Improvement on wheat bread quality by in situ produced dextran-A comprehensive review from the viewpoint of starch and gluten.

Deterioration of bread quality, characterized by the staling of bread crumb, the softening of bread crust and the loss of aroma, has caused a huge food waste and economic loss, which is a bottleneck restriction to the development of the breadmaking industry. Various bread improvers have been widely used to alleviate the issue. However, it is noteworthy that the sourdough technology has emerged as a pivotal factor in this regard. In sourdough, the metabolic breakdown of carbohydrates, proteins, and lipids leads to the production of exopolysaccharides, organic acids, aroma compounds, or prebiotics, which contributes to the preeminent ability of sourdough to enhance bread attributes. Moreover, sourdough exhibits a "green-label" feature, which satisfies the consumers' increasing demand for additive-free food products. In the past two decades, there has been a significant focus on sourdough with in situ produced dextran due to its exceptional performance. In this review, the behaviors of bread crucial compositions (i.e., starch and gluten) during dough mixing, proofing, baking and bread storing, as well as alterations induced by the acidic environment and the presence of dextran are systemically summarized. From the viewpoint of starch and gluten, results obtained confirm the synergistic amelioration on bread quality by the coadministration of acidity and dextran, and also highlight the central role of acidification. This review contributes to establishing a theoretical foundation for more effectively enhancing the quality of wheat breads through the application of in situ produced dextran.

Effect of yerba mate (Ilex paraguariensis) leaves on dough properties, antioxidant activity, and bread quality using whole wheat flour.

This study investigated the effects of different yerba mate (YM) proportions (1.5, 2.5, and 4.5 g YM/100 g whole wheat flour (WWF) and particle sizes (245, 415.5, and 623.9 µm) on dough rheological properties, antioxidant activity, and bread characteristics. The addition of YM leaves led to a possible interaction between its phenolic compounds and the gluten network within the dough, without negative effects on dough formation. However, the larger YM particle size (623.9 µm) caused a weakening of the protein network, resulting in lower quality product compared to the other samples. Improved bread quality was found when the YM leaves were added at 2.5 g YM/100 g WWF. The total amount of phenolic compounds and the antioxidant activity increased as the proportion of YM increased in both flour and bread. Moreover, the phenolic compounds in 2.5 g YM/100 g WWF breads were stable during baking, showing no significant losses in the amount of phenolic compounds and antioxidant activity. These results suggest the YM can be successfully incorporated into baked product, improving its functional characteristics. PRACTICAL APPLICATION: This study evaluates the technological quality of bakery product made by incorporating yerba mate leaves in whole wheat flour. The results will contribute to the production of a bread with greater functional properties due to the presence of polyphenols and phytochemicals.

Genetic estimation of grain yield and its attributes in three wheat (Triticum aestivum L.) crosses using six parameter model.

Grain yield is a complex polygenic trait representing a multiplicative end product of contributing yield attributes governed by simple to complex gene interactions. Deciphering the genetics and inheritance of traits/genes influencing yield is a prerequisite to harness the yield potential in any crop species. The objective of the present investigation was to estimate genetic variance components and type of gene action controlling yield and its component traits using six populations (P1, P2, F1, F2, BC1 and BC2) of the three bread wheat crosses. Cross I (25th HRWSN 2105 × WH 1080), cross II (22ndSAWYT323 × RSP 561) and cross III (22ndSAWYT333 × WH 1080) involving elite stripe rust resistant wheat genetic stocks in combination with commercial check varieties were used for analysis. A combination of morpho-physiological, biochemical and disease influencing traits were evaluated, thus exploring the possibility of multi-trait integration in future. Results revealed that the estimated mean effects (m) were highly significant for all the traits in all crosses, indicating that selected traits were quantitatively inherited. The estimate of dominant gene effect was highly significant for plant height, number of tillers per plant in all the three crosses. Grain yield per plant was highly significant in the cross II while total protein content was highly significant in both crosses II and III. Glycine betaine content showed significant additive genes effect. Duplicate epistasis was the most significant for traits like plant height, total protein content and grain yield per plant. Dominance gene effect was more important than additive gene effects in the inheritance of grain yield and most other traits studied. The magnitude of additive X additive gene effects was high and positively significant whereas dominance × dominance was negatively significant for most of the traits studied in the three crosses. Additive × dominance gene effects was of minor significance, thus indicating that selection for grain yield and its components should be delayed to later generations of breeding.

