Influence of hydrocolloids on dough handling and technological properties of gluten-free breads

BackgroundThe development of gluten-free breads has attracted great attention as a result of better diagnoses of relationship between gluten-free products and health. The market demand for gluten-free products is increasing day by day due to growing number of celiac disease cases. Development of gluten-free bread remains a technological challenge due to the key role of gluten in the breadmaking process and in bread structure, appearance, texture and shelf life.Scope and approachThis review covers recent advances in the application of hydrocolloids in dough handling, technological and nutritional properties of gluten-free breads, which affect its quality and value.Key findings and conclusionsGluten-free breads results from the combination of different ingredients and hydrocolloids required to building up network structures responsible for bread quality. Various gluten-free formulations have applied hydrocolloids to mimic the viscoelastic properties of gluten. In addition, the impact of different hydrocolloids on the characteristics of dough and bread quality is known to be highly dependent on raw materials, the nature and quantity of hydrocolloids. Hydrocolloids improve the texture, increase the moisture content and extend the overall quality of bread. The results of the reviewed studies indicate that some of those products were acceptable and presented similar or better sensory attributes than control formulations and some were even comparable to their wheat-based counterparts. Based on successful applications of hydrocolloids, it is suggested that novel nutritious ingredients, combined with hydrocolloids can be added to gluten-free bread formulations to improve the quality of life.     

Optimisation of formulations and infrared–microwave combination baking conditions of chestnut–rice breads

The main objective of this study was to design gluten‐free breads containing chestnut and rice flour and xanthan–guar gum blend to be baked in infrared–microwave combination oven. Response surface methodology (RSM) was used to optimise gluten‐free bread formulations and processing conditions. Weight loss, firmness, specific volume and colour change of the breads were determined. Rice flour mixed with different proportions of chestnut flour and different emulsifier contents were used to prepare breads. The gluten‐free formulations were baked using different upper halogen lamp powers, microwave powers and baking time which were varied from 40% to 80%, 30% to 70% and 9 to 17 min, respectively. Gluten‐free breads and wheat breads baked in conventional oven were used for comparison. Breads containing 46.5% chestnut flour and 0.62% emulsifier and baked using 40% infrared and 30% microwave power for 9 min had statistically comparable quality with conventionally baked ones.     

Gluten‐Free Breads: The Gap Between Research and Commercial Reality

The market for gluten‐free products is steadily growing and gluten‐free bread (GFB) keeps on being one of the most challenging products to develop. Although numerous research studies have worked on improving the manufacture of GFBs, some have adopted approaches far from commercial reality. This review analyzes the ingredient list and nutrition facts of 228 commercially available GFBs produced by different brands around the world. The results from studying the ingredient list of breads revealed that commercial breads do not tend to use a single starchy source or gluten replacer, but a combination of several ingredients to optimize bread quality. Maize, tuber starches, and rice flour were the main starchy sources. Regarding hydrocolloids, the most often included ingredients were hydroxypropyl methylcellulose, xanthan and guar gum, and psyllium. Proteins and sugars were added, respectively, in 81% and 87% of the commercial breads analyzed. Furthermore, it was found that vegetable oils were preferred over fats. A long list of ingredients was observed in commercial GFBs, with the presence of a wide range of additives, including acidifiers, emulsifiers, leavening agents, preservatives, and aromas or flavorings. Meanwhile, nutrition facts showed a lower protein and higher fat content for GFBs compared to a gluten‐containing counterpart, with small differences for salt and sugar. This research expands the current knowledge on GFB manufacturing, giving a panoramic outlook on the current situation in the GFB market, and helping both scientists and gluten‐free companies unify/identify common trends.     

Influence of maize flour particle size on gluten‐free breadmaking

BACKGROUND: Maize, one of the suitable grains for coeliac consumption, is, together with rice, the most cultivated cereal in the world. However, the inclusion of maize flour in gluten‐free bread is a minority and studies are scarce. This paper analyses the influence of different maize flour types and their particle sizes on the quality of two types of bread without gluten (80% and 110% water in the formulation) obtained from them. We also analysed the microstructure of the dough and its behaviour during the fermentation. RESULTS: Finer flours had a lower dough development during fermentation in all cases. Among the different types of flour, those whose microstructure revealed compact particles were those which had higher specific bread volume, especially when the particle size was greater. Among the formulations, the dough with more water gave breads with higher specific volume, an effect that was more important in more compact flours. The higher volume breads had lower values of hardness and resilience. CONCLUSION: The type of corn flour and mainly its particle size influence significantly the dough development of gluten‐free bread during fermentation and therefore the final volume and texture of the breads obtained. The flours having coarser particle size are the most suitable for making gluten‐free maize bread. © 2012 Society of Chemical Industry     

