Obtaining and evaluating of enzymatic extracts from hairless canary seed (CDC Maria) as gluten-free bread-improving agents.

In this study, enzyme extracts were obtained from hairless canary seeds (CDC Maria) and used as gluten-free bread improvers. The enzyme extraction was done with a specific protein buffer solution and subsequent centrifugation. The supernatant was called crude enzyme extract, a fraction of this extract was refrigerated (CE) and another fraction was lyophilized (CEL). The lyoprotective effect of corn fiber (CEL + CF), maltodextrin (CEL + M), and inulin (CEL + I) was evaluated. Each enzyme extract was added to a gluten-free bread at 0.25%, 0.5%, 0.75% and 1% (w/w). The quality of the gluten-free bread was determined by external and internal characteristically, physical and sensory analysis: analysis of the lamella thickness, the shape factor of pores, the final volume, the aeration percentage, the texture profile analysis, the pore size distribution and shelf-life time. The results showed that the formulation with CEL at 0.5% (w/w) significantly improved the gluten-free bread quality properties, generating an increase of the final volume and aeration percentage, a reduction of the firmness, chewiness and sample aging, and a finer and more uniform crumb structure when compared to a control sample (P < 0.001). This study revealed the potential of a food-improving additive obtained from a natural origin with a high-level production in Argentina.

Effects of germination and lactic acid fermentation on nutritional and rheological properties of sorghum: A graphical review.

Sorghum (Sorghum bicolor) is a nutritional grain considered an important source of micro- and macro-nutrients. Also, the flour obtained from sorghum is considered a suitable substitute for wheat flour for celiac disease patients due it is gluten-free. However, its use has some limitations due to anti-nutritional factors such as tannins, phytates, trypsin inhibitors, and protein crosslinkers. To prevent those effects, new strategies for sorghum processing have been explored. Germination of this grain has been shown to increase nutrient content further and reduce anti-nutrients. In addition, fermentation with lactic acid bacteria could modify starch and protein digestion in sorghum flour and increase their nutrient availability. Although there are many benefits to germination and fermentation, more research must be done to improve the products' texture and sensory properties to gain wider consumer acceptance. In this review, the mechanism behind changes in the nutritional and anti-nutritional profile of sorghum grain due to germination and fermentation treatments is shown, and the impact of these changes on dough rheological properties and bread quality.

A Systematic Review on Gluten-Free Bread Formulations Using Specific Volume as a Quality Indicator.

This study aimed to perform a systematic review on gluten-free bread formulations using specific volumes as a quality indicator. In this systematic review, we identified 259 studies that met inclusion criteria. From these studies, 43 met the requirements of having gluten-free bread with a specific volume greater than or equal to 3.5 cm3/g. Other parameters such as the texture profile, color (crumb and crust), and sensory analysis examined in these studies were presented. The formulations that best compensated the lack of the gluten-network were based on the combination of rice flour, rice flour with low amylose content, maize flour, rice starch, corn starch, potato starch, starch with proteins and added with transglutaminase (TGase), and hydrocolloids like hydroxypropylmethylcellulose (HPMC). Of the 43 studies, three did not present risk of bias, and the only parameter evaluated in common in the studies was the specific volume. However, it is necessary to jointly analyze other parameters that contribute to the quality, such as texture profile, external and internal characteristics, acceptability, and useful life of the bread, especially since it is a product obtained through raw materials and unconventional ingredients.

Glycemic Index of Gluten-Free Bread and Their Main Ingredients: A Systematic Review and Meta-Analysis.

This study aimed to perform a systematic review and meta-analysis of the glycemic index (GI) of gluten-free bread (GFB) and its main ingredients. The systematic review followed PRISMA guidelines, using seven electronic databases (PubMed, EMBASE, Scopus, Science Direct, Web of Science, gray literature research with Google Scholar, and patents with Google Patent tool), from inception to November 2020. Eighteen studies met the inclusion criteria evaluating 132 GFB samples. Five articles tested GI in vivo, eleven in vitro; and two studies tested both methods. The analysis showed that 60.7% (95% CI: 40.2-78.1%) of the samples presented high glycemic indexes, evidencing a high glycemic profile for GFB. Only 18.2% (95% CI: 11.7-27.2%) of the bread samples presented in the studies were classified as a low GI. Meta-analysis presented moderate/low heterogenicity between studies (I2 = 61% and <1% for both high and low GIs) and reinforced the proportion of high GIs. Lower GIs were found in formulations based on Colocasia esculenta flour or enriched with fiber, yogurt and curd cheese, sourdough, psyllium, hydrocolloids, enzymes, fructans, and resistant starch, highlighting the efficacy of these ingredients to lower GFBs' GI. GFB tends to present high GI, impacting the development of chronic diseases when consumed.

Chemical Composition and Glycemic Index of Gluten-Free Bread Commercialized in Brazil.

