Effect of phosphate salts on the gluten network structure and quality of wheat noodles

Variation in quality of noodles by regulating the dynamic transition behavior of gluten proteins though dough crumbles temperature control method at different stages of mixing

This work explored the gluten proteins evolution with various dough crumbles temperature control methods during mixing on noodles quality. The changes of gluten protein properties including structure, aggregation, and gluten network distribution in dough during mixing with HW-LF (high temperature water and low temperature flour), NW-NF (normal temperature water and normal temperature flour), and LW-HF (low temperature water and high temperature flour) dough crumbles temperature control method were analyzed. According to the results, by maintaining the dough crumbles temperature at 20 °C, HW-LF showed a stronger gluten cross-linking, a more continuous and dense gluten network structure, and a higher dough and noodles quality than LW-HF method at mixing time of 3 min. On the contrary, at mixing time of 9 min, the LW-HF method displayed a higher degree of gluten aggregation with an increase of 10.84 % (disulfide bonds), 4.32 % (hydrogen bonds), 15.29 % (GMP), and 28.57 % (gluten protein molecular chain height) than HW-LF. Besides, LW-HF achieved a 3.51 % augmentation in dough breaking force, 4.96 % reduction in relaxation degree, and 8.99 % and 5.66 % increment in chewiness and hardness, respectively, than HW-LF. Consequently, the LW-HF method facilitated a complete cross-linking of gluten molecules, thus forming a continuous and uniform gluten network, ultimately enhancing the noodles hardness and chewiness. Additionally, an extremely significant positive correlation (p<0.01) and negative correlation were observed between SS bonds with chewiness and protein average length with chewiness, respectively. Therefore, the SS and protein average length demonstrated considerable potential as predictors of noodles chewiness.

Alleviative effects of phosphates on quality deterioration of frozen dough during freeze-thaw cycles: A focus on gluten aggregation and dough fermentation

This study investigated the effects of phosphates on the quality of frozen steamed bread, focusing on rheological properties, water status, fermentation characteristics, and protein aggregation properties. The findings revealed that phosphates significantly improved the quality of frozen steamed bread. After 3 freeze-thaw (F/T), the specific volumes of 0.6 % sodium tripolyphosphate (STPP) and 0.4 % sodium hexametaphosphate (SHMP) samples increased by 17.65 % and 20.32 %, respectively, compared to the control. Hardness decreased by 38.12 % and 24.55 %, respectively, while internal porosity of the 0.6 % STPP and SHMP samples improved by 32.37 % and 21.76 %, respectively. Furthermore, phosphates enhanced dough elasticity and viscosity, effectively inhibiting water migration and reducing freezable water content. Yeast gas production also increased after F/T, as phosphates improved yeast tolerance by moderately slowing yeast growth. Notably, phosphates mitigated glutenin macropolymer (GMP) depolymerization by inhibiting yeast to reduce reductant production during F/T cycles. Phosphates also contributed to a more stable protein secondary structure. In conclusion, phosphates played a crucial role in alleviating the quality deterioration of frozen dough by influencing protein aggregation, thereby offering novel insights into their benefits for dough-based products.

Research progress on non covalent interaction dissolution characterization of insoluble wheat protein based on swelling

The non covalent interactions of proteins are usually characterized by solubility, which is based on the principle that specific solvents can disrupt non covalent interactions and promote protein dissolution. However, this method is generally applicable to highly soluble protein materials. The solubility of wheat protein is poor. When using this method to characterize non covalent interactions, there is always a portion of protein aggregates that can only reach a swollen state and cannot be completely dissolved. At present, there are no research reports on the role of non covalent interactions in swelling. In view of this, this article first reviews the swelling and dissolution processes of insoluble proteins such as wheat protein in solvents, focusing on the characterization mechanisms and influencing factors of three non covalent interactions using solubility characterization. At the same time, this article also explores the potential of swelling in characterizing non covalent interactions, aiming to improve the characterization methods of non covalent interactions between wheat proteins and provide methodological support for analyzing processing differences from the hierarchical analysis of wheat protein interactions in the future.

