Effect of the shape of rice starch granules on flour characteristics and gluten‐free bread quality

The effect of three different rice varieties with different starch shapes (Seolgaeng (SG), round starch structure; Samkwang (SK), polygonal starch structure and Boramchan (BRC), polygonal starch structure) on rice flour characteristics and gluten‐free bread baking quality was investigated. Rice flours were produced by dry milling and passed through a 200 mesh sieve. Electron microscopy revealed that the structure of SG grains, with round starch granules, possessed larger void spaces than SK and BRC, composed of polygonal starch granules. For this reason, SG grain had low grain hardness and consequently, it was milled to a fine flour with low damaged starch content. The thermo‐mechanical properties were determined by Mixolab, which revealed that SG was gelatinised rapidly and maintained high viscosity after gelatinisation. These characteristics gave SG flour the ability to build up bread structure without gluten. Specific volume and crumb hardness of gluten‐free rice breads made of SG, SK and BRC flours were 3.37, 3.11 and 2.12 mL g^?1 and 2.61, 2.76 and 6.46 N, respectively. The SG flour with round starch structure is appropriate for making gluten‐free rice breads.     

Production of gluten‐free bread using soybean flour

The effect of soybean flour on gluten‐free bread quality was studied. Full‐fat enzyme‐active, semiactive and inactive soybean flours were evaluated. Active soybean flour improved the volume and structure of gluten‐free bread, while semiactive and inactive soybean flours did not have positive effects on bread quality. The particle size and concentration of the soybean flours also affected bread quality. Levels of addition between 125 and 150 g kg^?1 and particle sizes between 90 and 120 µm of active soybean flour yielded the best results. Heating the active soybean flour destroyed its improving effect. The analysis of proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis and size exclusion chromatography showed that heating soybean flour at 60–200°C caused protein aggregation. The overall results indicated that the addition of active soybean flour improved gluten‐free bread quality, and this effect seemed to be due to both the structural proteins and the enzymatic activities of the soybean flour. Copyright © 2004 Society of Chemical Industry     

From wheat sourdough to gluten‐free sourdough: a non‐conventional process for producing gluten‐free bread

Gluten‐free (GF) sourdough was prepared from wheat sourdough and analysed both in fresh (GFS) and dried forms (DGFS). The gluten content in each GF sourdough sample was <20 mg kg^?1. The dough leavening capacity and the properties of the bread samples were investigated and compared to those of bread prepared using bakery yeast (Saccharomyces cerevisiae). Two commercial rice‐based mixtures (different for the presence/absence of buckwheat flour) were used to prepare bread samples. In GFS, lactic acid bacteria (LAB) and yeasts were found in amounts corresponding to 10⁸ and 10⁷ CFU g^?1, respectively, whereas both LAB and yeasts were detected in lower amounts (about 10⁶ CFU g^?1) in DGFS. When used in bread‐making, both GFS types produced significant dough acidification and exhibited good dough development during proofing, resulting in loaves with specific volume values between 3.00 and 4.12 mL g^?1, values similar to those obtained for reference bread (3.05÷4.15 mL g^?1). The use of GFS was effective in lowering the bread staling rate during storage for up to 7 days.     

Effect of hydroxypropyl methylcellulose,whey protein concentrate and soy protein isolate enrichment on characteristics of gluten‐free rice dough and bread

Due to a lack of gluten, rice dough needed some additives to improve its properties. This study aimed to investigate effect of hydroxypropyl methylcellulose (HPMC), whey protein concentrate (WPC) and soy protein isolate (SPI) on rice dough and bread. HPMC increased water absorption of the rice dough (P ≤ 0.05). Adding SPI (2–4 g per 100 g flour) together with HPMC tended to increase stability time and reduce tolerance index. During fermentation, HPMC increased maximum dough height, while SPI increased final dough height (P ≤ 0.05). All addition improved tan δ (G″/G′) to be comparable to the wheat dough, but it could not improve gas production and retention. Therefore, specific volume, springiness, cohesiveness and chewiness of rice bread were lower than those of wheat bread (P ≤ 0.05). Percentage of small pores in rice bread was reduced to be comparable to wheat bread, by adding WPC. All addition could improve porosity of the rice bread.     

