Effects of hydrocolloids and proteins on dough rheology and in vitro starch digestibility of sweet potato-wheat bread

Effects of soy protein isolate interaction with brown rice starch on the multiscale structure of brown rice bread

BACKGROUND

Gluten-free bread (GFB) has technical bottlenecks such as hard texture, rough taste and low nutrition in practical production. In order to solve these problems, this study used germinated brown rice starch as the main raw material, and investigated the effects of soybean isolate protein (SPI) on the multiscale structure of germinated brown rice starch and bread quality.

RESULTS

A gluten-free rice bread process simulation system was established, and the interaction between SPI and starch in the simulation system was characterized. The result shows that the interaction forces between SPI and germinated brown rice starch were mainly represented by hydrogen bonds, and with the addition of SPI, the crystallinity of starch showed a downward trend. At the same time, when the amount of SPI was 3%, the appearance quality was the best and the specific volume of bread was 1.08 mL g-1. When the amount of SPI was 6%, the texture quality was the best. Compared with the bread without SPI, the hardness of the bread with 6% SPI was reduced by 0.13 times, the springiness was increased by 0.03 times, the color was the most vibrant, the L* value being 1.02 times the original, and the baking loss was reduced to 0.98 times the original.

CONCLUSIONS

The interaction force between SPI and germinated brown rice starch and its effect on bread quality were clarified, and these results inform choices about providing a theoretical basis for the subsequent development of higher-quality GFB. © 2024 Society of Chemical Industry.

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.

Effect of different molecular weight β-glucan hydrated with highland barley protein on the quality and in vitro starch digestibility of whole wheat bread

Whole wheat bread has high nutritional value, but it has inferior baking quality and high glycemic index, which needs to be improved by methods such as adding protein and β-glucan. This study investigated the effects of β-glucan and highland barley protein of different molecular weights (2 × 104, 1 × 105, and 3 × 105 Da) and different hydrate methods (pre-hydrate and not pre-hydrate) on the characteristics of whole wheat dough and bread. The mixing properties and rheological properties demonstrated that β-glucan pre-hydrated with highland barley protein were able to reduce the dough tan δ, reduce the dough viscoelasticity, while enhance the gluten network structure and dough deformation resistance. Compared to the control sample, the medium molecular weight pre-hydrate bread had a better specific volume of 3.21 mL/g, lower hardness of 527.28 g. In vitro starch digestion characteristics and ATR-FTIR showed that low and high molecular weight pre-hydrate increased the short-range ordered structure of starch and reduced the starch digestibility, while not pre-hydrated medium molecular weight hydrate had the lowest level of starch digestibility.

Psyllium Fibre Inclusion in Gluten-Free Buckwheat Dough Improves Dough Structure and Lowers Glycaemic Index of the Resulting Bread

The demand for gluten-free (GF) bread is steadily increasing. However, the production of GF bread with improved baking quality and enhanced nutritional properties remains a challenge. In this study, we investigated the effects of adding psyllium fibre (PSY) in varying proportions to buckwheat flour on the dough characteristics, bread quality, and starch digestion properties of GF bread. Our results demonstrate that incorporating PSY contributes to the formation of a gluten-like network structure in the dough, leading to an increase in the gas holding capacity from 83.67% to 98.50%. The addition of PSY significantly increased the specific volume of the bread from 1.17 mL/g to 3.16 mL/g. Bread containing PSY displayed superior textural characteristics and colour. Our study also revealed that the inclusion of PSY reduced the digestibility of starch in GF bread. These findings highlight the positive impact of incorporating PSY into GF bread, suggesting its potential in guiding the production of GF bread with a lower glycaemic index. This may be particularly beneficial for individuals seeking to regulate their blood sugar levels or adopt a low-glycaemic diet.

Effects of Xanthan gum and Potassium carbonate on the quality and flavor properties of frozen Jiuniang doughs

Chinese Jiuniang (CJ) is a flavorful and nutritious food, but underutilized in frozen dough (FD) production. In addition, frozen storage can harm FD's gluten structure and degrade quality and flavor. Therefore, the impacts of two excellent protective agents (XG-Xanthan Gum; PC-Potassium Carbonate) on frozen Jiuniang dough (F-JD) quality and flavor during dynamic freezing were investigated. The results suggested that adding XG conferred F-JD with good processing stability, maintained the bound water levels, stabilized rheological properties, diminished ice crystal damage to the protein structure, and inhibited the increase in frozen water content during the freezing process. In contrast, although PC reduced free water production during freezing, it increased dough hardness and offered less protein protection than XG. Additionally, GC-QTOF/MS analysis showed that adding XG during freezing increased the relative content of pleasant flavor compounds like Phenylethyl Alcohol and decreased undesirable ones like Hexanal. Moreover, PC lowered the relative content of undesirable flavor substances (Formic acid) but reduced the relative content of beneficial flavor compounds (1-Hexanol). Importantly, the study confirmed that XG maintained the new F-JD product's storage quality during dynamic freezing. In conclusion, this study broadens CJ's application possibilities and provides new insights into mechanisms for preserving F-JD's quality and flavor.

