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.

Quality and functional properties of bread containing the addition of probiotically fermented Cicer arietinum.

This study aimed to determine the impact of supplementation with probiotically fermented chickpea (Cicer arietinum L) seeds on the quality parameters and functional characteristics of wheat bread. The addition of chickpea seeds caused significant changes in the chemical composition of the control wheat bread. The legume-supplemented products exhibited higher values of a* and b* color parameters and higher hardness after 24 h of storage than the control. The application of fermented or unfermented chickpeas contributed to an increase in total polyphenol and flavonoid contents, iron chelating capacity, and antioxidant properties of the final product. The variant containing unfermented seeds had the highest riboflavin content (29.53 ± 1.11 µg/100 g d.w.), Trolox equivalent antioxidant capacity (227.02 ± 7.29 µmol·L-1 TX/100 g d.w.), and free radical scavenging activity (71.37 ± 1.30 % DPPH inhibition). The results of this preliminary research have practical importance in the production of innovative bakery products with potential properties of functional food.

Effects of different thawing methods on physical and physicochemical properties of frozen dough and quality of corresponding steamed bread.

The thawing method is critical for the final quality of products based on the frozen dough. The effects of ultrasound thawing, proofer thawing, refrigerator thawing, water bath thawing, ambient thawing, and microwave thawing on the rheology, texture, water distribution, fermentation characteristics, and microstructure of frozen dough and the properties of steamed bread were investigated. The results indicated that the ultrasound thawing dough had better physicochemical properties than other doughs. It was found that ultrasound thawing restrained the water migration of dough, improved its rheological properties and fermentation capacity. The total gas volume value of the ultrasound thawing dough was reduced by 21.35% compared with that of unfrozen dough. The ultrasound thawing dough displayed a thoroughly uniform starch-gluten network, and an enhanced the specific volume and internal structure of the steamed bread. In conclusion, ultrasound thawing effectively mitigated the degradation of the frozen dough and enhanced the quality of steamed bread.

Breads formulated with avocado pulp powder as a fat substitute: Quality parameters and in vitro inhibition activities.

The aim of the current study was to evaluate the influence of increasing contents (5%-25%) of avocado pulp powder (APP) produced by foam-mat drying (FMD) as a substitute for hydrogenated vegetable fat in bread on its nutritional composition, physical properties, α-amylase, α-glucosidase, and lipase inhibition, total phenolic content, antioxidant activity, color, structure, and x-ray diffraction patterns. The increase in the APP content decreased the values of lipids, carbohydrates, energy, firmness, and specific volume of breads. The inhibition of lipase activity showed a pronounced increase, while the total phenolic content and antioxidant activity were significantly elevated. The color parameters a* and b* were higher in the breads with added APP. The crystalline structure transitioned from type A to type V with 15% APP incorporation. Taken together, these results suggest that APP has potential to act as a healthier substitute for saturated fats in breads, paving the way to develop creative and innovative solutions for the functionalization of bakery food products.

Rhubarb powder: Potential uses as a functional bread ingredient.

As a traditional staple food, bread lacks several nutrients such as fiber and minerals. In this study, the possibilities of using rhubarb powder to enrich wheat bread were investigated. Rhubarb powder was replaced with wheat flour at the ratios of 0%, 4%, 8%, and 12%. In order to reveal effects of rhubarb powder on quality properties of bread, color, moisture, total protein, fat content, antioxidant activity, textural, and sensory analysis were conducted. As the rhubarb powder ratio increased, the fiber (10.60 ± 0.55), ash (4.34 ± 0.13), and fat content (2.17 ± 0.55) of bread samples increased significantly (p < 0.05). Antioxidant activity (19.61% ± 0.53%) and total phenolic contents (916.38 ± 2.69) of bread samples also increased significantly (p < 0.05). The colors of the enriched breads were relatively dark. The breads containing 12% rhubarb powder had the highest ash content (4.34 ± 0.13). The samples containing 4% rhubarb powder took the highest sensory scores from the sensory panel in terms of odor, flavor, and overall impression. However, as the ratio of rhubarb powder increased, the sensory values of bread samples decreased. According to the results of this study, rhubarb powder could be used up to 4% to produce acceptable breads in terms of sensory properties with improved nutritional quality.

Clean-label products: Factors affecting liking and acceptability by Portuguese older adults.