Effect of green plantain flour addition to gluten‐free bread on functional bread properties and resistant starch content

Green plantain flour (GPF) was used as a functional ingredient to produce gluten‐free (GF) bread based on a flour blend of rice flour and GF wheat starch (50:50) to improve their functional properties and to increase their resistant starch (RS) content. In pretrials, an addition of up to 30% GPF provided acceptable bread quality with maximum RS content. Based on these trials, two 2³ factorial screening experimental designs were applied, where water content, baking temperature and baking time of GF bread containing 30% GPF addition were optimised. The best baking conditions to achieve satisfying GF bread quality – higher loaf volume, softer crumb firmness and regular porosity structure at the highest RS content could be defined to a maximum addition of water at 160%, baking temperature of 180 °C and baking time of 90 min. The incorporation of GPF showed good potential to improve the quality of GF bread.     

Effect of adding fresh and freeze‐dried buckwheat sourdough on gluten‐free bread quality

This study demonstrates new possibilities in using freeze‐dried buckwheat sourdoughs in the processing of gluten‐free bread (GFB). Fresh and freeze‐dried (at temperatures of 20, 40 and 60 °C) sourdoughs were added in the amounts of 10, 20, 30 and 40% of the total flour content. Significant and beneficial changes in the quality of bread under the influence of different quantities of fresh and freeze‐dried sourdoughs additive were observed. Freeze‐dried buckwheat sourdoughs at the level of 20 and 30% gave the best baking results for GFB. pH of bread significantly changed, which had a positive effect on increasing its suitability for the storage. Buckwheat sourdough dried at 40 °C is the most highly recommended for GFB processing. Higher temperatures (60 °C) caused the least change in bread volume; however, a bitter aftertaste from burning was slightly detectable. Freeze‐dried buckwheat sourdoughs can be used directly in processing, thus eliminating the long fermentation of sourdough.     

Influence of konjac flour on foaming properties of milk protein concentrate and quality characteristics of gluten‐free cookie

The effects of konjac flour (KF) for modifying the foaming properties of milk protein concentrate (MPC) and characteristics of gluten‐free rice cookies were investigated. The three variables of konjac concentration (0.1–0.4%), pH (pH 5–9) and NaCl concentration (0.2–0.6 м) were studied. Both KF and pH had considerable effects on the foaming capacity (FC) and foaming stability (FS) of MPC. The NaCl had a negligible effect. Lowered FC and FS observed at pH 9 and pH 5 were increased with the increase in KF addition. Batter characteristics (flowability and consistency), cookie quality (moisture, yield, spread ratio, specific volume, hardness and colour) and sensory acceptance were evaluated in gluten‐free cookies with 0%, 0.25% and 0.4% KF. Konjac supplementation increased batter characteristics, yield, specific volume and hardness, but decreased lightness. Panellist acceptance, especially regarding texture and overall acceptability, increased in gluten‐free cookies with 0.4% KF. A higher purchasing decision was found for cookies with added KF.     

Effect of hydrocolloids on gluten‐free batter properties and bread quality

The objectives of this study were to assess the effect of the addition of different hydrocolloids on gluten‐free batter properties and bread quality and to obtain information about the relationship between dough consistency and bread quality. Breads were made of rice, corn and soy flours and 158% water. Following hydrocolloids were added: carrageenan (C), alginate (Al), xanthan gum (XG), carboxymethylcellulose (CMC) and gelatine (Gel). Batter consistency, bread specific volume (SV), crumb analysis, crust colour, crumb hardness and staling rate were determined. Hydrocolloids increased batter consistencies: the highest value was obtained with XG, which doubled that of control batter, followed by CMC. Breads with hydrocolloid presented higher SV than control, especially with XG whose SV was 18.3% higher than that of control bread. A positive correlation was found between SV and batter consistency (r = 0.94; P < 0.05). Crumbs with Gel, XG and CMC presented higher cell average size. XG and CMC crumbs looked spongier. Breads containing hydrocolloid evidenced lighter crusts. Crumb firmness was decreased by XG and CMC addition, and staling rate was slower. Overall, XG was the hydrocolloid that most improved gluten‐free bread quality. These results show that, in formulations with high water content, batter consistency is strongly associated with bread volume.     