Incorporation of several additives into gluten free breads: Effect on dough properties and bread quality

The objective of this work was to assess the effect of emulsifiers, hydrocolloids and enzymes on gluten-free dough rheology and thermal properties and bread quality, while relating dough properties parameters to bread technological quality. Breads were based on rice flour, cassava starch and full-fat active soy flour, with 65% or 75% (flour-starch basis) of water incorporation. Additives used were emulsifiers (diacetyl tartaric acid ester of monoglycerides – DATEM and sodium stearoyl lactylate – SSL), enzymes (glucose oxidase and α-amylase) and hydrocolloids (xanthan gum, carboxymethylcellulose, alginate and carrageenan). Results showed that additive incorporation modified dough behavior, evidenced by different calorimetric and rheological properties. Besides, the electrophoretic pattern of dough extracted proteins changed with glucose oxidase addition. These modifications resulted in breads with different characteristics, such as specific volume, firmness and firming rate, and crumb structure. Nonetheless, they did not necessarily show better quality parameters than the control bread. The control dough displayed good performance for obtaining gluten-free breads of acceptable volume, crumb structure and, principally, with lower hardening rate during storage. Contrary to widespread opinion, this work shows that the presence of additives is not essential for gluten-free bread production. This fact provides new perspectives to the gluten free market at the moment of selecting raw materials and technological parameters, reducing production costs and facilitating gluten free products development.     

面筋蛋白在发酵面团加工中的作用机制及研究进展

面筋蛋白是小麦粉中的重要组成物质,其结构性质与面团流变学特性及对应产品品质密切相关。面团是以小麦粉为主要原料经过揉捏而成的混合物,其中面筋蛋白能形成面团的骨架结构并赋予面团独特的功能特性。文章综述了面筋蛋白的组成结构和作用成分及其在发酵面团中的作用机制,并阐述在不同的加工方式下面筋蛋白的结构和性质的不可逆变化以及对发酵面团产生的影响,最后为工业化生产及储藏条件下的发酵面团品质劣变提出针对性的改良措施,进一步改善发酵面团的典型产品（馒头）品质。文章可为进一步开发研究面筋蛋白和发酵面团工业化发展提供参考,对提高产品品质和经济效益具有重要指导意义。     

Selected Structural Characteristics of HPMC-Containing Gluten Free Bread: A Response Surface Methodology Study for Optimizing Quality

Gluten free (GF) breads require a gluten replacement to provide structure and gas retaining properties in the dough and mimic the viscoelastic properties of gluten. Hydroxypropylmethylcellulose (HPMC), which forms thermoreversible gel networks on heating had proved the most effective in structuring baked products. Response surface methodology was used to optimize a GF bread formulation based on ingredients such as maize starch and rice flour, which are naturally GF. (HPMC) and water (W) were the predictor variables (factors) and loaf specific volume, crumb firmness, and overall acceptability were the dependent variables (responses) used to assess the product quality. The optimal formulation, determined from the data, contained 1.5 kg/100 kg HPMC and 88.7 kg/100 kg Water, corn starch-rice flour blend basis (sfb). The developed mathematical models for the measured responses could be successfully used for their prediction during baking. Shelf life study of the optimized formulation revealed that bread stored under modified atmosphere packaging (MAP) exhibited lower crumb firmness and moisture content values, thus remained softer through storage. Scanning electron microscopy of the crumb showed continuum matrix between starch and HPMC, in the optimized formulation, obtaining a more aerated structure.     

Optimization of Additive Combination for Improved Soy–Wheat Bread Quality

The protein content of ordinary white bread ranges from 8% to 9%. Specialty breads can be made with 13–16% protein by including soy protein. However, incorporating high levels of soy protein depresses loaf volume, gives poor crumb characteristics, and decreases acceptability. The objective of this study was to determine the influence of sodium stearoyl-2-lactylate (SSL), transglutaminase (TG), and xylanase (HE) on high-protein dough properties and bread quality and to improve dough handling and bread quality of soy–wheat bread by using an optimized additive combination. The influence of SSL, TG, and HE on soy–wheat dough and bread properties was modeled by response surface methodology. The negative effect of soy products on gluten network was confirmed. With regards to the additives tested and their combination, TG showed a major improving effect on dough rheological properties and crumb uniformity, whereas SSL and HE enhanced both dough and bread quality. The best formulation tested produced an increment of approximately 65% soy–wheat bread volume and a decrease of 79% and 71% crumb hardness and chewiness, respectively, compared with the standard formulation.     