New insights into the alleviating role of starch derivatives on dough quality deterioration caused by freeze.

The alleviating role of starch derivatives on the quality deterioration of frozen steamed bread dough was investigated in terms of derivative structure, the bread characteristics and dough properties including freezable water contents, yeast activity as well as dough viscoelasticity. The addition of starch derivatives including short-clustered maltodextrin (SCMD), DE2 maltodextrin (MD) and pregelatinized starch (PGS) significantly increased the specific volume and decreased the hardness of steamed bread compared with Control bread after 8-week frozen storage. Lower freezable water content was found in PGS dough than SCMD dough, which was consistent with the results of water absorption index of starch derivatives. The analysis of dough gassing rate and yeast survival ratio demonstrated SCMD could provide more cryoprotection for yeast cells. Meanwhile, a higher elastic module and a more continuous gluten-network structure of SCMD dough were found after 8-week frozen storage. These results indicated starch derivatives especially SCMD were promising to be used as the alternative improvers in frozen dough production.

Rheological characteristics of wheat-chickpea composite flour doughs and effect of Amla powder (Phyllanthus emblica L.) addition on the functional properties of bread.

Bread is a staple food for majority of the people worldwide, but it has a high glycemic effect. Substituting wheat flour partly with chickpea flour and the presence of bran is suggested to improve the glycemic effect of bread; however, the non-gluten substances in wheat flour adversely affect dough rheology. The addition of amla powder was tested on the rheological properties of wheat-chickpea flour composite doughs; also, the physical and sensory qualities of bread made thereof. The results showed that when the level of replacement of refined white flour (WF) or whole wheat flour (WWF) with chickpea flour was increased from 0 to 40%, it significantly affected the rheological properties and functionality of dough. A decreased farinograph water absorption, higher mixing tolerance index (i.e., weakening of dough), decreased resistance to extension, and lower ratio numbers were obtained with some differences between WF and WWF at the higher level of chickpea flour substitution. The addition of amla powder to WF: chickpea flour (60:40) blends reduced the angle of ascending (from 7.0 ± 0.7 to 6.0 ± 0.7) and angel of descending (from 3.2 ± 0.21 to 2.4 ± 0.2), indicating the slight tightening of gluten leading to dough breakdown. The addition of amla powder improved the mixing characteristics of the composite flour doughs, as well as the physical and sensory qualities of the bread. In conclusion, amla powder can help overcome the deleterious impact of adding chickpea flour to WF or WWF for producing good quality pan bread for people with type-2 diabetes.

Overcoming bread quality decay concerns: main issues for bread shelf life as a function of biological leavening agents and different extra ingredients used in formulation. A review.

As is widely accepted, the quality decay of freshly baked bread that affects product shelf life is the result of a complex multifactorial process that involves physical staling, together with microbiological, chemical and sensorial spoilage. In this context, this paper provides a critical review of the recent literature about the main factors affecting shelf life of bread during post-baking. An overview of the recent findings about the mechanism of bread staling is firstly provided. Afterwards, the effect on staling induced by baker's yeasts and sourdough as well as by the extra ingredients commonly utilized for bread fortification is also addressed and discussed. As inclusion/exclusion criteria, only papers dealing with wheat bread and not with long-life bread or gluten-free bakery products are taken into consideration. Despite recent developments in international scientific literature, the whole mechanism that induces bread staling is far from being completely understood and the best analytical methods to be adopted to measure and/or describe in depth this process appear still debated. In this topic, the effects induced on bread shelf life by the use of biological leavening agents (baker's yeasts and sourdough) as well as by some extra ingredients included in the bread recipe have been individuated as two key issues to be addressed and discussed in terms of their influence on the kinetics of bread staling. © 2020 Society of Chemical Industry.

Acerola fruit as a natural antioxidant ingredient for gluten-free bread: An approach to improve bread quality.

