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.     

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.     

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.     

Effect of Microwave Radiation Pretreatment of Rice Flour on Gluten-Free Breadmaking and Molecular Size of β-Glucans in the Fortified Breads

Cereal β-glucan concentrates can be used in gluten-free breads to improve dough handling properties and quality of final products as well as to enhance their nutritional value; however, the presence of endogenous β-glucanases in rice flour, in combination with prolonged mixing, fermentation, and proofing time, can cause a substantial reduction in β-glucan molecular weight, affecting detrimentally their efficacy for bioactivity. In this study, microwave (MIWA) heating was applied to the rice flours before breadmaking at different flour water contents (13–25%) and treatment times (0-4 min) to reduce β-glucanase activity. Gluten-free breads made from the MIWA-treated rice flours were fortified with oat β-glucan concentrate to enhance their nutritional profile. The molecular weight of added β-glucan in the final products increased with increasing both flour water content and time of MIWA treatment, reflecting the magnitude of residual β-glucanase activity in the flour. Pretreatment with MIWA radiation for 4 min of the rice flour tempered at 25% moisture resulted in negligible residual β-glucanase activity and preserved to a great extent the molecular weight of β-glucans in the enriched breads. End-product quality was not affected by flour MIWA pretreatment, and even a slightly higher loaf specific volume was noted for breads made from the MIWA-treated flours (4 min MIWA at 25% moisture content) compared to that of untreated flour. These findings can contribute to the improvement of nutritional value of rice-based gluten-free breads for celiac consumers as well as of any β-glucan-containing yeast-leavened bakery product without altering its sensorial attributes. Additional studies are still required for further evaluation of the effect of more intense microwave treatment on rice flour and its application on breadmaking.     

PREDICTION OF INSTRUMENTAL AND SENSORY TEXTURAL CHARACTERISTICS OF MAHON CHEESE FROM ULTRASONIC MEASUREMENTS

Ultrasonic velocity was related to sensory and instrumental texture measurements. A semi-logarithmic model (Weber-Fechner) was used to relate the sensory and instrumental texture measurements. The ultrasonic velocity ranged from 1650 to 1723 m/s for the softest and hardest cheese, respectively. As expected from theoretical equations, the ultrasonic velocity was related to the square root of the instrumental measurements. The deformability modulus (r²=0.93) and the slope in puncture (r²=0.85) were the most closely related parameters. A model developed from the relationship between sensory and instrumental texture and the relationship between ultrasonic velocity and instrumental texture, was used to relate velocity to sensory measurements. Elasticity (r²= 0.84) and firmness (r²= 0.81) were the sensory attributes which best correlated with ultrasonic velocity. From the obtained results, it was concluded that ultrasonic velocity measurements could be used to assess instrumental and sensory properties of Mahon cheese texture nondestructively, and therefore could be used for grading purposes.     

Quality Indicators of Rice-Based Gluten-Free Bread-Like Products: Relationships Between Dough Rheology and Quality Characteristics

The design of gluten-free bread-like products involves the study of gluten-free dough rheology and the resulting baked product characteristics, but little information has been obtained connecting dough and baked product properties. The aim of this study was to determine quality predictors of gluten-free bread-like products at dough level by defining possible correlations between dough rheological properties and both instrumental parameters and sensory characteristics of those products. Diverse rice-based gluten-free doughs were defined and rheologically characterised at dough level, and the technological and sensorial quality of the resulting baked products was investigated. Dough Mixolab® parameters, bread-like quality parameters (moisture content, specific volume, water activity, colour and crumb texture) and chemical composition significantly (P?<?0.05) discriminated between the samples tested. In general, the highest correlation coefficients (r?>?0.70) were found when quality instrumental parameters of the baked products were correlated with the dough Mixolab® parameters, and lower correlation coefficients (r?<?0.70) were found when sensory characteristics were correlated with dough rheology or instrumental parameters. Dough consistency during mixing (C1), amplitude and dough consistency after cooling (C5) would be useful predictors of crumb hardness; and C5 would be also a predictor of perceived hardness of gluten-free bread-like products.     