A Study on the Structural and Digestive Properties of Rice Starch-Hydrocolloid Complexes Treated with Heat-Moisture Treatment

Rice starch-hydrophilic colloid complexes (SHCs) were prepared by incorporating xanthan gum and locust bean gum into natural rice starch. Subsequently, they underwent hygrothermal treatment (H-SHC) to investigate their structural and digestive properties with varying colloid types and added amounts of H-SHC. The results demonstrated that heat-moisture treatment (HMT) led to an increase in resistant starch (RS) content in rice starch. This effect was more pronounced after the addition of hydrophilic colloid, causing RS content to surge from 8.42 ± 0.39% to 38.36 ± 3.69%. Notably, the addition of locust bean gum had a more significant impact on enhancing RS content, and the RS content increased with the addition of hydrophilic colloids. Enzyme digestion curves indicated that H-SHC displayed a lower equilibrium concentration (C∞), hydrolysis index (HI), and gluconeogenesis index (eGI). Simultaneously, HMT reduced the solubility and swelling power of starch. However, the addition of hydrophilic colloid led to an increase in the solubility and swelling power of the samples. Scanning electron microscopy revealed that hydrophilic colloid encapsulated the starch granules, affording them protection. X-ray diffraction (XRD) showed that HMT resulted in the decreased crystallinity of the starch granules, a trend mitigated by the addition of hydrophilic colloid. Infrared (IR) results demonstrated no formation of new covalent bonds but indicated increased short-range ordering in H-SHC. Rapid viscosity analysis and differential scanning calorimetry indicated that HMT substantially decreased peak viscosity and starch breakdown, while it significantly delayed the onset, peak, and conclusion temperatures. This effect was further amplified by the addition of colloids. Rheological results indicated that H-SHC displayed lower values for G', G″, and static rheological parameters compared to natural starch. In summary, this study offers valuable insights into the development of healthy, low-GI functional foods.

Effects of tamarind seed polysaccharides on physicochemical characteristics of frozen dough: structure-function relationship

BACKGROUND

Recently, frozen dough has become more popular because of its ability to be quickly transformed into freshly baked foods. During the storage and transport process, frozen dough can suffer some degree of damage caused by ice crystallization and recrystallization. Adding polysaccharides to frozen dough is a good way to solve this problem. Tamarind seed polysaccharide (TSP) has excellent ice crystal steady ability and has also been widely used in frozen foods. However, there is no study on the use of TSP in frozen dough.

RESULTS

TSP can stabilize the bound water content, inhibit the freezable water content, and increase elasticity. However, the dough with different structures of TSP added was less firm after 30 days of freezing compared to the dough without TSP, and the porosity and stomatal density of the prepared steamed bread gradually decreased. The addition of TSP reduced gluten deterioration during the freezing process, thus decreasing the collapse and uneven porosity of the steamed bread.

CONCLUSIONS

The results could provide new insights into the structure of TSP and its effect on the quality characteristics of frozen dough. © 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.

Effects of sodium carboxymethyl cellulose on storage stability and qualities of different frozen dough

Hydrocolloids as Additives have been used for improving the quality of frozen dough for a long time. In this work, the effects of sodium carboxymethyl cellulose (CMC) on quality changes of frozen dough in storage were studied. The water loss rate of the dough and water holding capacity were measured. Rheological and texture properties of the frozen dough were measured by a rheometer and a texture analyzer, respectively. Scanning electron microscopy (SEM) was used to characterize surface network structure and protein structure changes of the frozen dough. Our results reveal that the addition of CMC can inhibit the formation of ice crystals and recrystallization, thus effectively stabilizing the molecular structure of starch, and resulting in more uniform moisture distribution in the frozen dough. When 3% addition of CMC, the water holding capacity of the two kinds of dough reached the best, and the water loss rate of corn dough reached the lowest. The cohesion of the two kinds of dough reaches the maximum with 3 wt% addition of CMC, while the hardness and chewiness of wheat and corn multigrain dough reaches the maximum with 3 wt% and 4 wt% addition of CMC, respectively. The results show proper CMC addition (3 wt% and 4 wt%) finally improves the stability and qualities of the frozen dough. The research concerning the effects of CMC on quality of frozen dough provides better understanding for the frozen food industry.

The Chemical, Rheological, and Sensorial Characteristics of Arabic Bread Prepared from Wheat-Orange Sweet Potatoes Flour or Peel

The current study investigates the feasibility of preparing Arabic bread from wheat flour, sweet potato flour, or peeled sweet potatoes based on the nutritional values, technological characteristics, and sensory properties of the final products. First, we analyzed the proximate, elemental, total and individual phytochemical compositions of the raw materials and bread samples. The analysis showed that potassium, calcium, and phosphorus were higher in peels than pulp, in the same manner to the total phenolics, flavonoids, and anti-radical scavenging activities. Phenolic acids and flavonols were quantified, where p-coumaric, feruloyl-D-glucose, eucomic, gallic, and ferulic acids were measured as major phenolic acids in either peels or pulp flours, and their quantities were higher in the peels. Furthermore, we evaluated the effects of wheat substitution on the properties of the dough blends and their final bakery. The results indicated that the fortified samples' nutritional and rheological properties were significantly improved, while their sensory qualities were comparable to those of the control. Thereby, the fortified dough blends presented higher dough stabilities, indicating a wider range of applications. Additionally, after the heat treatment, the fortified breads maintained significantly higher total phenolic, flavonoid, anthocyanin, and carotenoid contents, and total antioxidant activities, implying their accessibility for humans upon consumption.