Consumers are preferring more "natural" foods, made of "healthier" and "familiar" components - the "clean-label" trend. As the population ages, understanding the older adult consumer segment becomes increasingly important. This study aims to identify the factors influencing the acceptability and liking of clean-label products in older adults living in the community. A convenience sample of 100 older adults was used for this cross-sectional study. Socio-demographic data, health status, independence level, lifestyle characteristics, nutritional status, and food and nutrient intake data were collected. The acceptability and liking for clean-label products comprised two parts: Sensory analysis with overall liking evaluation of three pairs of products, using a 9-point hedonic scale and free comments; Willingness to eat and preference assessment of nine pairs of products using the Food Action scale and a simple preference test. The participants were 80% female with a mean age of 75 years old. The overall liking for clean-label versions of cookies and mayonnaise was lower than for traditional versions. However, participants were more willing to eat the clean-label versions of products, particularly ham and yogurt. Most of the participants would prefer buying the clean-label version of all nine pairs of products, especially for ham, loaf bread, sausages, and yogurt. In sum, older adults living in the community exhibit a lower liking but, a greater willingness to eat and a higher preference for buying clean-label products. Older adults who favor clean-label products have higher levels of education and are reported to have a more adequate diet.

Improvement of sorghum-wheat blended flours by E-beam irradiation: Physicochemical properties, rheological behavior, microstructure, and quality properties.

To enhance the processing suitability of blended flours, this study used 4 kGy E-beam irradiated (EBI) sorghum flour in different ratios blended with wheat flour and further verified the improvement mechanism of the processed products under the optimal ratios. The results suggested that the EBI can mitigate the deterioration of the blend flour farinograph properties while enhancing the gas release during dough fermentation. Under the same addition ratio, the irradiated blend flours showed higher expansion height, gas release, cavitation time, and gas retention coefficient than the control flours. Also, irradiated blend flours retained a gluten network at a higher addition rate (20 %). Moreover, the irradiated blend flours were optimized at 10 % as its pasting and thermal properties were improved. Notably, this ameliorating effect promotes a decrease in hardness and chewiness and an increase in cohesion of the bread cores, presenting better textural attributes and delaying the aging rate during storage. The findings are instructive for applying EBI technology in the manufacture and quality improvement of mixed grain breads and open a new research avenue for processing sorghum staple foods.

Use of Bacillus spp. as beneficial fermentation microbes in baking.

The development of minimally processed baked goods is dependent on new "clean label" functional ingredients that allow substitution of additives without compromising quality. We investigated the use of fermentation with Bacillus spp. as a novel approach to improve bread quality. Bacillus velezensis FUA2155 and Bacillus amyloliquefaciens Fad WE ferments were prepared using white wheat flour, wheat bran or buckwheat, and were added at a level of 2.5-20 % to bread dough. Ropy spoilage of bread was controlled by sourdough addition at a level of 10 or 20 %. The volume of white wheat bread and wheat bran bread increased by 47.4 and 62.5 % respectively with 2.5 % Bacillus ferments. Bread shelf-life was prolonged by the Bacillus ferment only at higher dosages that also reduced bread volume. The use of unfermented or sourdough fermented buckwheat improved bread volume and delayed mould spoilage. The characterization of water-soluble polysaccharides from sourdoughs and Bacillus ferments revealed that solubilization of arabinoxylans contributed to the increase in volume after fermentation of wheat but not after fermentation of buckwheat. In conclusion, Bacillus fermentation can be used to improve bread quality, adding to the diversity of microbes that are suitable for baking applications.

Co-culture fermentation by Saccharomycopsis fibuligera and lactic acid bacteria improves bioactivity and aroma profile of wheat bran and the bran-containing Chinese steamed bread.

