Influence of the fermentation time and potato pulp addition on the technological properties and volatile compounds of wheat dough and steamed bread

Investigating potato flour processing methods and ratios for noodle production

A partial substitution of wheat flour with potato flour processed by various procedures was used to determine an optimal potato pretreatment method for noodle processing. Wheat flour was substituted with 10%, 30%, and 50% potato flour. Potato flour (PF) was processed using two different methods, including freeze-drying (FD) and low-temperature blanching, then oven drying (LTB_OD). The results showed that substituting wheat flour with freeze-dried (FD) flour (44.29 μm) significantly decreased the mean particle size of the blended flour, while LTB_OD flour (223.09 μm) increased the mean particle size. The pasting properties of wheat flour significantly improved when potato flour was added, with FD flour blends having the highest results. The highest dough development time (14.46 min) was attained when LTB_OD potato flour was substituted up to 50%. The microstructure images showed a poor and discontinuous gluten framework when potato flour content reached 50%. Adding potato flour decreased noodles' brightness (L*) while increasing their yellowness (b*). Noodles made from wheat and LTB_OD flour blends resulted in the highest cooking loss. The texture properties of noodles deteriorated when potato flour content reached 30%. Substituting up to 30% with freeze-dried flour and 10% LTB_OD resulted in noodles with the highest overall liking scores. The study suggests that for optimal noodle processing, substituting wheat flour with FD potato flour is more favorable than using LTB_OD, as it improves particle size, pasting properties, and overall liking scores while minimizing adverse effects on texture and cooking loss.

Insights into the hierarchical structure and physicochemical properties of starch isolated from fermented dough

Understanding the hierarchical structure and physicochemical properties of starch isolated from fermented dough with different times (0-120 min) is valuable for improving the quality of fermented dough-based products. The results indicate that fermentation disrupted the starch granule surface and decreased the average particle size from 19.72 μm to 18.45 μm. Short-term fermentation (< 60 min) disrupted the crystalline, lamellar, short-range ordered molecular and helical structures of starch, while long-term fermentation (60-120 min) elevated the ordered degree of these structures. For example, relative crystallinity and double helix contents increased from 23.7 % to 26.8 % and 34.4 % to 37.2 %, respectively. During short-term fermentation, the structural amorphization facilitated interactions between starch molecular chains and water molecules, which increased the peak viscosity from 275.4 to 320.6 mPa·s and the swelling power from 7.99 to 8.52 g/g. In contrast, starches extracted from long-term fermented dough displayed the opposite results. Interestingly, the hardness and springiness of starch gels gradually decreased as fermentation time increased. These findings extend our understanding of the starch structure-property relationship during varied fermentation stages, potentially benefiting the production of better-fermented foods.

Effect of superfine grinding chestnut powder on the structural and physicochemical properties of wheat dough

This study evaluated the influence of chestnut powder, produced using ball mill superfine grinding (BMSG), jet superfine grinding (JSG), and ordinary grinding (OG), on wheat flour properties. Blending wheat flour with chestnut powder resulted in a darker flour blend (3 % decline of L*), with decreased the tap density and increased water holding capacity. Adding appropriate proportion of superfine chestnut powder can bolster the mixed flour's thermal stability (15 % BMSG/JSG) and freeze-thaw stability (10 % BMSG/JSG), while significantly enhancing the anti-aging properties of flour products. The proposition of 5 % superfine BMSG/JSG did not significantly affect the tensile resistance of the dough, and even improve the dough's tensile strength. In addition, the hardness, adhesiveness, springiness and pH of fermentation increased due to the addition of chestnut powder, as supported by the dough texture analyses and fermentation characteristics findings. However, the excessive addition of chestnut powder affected the dough network's structural integrity to some extent. Further study can focus on the influencing mechanism of chestnut powder on gluten formation and related nutritional properties. Overall, this research underscores the potential of utilizing chestnut powder to enhance the nutritional and functional qualities of wheat-based products.

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.