In this study, we evaluated the effect of enrichment of bread using acerola fruit powder on the physical, sensorial and antioxidant properties of gluten-free breads. We tested different proportions of acerola fruit powder (0-5% w/w) in rice flour. According to the results, loaf volume increased from 423.33 cm3 to 571.67 cm with increasing amount of acerola fruit powder cm3 with increasing amount of acerola fruit powder (from 0 to 5% w/w). Acerola fruit powder improved the structural parameters of the crumb by increasing the size and area fraction of cells. All tested quantities of acerola fruit powder improved textural parameters by decreasing firmness and chewiness and by increasing springiness. In addition, acerola fruit powder positively affected the antioxidant properties of enriched breads. The total phenolic content and antioxidant activity of extracts was found to be increased with the addition of acerola fruit powder. All antioxidant activities were found to be increased with increasing quantities of acerola fruit powder. The sensory attributes of the bread showed that a partial replacement of the rice flour with up to 3% of acerola fruit powder provided satisfactory results. The optimum level of acerola fruit powder for all parameters tested was found to be 3% w/w.

Effects of dry heat treatment temperature on the structure of wheat flour and starch in vitro digestibility of bread.

The effects of the dry heat treatment (DHT) temperature (20, 50, 100, 150, 200 °C) on the structure of wheat flour and on the texture and in vitro starch digestibility of breads were investigated. X-ray diffraction and FTIR showed that increasing temperatures produced reduction of the hydrated starch structures, increased crystallinity and molecular order of starch chains, and had important effects on the gluten secondary structure. High treatment temperatures produced significant reductions in rapidly digestible starch (RDS) (53.21% at 20 °C, 22.24% at 200 °C), and the slowly digestible starch fraction tended to increase (26.12% at 20 °C, 31.48% at 200 °C). On the other hand, bread hardness showed a significant increase from 11.25 N at 20 °C to 49.53 N at 200 °C, the latter value being similar to that reported for bread crusts. Principal component analysis results showed that the flour and bread characteristics were drastically changed by the DHT, with 100 °C representing a critical temperature. Below 100 °C, breads showed textural characteristics close to that of the control bread, with reduced RDS fractions, while at temperatures above 100 °C, hardness was boosted.

Understanding whole-wheat flour and its effect in breads: A review.

Although the consumption of whole grains, including bread made with whole-wheat flour, is promoted for health benefits and reduced risk for disease and mortality, consumer acceptance, and consumption of some whole-wheat products is low compared to that of white breads. This review focuses on the understanding of whole-wheat flours, both their positive and negative aspects, and how to improve those flours for the production of whole-wheat breads. The review addresses genetic aspects, various milling systems, and pretreatment of bran and germ. The baking process and use of additives and enzymes may also improve product quality to help consumers meet dietary recommendations for daily whole-wheat consumption.

A Cross between Bread Wheat and a 2D(2R) Disomic Substitution Triticale Line Leads to the Formation of a Novel Disomic Addition Line and Provides Information of the Role of Rye Secalins on Breadmaking Characteristics.

A bread wheat line (N11) and a disomic 2D(2R) substitution triticale line were crossed and backrossed four times. At each step electrophoretic selection for the seeds that possessed, simultaneously, the complete set of high molecular weight glutenin subunits of N11 and the two high molecular weight secalins of rye, present in the 2D(2R) line, was carried out. Molecular cytogenetic analyses of the BC4F8 generation revealed that the selection carried out produced a disomic addition line (2n = 44). The pair of additional chromosomes consisted of the long arm of chromosome 1R (1RL) from rye fused with the satellite body of the wheat chromosome 6B. Rheological analyses revealed that the dough obtained by the new addition line had higher quality characteristics when compared with the two parents. The role of the two additional high molecular weight secalins, present in the disomic addition line, in influencing improved dough characteristics is discussed.

Effects of HMW-GSs on quality related traits in wheat (Triticum aestivum L.) under different water regimes.