无麸质大米面包加工技术研究进展

大米不含面筋蛋白并且产量巨大,是无麸质食品的主要原料之一。因大米粉无法形成面筋网络,从而无法形成黏弹性的面团,所以大米面包存在组织不均匀、易塌陷、比容小、老化速度快等问题。目前对于无麸质大米面包的研究贯穿整个面包制作过程,并且不断深入,使得面包的品质有较大的改善,但市售的产品仍存在种类少、价格高和营养价值低的问题。本文从大米原料选取及处理、辅料和添加剂、加工工艺、营养强化4个方面系统综述了目前无麸质大米面包加工技术研究进展,并在目前的研究基础上进行了展望。     

Novel Approaches in Gluten‐Free Breadmaking: Interface between Food Science,Nutrition, and Health

The evidence that celiac disease is one of the commonest food intolerances in the world is driving an increasing demand for gluten‐free foods. However, gluten is a structure‐building protein essential for formulating leavened baked goods. Therefore, obtaining high‐quality gluten‐free bread (GFB) is a technological challenge. This review focuses on contemporary approaches in gluten‐free baking that allow improvements at the structure, texture, acceptability, nutritive value, and shelf life of GFB. Gluten‐free breadmaking is a relatively new, emerging research topic that is attracting worldwide attention in order to develop different kinds of GFB, including regional varieties. Several approaches have been used to understand and improve GFB systems by evaluating different flours and starch sources, ingredients added for nutritional purposes, additives, and technologies or a combination of these elements. Some studies aimed to assess or improve GFB's technological or nutritional properties, while others had multiple objectives. Several studies used food science tools in order to improve technological and sensory quality of GFB, together with nutritional value. Some GFBs are vehicles of nutrients and bioactive compounds. Furthermore, extensive research on interfacing food science, nutrition, and health is needed so that a GFB with both good technological and nutritional properties can be prepared and made more available to those with celiac disease, which will help them adhere to a strict gluten‐free diet, increase social inclusion, and improve their quality of life.     

添加剂对冷冻面团馒头品质的影响

对冷冻面团制作馒头进行了尝试,研究了羧甲基纤维素钠、硬酯酰乳酸钙钠、谷朊粉、维生素C以及它们复合对冷冻面团馒头品质的影响,结果表明:冷冻面团技术也可用于生产馒头,冷冻面团馒头复合品质改良剂的最优配方为:谷朊粉4%,硬酯酰乳酸钙钠0.05%,维生素C0.006%,羧甲基纤维素钠0.6%,此时冷冻面团馒头的品质较好。     

Effects of trypsin‐hydrolyzed wheat gluten peptide on wheat flour dough

BACKGROUND: Gluten peptide was prepared by trypsin hydrolysis and characterized by high‐performance liquid chromatographic analysis. The effects on non‐frozen and frozen doughs of trypsin‐hydrolyzed gluten peptide (THGP) and its combination with ascorbic acid or KBrO₃ were investigated. RESULTS: Molecular analysis of THGP showed a decrease in the high‐molecular‐weight and an increase in the low‐molecular‐weight sodium dodecyl sulfate‐soluble fractions, compared with those of control wheat gluten. The addition of 8% THGP decreased the mixing time and tolerance of the dough, both with and without ascorbic acid or KBrO₃. However, the maximum resistance and extensibility of the rested dough containing 8% THGP, with and without ascorbic acid or KBrO₃, were not significantly different from those of the control dough. The addition of 8% THGP significantly increased the loaf volume of bread baked from non‐frozen dough when combined with 60 ppm ascorbic acid or 30 ppm KBrO₃, but it had a significant effect both with and without ascorbic acid or KBrO₃ on frozen‐dough bread. A large difference in volume was observed between breads made with and without THGP at the oven‐spring, rather than at proofing. CONCLUSION: The addition of 8% THGP increased the loaf volume of bread made from freeze‐damaged dough and this effect increased when THGP was combined with 60 ppm ascorbic acid. Copyright © 2008 Society of Chemical Industry     