Application progress of ultrasonication in flour product processing: A review

Flour products played a vital role in the global diet structure. With the increasing demand for dietary health and food standardization, the staple food of flour products made from coarse grains due to its unique flavor and rich nutrition has become a trend and is favored by consumers. However, the lack of gluten protein in the raw materials prevented the formation of a stable gluten network structure, leading to the deterioration of the quality of flour products. Ultrasonic treatment, as an innovative food processing technology, generated energy during the action of ultrasonic waves that had a positive impact on the texture, organizational structure, or flavor characteristics of food. That was of great significance for improving food production efficiency, improving food processing quality, and extending food shelf life. This article applied ultrasonic technology to the processing of flour products from the perspective of promoting fermentation and improving production efficiency of flour products. The cavitation effect of ultrasound promoted the formation of gluten network structure, improved the rheology properties of dough and the quality of flour products by promoting protein cross-linking, improving the foaming and emulsifying stability of gluten protein, and promoting the growth and reproduction of yeast. All reviewed studies indicate that ultrasound would be a promising technology for producing high-quality surface products under appropriate conditions.

Studying the Role of Potato Powder on the Physicochemical Properties and Dough Characteristics of Wheat Flour

Potato flour (PF) is rich in health-promoting compounds that can improve the nutritional benefits of food products after blending with wheat flour. However, the incorporation of PF may influence the processing characteristics of mixed powders and the quality properties of products. In this study, the physicochemical properties, processing characteristics, and structures of mixed powders and their corresponding doughs with different PF content (0%, 10%, 20%, 30%, 40%, 60%, 80%, and 100%) were investigated. The addition of PF dramatically increased the fiber content from 0.09 to 1.10 g·kg^-1 but diluted the protein in wheat flour. The peak and final viscosity of mixed powders decreased (from 5111.00 to 1806.33 cP and 5195.33 to 2135.33 cP, respectively) with an increase in PF fraction. The incorporation of PF significantly increased gelatinization temperature. The rapidly digestible starch decreased from 30.48% to 19.67%, and resistant starch increased from 16.93% to 41.84% when the PF content increased from 0% to 100%. The water absorption, stability time, and development time decreased with an increase in PF levels. The G' and G″ of the dough decreased as the addition amount of PF increased, while tan δ presented a complex change tendency. Due to the decrease in protein content in the mixed powders, the addition of PF in wheat flour notably decreased the Hm values of doughs and total carbon dioxide volume produced during fermentation. Additionally, the SH and S-S contents decreased with an increase in PF fraction. Scanning electron microscopy results showed that when the PF content reached up to 80%, a poor and discontinuous gluten framework was formed in the dough. Results showed that PF affected the processing characteristics and gluten structures of wheat dough and was related to the interaction or competition for water molecules between protein and starch, as well as potato starch and wheat starch. Thus, the results of the present study can provide insights into the optimal level of addition of PF during the development of potato-based food products.

Fortification of Chinese Steamed Bread with Glycyrrhizauralensis Polysaccharides and Evaluation of Its Quality and Performance Attributes

Natural polysaccharides are new popular healthy food material, and the materials are widely used in various functional foods. The influences of polysaccharides from Glycyrrhiza uralensis on the quality and sensory properties of Chinese steamed bread (CSB), as well as the performance (starch digestion in vitro and starch staling) of CSB, were investigated in this study. The addition of Glycyrrhiza polysaccharide (GP) increased the specific volume of CSB in a dose-dependent manner, and the specific volume of CSB-2 was 2.55 mL/g. GP also contributed to the increase in hardness (from 1240.17 to 2539.34 g) and chewiness (893.85 to 1959.27 g) of fresh CSB. In addition, GP could maintain the integrity of the protein network within the CSB. The scores for sensory evaluation indicators of CSB-1 were relatively balanced. More importantly, the addition of GP altered starch digestive properties, and the content of the resistant starch (RS) was increased from 8.62 (CSB-0) to 43.46% (CSB-2). GP led to a significant reduction of the expected glycemic index (eGI) of CSB, and the eGI of CSB was decreased from 97.50 (CSB-0) to 73.8 (CSB-2), which was classified as a medium-GI (MGI) food. In addition, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) revealed the addition of GP delayed the staling of CSB during storage. In general, adding the proper amount of GP could improve the quality of CSB and show the potential as a functional component of CSB to reduce the postprandial blood glucose level resulted by the CSB.