Thermorheological and Textural Behaviour of Gluten-Free Gels Obtained from Chestnut and Rice Flours

Nowadays, as celiac disease is becoming more common the consumers’ demand for gluten-free products with high nutritional and taste quality is increasing. This work deals with the study of the impact of four novelty gluten-free sources: chestnut flour (Cf), whole rice flour (Rw), Carolino rice flour (Rc) and Agulha rice flour (Ra). Textural, thermorheological and stability performance of gluten-free gels using different experimental techniques were evaluated. Mixed gels were also produced for comparison. Texture parameters were determined from the texture profile analysis using a texturometer. Thermorheological oscillatory measurements were conducted in a stress-controlled rheometer in order to clarify the kinetics of gel formation and to characterise the structure of the matured gels. The stability of the gels was evaluated using transmittance profiling of the gels under gravitational fields (LUMiSizer®). Texture studies suggested that gels from mixtures of chestnut flour at 30 % and rice flour at 20 % showed the right texture to develop gel-based new desserts. Rheological results showed that the thermal profiles on heating of Cf gels were similar to those obtained for Rw and Ra, whereas Rc gels exhibited a particular pattern. Once the final gelatinisation temperature was achieved, no significant differences on the viscoelastic properties were noticed for all the tested gels. Stability tests showed that gels with Rc should present an industrial advantage over the other assayed formulations, since the stability of these gels is of the order of four times larger.     

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.     

The role of hydrocolloids in the development of gluten-free cereal-based products for coeliac patients: a review

A growing number of diseases in association with gluten intake, such as coeliac disease, have led to increasing demand for gluten-free products as a crucial economic and health issue. Gluten-free products, because of the absence of gluten, usually have a poor texture, taste and appearance. Therefore, the production of good quality gluten-free products with substances that can somehow mimic the viscoelastic properties of gluten is an important challenge. Recently, hydrocolloids are widely used to improve the quality and shelf-life of gluten-free products. In this study, the effect of hydrocolloids on the production of gluten-free cereal-based products, such as breads, cakes and muffins, biscuits and cookies, pasta and noodles, has been reviewed as well as their nutritional values. In general, this study could suggest key factors in the improvement of gluten-free products.     

BRNING TIME AND SMOKING INFLUENCE ON ACCEPTABILITY OF IDIAZABAL CHEESE

Brining time and traditional smoking effects on sensory characteristics (appearance, odor, texture, taste and aftertaste) during ripening of Idiazabal cheese were studied in terms of acceptability. The range of brining time (12, 24 and 36 h) considered in this study showed little effect on sensory parameters. In longer brined cheeses, an improvement of rind acceptability was observed especially at the beginning of the ripening period. In young products the texture of the more salted cheese was preferred, in hard cheeses consumers preferred the less salty ones. The traditional smoking process had a greater effect on sensory parameters perceived by consumers than brining time did. It was observed that smoking had a positive influence on acceptability of rind, paste color and eyes. Smoking also increased odor and texture acceptability.     

STEAMED BREADS MADE FROM COLORADO GROWN WHITE WHEATS

Seven Colorado grown white wheats and a commercial all-purpose flour were used to prepare Chinese steamed bread. Steamed bread doughs were made from 41.8% flour (200g per batch), 0.7% instant active dry yeast, and 57.5% water. Steamed breads were evaluated for specific volume (cm³/g), color of crumb and crust, texture using a texture analyzer, and by a subjective sensory evaluation.
Specific volume of steamed bread ranged from 3.3 to 3.6 cm³/g. There was no statistical significant difference in crust and crumb color among breads from all flour samples. Low peak force and area texture measurements which indicate softness, were correlated with high specific volume. Overall, the flours from Colorado grown white wheats were desirable for making steamed bread with one exception. The all-purpose commercial flour was found to be desirable for making steamed bread.     

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.     

Gluten-free Bread Based on Tapioca Starch: Texture and Sensory Studies

In the present work, gluten-free formulations for breadmaking, destined to celiac people, were studied. A base blend of tapioca starch and corn flour (80:20) and typical bread ingredients such as yeast, salt, sugar and water were utilised. Ingredients such us vegetable fat, hen egg, and soybean flour were incorporated in different levels by means of an experimental design of three factors. Bread quality was analysed throughout physical (specific volume, weight loss percentage) and textural (firmness, elasticity and firmness recovery) parameters. The optimum bread selected, the bread with highest levels of fat and soybean flour and one egg, presented low values of firmness (≤100 N) and elasticity (>65%) and the lowest variation of these parameters with storage. Overall acceptability of this bread was 84% for habitual consumers of wheat bread and 100% by celiac people. Therefore, tapioca starch-based breads with spongy crumb, high volume and a good sensory acceptance were obtained.