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     

Diversity among maize populations from Spain and the United States for dough rheology and gluten‐free breadmaking performance

Maize is used for bakery and for gluten‐free food for coeliac patients. Our objective was assessing diversity for dough rheology and breadmaking in maize with different origins, grain types and growth cycles. Endosperm type affected bread crumb colour having dent maize higher L* and a* and instant recovery speed. Population origin affected flotation index, onset pasting temperature, bread crumb colour, hardness and instant recovery speed. Finally, growth cycle affected flotation index, crumb colour L* and a* and cohesiveness. Water‐binding capacity, crumb colour and hardness were the most discriminative parameters for maize. The maize population Andaluz/Daxa was the less distant from wheat parameters, and Tremesino was the most different.     

Apple pomace in gluten‐free formulations: effect on rheology and product quality

The objective of the present work was to formulate a gluten‐free (GF) baked product based on a cassava starch, rice flour and egg white mixture and enriched with apple pomace with minimum processing as source of fibre. Effects of apple pomace and water amount on batters and product quality were analysed by response surface methodology (RSM). Dynamic moduli of batters, specific volume and crumb texture were highly dependent on both apple pomace and water. Higher levels of fibre rendered less cohesive and less resilient crumbs and diminished specific volumes. A suitable balance between amounts of apple pomace and water led to products with enough specific volume and sponginess. Up to 12.5 g apple pomace and water ranging from 115 to 150 g (each 100 g mixture), specific volumes were maintained higher than 2 cm³ g^?1; if apple pomace was increased up to 20 g, water amounts higher than 140 g were necessary to obtain similar results.     

Effect of butter content and baking condition on characteristics of the gluten‐free dough and bread

This study aimed to investigate effect of butter content (0–30 g/100 g flour) and baking conditions hot air baking (HA), microwave baking (MW) and hot air‐microwave baking (HA‐MW) on quality of the rice flour dough and bread. The increased butter (up to 15 g butter/100 g flour) enhanced elastic modulus (G′) and viscous modulus (G″) of dough and specific volume of bread. Additionally, the increased butter improved crust colour and reduced hardness of the bread. The HA‐MW and MW conditions were useful for the gluten‐free bread by reducing baking time and predicted glycemic index (GI), regardless of butter content. However, enthalpy of retrogradation and crystallinity in the HA‐MW and MW bread stored at 4 °C for 7 days were increased and higher than those of the HA bread, indicating a faster staling. The predicted GI of both MW and HA‐MW bread remained at a medium level during storage.     

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.     

Incorporation of canola proteins extracted by electroactivated solutions in gluten‐free biscuit formulation of rice–buckwheat flour blend: assessment of quality characteristics and textural properties of the product

Canola proteins extracted by electroactivated solutions were incorporated to gluten‐free biscuits made from blend of rice and buckwheat flours. Physical and textural properties were significantly influenced by these proteins. Isolates and concentrates did not behave in a similar way. A significant increase in diameter was noted for all of the supplemented samples. An increase in thickness was observed for the samples added with protein concentrate, whereas the spread ratio decreased for all the samples compared to control. The hardness of biscuits decreased with the addition of the proteins as compared to the control. The changes in biscuit hardness or fracture strength were in line with the changes in dough hardness. Biscuits containing protein concentrate had lighter, more aerated texture as shown by scanning electron microscopy with lesser amounts of gelatinised starch, indicating improved gas‐holding capacity and more stabilised structure. Protein‐supplemented biscuits have lower moisture and water activity.     