Effect of Highland Barley on Rheological Properties, Textural Properties and Starch Digestibility of Chinese Steamed Bread

Highland barley has a different composition and structure to other crops. It has higher contents of total polyphenol (TPC), total flavonoid (TFC) and β-glucan, which can be supplemented to improve the nutrition of wheat-flour-based food. In this study, the flours of three different grain-colored highland barley varieties Beiqing 6 (BQ), Dulihuang (DLH), and Heilaoya (HLY), were added to Jimai60 (JM, a wheat variety with medium gluten) wheat flour at different substitution levels to investigate their effects on the unextractable polymeric protein (UPP) content, micro-structure, rheological properties and mixing properties of dough, and the color, texture, flavor, and in vitro digestion of Chinese steam bread (CSB). The results showed that the moderate substitution of highland barley (20%) increased the UPP%, optimized the micro-structure of gluten, and improved its rheological properties by increasing dough viscoelasticity. The CSBs made from the composite flours exhibited a similar specific volume, cohesiveness, springiness and resilience to wheat CSB, while the firmness of composite CSBs (particularly JM-HLY-20) was delayed during storage. Importantly, the addition of highland barley increased the contents of TPC, TFC and β-glucan, but decreased the in vitro starch digestibility of CSBs. A sensory evaluation showed that JM-HLY CSB was the most preferable. Taken together, highland barley can be used as a fine supplement to food products, with health-promoting properties.

Effects of different gelatinization degrees of starch in potato flour on the quality of steamed bread

The effect of four kinds of potato flour with different gelatinization degrees on the quality of steam bread was investigated in the present study. Results showed that medium-well flour (MWF) and potato flakes (PF) steamed bread, particularly MWF steamed bread, possessed the desired product properties liked by consumers. The MWF steamed bread had the highest appearance score (42.78) and total sensory evaluation score (81.60), and the PF steamed bread exhibited the highest specific volume (1.84 mL/g) and taste score (43.05). An increase in the degree of potato flour gelatinization led to an increase in dough gas retention coefficient from 80.20 mL/100 mL to 85.17 mL/100 mL and a more uniform and dense dough microstructure. During dough preparation, the increased gelatinization degree of potato flours enhanced the hydroscopicity competition between potato starch and gluten, resulting in a flocculent gluten network and increased potato starch volume during steaming. During steaming, steamed bread with higher gelatinization degree of potato flour formed a homogenous and dense starch gel-gluten double network, making them softer with more uniform gas cells and larger specific volume. Thus, this study provides a perspective of the effect of starch gelatinization on steamed bread quality.

Effects of Konjac glucomannan with different viscosities on the rheological and microstructural properties of dough and the performance of steamed bread

Konjac glucomannan (KGM) is used as an additive to improve the properties of wheat products. The effects of three types of KGM on the rheological properties and microstructure of dough, as well as the performance of steamed bread were investigated in this study. Particularly, dough with KGM displayed new features such as reduced peak viscosity, breakdown and setback. As the viscosity of KGM increased, the stability of the dough structure increased, while the viscosity and fluidity of the dough decreased. More interestingly, the gluten film of dough also increased with increasing substitution level and viscosity of KGM. Consistently, KGM with higher viscosity improved the quality of steamed bread. Generally, three types of KGM have different effects on the rheological characteristics and microstructure of dough, as well as the performance of steamed bread, which provide useful information for the proper application of KGM in wheat-based foods.

