Influence of emulsifiers and enzymes on dough rheological properties and quality characteristics of steamed bread enriched with potato pulp

Using salted egg white in steamed bread: Impact on functional and structural characteristics

Steamed bread has long been an important part of Chinese cuisine. This study investigated the effects of salted egg white (SEW) (5, 10, 15, and 20% w/w) on the quality of steamed breads. Findings revealed that SEW notably enhanced the bread's volume and texture, with a 20% inclusion significantly boosting water retention and rheological properties, albeit reducing bread's lightness. In addition, the H-bond absorption band intensity in the Fourier transform infrared spectroscopy (FTIR) analysis showed increased peak intensities with higher SEW levels, indicative of protein structure alterations. X-ray diffraction confirmed the presence of an amylose-lipid complex. Scanning electron microscope (SEM) and Confocal laser scanning microscope (CLSM) imaging depicted a smooth, consistent protein network with SEW addition. Consumer sensory evaluation responded favourably to the SEW15 steamed bread, suggesting its potential for food industry application. Overall, the study considers SEW an effective ingredient for improving steamed bread quality.

Postbiotics in the Bakery Products: Applications and Nutritional Values

In recent years, the consumption of postbiotics has gained significant attention due to their potential health benefits. However, their application in the bakery industry remains underutilized. This review focuses on recent advances in the use of postbiotics, specifically the metabolites of lactic acid bacteria, in bakery products. We provide a concise overview of the multifaceted benefits of postbiotics, including their role as natural antioxidants, antimicrobials, and preservatives, and their potential to enhance product quality, extend shelf-life, and contribute to consumer welfare. This review combines information from various sources to provide a comprehensive update on recent advances in the role of postbiotics in bakery products, subsequently discussing the concept of sourdough as a leavening agent and its role in improving the nutritional profile of bakery products. We highlighted the positive effects of postbiotics on bakery items, such as improved texture, flavor, and shelf life, as well as their potential to contribute to overall health through their antioxidant properties and their impact on gut health. Overall, this review emphasizes the promising potential of postbiotics to revolutionize the bakery industry and promote healthier and more sustainable food options. The integration of postbiotics into bakery products represents a promising frontier and offers innovative possibilities to increase product quality, reduce food waste, and improve consumer health. Further research into refining techniques to incorporate postbiotics into bakery products is essential for advancing the health benefits and eco-friendly nature of these vital food items.

Effect of cellulase on dough structure and quality characteristics of tough biscuits enriched with potato whole flour

Potato whole flour is a promising way to improve the nutrition of tough biscuits, while its gluten-free characteristic was difficult to form acceptable texture properties. In this study, cellulase was used to degrade the cellulose in dough enriched with potato whole flour, so as to mitigate the interference of cellulose with the gluten network, resulting in forming the potato whole flour biscuit with great characteristics. Results indicated that cellulase within 0.2% led to the gradually reduced G' and G'' values of dough from 5.50×104 to 4.00×104 and 2.66×104 to 1.35×104, respectively. Cellulase at 0.2% resulted in the significantly increased tensile properties of the dough compared to the control. The incorporation of cellulase within 0.2% also led to the tightly ordered and intact network structure base on the results of SEM, disulfide bonds determination and FTIR. Those results indicated that cellulase was beneficial to improve the baking quality of dough, which was conductive to form tough biscuit with great characteristics. The hardness, crunchiness, crispness and specific volume analysis results confirmed that 0.2% cellulase resulted in the significantly decreased hardness by 45.25% and the significantly increased specific volume, crunchiness and crispness by 24.74%, 121.20% and 156.47%, respectively. Overall, cellulase ultimately improved the quality of the biscuits by improving the properties and structure of the dough. It was of great significance for the utilization of potato whole flour resources and the industrial production of its tough biscuits. PRACTICAL APPLICATION: The results showed that inclusion of cellulase led to the reduced hardness and increased crunchiness, crispness, and specific volume of potato whole flour tough biscuits. Cellulase could be used as a potential improver of tough biscuits. This study will provide guidance for practical uses of cellulase in improving potato whole flour dough and tough biscuit quality.