Co-culture fermentation with yeast and lactic acid bacteria (LAB) exhibits advantages in improving the bioactivity and flavor of wheat bran compared to single-culture fermentation, showing application potentials in bran-containing Chinese steamed bread (CSB). To explore the effects of combination of yeast and different LAB on the bioactivity and flavor of fermented wheat bran, this study analyzed the physicochemical properties, phytate degradation capacity, antioxidant activities, and aroma profile of wheat bran treated with co-culture fermentation by Saccharomycopsis fibuligera and eight different species of LAB. Further, the phenolic acid composition, antioxidant activities, texture properties, aroma profile, and sensory quality of CSB containing fermented wheat bran were evaluated. The results revealed that co-culture fermentation brought about three types of volatile characteristics for wheat bran, including ester-feature, alcohol and acid-feature, and phenol-feature, and the representative strain combinations for these characteristics were S. fibuligera with Limosilactobacillus fermentum, Pediococcus pentosaceus, and Latilactobacillus curvatus, respectively. Co-culture fermentation by S. fibuligera and L. fermentum for 36 h promoted acidification with a phytate degradation rate reaching 51.70 %, and improved the production of volatile ethyl esters with a relative content of 58.47 % in wheat bran. Wheat bran treated with co-culture fermentation by S. fibuligera and L. curvatus for 36 h had high relative content of 4-ethylguaiacol at 52.81 %, and exhibited strong antioxidant activities, with ABTS•+ and DPPH• scavenging rates at 65.87 % and 69.41 %, respectively, and ferric reducing antioxidant power (FRAP) at 37.91 µmol/g. In addition, CSB containing wheat bran treated with co-culture fermentation by S. fibuligera and L. fermentum showed a large specific volume, soft texture, and pleasant aroma, and received high sensory scores. CSB containing wheat bran treated with co-culture fermentation by S. fibuligera and L. curvatus, with high contents of 4-ethylguaiacol, 4-vinylguaiacol, ferulic acid, vanillin, syringaldehyde, and protocatechualdehyde, demonstrated strong antioxidant activities. This study is beneficial to the comprehensive utilization of wheat bran resources and provides novel insights into the enhancement of functions and quality for CSB.

Nutritional profiling, fiber content and in vitro bioactivities of wheat-based biscuits formulated with novel ingredients.

This study evaluated the nutritional profile and fiber content of innovative formulations of wheat-based biscuits enriched with chia seeds, carob flour and coconut sugar. The in vitro antioxidant, cytotoxic, anti-inflammatory and antimicrobial activities were also investigated to understand the potential health advantages of the incorporation of these new ingredients. The novel biscuits demonstrated significant improvements in protein and mineral content, with increases of 50% and 100% in chia biscuits, and up to 20% and 40% in carob biscuits, respectively. Fiber also notably increased, particularly in samples containing 10% carob flour, which increased four times as compared to wheat-based samples. The new ingredients exhibited antibacterial and antifungal activity, particularly against Yersinia enterocolitica (minimum inhibitory concentration 1.25 mg mL-1 in coconut sugar) and Aspergillus fumigatus (minimum inhibitory concentration/minimum fungicidal concentrations 2.5/5 mg mL-1 in chia seeds). However, the final biscuits only displayed antifungal properties. Carob flour and chia seeds had a remarkably high capacity to inhibit the formation of TBARS and promoted greater antioxidant activity in biscuit formulations, with EC50 values decreasing from 23.25 mg mL-1 (control) to 4.54 mg mL-1 (15% defatted ground chia seeds) and 1.19 mg mL-1 (10% carob flour). Only chia seeds exhibited cellular antioxidant, anti-inflammatory and cytotoxic activity, attributes that were lost when seeds were added into the biscuits. These findings highlight the potential health benefits of these ingredients, particularly when incorporated in new wheat-based formulations.

Bioprospecting of sourdough microbial species from artisan bakeries in the city of Valencia.

This work describes the characterization of an artisanal sourdough set of bakeries located in the city of Valencia. Culture-dependent and -independent analyses detected Fructilactobacillus sanfranciscensis, Saccharomyces cerevisiae and Kazachstania humilis as dominant species. Nevertheless, specific technological parameters, including backslopping temperature, dough yield, or the addition of salt affected microbial counting, LAB/Yeast ratio, and gassing performance, favouring the appearance of several species of Lactobacillus sp., Limosilactobacillus pontis or Torulaspora delbrueckii as additional players. Sourdough leavening activity was affected positively by yeast counts and negatively by the presence of salt. In addition, the predominance of a particular yeast species appeared to impact the dynamics of CO2 release. Seven important flavour-active compounds (ethyl acetate, 1-hexanol, 2-penthylfuran, 3-ethyl-2-methyl-1,3-hexadiene, 2-octen-1-ol, nonanal and 1-nonanol) were detected in all samples and together with 3-methyl butanol and hexyl acetate represented more than the 53% of volatile abundancy in nine of the ten sourdoughs analysed. Even so, the specific microbial composition of each sample influenced the volatile profile. For example, the occurrence of K. humilis or S. cerevisiae as dominant yeast influenced the composition of major alcohol species, while F. sanfranciscensis and L. pontis positively correlated with aldehydes and octanoic acid content. In addition, relevant correlations could be also found among different technological parameters and between these, volatile compounds and microbial species. Overall, our study emphasises on how differences in technological parameters generate biodiversity in a relatively small set of artisan sourdoughs providing opportunities for excellence and quality baking products.

