Three highland barley varieties with distinct amylose-to-amylopectin ratios of 6.62% (22Y-40-6), 20.51% (XZW011), and 44.55% (20-800) were selected to investigate the relationship between starch molecular structure, physicochemical properties, and the eating quality of highland barley kernels. Although all starches exhibited Atype crystallinity, their fine structures differed significantly. The low-ratio starch 22Y-40-6, with a branching degree of 5.15% and a double-helix of 1.06, formed a weak gel network characterized by the lowest G ' and the highest breakdown value of 2377 cP, resulting in cooked kernels with a 46.84% reduction in hardness and the highest rapidly digestible starch content of 24.03%. In contrast, the high-ratio starch 20-800 possessed the thickest lamellae of 10.81 nm-1 and the highest amorphous content of 59.65%, forming a strong gel network with the highest G ' and the lowest breakdown of 970 cP. Its cooked kernels were the hardest at 21.65 N and chewiest at 16.05 N, and contained the highest resistant starch at 53.23%. The moderate-ratio starch XZW-011 showed the highest crystallinity of 26.64% and the most balanced short-range order with a double-helix of 1.14. It exhibited a moderate peak viscosity of 4080 cP, and its cooked kernels achieved optimal texture with a hardness of 14.37 N and adhesiveness of 0.13, along with the highest sensory score of 86.17 and the lowest astringency of 1.34. Correlation analysis confirmed the amylose-to-amylopectin ratio was positively correlated with resistant starch but negatively with eating quality, identifying the moderate-ratio variety as superior, providing a basis for breeding optimized varieties.

To enhance the sensory quality of gluten-free highland barley flour products, this study investigated the effects of incorporating a highland barley flour-zein composite gel (at levels of 0%, 10%, 20%, 30%, 40% and 50%, mass fractions) on the dough processing characteristics and noodle quality. The results showed that with the increase of the addition amount from 0% to 50%, the peak gelatinization temperature of dough freeze-dried powder increased from 76.57 ℃ to 83.58 ℃, the breakdown value decreased from 876.00 cP to 349.67 cP, and the setback value decreased from 1141.00 cP to 816.67 cP. After adding composite gel, the viscoelasticity of the dough was enhanced, and the microstructure also confirmed that zein formed a continuous network structure, and the composite gel network could provide structural support for highland barley dough. Compared with the 0% addition of composite gel, the highland barley noodles with 40% compound gel had good cooking quality and texture characteristics, and the cooking loss of highland barley noodles was reduced by 55.75%, the breakage rate was reduced by 76.67%, the hardness was increased by 58.09 N, and the sensory score was higher than that of the other noodles. In conclusion, the highland barley flour-zein gel network serves as a structural support mechanism in gluten-free highland barley doughs and significantly improves cooking quality in highland barley noodles.

The purpose of this study was to investigate how the gelatinization behavior of pea starch (PS) was affected by pea protein isolate (PPI). The findings revealed that higher PPI levels decreased the swelling power of PS. Incorporating PPI raised the hot paste viscosity of PS, lowered the pasting temperature, and notably increased the gelatinization enthalpy according to differential scanning calorimetry analysis. Furthermore, the presence of PPI reduced the storage moduli of the starch paste, enhanced shear thinning behavior, and hindered starch molecular chain aggregation. With increasing PPI content from 0 to 12 %, amylose leaching and gel strength decreased by 25.6 % and 38.2 % respectively, indicating weak gel formation induced by PPI in PS. Confocal laser scanning microscopy confirmed that PPI envelopment of starch granules restricted their gelatinization by limiting granule swelling. These results carry significant implications for crafting pea-based foods with desired texture.

This study aimed to explore the effects of electron beam irradiation (EBI) at varying doses (2, 4, 6, 8, and 10 kGy) on the functional properties of highland barley rice (HBR), focusing on structural changes in starch and protein. As irradiation doses increased, the water-holding capacity, oil-holding capacity, and swelling degree of HBR significantly improved, while solubility and gelatinization viscosity decreased (p < .05). Analyses using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) demonstrated that higher irradiation doses (>= 6 kGy) disrupted starch granules and promoted aggregation of starch and protein. The crystalline form of starch remains unchanged after irradiation, but the short-range ordered structure is disrupted and the degree of crystallinity is reduced; the beta-sheets content in the secondary structure of proteins decreases while the random coils increases. Thus, the application of EBI at doses ranging from 6 to 10 kGy can be utilised in the modification of starch and proteins. This serves as a theoretical foundation for the application of EBI in the processing of HBR and the enhancement of the properties of starch and proteins.