IMPROVEMENT OF THE WHEAT AND CORN BRAN BREAD QUALITY BY USING GLUCOSE OXIDASE AND HEXOSE OXIDASE

The effects of addition of wheat (10, 20 and 30%) and corn bran (10 and 20%) on rheological and bread making properties of flour were examined. To improve dough and bread properties, glucose oxidase (GO) and hexose oxidase (HO) (15–30 and 45 mg/kg) were used separately in each bran-wheat flour formula with L-ascorbic acid at 75 mg/kg, glucose at 0.5% and vital gluten at 9.2%. Water absorption and development time increased as the amount of wheat and corn bran increased, while dough stability, maximum resistance to extension, extensibility, energy and loaf volume decreased. Corn bran was found to be more detrimental to dough rheology and bread characteristics than wheat bran. Corn bran and wheat bran could be used at bread making up to levels of 10 and 20%, respectively. Addition of 30 mg/kg of HO in combination with constant additives was most effective in improving dough and bread characteristics and GO with its 15 mg/kg usage level followed it. Further increasing of enzyme levels led to over oxidizing of doughs and breads.

PRACTICAL APPLICATIONS

Corn bran up to 10% and wheat bran up to 20% levels can be used in bread making. To improve dough and bread quality, besides L-ascorbic acid (75 mg/kg) and vital gluten (as a percentage of added bran weight), GO (15 mg/kg) or HO (30 mg/kg) could be incorporated into wheat flour-bran mixtures. However, the amount of enzyme should be carefully chosen because when they are used above the mentioned levels, they cause overoxidation of doughs and small loaf volumes are obtained. As a conclusion; by using the corn bran, which is a by-product of the starch industry, not only could it be possible to offer healthy alternative breads which contain high amounts of dietary fiber to consumers, but it could also be possible to obtain economical value by evaluating such a by-product in the bread industry.     

An investigation of the consumer perception on the quality of the gluten and wheat free breads available on the UK market

There is a growing demand for bread and other baked products that are gluten and wheat free due to the increased diagnosis and self-diagnosis of adverse reactions to wheat and gluten and an increase in the number of people who perceive a gluten or wheat free diet as a healthy lifestyle option. The removal of wheat from bread presents a number of technological challenges resulting in quality issues and nutrition. The increased consumer demand and growing industry response to these demands has meant that consumers will no longer accept compromise on taste or quality when purchasing gluten and wheat free bread. There is little information available that demonstrates customers’ expectations in terms of quality of gluten and wheat free breads. The aim of this research was to establish whether gluten and wheat free breads currently on the market are meeting consumer expectations and if not the key areas for product improvement and new product development. The research indicates that there are still significant improvements needed to produce gluten and wheat free bread that meets consumer expectations.     

Antioxidative and reducing capacity,macroelements content and sensorial properties of buckwheat‐enhanced gluten‐free bread

Common buckwheat flour (BF) was used to substitute 10%, 20%, 30% and 40% of corn starch, the main component of a gluten‐free bread formula, to make buckwheat‐enhanced gluten‐free breads. The 40% BF‐enhanced gluten‐free bread showed the highest antioxidant capacity against ABTS⁺˙ and DPPH˙ radicals (4.1 and 2.5 μmol Trolox g^?1 DM, respectively) and reducing capacity measured by cyclic voltammetry (1.5 μmol Trolox g^?1 DM). The antioxidant and reducing capacity of buckwheat‐enhanced gluten‐free breads were positively correlated with their total phenolic contents (r = 0.97). The 40% BF‐enhanced gluten‐free bread showed the highest overall sensory quality (7.1 units) when compared to control gluten‐free bread (1.8 units). The linear relationship between applied increasing BF doses in gluten‐free bread formula and magnesium, phosphorus and potassium content in breads was noted. It was concluded that 40% BF‐enhanced gluten‐free bread could be developed and dedicated to those people suffering from coeliac disease.     

Rheological properties and baking quality of commercial durum wheat meals used to make flat crispy bread

Four commercial semolinas and four low-grade semolinas (LGS) samples were used in this study to make flat crispy bread (Carasau). The meals, doughs, and bread were compared with respect to a set of physical, chemical, and textural characteristics, and the bread evaluated by a trained sensory panel. LGSs had a higher extraction rate (higher ash content), finer granularity, and a higher damaged starch content than semolinas. The study revealed the key role of dry gluten content in determining hydration capacity of the dough, whereas damaged starch affected water absorption only in semolina samples. Gluten index and the ratio of gluten tenacity to extensibility (alveograph P/L) were significantly correlated with the weight of the dough discs following sheeting and molding. The panelists gave the highest quality score to the bread with the highest values of crackling and hardness. Textural and sensory attributes were both correlated with one another, and with gluten strength and tenacity, but not with the gluten content of the meal, which only affected final moisture content of the bread. Meal samples with a more tenacious and elastic gluten were more suited to produce flat crispy breads. The yellowness of durum wheat bread could not be predicted by measuring the color of the meal with a reflectance method.     