Sourdough starter culture microbiomes influence physical and chemical properties of wheat bread.

Sourdough fermentation is an ancient leavening method that uses wild yeasts to produce carbon dioxide, contributing to bread rise, and bacteria which produce organic acids. Sourdough starter cultures are known to be diverse in terms of the microorganisms they comprise and while specific genera and species of microorganisms have been identified from starters and associated with specific attributes, overarching relationships between sourdough starter culture microbiomes and bread quality are not well understood. The objective of this study was to characterize differences in the physical and chemical properties of breads produced with sourdough starter cultures with unique microbiomes. Sourdough starter cultures (n = 20) of known microbial populations were used to produce wheat-based dough and bread, which were analyzed for chemical and physical properties then compared to their microbial populations in order to identify relationships between microbial profiles and dough/bread qualities. All samples were also compared to bread produced only with Saccharomyces cerevisiae (baker's yeast). Significant differences among pH, titratable acidity, loaf volume, crumb firmness, crust color, free amino acids, and organic acids were observed when comparing sourdough breads to the yeast-only control (p ≤ 0.05). Furthermore, bacterial diversity of sourdough starter cultures was correlated with lactic acid and free amino acid in the dough and loaf volume and crumb firmness of baked breads. No significant correlations were found between fungal diversity and measured outcomes. These data demonstrate the importance of considering sourdough starter microbiomes as an ingredient in baked goods and they contribute to quality and safety outcomes in bread production. PRACTICAL APPLICATION: Sourdough starter cultures have diverse and dynamic populations of bacteria and yeasts, which contribute to the production of bread products. These populations can influence the physical and chemical properties of sourdough fermentation and final breads. Understanding of the relationship between sourdough starter microbiomes and bread quality parameters can lead to targeted development of sourdough bread products with specific physical and chemical properties.

Chemical, rheological, and sensorial properties of Baladi bread supplemented with buckwheat flour produced in Egypt.

This research aimed to enhance the nutritional and sensory qualities of Balady bread by adding locally Egyptian buckwheat flours, Fagopyrum esculentum (FE) and Fagopyrum tataricum (FT), to Hard Wheat Flour (HWF) 82% extraction at three levels (10%, 20%, and 30%). The chemical composition, rheological properties, color, sensory evaluation and stalling of the balady bread were determined. The chemical composition of raw materials revealed that FE was significantly (P ≤ 0.05) higher in protein and fat contents compared to HWF and FT. While FT was higher in fiber and ash contents. The findings show that a 30% replacement with FE or FT significantly enhances the bread's nutritional profile, notably increasing protein, fiber, ash, and moisture content. Rheological analysis revealed that FE and FT alter dough handling, with a notable improvement in dough stability and mixing tolerance at 30% FT. Sensory evaluation indicated acceptable qualities even at higher substitution levels, although 30% FE showed slight declines in certain attributes. Furthermore, bread supplemented with 30% FT demonstrated slower staling and potentially extended shelf life. These results highlight the potential of FE and FT as nutritional enhancers in bread formulations, with 30% FT emerging as the optimal replacement level for balancing nutritional benefits and sensory acceptance.

Influence of sesame cake on physicochemical, antioxidant and sensorial characteristics of fortified wheat breads.

Incorporation of two sesame cake preparations, differing in fat, 11 % (LF) and 17 % (HF), and protein, 51 % (LF) and 44 % (HF), contents, respectively, into breads at 6, 12 and 20 % wheat flour substitution levels, led to enriched end-products with antioxidants, suitable also to carry the 'high protein' and 'fiber source' nutrition claims (at ≥ 12 % substitution level). Sesame cake decreased wheat dough resistance to mixing and extension, and peak viscosity (empirical rheology), in a concentration-dependent manner, being more pronounced for LF formulations. Breads with LF incorporation ≥ 12 % had lower specific volumes and harder crumb (texture analysis) throughout storage, than control (100 % wheat flour); however, such adverse effects were diminished in HF bread formulations due to the plasticizing and emulsifying action of the sesame cake fat. Calorimetry showed that the sesame cake had no effect on starch retrogradation, but enhanced amylose-lipid complex formation. Antioxidant activity (ABTS, DPPH and FRAP assays), and phenolic acids (ferulic, p-coumaric and sinapic) and lignan (sesaminol glucosides and sesamolin) contents, determined by HPLC-DAD-MS, were higher in LF breads than their HF counterparts. The presence of some sulfur (off-flavor) and pyrazine (nutty flavor) compounds (SPME-GC-MS), as well as the sesame flavor and bitterness (sensory analysis) were of higher intensity in HF breads, while the 6 % LF product received the highest overall acceptability score among all fortified products. Overall, the sesame cake can be a promising ingredient for production of functional wheat bread depending on its composition and fortification level.