Gluten Unraveled: Latest Insights on Terminology, Diagnosis, Pathophysiology, Dietary Strategies, and Intestinal Microbiota Modulations-A Decade in Review

A decade of research on gluten-related disorders (GRDs) is reviewed in this study, with a particular emphasis on celiac disease (CD) and non-celiac gluten sensitivity (NCGS). GRDs are triggered by the ingestion of gluten and gluten-like proteins found in wheat, barley, and rye. These proteins lead to intestinal damage in celiac disease, an autoimmune condition characterized by villous atrophy and a variety of gastrointestinal and extraintestinal symptoms. More enigmatic and less understood, NCGS involves symptoms similar to CD but without the immunological reaction or intestinal damage. Recent years have seen advances in the understanding of GRDs, particularly in connection to how intestinal microbiota influences disease progression and patient outcomes. The gluten-free diet (GFD) is still the standard therapy recommended for GRDs despite significant challenges, as discussed in this article. Precise diagnostic methods, patient education and dietary counseling are critical for improving patients' quality of life. The purpose of this review is to provide a more clear and up-to-date understanding of GRDs, and to help further research on this important topic.

Dynamic behaviors of protein and water associated with fresh noodle quality during processing based on different HMW-GSs at Glu-D1

In this study, dynamic behaviors of proteins and water during fresh noodles processing associated with the quality of fresh noodles were systematically investigated by using wheat near-isogenic lines carrying high-molecular-weight glutenin subunits (HMW-GS) 2 + 12, 3 + 12 or 5 + 10 at the Glu-D1 locus. The results showed that subunits 5 + 10 tend to form a complex gluten network and had a poorly hydrated ability, that prevent the intrusion of external water during cooking; subunits 3 + 12 formed a moderate strength gluten network that generated a medium ability to resist the hydrated and mechanical treatment, which explained the highest water absorption and less cooking loss of cooked noodles; while subunits 2 + 12 formed fragile protein aggregates that had a poor ability to resist mechanical. The findings demonstrated that subunits 3 + 12 provided a suitable gluten network which was crucial for intrusion and hydration of external water thus formed a uniform gluten network and excellent fresh noodle quality.

Insights into the enhancement mechanism of immersion resistance of cooked noodles induced by wheat flour post-ripening: The view from protein cross-linking

To overcome the problem that takeaway noodles possessed poor immersion resistance, in this study noodles were prepared from post-ripened wheat flour, and changes in textural properties, protein components, and water status of noodles were determined. The firmness and tensile distance of noodles were gradually increased by 7.40%-35.88% when wheat flour was post-ripened for 20-40 d. Afterwards, noodle textural qualities were slightly decreased. Compared with control groups, contents of glutenin macropolymer (GMP) and disulfide bonds were significantly (p<0.05) increased and protein network was also more compact, whereas the Glutenin/Gliadin ratio and free sulfhydryl groups content were significantly (p<0.05) reduced. Contents of sodium dodecyl sulfate extractable protein (SDSEP) were reduced by 3.22%-6.23%. Meanwhile, the decrease in A23 indicated that wheat flour post-ripening limited water-absorbing capacity of noodles during immersion. In conclusion, wheat flour post-ripening promoted the immersion resistance of noodles by inducing protein cross-linking, and the best post-ripening time was 20-40 d.

Insight into the mechanism of the aggregation behavior of wheat protein modulated by l-lysine under microwave irradiation

This study explored the mechanism of l-lysine intervention in wheat gluten protein (WG) gel formation under a microwave (MW) field. The results showed that the MW treatment had higher ζ-potential values at the same heating rate. After adding l-lysine, the solution conductivity and dielectric loss were significantly increased. Moreover, the WG gel strength enhanced 4.40% under the MW treatment. The Fourier spectra showed that the α-helix content was decreased 13.78% with the addition of lysine. The ultraviolet absorption spectra and fluorescence spectra indicated that MW irradiation impacted the interactions between WG molecules more effectively than the water bath heating, promoting the denaturation and unfolding of the protein structure. In addition, scanning electron microscopy analysis showed that the incorporation of lysine promoted an ordered network structure formation of the protein, which enhanced the gel properties. This indicated that the zwitterion of l-lysine played a regulatory role in the aggregation of proteins in the MW field.

Understanding the mechanism for sodium tripolyphosphate in improving the physicochemical properties of low-moisture extrusion textured protein from rapeseed protein and soybean protein blends

Our previous experiments found that rapeseed protein (RP) has applicability in low-moisture textured proteins. The amount of RP added is limited to <20 %, but the addition of 20 % RP still brings some negative effects. Therefore, in order to improve the quality of 20%RP textured protein, this experiment added different proportions of sodium tripolyphosphate (STPP) to improve the quality of the product, and studied the physical-chemical properties and molecular structure changes of the product to explore the possible modification mechanism. The STPP not only improved the expansion characteristics of extrudates, but also increased the brightness of the extrudates, the rehydration rate. In addition, STPP increased the specific mechanical energy during extrusion, decreased the material mass flow rate. Furthermore, STPP decreased the starch digestibility, increased the content of slow-digesting starch and resistant starch. STPP increased the degree of denaturation of extrudate proteins, the proportion of β-sheets in the secondary structure of proteins, as well as the intermolecular hydrogen bonding interactions. The gelatinization degradation degree of starch molecules also decreased with the addition of STPP. STPP also increased the protein-starch interactions and enhanced the thermal stability of the extrudate. All these indicate that STPP can improve the physical-chemical properties of extrudate.

