common flour, CW were used. There were some differences on the compounds and proportions of volatile flavors in all flours between the both methods. The sourdough-method increased the proportions of acids and aldehydes in crust, but decreased those of alcohols and methoxybenzenes identified in the outermost fraction, rather than the straight-common-method. In addition, the sourdough-method lowered the amounts of some compounds related to oxidation products from unsaturated fatty acids and metabolites of species with moldy grains, as compared with the straight-common-method. Furthermore, the amounts of 2-methylpropanol (iso-butanol) and 2-phenylethanol (β-phenyl-ethyl-alcohol) that have been known as favorable flavor compounds on breadmaking distinctly increased in polished flour breads than CW bread, regardless of baking methods. Therefore, the sourdough-method with lactic acid fermentation would be suitable baking procedure for polished flours from the viewpoints of flavor properties. Furthermore, the utilization of sourdough-method for polished flours from middle and innermost fractions might be appropriate to taste and texture of consumers’ request for bread qualities.     

Effects of genotype, location and baking on the phenolic content and some antioxidant properties of cereal species

In order to assess the effect of genotype, location and their interaction on total phenolic content (TPC) of chemical extracts, the whole grains of durum and soft wheat, oat, barley and triticale were evaluated. Data showed differences in phenolic content of chemical extracts among cereal species and the analysis of variance confirmed the key role of location. Besides TPC and trolox equivalent antioxidant capacity (TEAC) values assessed by chemical extraction were compared with those obtained with an in vitro digestive enzymatic extraction. Differences were found between methanolic and enzymatic extracts, and data confirmed that enzymatic technique enhanced extraction of antioxidants but pointed out lesser differences among cereal types. The breads obtained by flours enriched with different levels of bran were also evaluated. Chemical extracts highlighted the increasing levels of antioxidants according to bran enrichments, without pointing out changes caused by baking. The enzymatic extraction instead did not show differences regarding to bran enrichments, but documented a loss in antioxidant properties of breads in respect to corresponding flours. On the other hand the scarce differences between flours and corresponding breads did not allow asserting that baking modified the TPC and TEAC, independently of the extraction methods used. Indeed, during baking process, also the observed phenolic acids profile variations did not vary the antioxidant properties of breads.     

Increasing the health benefits of bread: Assessment of the physical and sensory qualities of bread formulated using a renin inhibitory Palmaria palmata protein hydrolysate

This study examined the textural and sensory effects of bread formulated using a Palmaria palmata protein hydrolysate with in vitro renin inhibitory properties. Four formulations were examined; a wheat flour control bread, a control bread containing 4% P. palmata protein hydrolysate, a buckwheat bread consisting of a blend of 70% wheat: 30% buckwheat, and a fourth formulation of the buckwheat bread containing 4% P. palmata hydrolysate. The volume, colour, texture profile, moisture, crumb structure, sensory attributes and renin inhibitory activity of all four baked breads are presented. Bright field light microscopy and confocal scanning laser microscopy images using a new triple labelling protocol were also obtained to visualise the main ingredients of the breads. It was observed that the addition of 4% P. palmata protein hydrolysate to the wheat bread control did not affect the texture or sensory properties of the bread to a large degree. Furthermore, when compared to the control, the bread containing the hydrolysate retained renin inhibitory bioactivity after the baking process. This study highlights that baked products may be a suitable delivery vehicle for bioactive compounds. The study demonstrates that the health value of bread was increased through the addition of a seaweed protein hydrolysate.     

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.     

Role of fat on the quality and shelf-life of gluten-free bread baked by Ohmic heating and conventional deck oven

The addition of fat to gluten-free (GF) bread can influence several quality attributes, such as texture and starch retrogradation. Therefore, the aim of this study was to investigate the influence of different fats on GF bread properties using two different baking methods (conventional and ohmic heating), in order to understand how these affect the physical bread quality, the formation of amylose-lipid complexes and its effect on crumb firming behavior. Fats (coconut, rapeseed, butter, and palm) with different physico-chemical properties, and physical state (solid, liquid) were tested in standard GF bread formulations. Results showed that fat significantly improved crumb pore uniformity. Crumb texture and pasting properties were mostly influenced by the type of fat, storage time and baking method. Staling was delayed in all breads added with fat due to the formation of amylose-lipid complexes, which were highest with palm fat and were usually higher when baked by ohmic heating.     