Recent advances in enzymatic modification techniques to improve the quality of flour-based fried foods

Flour-based fried foods are among the most commonly consumed foods worldwide. However, the sensory attributes and nutritional value of fried foods are inconsistent and unstable. Therefore, the creation of fried foods with desirable sensory attributes and good nutritional value remains a major challenge for the development of the fried food industry. The quality of flour-based fried foods can sometimes be improved by physical methods and the addition of chemical modifiers. However, enzyme modification is widely accepted by consumers due to its unique advantages of specificity, mild processing conditions and high safety. Therefore, it is important to elucidate the effects of enzyme treatments on the sensory attributes (color, flavor and texture), oil absorption and digestibility of flour-based fried foods. This paper reviews recent research progress in utilizing enzyme modification to improve the quality of flour-based fried foods. This paper begins with the effects of common enzymes on the physicochemical properties (rheological property, retrogradation property and specific volume) of dough. Based on the analysis of the mechanism of formation of sensory attributes and nutritional properties, it focuses on the application of amylase, protease, transglutaminase, and lipase in the regulation of sensory attributes and nutritional properties of flour-based fried foods.

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.

Effect of Fucoidan on Structure and Bioactivity of Chinese Steamed Bread

Fucoidan refers to a group of sulphated polysaccharides obtained from brown seaweed, with numerous biological activities. In this study, fucoidan was fortified into Chinese steamed bread (CSB) at different concentrations (0, 1%, 3% and 5%) and the effect of fucoidan on the dough properties, structure properties and bioactivity were investigated. The results showed that fucoidan could change the viscosity of unfermented dough, and a high concentration of fucoidan could remove the free radicals produced by the SH-SS exchange reaction (GS-) in the dough, which significantly reduced the content of disulfide bond and reduced the expanded volume of fermented dough (p < 0.05). In addition, fucoidan forms a physical barrier on the surface of starch particles and hinders the reaction between protein-to-protein; therefore, fucoidan increased the hardness, gumminess and chewiness in CSB, and reduced the specific volume in CSB. Furthermore, the fucoidan-fortified CSB samples were found to have both the ability to significantly reduce the predicted glycemic index (pGI) (p < 0.05) and improve antioxidant activity (p < 0.05). Collectively, these findings could provide a theoretical basis for the applications of fucoidan as a functional component in fermented foods.

Effect of partial substitution of wheat flour with kiwi starch on dough rheology, microstructure, the quality attributes and shelf life of Chinese steamed bread

Chinese steamed bread (CSB), a conventional high-GI staple food, with a short shelf life and a single flavor. In this work, 10-20 % kiwi starch (KS) was used to substitute wheat flour for the production of CSB and the effects of different substitution ratios on the quality and shelf life of mixed flour, dough, and CSB were explored. The results showed that the substitution of KS could improve the water binding capacity of mixed flour and lead to easier pasting in the system, lower the cooking power consumption, increase and improve the viscoelasticity and gas holding capacity of the dough, and make the microstructure more compact and uniform. As the substitution ratio increased, the reduction in protein content within the system further affected the formation of the gluten network, leading to a significant decrease in the CSB's specific volume and cohesiveness, whereas the chewiness and hardness were significantly improved. Meanwhile, KS substitution significantly reduced the starch hydrolysis rate and estimated glycemic index of CSB. 10 % KS substitution enriched the aroma and color of CSB, improved its internal organizational structure, and became more popular among consumers. A substitution ratio of 15-20 % was beneficial for extending the shelf life of CSB.