Effects of Grinding Methods of Tartary Buckwheat Leaf Powder on the Characteristics and Micromorphology of Wheat Dough

The functional components in tartary buckwheat leaf powder can give flour products higher nutritional value. To comprehensively realize the high-value utilization of tartary buckwheat and its by-products, electric stone mill powder (EMP), ultra-fine mill powder (UMP), steel mill powder (SMP), and grain mill powder (GMP) from tartary buckwheat leaves were used in the preparation of wheat dough, and this was used to explore their effects on dough properties and protein microstructure. With an increase in tartary buckwheat leaf powder, the hydration characteristics, protein weakening rate, and starch gelatinization characteristics of the dough changed, and the water holding capacity and swelling capacity decreased. The retrogradation value increased, which could prolong the shelf life of related products. The water solubility of the dough showed an upward trend and was the lowest at 10% UMP. The addition of UMP produced a more uniform dough stability time and the lowest degree of protein weakening, which made the dough more resistant to kneading. An increasing amount of tartary buckwheat leaf powder augmented the free sulfhydryl content of the dough and decreased the disulfide bond content. The disulfide bond content of the dough containing UMP was higher than that of the other doughs, and the stability of the dough was better. The peaks of the infrared spectrum of the dough changed after adding 10% UMP and 20% EMP. The content of α-helical structures was the highest at 10% UMP, and the content of ordered structures was enhanced. The polymerization of low molecular weight proteins to form macromolecular polymers led to a reduction in surface hydrophobic regions and the aggregation of hydrophobic groups. The SEM results also demonstrated that at 10% tartary buckwheat leaf powder, the addition of UMP was significantly different from that of the other three leaf powders, and at 20%, the addition of EMP substantially altered the structure of the dough proteins. Considering the effects of different milling methods and different added amounts of tartary buckwheat leaf powder on various characteristics of dough, 10% UMP is the most suitable amount to add to the dough.

Impact of pre-meal immersion on multi-scale structural changes and starch digestibility of cooked dried noodles

Pre-meal immersion is a common process for both the consumption of dried noodles and development of takeaway noodles, but its impact on the structure and digestibility of dried noodles is still unclear. In this study, dried noodles cooked for the optimal time were immersed at 80 °C for different time durations. Multi-scale structural changes, including texture, molecular structure, microstructure, and in vitro starch digestibility were studied using a combination of kinetic (first-order exponential decay function, the Peleg model, and LOS plots), physicochemical, and microscopic analysis. The relationship between multi-scale structural changes and starch digestibility was derived. As the immersion progressed, the hardness first rapidly decayed and then reached equilibrium. The decay rate in the initial stage depended on the gluten content. In most cases, the immersion process caused depolymerization of gluten proteins and further gelatinization of starch granules, which was observed from an increase in the free -SH content and decrease in the short-range ordered structure, although there were fluctuations over immersion time. Structural changes resulted in the corresponding changes in substance migration. However, a high gluten content (∼15% w/w) imparted a denser microstructure to the noodles, weakening the deterioration effects compared with a low gluten content (∼10% w/w). In vitro digestion experiments proved that samples with higher gluten content had higher starch digestion rates and lower starch digestion extent during immersion. Correlation analysis revealed that there was a negative correlation between k1 and the tightness of the gel. This study helps to reveal the structural mechanisms of starch digestibility in cooked noodles during immersion.

Effects of glutenin and gliadin on the surface tackiness of frozen cooked noodles

The mechanism of glutenin and gliadin on the surface tackiness of recooked frozen cooked noodles (FCNs) is unclear. In this study, the effects of glutenin and gliadin addition on the surface tackiness of FCNs were investigated. The addition of glutenin and gliadin reduced the surface tackiness (3.60 and 3.50 N) of recooked FCNs stored for 0 min. The addition of glutenin increased the rigidity of the gluten network and the compactness of FCNs and made the FCNs have a moisture-distribution with multilayers. The addition of gliadin increased the tensile distance of FCNs, restricted water migration during frozen storage, and increased the membranous structure of the gluten network to wrap starch particles. Glutenin had a stronger effect on reducing the surface tackiness of FCNs than gliadin. In the future, the synergistic effects of different proportions of glutenin and gliadin on the gluten network of FCNs could be further studied.