Effect of water,albumen and fat on the quality of gluten‐free bread containing amaranth

The aim of the research was the development of an alternative formula for gluten‐free bread (GFB) containing amaranth flour. GFBs were prepared using a 2³ factorial screening experimental design. The amount of water, albumen and fat varied in order to evaluate their impact on the textural, structural and sensory characteristics of the final product. Water amount had the greatest influence on bread characteristics. For a 33% water content increase (from 0.6 to 0.8 g g^?1 of flour) the firmness of the crumb decreased to 20% of the initial value. Also, for the same water content increase, the average pore size became 2.5‐fold greater. Albumen addition (from 0 to 0.04 g g^?1 of flour) influenced mainly crumb viscoelasticity (20% increase). Variations in fat amount did not significantly influence any of the response variables investigated. However, the combined addition of fat and albumen resulted in breads that received the best rankings in overall acceptance in sensory evaluation.     

Effect of zein protein and hydroxypropyl methylcellulose on the texture of model gluten‐free bread

The influence of zein protein and hydroxypropyl methylcellulose (HPMC) on the texture and volume of gluten‐free bread was investigated. The addition of HPMC to starch affected the dough viscoelasticity and it improved the bread volume during baking since it acts as an emulsifier. The addition of zein protein to gluten‐free bread increased the crumb firmness and reduced the crust hardness within the range of concentrations investigated. No zein protein network could be observed in the bread crumb. The zein protein, cold mixed at low concentration, did not enhance the dough elasticity. Due to the lack of a protein network noncovalent interactions may stabilize the bubble structure stabilization within the crumb, rather than covalent links of the protein chain. With an optimized amount of zein protein and HPMC hydrocolloid, the gluten‐free bread showed similar texture and staling behavior to that of model wheat bread. The optimized recipe, compiled into a spreadsheet, is available in the supporting information. The microstructural observations suggest that zein could be replaced with another protein for this recipe resulting in a similar bread texture.     

Influence of quinoa roasting on sensory and physicochemical properties of allergen‐free,gluten‐free cakes

The objectives of this study were to determine pasting properties of non‐roasted (NR) and roasted quinoa (RQ) and to investigate the effect of RQ on consumer acceptance and physicochemical properties of an allergen‐free, gluten‐free cake formulation. Quinoa seeds were roasted at 177 °C for 15 (R15), 30 (R30) and 45 min (R45), and flours were analysed for pasting properties. Five cakes including a commercial chocolate cake (CCC) and cakes made with NR and RQ flours were evaluated for preference by fifty panelists. Quality parameters included colour, water activity, moisture content, firmness, weight and height. Peak and final viscosity increased with roasting time. The NR cake had the highest sensory scores for appearance, colour and texture. On flavour and overall acceptability, CCC was the highest. Regarding quality data, CCC, NR and R15 cakes had similar L* values, while CCC had the lowest a*, b*, a_w, moisture content and firmness values.     

Effect of defatted almond flour on cooking,chemical and sensorial properties of gluten‐free fresh pasta

The aim of this work was to analyse the influence of defatted almond flour on soya bean‐based gluten‐free pasta. Optimal cooking time of pasta varied between 2.0 and 3.5 min, while cooking loss ranged 6.1% and 19.7%. The total protein content of samples varied from 30.4% to 41.0% (dry basis, db) in cooked pasta. The total phenols content of cooked samples varied between 1.66 and 2.99 mg ellagic acid equivalent/g, while the antioxidant activity (DPPH?) ranged between 19.1% and 41.9%. The sensory test showed no significant differences between the formulated pasta samples among brightness (3.20–3.27), surface appearance (1.14–1.20), hardness (2.14–2.36) and elasticity (1.56–1.71). Pasta developed is an innovative product that improves nutritional and functional properties of gluten‐free pasta compared to gluten‐free and traditional wheat flour pasta available on market.