Modified celluloses improve the proofing performance and quality of bread made with a high content of resistant starch

BACKGROUND

Adding resistant starch (RS) to bread formulations is a promising way of increasing fiber content of white bread. However, the partial replacement of wheat flour (WF) by RS can lead to a decrease in technological quality. The objective of this study was to analyze the performance of hydroxypropylmethylcellulose and carboxymethylcellulose as improvers of wheat bread with a high level of replacement (30%) with maize RS. The levels of the modified celluloses were 1% and 1.5% (WF + RS basis), and a formulation without modified celluloses was used as control. Proofing time, loaf volume, crumb characteristics (porosity, texture), and bread staling parameters (hardness increase, moisture loss), among other attributes, were analyzed, and principal component analysis was applied to compare samples.

RESULTS

The use of both modified celluloses was effective in improving the quality of breads. Specific volume and crumb porosity were enhanced, particularly at the 1.5% level. Breads with modified celluloses also allowed a higher retention of water and a better preservation of mechanical properties during storage. The principal component analysis projection graph for the first two principal components showed that samples with modified celluloses were clustered by the level of hydrocolloid addition rather than by the type of hydrocolloid used, although all the samples with modified celluloses were close to each other and distant from the control sample without hydrocolloids.

CONCLUSION

The quality decrease resulting from the replacement of WF by a high level of RS can be greatly compensated by the use of structuring agents such as hydroxypropylmethylcellulose and carboxymethylcellulose. © 2022 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.

Optimizing the Rheological and Textural Properties of Chapatti Enriched with House Crickets (Acheta domesticus) Flour Using Hydrocolloids by an I-Optimal Design

The fortification of food with edible insect flour can improve its nutrition profile, but also affect its techno-functional characteristics. In this study, an I-optimal design was applied to improve the rheological and textural properties of wheat flour chapatti containing 10% cricket (Acheta domesticus) flour. More specifically, the impact and optimal addition of hydrocolloids (carboxymethyl cellulose, hydroxypropyl methylcellulose, guar gum and xanthan gum) and water content were studied. For all the responses, the model and model terms were highly significant and showed the different impact of the hydrocolloids on the rheological properties. To evaluate the predictive power of the models, two sets of optimal process settings were chosen: one based on dough properties, and another on baked chapatti. For both sets, the actual responses were in the range of predicted responses for almost all properties. In addition, it was shown that using the settings based on dough properties, the actual responses were not significantly different from the control chapatti, whereas for the settings based on baked chapatti, there were differences in terms of the extensibility of both dough and chapatti. Thus, the I-optimal design is suitable to optimize the dough properties and the baked chapatti when enriching chapatti with cricket flour.

Effect of Tremella fuciformis and Different Hydrocolloids on the Quality Characteristics of Wheat Noodles

To improve the quality characteristics of noodles and enrich nutritional value, Tremella fuciformis (TF) powder was incorporated into noodles. Tremella fuciformis (TF) is an edible fungus with rich nutritional value, and TF gel has good viscosity properties. This paper explored the effect of TF on noodle quality, and compared the difference between TF and three hydrocolloids: sodium alginate (SA), guar gum (GG) and xanthan gum (XG). The results showed that TF could significantly (p < 0.05) increase the hardness, adhesiveness and chewiness of noodles, and showed a decreasing trend for additions greater than 3%. The addition of 3% TF enhanced storage modulus (G′), loss modulus (G″) and elasticity of dough. The addition of 3% TF also increased α-helix and β-sheet content, and degradation temperature in noodles. Meanwhile, it elevated the deeply bound water content and retarded water mobility. In addition, the content of slowly digestible starch and resistant starch in the noodles increased with the addition of 3% TF. It was found that the effect of 3% TF on the above data was not different from the effects of the three hydrocolloids (respectively, their optimal additions), and improved the quality characteristics of the noodles. The results provide guidance for the application of TF and the development of a new natural hydrocolloid and nutritionally fortified noodles.

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 potato and sweet potato flour addition on properties of wheat flour and dough, and bread quality

The effects of 10%-30% of wheat flour substitution with potato flour (PF) and sweet potato flour (SPF) on the flour and dough properties, the total polyphenol (TPC), and carotenoid contents (TCC) of bread, as well as their correlation with bread texture and starch digestibility, were investigated. With PF and SPF addition, the peak, breakdown, and setback viscosity of the flour decreased. The addition of PF and SPF reduced the dough formation and stabilization duration, as well as the hardness of the bread. The specific volume of the bread depended on the addition amount of PF and SPF. When the addition of PF and SPF was 15%, the bread had the lowest hardness and highest specific volume. The TPC and TCC in the bread depended on the added flour variety, and negatively influenced specific volume and positively influenced the content of resistant starch (RS).