Ratiometric fluorescent detection of total phosphates in frozen shrimp samples using catalytic active Zr(IV) modified gold nanoclusters

Phosphate salts are important food additives in a variety of foods. In this study, the Zr(IV) modified gold nanoclusters (Au NCs) were prepared for ratiometric fluorescent sensing of phosphate additives in seafood samples. Compared with bare Au NCs, the synthesized Zr(IV)/Au NCs showed stronger orange fluorescence at 610 nm. On the other hand, the Zr(IV)/Au NCs retained the phosphatase-like activity of Zr(IV) ions and could catalyze the hydrolysis of fluorescent substrate 4-methylumbelliferyl phosphate to produce blue emission at 450 nm. The addition of phosphate salts could effectively inhibit the catalytic activity of Zr(IV)/Au NCs, resulting the fluorescence decrease at 450 nm. However, the fluorescence at 610 nm almost unchanged upon the addition of phosphates. Based on this finding, the ratiometric detection of phosphates using the fluorescence intensity ratio (I₄₅₀/I₆₁₀) was demonstrated. The method has been further applied for sensing total phosphates in frozen shrimp samples with satisfactory results.

Effect of White Kidney Bean Flour on the Rheological Properties and Starch Digestion Characteristics of Noodle Dough

The aim of this study was to investigate the effect of adding white kidney bean flour on the quality of noodles. We selected four different proportions of white kidney bean flour (10−40%) in wheat flour to make the noodles, after which the noodles were analysed for their physical and chemical properties. The statistical method of correlation analysis was used in this study. The results showed that the noodles’ sensory and textural characteristics significantly improved after adding white kidney bean flour (p < 0.05). Compared with the control, the noodles’ surface with white kidney bean flour was denser and smoother. Moreover, microstructural observations indicated that the noodles with white kidney bean flour showed a more continuous protein network. The in vitro digestion results showed that the addition of white kidney bean flour reduced the digestibility of the noodles. Low addition of the flour (10−20%) improved the quality of the noodles, whereas high amounts (30−40%) showed the opposite effect. In this study, the optimal amount of white kidney bean powder was found to be 20%.

The intervening effect of l-Lysine on the gel properties of wheat gluten under microwave irradiation

To improve the quality of wheat gluten (WG) gels, the effect of l-Lysine on gelatin formation of WG under microwave (MW) irradiation was studied. The strength of WG gels treated by MW heating increased significantly (P < 0.05) in the alternating electromagnetic fields with zwitterionic l-Lysine. l-Lysine enhanced the surface hydrophobicity of WG under MW irradiation indicating that the dielectric buffering of l-Lysine changed the conformation of WG. The second structure of WG by Fourier transformed infrared spectroscopy showed that the α-helix content of WG decreased, while the β-sheet content. Furthermore, compared to the non-l-Lysine addition group, the ultraviolet absorption and fluorescence intensity of the WG increased. Scanning electron microscopy presented denser porous network microstructure of WG gels by MW treatment with adding l-Lysine. These results elucidate the regulation effect of l-Lysine on WG gelation in the MW field.

Low-sodium salt mediated aggregation behavior of gluten in wheat dough

Reducing sodium in foods has attracted the attention of consumers, it is therefore necessary to explore sodium alternatives (i.e., low-sodium salt). However, the mechanism of low-sodium salt on gluten in dough remains unclear. Effect of low-sodium salt on the aggregation behaviors of gluten in dough was investigated and compared with those with NaCl and KCl in this study. The results showed that low-sodium salt enhanced gluten strength and prolonged gluten aggregation time. Low-sodium salt decreased the content of SDS extractable protein under non-reducing conditions. Low-sodium salt changed the spatial conformation of gluten by reducing β-turn structure and increasing β-sheet structure. Confocal laser scanning microscopy images indicated that low-sodium salt promoted the formation of a larger and dense gluten network. In summary, this study showed that low-sodium salt promoted the aggregation of gluten in dough, and the change of gluten structure explained this aggregation mechanism. Its mode of action was similar to NaCl and KCl, which provided a theoretical basis for the study of sodium substitutes in flour products.