Alleles at the Glu-1 loci play important roles in the functional properties of wheat flour. The effects of various high-molecular-weight glutenin subunit (HMW-GS) compositions on quality traits and bread-making properties were evaluated using 235 doubled haploid lines (DHs). The experiment was conducted in a split plot design with two water regimes as the main plot treatment, and DH lines as the subplot treatments. Results showed that the presence of subunit pair 5+10 at the Glu-D1 locus, either alone or in combination with others, appears to provide an improvement in quality and bread-making properties. At the Glu-A1 locus, subunit 1 produced a higher Zeleny sedimentation value (Zel) and stretch area (SA) than subunit 2* when subunits 14+15 and 5+10 were expressed at the Glu-B1 and Glu-D1 loci, and 2* had a positive effect on the maximum dough resistance (Rmax) when subunits 14+15 and 5'+12 were expressed at the Glu-B1 and Glu-D1 loci, respectively. Given subunit 1 at the Glu-A1 locus and 5'+12 at the Glu-D1 locus, the effects of Glu-B1 subunits 14+15 on the tractility (Tra), dough stability time (ST), and dough development time (DT) under the well-watered regime were significantly higher than those of Glu-B1 subunits 13+16. However, 13+16 had a positive effect on SA under the rain-fed regime when subunits 2* and 5+10 were expressed at the Glu-A1 and Glu-D1 loci, respectively. Multiple comparisons analysis revealed that the Zel and Rmax of the six subunits and eight HMW-GS compositions were stable under different water regimes. Overall, subunit compositions 1, 13+16 and 5+10 and 1, 14+15 and 5+10 had higher values for quality traits and bread-baking properties under the two water regimes. These results could play a positive guiding role in selecting and popularizing varieties suitable for production and cultivation in local areas.

Waste bread recycling as a baking ingredient by tailored lactic acid fermentation.

Food-grade waste and side streams should be strictly kept in food use in order to achieve sustainable food systems. At present, the baking industry creates food-grade waste as excess and deformed products that are mainly utilized for non-food uses, such as bioethanol production. The purpose of this study was therefore to explore the potential of waste wheat bread recycling for fresh wheat bread production. Waste bread recycling was assessed without further processing or after tailored fermentation with lactic acid bacteria producing either dextran or ß-glucan exopolysaccharides. When non-treated waste bread slurry was added to new bread dough, bread quality (specific volume and softness) decreased with increasing content of waste bread addition. In situ EPS-production (dextran and microbial ß-glucan) significantly increased waste bread slurry viscosity and yielded residual fructose or glucose that could effectively replace the sugar added for yeast leavening. Furthermore, fermentation acidified waste bread matrix, thus improving the hygienic safety of the process. Bread containing dextran synthesized in situ by Weissella confusa A16 showed good technological quality. The produced dextran compensated the adverse effect of recycled bread on new bread quality attributes by 12% increase in bread specific volume and 37% decrease in crumb hardness. In this study, a positive technological outcome of the bread containing microbial ß-glucan was not detected. The waste bread fermented by W. confusa A16 containing dextran appears to enable safe bread recycling with low acidity and minimal quality loss.

A Comparison of the Nutritional Qualities of Supermarket's Own and Regular Brands of Bread in Sweden.

Processed food is associated with unhealthy qualities such as higher content of harmful fats, sugars and salt. The aim of our study was to compare the nutritional qualities of supermarket's own brands and regular brands of bread sold in Sweden. Additionally, we compared the nutritional qualities of gluten-free and gluten-containing bread. We collected information from the labels of 332 bread products available in the largest grocery store chains. The Australian Health Star Rating (HSR) system was used to quantify the nutritional quality of each bread product. We compared all supermarket's own brand products to regular brand products, and gluten-free to gluten-containing bread. The mean HSR for the supermarket's own brands was lower than the regular brands (3.6 vs. 3.7; p = 0.046). For the regular brand products, the fibre, sugar and total fat content were greater (p < 0.001, p = 0.002 and p = 0.021, respectively), while less protein (p = 0.009) compared to regular bread products. Gluten-free bread had a lower HSR than gluten-containing bread (mean 3.5 vs. 3.8, respectively; p < 0.001). The regular brand products were slightly healthier than the supermarket's own brands, primarily as a result of a higher fibre content. Gluten-free bread products were slightly unhealthier due to a lower protein content.