Effect of sourdough starter and fungal proteases on gluten content and sensory properties of tarhana

In this study, gluten degradation during prolonged tarhana fermentation was monitored in a traditional dough as well as in dough containing sourdough starter, peptidase additives and combination of both. Gluten content, determined using the sandwich ELISA assay method, was reduced significantly in the first 5 days of fermentation for all formulations. After 30 days into fermentation, approximately 15% and 20% reduction of gluten was observed in the traditional dough and sourdough starter added dough, respectively. In enzyme supplemented formulations, the mean gluten levels were below 20 ppm by 20 days of fermentation. Results showed that proteolytic enzyme addition to the dough mix can potentially render long fermented tarhana a food which conforms to regulations set forth for gluten-free foods, even though wheat flour is one of the main production ingredients. Sensory evaluation of the 30 day fermented tarhana samples revealed differences in sourness and odour properties of the products.     

无麸质大米面包研究进展

开发大米面包不但可以丰富中国大米类产品的花色品种,还能解决麸质过敏人群对饮食多样化的需求。由于无麸质大米面包中不含面筋蛋白,在制作过程中存在面团难以形成有效的网络结构、不易成型、品质差(持水性、持气性、弹性和内聚性)、老化速率快等缺点。近年来,研究人员通过改进工艺条件、添加品质改良剂等方法,对无麸质大米面包品质进行改善,文章简述了无麸质食品的相关标准和大米面包使用的原料,并介绍了其工艺和品质改良研究进展,以期为无麸质大米面包的产业化开发提供参考。     

Effect of Ingredients on Rheological, Nutritional and Quality Characteristics of High Protein, High Fibre and Low Carbohydrate Bread

Effect of replacement of wheat flour with a combination of soy protein isolate, oat bran and chickpea flour (SPOBCP) at the levels of 20%, 40% and 60% and addition of combination of additives such as fungal ??-amylase, dry gluten powder, sodium stearoyl-2-lactylate, hydroxypropylmethylcellulose (CA) on the rheological and nutritional characteristics of bread was studied. Use of SPOBCP decreased farinograph dough stability, increased pasting temperature, decreased cold paste viscosity and overall quality score of bread. Scanning electron microscopy images showed higher degree of disruption of protein matrix in bread dough with 60% SPOBCP than 20% and 40% SPOBCP. Addition of 60% SPOBCP resulted in flat, uneven shaped bread with an overall quality score of 38 when compared with 54, 81 and 91 for breads with 40%, 20% and 0% SPOBCP, respectively. However, use of CA increased the strength of the dough and improved the overall quality of bread with 40% SPOBCP. Nutritional profile of bread with 40% SPOBCP?+?CA showed higher protein, in vitro protein digestibility, total dietary fibre, resistant starch, ??-glucan and lower starch hydrolysis index than control bread.     

Improvers and functional ingredients in whole wheat bread: A review of their effects on dough properties and bread quality

BackgroundDespite the associated health benefits of whole grains, consumption of whole grain products remains far below recommended levels. Whole wheat bread is often associated with many distinctive attributes such as low loaf volume, firm and gritty texture, dark and rough crust and crumb appearance, bitter flavor, and reduced shelf-life. There is a need to improve its quality and sensory characteristics so as to increase consumer appeal and, ultimately, increase the intake of whole wheat bread. The inclusion of various ingredients improves dough and bread properties.Scope and approachThis review examines the effects of enzymes, emulsifiers, hydrocolloids, and oxidants on the properties of whole wheat bread and dough, with particular attention to effects on loaf volume and hardness. Wheat gluten and other plant materials are also discussed. Gaps in the research into whole wheat bread are identified, and future research needs are recommended.Key findings and conclusionsXylanase reduces the water absorption of whole wheat flour and increases loaf volume and crumb softness by hydrolyzing ararbinoxylans. α-amylase can be beneficial under certain conditions. Phytase may activate endogenous α-amylase. G4-amylase is promising but needs validation by further research on its effect on loaf volume, crumb hardness, and staling. Vital wheat gluten overcomes many of the challenges of whole wheat bread production and is found in the majority of commercial whole wheat breads. Emulsifiers DATEM and SSL can improve the volume, texture and staling profile of whole wheat bread. Several types of improvers are generally needed in combination to provide the greatest improvement to whole wheat dough and bread.