Nowadays, the world is experiencing an increased demand for gluten-free products associated with the high prevalence of gluten-related disorders (GRD). As this market thrives, bread stands out as the most demanded and consumed product, highlighting the need to evaluate its nutritional quality. In this sense, this cross-sectional study aimed to assess the ingredients, chemical composition, and glycemic index of gluten-free bread (GFB) commercialized nationwide in Brazil. The labels were analyzed according to their ingredients and composition. In addition, centesimal composition analysis (moisture, carbohydrates, protein, ash, lipid, and fiber) was performed using the official methods, as well as the in vivo glycemic index. Significant differences between manufacturing lots of each brand and between different gluten-free bread samples were found. There is a mismatch from what is stipulated by the Brazilian legislation between analytical data and the data described on sample labels. Samples showed predominantly refined starch and high glycemic index profile. Most samples (75%, n = 6) of the non-whole gluten-free bread (n = 8) presented high glycemic index (GI). From four whole food/multigrain gluten-free bread samples, three of them (75%) presented medium GI. However, two samples presented GI near the value to be considered high. The results suggest a lack of production control, impairing the gluten-free nutritional label as a reliable information source and tool for dietary control. Therefore, it is necessary to standardize the process of gluten-free bread production and labeling, as well as to improve the nutritional characteristics of these products, aiming the give accurate information to consumers and provide a healthier product beyond the sensory characteristics.

Gluten-free breadmaking affected by the particle size and chemical composition of quinoa and buckwheat flour fractions.

This study aimed at assessing the effect of physicochemical properties and the particle size of different fractions of buckwheat and quinoa on the behaviour of gluten-free dough and bread quality. Quinoa and buckwheat grains were milled with a hammer mill and then separated in three fractions. These fractions where then re-milled with a cyclonic mill to obtain samples of similar sizes. Results showed that the chemical composition of these fractions was very different and played a major role on bread quality. Proteins, lipids and fibre negatively affected bread quality, whereas starch-rich fractions were more adequate for breadmaking. Re-milling quinoa and buckwheat fractions increased bread volume, although chemical composition still influenced bread properties. For hammer-milled fractions, both the finest fractions resulted in breads with higher technological quality, as well as a final product with more fibre, minerals and proteins.

Analysis of ingredient and nutritional labeling of commercially available gluten-free bread in Brazil.

This study aimed at evaluating the ingredients and nutritional information of commercially-available gluten-free bread (GFB) in Brazil. A total of 128 products were studied, of which 87% presented the sandwich loaf shape. Traditional GFBs (n = 114) had as main ingredient the refined rice flour and starches, whereas alternative ones (n = 14) presented whole rice flour. Raw materials suggested by science to improve nutrients and bioactive compounds of gluten-free foodstuffs were observed in the ingredient list of most products (n = 86); however, they were used in lower levels, thus no significant differences were observed for nutritional information between the different categories of GFB. No products with added vitamins or minerals were found, though 77% of them included hydrocolloids in their formulations - other food additives were also observed. Despite the increased gluten-free food market, there is still a gap between science and market, especially regarding the approaches to improve the GFB diversity and nutritional quality.

A study on fibre addition to gluten free bread: its effects on bread quality and in vitro digestibility.

The aim of this study was to assess the impact of fibre addition on gluten-free (GF) dough properties and bread technological quality, and on protein and starch in vitro digestibility. Soluble (Inulin, In) and insoluble fibres (oat fibre, OF, and type IV resistant starch, RSIV) were used at 5 and 10% substitution levels. Dough firmness increased when insoluble fibres were added, and decreased when In was used. Incorporation of insoluble fibres resulted into bread with a low specific volume (SBV) since firmer dough were more difficult to expand during proofing and baking. Staling rate was reduced after fibre addition, with the exception being OF 10%, as its lower SBV may have favoured molecule re-association. In general, protein and starch digestibility increased when fibres were added at 5%, and then decreased after further increasing the level. Fibres may have disrupted bread crumb structure, thus increasing digestibility, although the higher addition may have led to a physical and/or chemical impediment to digestion. Inulin has well-known physiological effects, while RS presented the most important effect on in vitro starch digestibility (GI). These results showed the possibility of adding different fibres to GF bread to decrease the GI and increase protein digestibility, while obtaining an overall high quality end-product.

Influence of germination time of brown rice in relation to flour and gluten free bread quality.

The effect of germination time on physicochemical characteristics of brown rice flour and its effect on gluten free bread qualities have been investigated. Germination was carried out at 28 °C and 100 % RH for 12, 24 and 48 h; brown rice and soaked brown rice was also analyzed. Significant changes on hydration and pasting properties of brown rice flour were found during germination. The starch degradation by enzyme activity could be evidenced with the decrease in viscosity and water binding capacity (WBC). No significant effect in specific volume, humidity and water activity of the gluten free bread was found as germination time increase, but a significant softness of the crumb was obtained. However, at 48 h of germination, the intense action of α amylase could result in excessive liquefaction and dextrinisation, causing inferior bread quality. Overall, germinated rice flour showed appropriate functionality for being used as raw ingredient in gluten free breadmaking.

Improvement of gluten-free bread properties by the incorporation of bovine plasma proteins and different saccharides into the matrix.

The aim of this work was to improve the quality of gluten-free bread, incorporating plasma bovine proteins concentrated by ultrafiltration and freeze-dried with saccharides (inulin and sucrose). The influence of these compounds on textural properties and final bread quality was assessed. The textural studies revealed that with the addition of proteins and inulin, homogeneous and smaller air cells were achieved improving the textural properties while the bread hardness was comparable with breads with gluten. The volume of gluten-free breads increased with increasing proteins and inulin concentrations, reaching a maximum at a protein concentration of 3.5% (w/w). The addition of the enhancers improved moisture retention of the loaves after cooking and an increase of lightness of crumb with respect to the control was observed. The sensory analysis found no statistically significant difference in sensory attributes evaluated with respect to the control, so these ingredients do not negatively affect the organoleptic properties of bread.