Influence of magnetic field on gluten aggregation behavior and quality characteristics of dough enriched with potato pulp

This study investigated the effect of varying magnetic field intensities (ranging from 0 to 10 mT) on the quality characteristics of dough with 40 % potato pulp substitution (DPP). The results indicated that the DPP fermented with a 4 mT magnetic field exhibited a significant enhancement in the combination of water and substrate, thereby elevating the viscoelastic properties of DPP through reinforcing the stability of gluten network. Meanwhile, DPP treated with a 4 mT magnetic field exhibited the highest amount of disulfide bonds (11.64 μmol SS/g sample). This is accompanied by a prominent cross-linkage structure, as evidenced by SDS-PAGE and CLSM. Notably, the application of a magnetic field substantially augments the dough's capacity to retain gas during fermentation. In addition, the application of magnetic field significantly increased the wet gluten content (20.85 %, P < 0.05) in DPP, which improved tensile properties and an acceptable color profile. The introduction of a magnetic field induces gluten aggregation, which in turn results in heightened particle size distribution and ζ-potential values. In conclusion, this study emphasize the potential of magnetic field technology as a viable method to enhance the overall quality attributes of dough enriched with potato pulp substitution.

Potential application of bioemulsifier RAG-1 as an anti-staling agent in flat bread quality

Bread undergoes physicochemical processes known as 'staling', which limits shelf life and quality. Despite the fact that several chemical emulsifiers have been employed to combat this issue, they may offer risks to human health. In this investigation, the effects of bioemulsan, a natural bioemulsifier (BE), on bread quality and staleness were examined. The yield of emulsan generated by Acinetobacter calcoaceticus RAG-1 was 1.49 g/L. The presence of clear zones around colonies, high emulsification value of 100%, and remaining surface tension below 40 mN/m after heating (at 250 °C for 15-20 min) verified emulsan thermal stability. BE-supplemented bread had a greater moisture percentage than the control, resulting in reduced crumb hardening and improved bread quality during storage as measured by moisture content. The first day after adding 0.5% emulsan, the hardness rose from 90.45 N (for the control) to 150.45 N. Texture analysis showed that although the hardness increased during storage, adding emulsan allowed obtaining bread with clearly softer crumb after 2 and 3 days of baking, especially at 0.5% level (from 215.6 N for the control to 150.5 N for 0.5% BE-enriched bread after 2 days, and from 425.7 to 210.25 N after 3 days). Based on the sensory evaluation results, emulsan did not lead to any unpleasant changes on bread organoleptic parameters. Therefore, using bioemulsifier RAG-1 as a green emulsifier and anti-staling agent found to be more promising.

Microbiota structure of traditional starters from around the Tai-hang mountains and their influence on the fermentation properties, aroma profile and quality of Chinese steamed bread

BACKGROUND

Steamed bread is a popular staple food in China, and the significant regional differences of the microbiota in traditional starters make the flavor and quality of steamed bread highly variable along with long preparation times. Therefore, analyzing the microbial flora of traditional starters and their influences on the flavor and quality may help to solve the problems mentioned earlier, and it may also be conducive to potentially meet consumer needs and permit industrialization of this traditional fermented food.

RESULTS

One hundred and thirty-two fungal and 50 bacterial species were identified in five traditional starters, each with a different dominant genus. The fermentation properties of dough showed that total titratable acid, dough volume and gas production increased and the pH decreased with fermentation time. The traditional starters improved the quality of Chinese steamed bread (CSB) including the crumb structure, specific volume and sensory attributes. Thirty-three aroma compounds with a VIP (variable importance for the projection) > 1 were identified as characteristic aroma compounds. The correlations among the microbiota, aroma and qualities of CSB showed a greater contribution from the bacteria, which was consistent with the predictions of metabolic pathways in the sequenced genomes.

CONCLUSION

The quality of CSB fermented with traditional starters was improved induced by their different microbial profiles, and bacteria made a greater contribution than fungus to the aroma and qualities of CSB. © 2023 Society of Chemical Industry.

