Production Of Gluten-free Bread Research Articles

Harinas y almidones de yuca, ñame, camote y ñampí: propiedades funcionales y posibles aplicaciones en la industria alimentaria.

<p style="text-align: justify;">Se realizó una revisión de las características fisicoquímicas de las harinas y almidones de yuca, ñame, ñampí y camote, tales como el contenido de amilosa-amilopectina, la viscosidad, el valor nutricional y la fibra, con el fin de relacionarlas con sus propiedades funcionales y técnico-funcionales. Se obtuvo una relación entre el contenido de amilosa-amilopectina, viscosidad y contenido de fibra en la digestibilidad de estos almidones y los valores de índice glicémico. Se encontró que es posible introducir modificaciones por medio de la fermentación para mejorar el valor funcional de estos almidones. La fermentación permite elaborar pan sin gluten y bebidas energéticas como nuevas opciones de productos. También se encontró que existe una relación entre la viscosidad de los almidones y la disminución de absorción de la grasa en frituras.</p>

Influence of inulin on physical characteristics and staling rate of gluten-free bread

Inulin preparations with different degree of polymerization (HSI with a DP<10, GR−DP⩾10 and HPX−DP>23) were used for the production of gluten-free bread. It was found that an addition of investigated compounds resulted in an increase of loaf volume and reduction of crumb hardness. However, internal structure of the obtained loaves was less uniform and more open than in control bread. Generally, inulin preparations with lower degree of polymerization had stronger effect on all analyzed parameters than that with higher DP. A decrease in staling was observed (measured as the rate of crumb hardening), which was caused by the presence of inulin. The highest content of retrograded amylopectin was found for crumb with HSI, and the lowest for samples with HPX.

Possibilities to increase the quality in gluten-free bread production: an overview

The market for gluten-free products is increasing. Owing to better diagnostic methods, more and more people are identified to have coeliac diseases. Production of bakery products that do not harm these people is a big challenge for bakers and cereal scientists in the twenty-first century. The use of different cereals and flours makes it necessary to find possibilities to take over the task of gluten by other flour ingredients, by the addition of different components, by different flour and dough treatment or by changing the method of baking. The purpose of this review is to give an overview about the various possibilities to increase the baking quality of gluten-free bakery products, increasing their water-binding capacity, uniform the crumb structure and increase the final bread volume. All the listed methods and ingredients are already in single use helpful to increase the quality in gluten-free bread production.

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.

Impact of different isolation procedures on the functionality of zein and kafirin

Commercial corn prolamin (zein) aggregates in water at elevated temperatures into an extensible, viscoelastic gluten-like substance. This specific functionality of zein can be used in the production of gluten-free bread from true dough systems and not from batters. The present study examined laboratory-scale isolation of such functional zein from dry milled corn. RP-HPLC indicated that successful isolation procedures resulted in relatively pure α-zeins, with a maximum ratio of (β + γ)/α-zeins of about 10%. In the present study, such functional zeins were obtained by using 70% ethanol as the extractant, without added alkali or reducing agent in the main extraction step. In contrast, films could be cast from a wider range of zein isolates, also with higher ratios of (β + γ)/α-zeins. Isolation of the analogous prolamin (kafirin) from dry milled sorghum required a more hydrophobic extractant such as 83% isopropanol to achieve partial functionality. Such kafirin was able to aggregate in warm water, preferably when a reducing agent was added; however, it quickly became firm and lost its extensibility. The present study suggests that hydrophobic interactions rather than disulfide bonds are the key to gluten-like functionality of zein and kafirin.