Adequately increasing the wheat B-starch ratio can improve the structure-properties of dough during freeze-thaw cycles: Mechanisms and conformational relations.

To reveal the influence of wheat starch particle size distribution on frozen dough quality, this study reconstituted A/B starch according to 100:0, 75:25, 50:50, 25:75 and 0:100 and prepared reconstituted dough by compounding with gluten proteins. Further, the freeze-thaw cycle of 1, 3, and 9 times for reconstituted dough was performed to investigate its ratio-regulatory role of A- and B-starch. The results showed that the freeze-thaw cycle induced gluten network breakage and starch granule exposure in doughs mainly by disrupting disulfide and hydrogen bonds between gluten protein molecules and upsetting their secondary structures, leading to a reduction in GMP and polymer protein content and an increase in freezing water content. Moreover, a moderate increase (25-50 %) in the B-starch proportion can minimize gluten protein deterioration by freeze-thaw cycles. However, excessive B-starch amounts (75-100 %) can also adversely affect gluten structure. The prepared dumpling wrappers under the 50A-50B ratio showed optimal steaming loss rate, hardness, and chewiness during the freeze-thaw cycle. Correlation analysis indicated that the B-starch ratio and its filling pattern improved dough freeze-thaw deterioration primarily by affecting dough-free sulfhydryl content, protein molecular weight distribution, secondary structure, and ΔH. The results may provide insights and guidelines for product development and storage for frozen pasta.

Esterified wheat bran: Physicochemical properties, structure and quality improvement of Chinese steamed bread during refrigerated storage.

To develop the application of wheat bran and improve the nutrition and anti-staling capacity of Chinese steamed bread (CSB), oleic acid-esterified wheat bran (OWB) was prepared by esterification of wheat bran with oleic acid, and its physicochemical properties, structure, and quality improvement for CSB during refrigerated storage were investigated. The hydrophilic-lipophilic balance value of OWB was 16.0, the maximum degree of substitution was 0.146, and its emulsifying capacity was similar to that of glycerol monostearate. The starch gelatinization degree of CSB containing 3 % OWB and the control decreased by 19.55 % and 27.12 % within 7 days of refrigerated storage, respectively, while the hardness of CSB with OWB was lower than that with wheat bran. OWB inhibited starch recrystallization and increased bound water in the corresponding CSB, which effectively delayed starch retrogradation. OWB had a positive emulsifying capacity and showed potential as a functional material for preventing retrogradation of starch-based foods.

Expression and characterization of ß-1,3-1,4-glucanase of Aspergillus usamii in Escherichia coli and its application in sourdough bread making.

A ß-1,3-1,4-glucanase gene (Auglu12A) from Aspergillus usamii was successfully expressed in Escherichia coli BL21(DE3). The recombinant enzyme, reAuglu12A was efficiently purified using the one-step nickel-nitrilotriacetic acid affinity chromatography. The specific activity of reAuglu12A was 694.8 U/mg, with an optimal temperature of 55°C and pH of 5.0. The reAuglu12A exhibited stability at temperatures up to 60°C and within the pH range of 4.0-5.5. The reAuglu12A hydrolytic activity was increased in the presence of metal ions, especially K+ and Na+ , whereas it exhibited a Km and Vmax of 8.35 mg/mL and 1254.02 µmol/min/mg, respectively, toward barley ß-glucan at pH 5.0 and 55°C. The addition of reAuglu12A significantly increased the specific volume (p < 0.05) and reduced crumb firmness and chewiness (p < 0.05) of wheat-barley sourdough bread during a 7-day storage period compared to the control. Overall, the quality of wheat-barley sourdough bread was improved after incorporation of reAuglu12A (especially at 3000 U/300 g). These changes were attributed to the synergistic effect of acidification by sourdough and its metabolites which provided a conducive environment for the optimal action of reAuglu12A in the degradation of ß-glucans of barley flour in sourdough. This stabilized the dough structure, thereby enhancing the quality, texture, and shelf life of the bread. These findings suggest that reAuglu12A holds promise as a candidate for ß-glucanase application in the baking industry.