Effect of fermentation methods on properties of dough and whole wheat bread

BACKGROUND

Whole wheat bread is high in nutritional value but poor in technological quality; therefore, research on how to improve its technological quality has attracted extensive attention. The effects of fermentation methods, including straight dough(STD), sourdough (SOD), sponge dough (SPD), and refrigerated SPD (RSD) methods, on the dough and bread quality of whole wheat bread were investigated, focusing on pasting properties, rheological properties, thermal properties, microstructure, basic quality, and starch digestibility.

RESULTS

The rapid viscosity analysis and rheological results demonstrated that SOD had the highest pasting temperature and the lowest viscosity, indicating an inhibition of starch pasting and partial protein hydrolysis, whereas the opposite trend presented by SPD and RSD indicated a greater starch hydration and a stronger gluten network. Thermal gravimetric analysis and differential scanning calorimetry results indicated reduced starch thermal degradation and increased starch pasting enthalpy in SOD and RSD. Scanning electron microscopy images revealed that the starch granules of SOD and RSD were tightly wrapped by a gluten network. SOD and RSD breads had the largest specific volume, the softest texture, and the lowest glycemic index.

CONCLUSION

The effects of different fermentation methods on dough and bread structure can provide instructive information for future studies on their applications in whole wheat bread production. © 2023 Society of Chemical Industry.

Exploration of microbial profile of traditional starters and its influence on aroma profile and quality of Chinese steamed bread

BACKGROUND

Chinese steamed bread (CSB) is a popular staple food in China with traditional ethnic characteristics. CSB with traditional starters has good flavor and texture but is unstable and requires a long preparation time. Therefore, it is necessary to analyze the traditional starters (ST) and their influence on the flavor and quality of steamed bread to meet people's requirements as a staple food.

RESULTS

The count of yeast, lactic acid bacteria and total microbial population significantly varied in different traditional starters; Saccharomyces and Lactobacillus were the predominant genera. Among the tested samples, fungi were found in ST from Shijiazhuang (SJ), Handan (HD) and Langfang (LF), while bacteria were found in ST from Tangshan (TS) and SJ at sub-predominant levels. In terms of the bread quality, the highest specific volume and porosity were in XT-CSB (Xingtai); the highest height/diameter ratio was in SJ-CSB; and the highest sensory score was in TS-CSB. A total of 26 aroma compounds (VIP > 1; variable importance for predictive components) were identified to discriminate CSB fermented with different starters, which were separated by stepwise canonical discriminant analysis using two functions. The correlation analysis among microbiota, aroma compounds and bread quality showed a higher contribution of bacteria than of fungi.

CONCLUSION

Differences in microbial profiles caused different aroma profiles and quality of CSB; and the CSB fermented with traditional starters were sufficiently separated by stepwise canonical discriminant analysis based on aroma compounds. © 2023 Society of Chemical Industry.

The properties of potato gluten-free doughs: comparative and combined effects of propylene glycol alginate and hydroxypropyl methyl cellulose or flaxseed gum

Different methods are often used to make gluten-free (GF) bread to get better bread characteristics. To explore the effects of emulsifiers and hydrocolloids on the characteristics of GF dough, different esterification levels of propylene glycol alginate (PGA), hydroxypropyl methyl cellulose (HPMC), flaxseed gum with (FG) different molecular weight, and the binary blends of HPMC/PGA and FG/PGA were added to GF dough, made with potato starch and potato protein in a ratio of 6:4. The results showed that the potato GF dough with FG and FG/PGA obtained a higher viscoelasticity than the other doughs. HPMC and FG promoted to the formation of network structure, but the network structure formed by PGA and their combination was more developed. It was found that all PGA, HPMC, FG and their combination could improve the softness of GF breads. The results provided a basis for optimizing the quality of potato GF bread.