The absence of viscoelastic gluten networks poses significant challenges in developing highland barley dough products. Inspired by the structural advantages of interpenetrating polymer networks, this study investigated the rheological behavior, thermal properties, microstructural evolution, and intermolecular interactions of microwave-induced starch-zein composite gels, as well as their structural support effects on gluten-free highland barley dough. The results demonstrated that increasing zein content (0-40 %) enhanced the viscoelasticity and deformation resistance of composite gels, with gel strength showing a 106.5 % improvement at 40 % zein incorporation compared to the control. Microstructural analysis confirmed that mutual interpenetration between starch and zein matrices through molecular entanglement, forming a stronger three-dimensional composite gel network structure. Molecular dynamics simulation indicated that hydrogen bonding dominated the starch-zein interactions, accounting for the enhanced thermal stability of the composite gel system. Dough structural characteristics demonstrated that the starch-zein composite gel network tightly integrated with highland barley flour, effectively transferring its viscoelasticity and extensibility to the gluten-free dough, thereby improving the dough's resistance to external forces. This study confirmed that starch-zein composite gel networks could serve as structural support for gluten-free highland barley dough, providing theoretical support for developing highland barley products.

The objective of this study was to assess the differences in the quality of fried potato fries across various potato varieties(lines)in Qinghai Province,as well as to identify suitable potato varieties(lines)for the production of fried potato fries.Twenty-one representative potato varieties(lines)were selected as raw materials for the production of fried potato fries,and then their fundamental nutritional attributes and quality characteristics were evaluated.The suitability of the fried potato fries was assessed using principal component analysis,correlation analysis,and iterative clustering.The results revealed considerable differences in the nutritional indicators among different potato varieties(lines)in Qinghai Province.Principal component analysis identified five principal components,which accounted for 86.43%of the cumulative variance contribution rate.Leveraging the comprehensive scores from iterative clustering,three suitable potato varieties(lines)for processing fried potato fries were identified,namely,Qingshu 15,Qingshu 14,and Qing 11-2-9.Evaluation of their palatability characteristics demonstrated that the fried potato fries exhibited a crispy exterior and tender interior texture(sensory score of 62～73),favorable chewiness(52～53),and bright color(a* value of 4.0～6.5),aligning with practical applications.The results achieved efficient utilization of potato processing in Qinghai Province,which could meet consumer demand,and provided a theoretical basis for potato quality improvement and special variety breeding.

The purpose of this study was to investigate the effects of different structures of corn starch(high amylose corn starch,normal corn starch,and waxy corn starch)on the processing quality of dough.The rheological properties,thermal properties,microstructure and physicochemical properties of gluten proteins in the simulated dough of corn starch were determined.The results showed that the viscoelasticity of the high-amylose corn starch mock dough was significantly higher than that of the normal/waxy cornstarch mock dough,which was attributed to its non-gelatinization and highly filling characteristics.Waxy corn starch significantly inhibited the thermal aggregation of gluten proteins through competitive water absorption,resulting in a relatively loose structure of the dough after heat treatment.The results of molecular weight distribution and intermolecular interactions also confirmed that waxy corn starch mainly inhibited the formation of high molecular weight gluten proteins by hindering the crosslinking of disulfide bonds,leading to the transition of gluten proteins from a rigid a-helix to a disordered β-turn structure.This study helps to gain a deeper understanding of the interaction mechanism between starch and gluten proteins,and provides a reference for improving the processing quality of flour products by regulating the structural characteristics of starch.

Summary This study examined changes in heat‐induced gluten proteins, focusing on their structure, physicochemical properties, and molecular analysis. The results demonstrated that gliadin had a high denaturation temperature (68.04 °C) and minimal aggregation during heating (25 °C–95 °C), yet it hindered thermal reaction progress of gluten effectively. Heating caused a shift from α‐helical structure to random coil and β‐turn structures, with a decrease in fluorescence intensity. High temperature reduced sulphydryl groups in gluten and glutenin, reaching 0.64 and 0.58 mmol L −1 , respectively. However, the content of sulphydryl groups in gliadin remained relatively stable at around 0.37 mmol L −1 . Notably, the configuration of disulphide bonds in gliadin, particularly in the g‐g‐g configuration, displayed greater stability. Microstructure analysis revealed increased compactness in all protein fractions as temperature rose. Overall, gliadin had greater thermal stability, impeding glutenin aggregation and gluten network formation. These findings provide valuable insights for cooking, processing, and storage of gluten proteins.