Limited micronutrient data for gluten-free bread products prevents accurate dietary analysis

Background: Gluten containing staple foods including bread are an important source of B vitamins, folate, iron and calcium. In coeliac disease (CD), bread is commonly substituted with specialist gluten-free (SGF) bread, most obtained on prescription (Kinsey, 2008). In the UK, mandatory fortification of bread-flour with four nutrients; iron, thiamin, niacin and calcium, does not apply to GF bread flour. Several studies highlight low intakes of micronutrients in CD (Wild et al., 2010); it is unclear whether this is a result of a lack of fortification, lack of compositional data for the SGF products or absence of nutrients. The aim of this preliminary study was to investigate the fortification of prescription SGF bread products and the availability of micronutrient compositional data. Methods: Gluten-free breads available on prescription were identified from the National Health Service Drug Tariff and the British National Formulary. Manufacturers were contacted by e-mail/phone to obtain information on the fortification of SGF breads and data available for the micronutrient content of finished goods. Results: Of 13 brands providing SGF breads on prescription, only four were fortified with some but not all of the four micronutrients recommended for bread flour. All four of these brands were fortified with folate. Table 1 illustrates the variability in micronutrient levels within and between brands. Unlike compositional data for ordinary gluten containing bread available from McCance and Widdowson, no manufacturer was able to provide a complete micronutrient profile (e.g. data on magnesium, zinc, selenium were not available). Table 1. Micronutrient data per 100 g of SGF white breads available on prescription: 4 of 13 brands White Bread Data Source Calcium (mg) Folate (ug) Iron (mg) Thiamin (mg) Niacin (mg) Dietary Specials 1 loaf a 120 a 30 NA NA NA Ener-G* 2 loaves b240–247 a 76–83 c 1.88–2.39 c 0.33–0.39 c 2.35–2.39 Glutafin/Select 3 loaves a 120–120–380 a 30 NA NA NA Juvela 2 loaves b113–121 c 30 c 4.0–4.3 c 0.21 c 2.7 (FSA, 2002) Avg 15 samples 177 25 2.2 0.24 1.6 Bold italic = nutrient fortified. NA = Not available. *Excludes non-fortified Yeast free rice loaf. aLevels of added nutrients on product label. bLevels on label but not fortified. CLevels available from company on request. Discussion: Although a European standard exists that recommends that foods for special medical purposes contain nutrients at levels of the foods that they intend to replace, this study demonstrates that fortification of SGF bread products in the UK is limited and inconsistent. As is demonstrated in this preliminary study, the complete micronutrient content of SGF bread products is not available. This is not unexpected given that labelling legislation requires manufacturers to state only energy, macronutrient, fibre and sodium content unless a nutritional claim is made. The outcome of UK studies evaluating the nutritional adequacy of gluten-free diets may therefore reflect inconsistent fortification plus the paucity of analytical data for micronutrients present in the natural ingredients, rather than a genuine absence. Conclusions: To accurately assess the nutritional adequacy of gluten-free diets, consideration needs to be given to the development of a comprehensive SGF product database comparable with McCance and Widdowson. The mandatory fortification of SGF bread products also warrants further consideration.

The use of whey protein particles in gluten-free bread production, the effect of particle stability

Wheat dough has unique properties for bread making due to its elastic and strain hardening behaviour. A mesoscopically structured whey protein particle system possesses those elastic and strain hardening properties when mixed with starch to a certain extent. However, the extensibility is lower and the particles are more stable than gluten particles upon kneading, probably due to a too high degree of internal crosslinking. This study describes the relation between the number of disulphide bonds of a mesoscopic whey protein particle suspension blocked by NEM treatment and the resulting properties of a dough and bread prepared with that suspension. This study shows that the properties of the particle network are influenced by the ability to form disulphide bonds. Our study shows that a certain amount of disulphide bonds is essential, but too many disulphide bonds can lead to too stiff dough and poorer bread properties.

Colloidal Protein Particles Can Be Used to Develop a Gluten-free Bread

This paper presents a novel approach for the production of gluten-free breads. Rather than mimicking the molecular structure and properties of gluten, gluten functionality was mimicked by creating a colloidal protein particle network (based on whey protein). The addition of this protein particle network transformed a starch slurry into a material with dough-like properties that could be used in a standard baking process to produce gluten-free breads. An overview of the potential and limitations of this novel technology is given.