Effect of chemical oxidizers and enzymatic treatments on the baking quality of doughs formulated with five Canadian spring wheat cultivars.

For many years, the baking industry has been using chemical improvers as a way for compensating for flour quality variation due to growing conditions or wheat cultivar. However, the replacement of chemical dough improvers with natural ingredients or processing aids (i.e. enzymes) allows for the production of 'cleaner label' products. In the present research, dough and bread properties (mixing time, oven rise, loaf volume, crumb firmness and C-cell parameters) were analysed as a function of wheat cultivar (Glenn, Harvest, Lillian, CDC Plentiful and Stettler), additive-type (ascorbic acid, azodicarbonamide, glucose oxidase and fungal xylanase) and concentration. Overall, the cultivar Glenn appeared to have improved baking performance relative to the other cultivars, regardless of the additive and additive concentration. On the other hand, Stettler showed poorer baking quality and performance even with the addition of oxidizers and enzymes in relation to the control. The concentration of additive was found to have little or no effect on improving baking properties within each cultivar. Enzymes had similar or better performance than oxidizers in most cases.

Type I sourdough steamed bread made by retarded sponge-dough method.

A retarded sponge-dough method was adopted to make type I sourdough steamed bread (SSB). When matured from 9 to 21 h, sourdoughs attained a properly developed state with desirable acidifying and leavening capacity. Optimal parameters were obtained as follows: sourdough maturing time of 15 h, 40% of sourdough, 72% of flour in sponge dough and retarding time of 24 h. SSB under optimized parameters had large specific volume, fine crumb texture and a high sensory score. Flavor compounds in SSB (a total of 85) were more abundant than that in the control. Many aroma-active esters were identified of which ethyl hexanoate was the most abundant. Anti-staling effects were observed, including a great delay of crumb firmness and starch retrogradation. Retarding up to 24 h of sponge-dough allowed sufficient time for microbial metabolism and endogenous enzyme bioconversion, providing SSB with desirable balanced flavor and aromatic characteristics.

Mechanism by which ß-glucanase improves the quality of fermented barley flour-based food products.

The enrichment of ß-glucan in barley significantly decreases the quality of dough and baked bread, and ß-glucanase can improve dough and bread quality. Nevertheless, the mechanism by which ß-glucanase improves the quality of fermented barley flour-based products is still poorly understood. The gluten microcosmic structure, molecular structure and yeast gas production capacity were investigated using Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Scanning electron microscopy (SEM) and F3 rheological fermentation techniques. The results showed that ß-Glucanase can degrade the high-molecular-weight ß-glucan to low-molecular-weight oligosaccharide fragments, which reduces the viscosity of the ß-glucans, promotes cross-linking between the gluten molecules, and indirectly improves the gluten network structure, thereby alleviating the negative effects of ß-glucans. The ß-glucosidase produced during yeast metabolism can further hydrolyse low-molecular-weight oligosaccharides into reducing sugars that can be used by yeast, increasing the carbon sources available to yeasts and the gas production capability of yeasts.

Mineral Content of Various Portuguese Breads: Characterization, Dietary Intake, and Discriminant Analysis.

The chemical composition and daily mineral intake (DMI) of six macro (calcium, magnesium, sodium, potassium, phosphorous, and chloride) and four microminerals (copper, iron, manganese, and zinc) were determined in four types of Portuguese breads (white wheat, maize, wheat/maize, and maize/rye breads). Samples were processed with microwave assisted digestion and mineral composition was determined with a high-resolution continuum-source atomic absorption spectrometer with flame and graphite furnace. Bread contributes to an equilibrated diet since it is rich in several minerals (0.21 mg/100 g of copper in wheat bread to 537 mg/100 g of sodium in maize/rye bread). Maize/rye bread presented the highest content of all minerals (except phosphorous and chloride), while the lowest levels were mainly found in wheat bread. Median sodium concentrations (422-537 mg/100 g) represented more than 28% of the recommended daily allowance, being in close range of the maximum Portuguese limit (550 mg/100 g). Maize/rye bread exhibited the highest DMI of manganese (181%), sodium (36%), magnesium (32%), copper (32%), zinc (24%), iron (22%), potassium (20%), and calcium (3.0%). A Principal Component Analysis (PCA) model based on the mineral content allowed the differentiation among white wheat, maize, and maize/rye bread. Zinc, magnesium, manganese, iron, phosphorus, potassium, copper, and calcium proved to be good chemical markers to differentiate bread compositions.