This study evaluated the effects of starch with varying degree of debranching on the rheological, thermal, and structural properties of heat-induced gluten gel. As the duration of starch debranching treatment increased from 0 to 8 h, the viscoelasticity of the gel containing debranched starch (DBS) improved. Compared with the gluten gel (G), the gel strength of the G + DBS (8 h) sample increased by 65.2 %. The degradation temperature of gluten was minimally affected by DBS, while the weight loss rate increased by 4.4 %. Furthermore, the alpha-helical structure of gluten decreased, concomitant with an increase in beta-sheet content. Notably, DBS treated for 8 h exhibited more hydrogen bonds with the tyrosine of gluten and triggered disulfide bridge conformation to transition from g-g-g to t-g-g, thereby reducing the stability of the molecular conformation of gluten proteins, as evidenced by the decreased height and width of the molecular chains observed in atomic force microscopy images. Overall, the composite gel structure induced by DBS exhibited a more continuous and homogeneous owing to the improved compatibility between DBS and gluten proteins, favoring the formation of a robust gel. These findings provide valuable insights for utilizing DBS to enhance gluten gel properties.

BACKGROUND:Understanding the interactions between protein and starch is crucial in revealing the mechanisms by which protein influences starch digestibility. The present study investigated the impact of different contents of pea protein isolate (PPI) on the physicochemical properties and digestibility of pea starch (PS). RESULTS:The results demonstrated that as the content of PPI increased from 0% to 12%, and the digestion of PS decreased by 12.3%. Rheological analysis indicated that PPI primarily interacted with molecular chains of PS through hydrogen bonds. Increasing the content of PPI resulted in a 30.6% decrease in the hardness of the composite gels, accompanied by a 10% reduction in the short-ordered structure of PS. This hindered the formation of molecular aggregation and resulted in a loose and disordered gel network structure. The microstructure confirmed that the attachment of PPI to PS served as a physical barrier, impeding starch digestibility. CONCLUSION:In summary, the primary mechanism by which PPI inhibited PS digestion involved steric hindrance exerted by PPI and its interaction with PS via hydrogen bonds. These findings contribute to a better understanding of the interaction mechanisms between PS and PPI and offer insights for the optimal utilization of pea resources. © 2024 Society of Chemical Industry.

Chenopodium quinoa Willd. is rich in phenolic compounds and exhibits diverse biological activities. Few studies have focused on the effect of colored quinoa’s phenolic profile on potential biological activity. This study used a UPLC–MS/MS-based metabolomic approach to examine the quinoa phenolics and their association with in vitro antioxidant and hypoglycemic properties. In total, 430 polyphenols, mainly phenolic acids, flavonoids, and flavonols, were identified. Additionally, 121, 116, and 148 differential polyphenols were found between the white and black, white and red, and black and red comparison groups, respectively; 67 polyphenols were screened as shared key differential metabolites. Phenylalanine, tyrosine, and the biosynthesis of plant secondary metabolites were the main differently regulated pathways. Black quinoa had better total phenolic contents (643.68 mg/100 g DW) and antioxidant capacity, while white quinoa had better total flavonoid contents (90.95 mg/100 g DW) and in vitro α-amylase (IC50 value of 3.97 mg/mL) and α-glucosidase (IC50 value of 1.08 mg/mL) inhibition activities. Thirty-six polyphenols, including epicatechin and linarin, etc., were highly correlated with in vitro antioxidant activity, while six polyphenols, including tiliroside and chrysoeriol, etc., were highly correlated with in vitro hypoglycemic activity. This study may provide important information for colored quinoa resources to develop their healthy food applications.

The study investigated the impact of pea protein isolate (PPI) on the short-term and long-term retrogradation behavior of pea starch (PS). Dynamic time scanning and water migration analysis revealed that the presence of PPI enhanced water mobility within the PS gel during short-term storage (4 degrees C, 8 h) and impeded amylose gelation, effectively suppressing the short-term retrogradation of amylose. Over long-term storage (4 degrees C, 14 d), PPI reduced the retrogradation enthalpy and the ordered structure of starch molecules. The relative crystallinity and retrogradation degree reduced by 40.6% and 29.9%, respectively, as the PPI content increased from 0 to 12%. Textural profile analysis showed PPI decreased the gel hardness and induced the formation of a weak gel of PS, thereby delaying the long-term retrogradation of amylopectin. Scanning electron microscopy analysis further confirmed that the PS-PPI mixed gel exhibited a more disordered and loose structure compared to the PS gel, which resulted from PPI inhibiting the rearrangement and aggregation of amylose and amylopectin molecules. These findings suggested that PPI exhibited the potential to inhibit the short-term and long-term retrogradation of PS, thus providing valuable theoretical evidence for enhancing the development and research of pea -based products.