Effect of ultrasound-assisted dough fermentation on the quality of dough and steamed bread with 50% sweet potato pulp

Ultrasound at an intensity of 17.5, 20.0, 22.5, 25.0 and 27.5 W/L was used to assist dough fermentation to prepare steamed bread with 50% sweet potato pulp (SB-50% SPP), which was compared with SB-50% SPP without ultrasonic treatment. The dough rheology, starch-gluten network, texture characteristics and sensory quality of steamed bread with different ultrasonic power densities (UPDs) were investigated. Dough samples at UPD of 22.5 W/L showed optimal viscoelasticity. The microstructure images exhibited that the content of starch particles wrapped in the gluten network increased significantly after sonication. In addition, the reduction in free sulfhydryl (SH) content and increase in wet gluten content after ultrasonic treatment led to significantly improved dough extensibility (p < 0.05). Results exhibited that the specific volume of SB-50% SPP increased by 13.93% and the hardness decreased by 21.96% compared with the control under UPD of 22.5 W/L. This study suggested that the application of ultrasound as a green technology to dough fermentation could lead to SB-50% SPP with good quality and sensory characteristics.

Physicochemical and in vitro digestibility properties on complexes of fermented wheat starches with konjac gum

In this study, the wheat starch with natural fermentation for 72 h was combined with konjac gum (KGM) at different concentrations (0, 0.1, 0.3, 0.5%, w/w), and the changes in physicochemical and digestible characteristics of the complexes were investigated. The results showed that KGM clumped fermented starch (FS) granules together and caused the FS gels to form a close network structure. The addition of KGM significantly decreased the amylose content and swelling power, and reduced peak viscosity, final viscosity, and setback value (SB), which indicated that FS-KGM complexes possessed soft gel structure and could resist the short-term retrogradation. KGM impeded the increase of relative crystallinity, retrogradation enthalpy and gel firmness of FS during storage, suggesting the long-term retrogradation of FS was retarded by KGM. All starch pastes had a weak gel-like structure, and higher storage modulus (G') and loss tangent (tan δ) values obtained after the addition of KGM. In vitro digestion results showed that KGM could slow the hydrolysis of FS, resulting in the increase of slowly digested starch (SDS) and resistant starch (RS). In particularly, the FS-0.3KGM showed the ideal structure, the best anti-retrogradation effected, and slowest the hydrolysis.

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

The aim of this study was to evaluate whether processing characteristics of steamed bread enriched with potato pulp could be improved through the addition of different emulsifiers (soy lecithin-Soy L, sodium stearoyl lactate and diacetyl tartaric esters of monoglyceride) and enzymes (glucose oxidase-GOX and transglutaminase). Results showed that separate addition of each emulsifier at 1% concentration or each enzyme at 1.5 U/g could increase the viscoelasticity and strength of potato pulp dough due to enhancement of gluten network. Fermentation properties of dough showed that Soy L and GOX significantly (P < 0.05) increased the maximum dough height and the gas retention capacity during fermentation which promoting dough expansion. Moreover, Soy L and GOX increased specific volume and improved crumb structure and softness of steamed bread, which were consistent with the results of sensory analysis. In conclusion, Soy L and GOX could be used as improvers of potato pulp steamed bread.

Identification of saprophytic microorganisms and analysis of changes in sensory, physicochemical, and nutritional characteristics of potato and wheat steamed bread during different storage periods

Due to its nutritional value and no gluten, potato flour has recently been used as a new type of material to make steamed bread. However, compared to traditional wheat steamed bread, its shelf life is considerably shorter, the dominant microorganisms and storage properties also differ. High-throughput sequencing combined with molecular biology assay revealed that Bacillus methylotrophic and Bacillus subtilis were the dominant bacteria in the crumb of potato and wheat steamed bread, respectively. Moreover, Meyerozyma, Penicillium chrysogenum, Penicillium citrinum, and Aspergillus parasiticus were the main fungi in the crusts. Ethanol was the most volatile compound in fresh potato and wheat steamed bread. Following storage for 48 h, 2,3-butanediol and 3-hydroxy-2-butanone were established as the most volatile compounds. Although decreased sourness was observed, the specific volume, brightness, and nutritional composition remained nearly unchanged. These findings provide a valuable theoretical basis for the development of potato and wheat steamed bread preservation technologies.