Characterization of wheat dough and Chinese steamed bread using mealworm powder formulated with medium-gluten and whole wheat flour.

BACKGROUND: Mealworm (Tenebrio molitor) larvae are nutritious edible insects and exhibit the potential to act as protein substitutes in food products. In this study, we added mealworm powder as a substitute to medium-gluten wheat and whole wheat flours to enhance the quality of baked products. We compared the pasting, farinograph and extensograph properties of medium-gluten wheat and whole wheat flours replaced with different concentrations of mealworm powder to explore the interactions between flour and mealworm powder. RESULTS: Mealworm powder changed the pasting characteristics of medium-gluten wheat and whole wheat flours. After adding 20% mealworm powder, the pasting temperature of the medium-gluten wheat flour remained unchanged (approximately 89.9 °C), while the pasting temperature of whole wheat flour increased from 88.83 to 90.27 °C. Water absorption of medium-gluten and whole wheat flours exhibited a decreasing trend with increasing mealworm powder concentrations. Mealworm powder substitution resulted in stronger medium-gluten dough but exerted an opposite effect on the farinograph properties of whole wheat dough. Mealworm powder substitution decreased the stretching resistance of medium-gluten dough but increased that of whole wheat dough. With an increase in the concentration of mealworm powder, the specific volume of medium-gluten wheat steamed bread significantly increased from 1.69 mL g-1 (M0) to 3.31 mL g-1 (M10) whereas that of whole wheat steamed bread increased from 1.64 mL g-1 (M0) to 2.34 mL g-1 (M15). The addition of mealworm powder increased the protein, dietary fiber, lipid and sodium contents of steamed bread samples. CONCLUSIONS: This study provides a reference for the rheological properties of medium-gluten wheat and whole wheat flours substituted with mealworm powder and supports the addition of insects as a protein source in food products. © 2023 Society of Chemical Industry.

Regulation of baking quality and starch digestibility in whole wheat bread based on ß-glucans and protein addition strategy: Significance of protein-starch-water interaction in dough.

Whole wheat bread has high nutritional value but is characterized by inferior quality and a high glycemic index. Studies have shown that adding ß-glucans and protein can improve bread quality. This study investigated the effects of added oat ß-glucan, barley ß-glucan, or yeast ß-glucan on protein synergy and whole wheat dough and bread quality. The mixing properties, rheological properties, and scanning electron microscopy observations showed that the addition of ß-glucan promoted the formation of gluten networks, while the synergy between the wheat proteins and ß-glucan resulted in a more robust and stable gluten network and a stronger physical starch envelope. Rapid visco-analysis and thermal property evaluations showed that ß-glucan addition inhibited the thermal degradation, gelatinization, and retrogradation of starch. Based on the bread quality results, it was found the ß-glucan could cause some damage to the bread baking quality. For example, the hardness of samples with oats, barley, and yeast increased to 881.69 g, 952.97 g, and 631.75 g, respectively, compared to samples without ß-glucan (317.49 g), whereas the inclusion of yeast ß-glucan proved to be less detrimental. Protein and ß-glucan both reduced starch digestion to some degree, and showed better synergistic effects, with the lowest estimated glycemic index of 70.08 observed in bread containing added yeast ß-glucan and protein. Therefore, yeast ß-glucan and protein mixtures could be selected as viable formulations for enhancing the quality of whole wheat bread.

Physicochemical changes in starch during the conversion of corn to tortilla in the traditional nixtamalization process associated with RS2.

This work aimed to study the changes in starch and isolated starch resulting from the conversion of corn to tortilla, focusing on the orthorhombic crystal structure and its association with resistant starch. Scanning electron microscopy images show whole, partially, and completely damaged starch granules in nixtamalized corn, masa, and tortillas. More importantly, whole isolated starch granules were found in nixtamal, masa, and tortillas. Transmission electron microscopy shows the presence of nanocrystals with orthorhombic structures in isolated starch. Some of them remained almost undamaged during the nixtamalization process. The X-ray patterns showed orthorhombic crystals in nixtamal, masa, and tortilla and their isolated starches. The RS increased from 2.61 to 5.31 % from corn to tortilla and from 2.52 to 5.61 % for isolated starches from corn and tortilla during the traditional nixtamalization process. The results suggest that the nanocrystals in corn to tortilla are part of RS2.