Effect of mixed Saccharomyces cerevisiae Y10 and Torulaspora delbrueckii Y22 on dough fermentation for steamed bread making.

The use of non-Saccharomyces yeasts in dough fermentation has become increasingly popular because of their effects on product composition, texture and flavour. These yeasts are co-cultured with Saccharomyces cerevisiae. In this study, the characteristics of dough fermentation with combined Torulaspora delbrueckii Y22 and S. cerevisiae Y10 were investigated. In the dough containing co-cultures, S. cerevisiae Y10 cell populations increased rapidly and reached approximately 8.5 Log CFU/g wet dough, which is comparable to the monoculture after 24 h of fermentation. However, the cell number of T. delbrueckii Y22 did not significantly change throughout the dough fermentation (p > 0.05). When co-culture was used, the gas holding capacity and CO2 production profile of the dough improved, and a high maltose concentration reaching 5.93 mg/g dry dough was observed after 12 h of dough fermentation. The mixed inocula of S. cerevisiae Y10 and T. delbrueckii Y22 enhanced the production of succinic acid, acetic acid and essential amino acids in the fermented dough. These results revealed the synergistic behaviour between S. cerevisiae Y10 and T. delbrueckii Y22 during dough fermentation and suggested the potential use of mixed yeast cultures in dough fermentation for steamed bread making.

Novel insights on the functional/nutritional features of the sourdough fermentation.

As one of the most traditional biotechnologies, sourdough fermentation has deep effects on rheology, sensory and shelf life attributes of baked goods. The most recent literature has also highlighted the effects of sourdough fermentations on several functional/nutritional features of baked goods. While some aspects such as the potential to lower glycemic index, increase mineral bioavailability and decrease the gluten content have been proven almost definitively, others potentialities are emerging, which deserve novel insights. This reviews reports the main evidence on the use of sourdough fermentation for salt reduction in baked goods, management of irritable bowel syndrome (IBS), synthesis/release of bioactive compounds, especially the metabolism of phenolic compounds, and exploitation of the potential of non-conventional flours (legumes and pseudo-cereals) and milling by-products (bran and germ). A brief description on the spiritual, cultural and functional/nutritional significance of leavened bread throughout centuries has also given.

Lifestyles of sourdough lactobacilli - Do they matter for microbial ecology and bread quality?

Sourdough is used in production of (steamed) bread as leavening agent (type I sourdoughs) or as baking improver to enhance flavour, texture, and shelf life of bread (type II sourdoughs). The long-term propagation of sourdoughs eliminates dispersal limitation and consistently leads to sourdough microbiota that are composed of host adapted lactobacilli. In contrast, community assembly in spontaneous cereal fermentations is limited by dispersal and nomadic or environmental lactic acid bacteria are the first colonizers of these sourdoughs. Propagation of sourdoughs for use as sole leavening agent (type I sourdoughs) dictates fermentation conditions that select for rapid growth. Type I wheat- and rye sourdoughs are consistently populated by insect-adapted lactobacilli, particularly Lactobacillus sanfranciscensis, which is characterized by a small genome size and a restricted metabolic potential. The diverse fermentation conditions employed in industrial or artisanal Type II sourdough fermentation processes also result in a more diverse microbiota. Nevertheless, type II sourdoughs are typically populated by vertebrate host adapted lactobacilli of the L. delbrueckii and L. reuteri groups. Metabolic traits of host-adapted lactobacilli that enhance competitiveness in intestinal ecosystems also provide technological functionality in bread making. Examples include formation of exopolysaccharides, arginine-, glutamine- and glutamate based mechanisms of acid resistance, and glycosyl hydrolases that reduce FODMAP levels in sourdough and sourdough bread. In conclusion, consideration of the lifestyle of sourdough lactobacilli facilitates the selection of competitive and functional sourdough starter cultures.