Enrichment of Wheat Bread with Platycodon grandiflorus Root (PGR) Flour: Rheological Properties and Microstructure of Dough and Physicochemical Characterization of Bread

Platycodon grandiflorus (Jacq.) A.DC. root (PGR) flour is well known for its medical and edible values. In order to develop nutritionally fortified products, breads were prepared using wheat flour, partially replaced with PGR flour. The rheological properties and microstructure of dough and the physicochemical characterization of bread were investigated. Results showed that lower level of PGR addition (3 and 6 g/100 g) would improve the baking performance of breads, while the higher level of PGR addition (9 g/100 g) led to smaller specific volume (3.78 mL/g), increased hardness (7.5 ± 1.35 N), and unpalatable mouthfeel (21.8% of resilience and 92.6% of springiness) since its negative effect on the viscoelasticity and microstructure of dough. Moreover, sensory evaluation analysis also showed that the PGR3 and PGR6 breads exhibited a similar flavor to the control bread, but the 9 g/100 g addition of PGR provided bread with an unpleasant odor through its richer volatile components. As expected, the phenolic content and antioxidant capacity of bread increased significantly (p < 0.05) as PGR flour was added to the bread formulation. The total phenolic content (TPC) ranged from 14.23 to 22.36 g GAE/g; thus, DPPH• and ABTS•+ scavenging capacity increased from 10.44 and 10.06 μg Trolox/g to 14.69 and 15.12 μg Trolox/g, respectively. Therefore, our findings emphasized the feasibility of PGR flour partially replacing wheat flour in bread-making systems.

Study of ultrasonic treatment on the structural characteristics of gluten protein and the quality of steamed bread with potato pulp

Physicochemical properties and microstructure of gluten protein, and the structural characteristics of steamed bread with 30 % potato pulp (SBPP) were investigated by ultrasonic treatments. Results showed that 400 W ultrasonic treatment significantly (P < 0.05) increased the combination of water and substrate in the dough with 30 % potato pulp (DPP). The contents of wet gluten, free sulfhydryl (SH), and disulfide bond (SS) were influenced by ultrasonic treatment. Moreover, UV-visible and fluorescence spectroscopy demonstrated that the conformation of gluten protein was changed by ultrasonic treatment (400 W). Fourier transform infrared (FT-IR) illustrated that the β-sheet content was significantly (P < 0.05) increased (42 %) after 400 W ultrasonic treatment, and the surface hydrophobicity of gluten protein in SBPP increased from 1225.37 (0 W ultrasonic treatment) to 4588.74 (400 W ultrasonic treatment). Ultrasonic treatment facilitated the generation of a continuous gluten network and stabilized crumb structure, further increased the specific volume and springiness of SBPP to 18.9 % and 6.9 %, respectively. Those findings suggested that ultrasonic treatment would be an efficient method to modify gluten protein and improve the quality of SBPP.

Moisture Distribution and Structural Properties of Frozen Cooked Noodles with NaCl and Kansui

The effects of NaCl (1-3%) and kansui (0.5-1.5%) on the quality of frozen cooked noodles (FCNs) were investigated, which provided a reference for alleviating the quality deterioration of FCNs. Textural testing illustrated that the optimal tensile properties were observed in 2% NaCl (N-2) and the maximum hardness and chewiness were reached at 1% kansui (K-1). Compared to NaCl, the water absorption and cooking loss of recooked FCNs increased significantly with increasing kansui levels (p < 0.05). Rheological results confirmed NaCl and kansui improved the resistance to deformation and recovery ability of thawed dough; K-1 especially had the highest dough strength. SEM showed N-2 induced a more elongated fibrous protein network that contributed to the extensibility, while excessive levels of kansui formed a deformed membrane-like gluten network that increased the solid loss. Moisture analysis revealed that N-2 reduced the free water content, while K-1 had the lowest freezable water content and highest binding capacity for deeply adsorbed water. The N-2 and K-1 induced more ordered protein secondary structures with stronger intermolecular disulfide bonds, which were maximally improved in K-1. This study provides more comprehensive theories for the strengthening effect of NaCl and kansui on FCNs quality.