Kiwifruit-based polyphenols and related antioxidants for functional foods: kiwifruit extract-enhanced gluten-free bread

The present study investigates the production of gluten-free bread enhanced with polyphenols and related antioxidants derived from a natural aqueous extract from green-fleshed kiwifruit (Actinidia deliciosa). Puree and four aqueous extracts, produced from ripe green kiwifruit in the absence of artificial preservatives, were subjected to storage stability trials at 4°C, 20°C and 38°C, and were chemically characterized (phenolic, vitamin C and pectic polysaccharide contents). The aqueous extract with good stability and high phenolic and vitamin C contents was used for gluten-free bread-making. The resultant kiwifruit extract-enhanced bread was acceptable to a taste panel, possessing softer and smoother texture than plain gluten-free bread. Thus, the aqueous extract of kiwifruit puree containing health-beneficial constituents can be considered a functional ingredient for gluten-free bread formulation.

Production of acidic extruded rice flour and its influence on the qualities of gluten-free bread

One of the greatest technological challenges in the production of gluten-free bread (GFB) is to find a low-cost ingredient capable of retaining gas during fermentation and the baking process. The use of gelatinized starch appears to show promise for this purpose. In this study, GFB was made using raw rice flour (100 g) with the addition of 10 g acidic extruded rice flour (AERF). The AERF was produced in a single-screw extruder, varying the extrusion temperature and lactic acid concentration. Response surface methodology (RSM) and the principle components analysis (PCA) were used to analyze the results. The results of RSM showed no significant difference, but the mean volume obtained with the AERF (1.95 mL g−1) was still low when compared with that of wheat bread (6 mL g−1). The crust and crumb colors and the texture (hardness = 173 g; chewiness = 90.5 and fracturability = 178) presented results similar to those of wheat bread and better than other GFB found in the literature. When analyzed by PCA the AERF obtained at 150 °C–0.5 mol L−1 lactic acid, showed the best results for the GFB obtained. IR spectroscopy showed that no bands were found for esters (1740 cm−1) in the AERFs, which could indicate that no new bonds were formed between the rice flour and the lactic acid.

Hydrocolloids in gluten-free breads: A review

Bread is a traditional food generally prepared from wheat flour. The main wheat component responsible for bread quality is gluten, which is an essential structure-binding protein. Although important, this protein can cause health problems in predisposed individuals, and is avoided in the diet of celiac disease patients. As diagnosis methods are improved, revealing the high incidence of gluten-intolerance in the western world, the demand for novel, nutritious and high-quality gluten-free foods also ascends. However, for the production of gluten-free breads the absence of gluten is critical and challenging in regards to the bread structure. Various gluten-free formulations have applied hydrocolloids to mimic the viscoelastic properties of gluten. They comprise a number of water-soluble polysaccharides with varied chemical structures providing a range of functional properties that make them suitable to this application. This paper reviews some actual facts about celiac disease and focuses on the reported applications of hydrocolloids in gluten-free breads.

Use of Response Surface Methodology to Optimize Gluten-Free Bread Fortified with Soy Flour and Dry Milk

The percentages of soy flour (X1) and dry milk (X2) were varied for the production of gluten-free bread to optimize batter softness (Y1), specific volume (Y2), crumb grain score (Y3), bread score (Y4) and bread protein content (Y5). A central composite design was used and second-order models for Y1 were employed to generate response surfaces. When bread protein content was decreased from 10 to 3%, specific volume increased from 3.2 to 4.6 cm3/g and bread score increased too. Nevertheless, the highest crumb grain score was obtained at 7.3% of bread protein content. The results demonstrated that a gluten-free bread can be prepared by adding 7.5% soy flour and 7.8% dry milk to a previously developed formulation, increasing its protein content from 1 to 7.3% and modifying in a small degree, its sensory quality.