Development of gluten-free fresh egg pasta analogues containing buckwheat

To improve the use of common buckwheat (Fagopyrum esculentum), characterized by interesting nutritional properties, it could be used in pasta formulations. In particular, as buckwheat is devoid of the gluten-forming proteins, it might be an ingredient for celiac patient food. The aim of this study was to develop both fresh egg pastas integrated with buckwheat and fresh egg pasta analogues classifiable as gluten-free, based on buckwheat and rice flours. Matter loss in the cooking water and weight increase during cooking of buckwheat pasta were higher than those of a reference sample made of common wheat flour. As buckwheat integration increased, sample break strain was significantly lower, as a result of the progressive reduction in gluten content. In the production of gluten-free pasta analogues, wheat flour was substituted with rice flour, precooked rice flour or pregelatinized rice starch. Since samples containing precooked rice flour gave the best results, in terms of workability, break strain and weight increase during cooking, they were also produced on an industrial scale. Industrial gluten-free fresh egg pasta analogues were tougher and less deformable in comparison with the laboratory-produced samples. These results were determined by the presence of the double thermal pasteurisation treatment, which allows to obtain a better structure of the product, showing also a lower matter loss during cooking.     

Effect of Starch Substitution by Buckwheat Flour on Gluten-Free Bread Quality

The buckwheat flour was studied as a potential healthy ingredient for improving the nutritional and technological quality of gluten-free bread. The effect of exchange of gluten-free formulation mass by buckwheat flour in 10, 20, 30 and 40 % was investigated. The increase in loaf specific volume with rising buckwheat flour addition was observed. Compared with the control sample, decrease in whiteness and increase in redness and yellowness of crumb were noticed. The rising amount of buckwheat flour in gluten-free bread formulation caused a decrease in crumb hardness during storage. This was in agreement with the decrease in starch gelatinisation enthalpy with the increasing amount of buckwheat flour in gluten-free formula in comparison with the control sample. Buckwheat flour could be incorporated into gluten-free formula and have a positive influence on bread texture and delaying its staling.     

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.     

Comparison of rheological, fermentative and baking properties of gluten-free dough formulations

This paper examines the fundamental rheological properties, capability of CO₂ retention during proofing, and baking behaviour of gluten-free (GF) dough. Maize flour, maize starch, rice flour, and buckwheat flour formulations are compared. Apple pectin is used as the structuring agent. Rheologically, the GF dough formulations can be defined as physical gels of different viscoelasticity and structural networking. The curves of CO₂ retention in the GF dough best fit with the asymmetric transition sigmoidal function. Some correlations between characteristic parameters of the transition sigmoids versus rheological parameters of the GF dough, the spread parameter n of Cole–Cole model and the shear-thinning consistency index k, were found. In baking tests, extending the proofing time improved the taste, aroma, and mouth feel of gluten-free breads, particularly when a sourdough step was applied or flaxseed was added to the formulation.     

Rheological,textural and sensory properties of gluten-free bread formulations based on rice and buckwheat flour

Mixolab, as the rheological instrument, was utilized to create gluten-free products. According to obtained Mixolab profiles, mixtures of rice flour and husked buckwheat and rice flour and unhusked buckwheat flour expressed rheological properties similar to wheat flour. In both types of mixtures the ratio of rice flour to buckwheat flour was 90:10, 80:20 and 70:30. According to the Mixolab profiles of the investigated systems, gluten-free products containing unhusked buckwheat flour had higher water absorption values, lower stability and weaker protein network structure, as well as lower peak viscosity than those consisted of husked buckwheat flour.Increasing the amount of husked buckwheat flour from 10% to 20% resulted in both G′ and yield stress value increase, but further increase of the husked buckwheat flour on 30% resulted in both G′ and yield stress value decrease. However, increasing the amount of unhusked buckwheat flour from 10% to 20% resulted in significant decrease of G′ and yield stress value having no significant impact with the addition of 30% of unhusked buckwheat flour.Hardness, expressed as a work of compression of the final product, increased with the amount of both types of buckwheat flour. Samples containing UBF expressed not significantly higher values of hardness than those prepared with HBF. According to obtained results of sensory evaluation of the final products it can be concluded that all six combinations of tested gluten-free breads were sensory acceptable.