淀粉回生是影响预制饸饹品质的关键因素,研究冷藏过程中淀粉回生机制对于预制荞麦饸饹实现工业化生产具有重要意义.将预煮后的荞麦饸饹在 4℃分别冷藏 0d、1 d、3d、5d、7d,对其水分分布、晶体结构、短程有序结构,以及复热后质构特性、微观结构及感官特性进行分析.结果表明,冷藏时间从 0d至 7d,水分含量降低 3.87%,强结合水逐渐转化为弱结合水和自由水.硬度从 288.21 g增加到 338.02 g,拉伸力从 24.34 g降低到 11.13 g.预制荞麦饸饹中淀粉分子之间交联加剧,导致其相对结晶度增加 11%,分子的短程有序度增大.扫描电镜结果显示,冷藏 7d后的预制荞麦饸饹内部网络结构断裂,孔洞逐渐缩小且不均匀.冷藏导致了预制荞麦饸饹感官品质的总分从 87.75 下降到 76.10.根据研究结果及感官评价分析,预制荞麦饸饹按照传统工艺适合开发为冷藏 3 d 的短保产品.上述研究结果可为提高预制荞麦饸饹品质稳定、实现工业化生产提供理论基础.

Understanding the interplay between gluten and wheat starch is crucial for elucidating the digestibility mechanism of gluten in wheat-based products. However, this mechanism remains under-investigated. This study sought to elucidate the influence of starch-induced protein structural modifications on gluten digestion. Our findings revealed that starch considerably enhanced gluten digestion. In the presence of starch, gluten protein digestibility increased from 10.91 % (in the control group with a gluten-to-starch ratio of 1:0) to 14.40 % (in the complex with a gluten-to-corn starch ratio of 1:1). The diminished gluten protein digestibility due to starch may be ascribed to modifications in protein configuration and aggregation behavior. Morphological studies suggested that starch not only functioned as filler particles but also diluted the gluten matrix. A protein network assessment further affirmed that both the junction density and branching rate of gluten proteins decreased notably by 29.9 % and 25.1 %, respectively. Conversely, lacunarity increased by 1.92-fold, compromising the cohesiveness and connectivity of the gluten matrix. Elevated starch concentrations suppressed the formation of disulfide bonds, impeding gluten protein aggregation. Concurrently, gluten-starch interactions were governed by hydrogen bonds and hydrophobic associations. In summary, starch augmented gluten protein digestibility by curtailing their polymerization. This revelation might offer novel perspectives on optimizing gluten protein digestion and utilization.

The objective of this study was to investigate the effect of pH-shifting on the textural and microstructural properties of mung bean starch (MBS)-flaxseed protein (FP) composite gels. Results showed that different pH-shifting treatments caused changes in hydrogen bond interactions and secondary structures in composite gels, leading to the formation of loose or compact gel networks. The pH 2-shifting modified protein and starch molecules with shorter chains tended to form smaller intermolecular aggregates, resulting in the formation of a looser gel network. For pH 12-shifting treatment, conformational change of FP caused the unfolding of protein and the exposure of more hydrophobic groups, which enhanced the hydrogen bond and hydrophobic interactions between polymers, contributing to the formation of a compact gel network. Furthermore, pH 12-shifting improved the water-holding capacity (WHC), storage modulus, and strength of gels, while pH 2-treated gels exhibited lower WHC, hardness, and gumminess due to the degradation of MBS and denaturation of FP caused by extreme acid condition. These findings suggest that pH-shifting can alter the gel properties of bi-polymeric starch-protein composite systems by affecting the secondary structures of proteins and the hydrogen bonding between the polymers, and provide a promising way for a wide application of FP in soft gel-type food production.

【Objective】Ethylene is an important plant hormone that has a key influence on the quality and shelf life of fruit.In this study,zein was modified to transform into a stretched structure and consequently expose its internal active functional groups by the high-field intensity ultrasound treatment （HIU）.Numerous functional groups （-SH） exposed in modified zein film could rapidly react with ethylene via a click reaction,resulting in an extended shelf life of the fruit.【Method】The 5 g zein was dissolved in acetic acid-DI water （4:1） solution.The zein solutions were sonicated for 0,5,15,and 30 min at an ultrasonic power of 400 W and dried in a drying oven at 40℃for 24 h to obtain the zein-0 film,zein-5 film,zein-15 film,and zein-30 film.The structures of zein before and after HIU treatment were analyzed by circular dichroism spectroscopy,endogenous fluorescence,particle size potentiometer,and scanning electron microscope.The mechanical and ethylene adsorption properties of zein-based films were characterized by the texture analyzer and the VOC detector.Bananas were used as the climacteric fruit samples to investigate the effectiveness of the zein films as ethylene scavengers.The ultrasonic treated zein film and banana samples were placed in the same plastic sealing bag and then stored at room temperature for 10 d.The performance for extending shelf life was evaluating by browning rate,the flesh hardness,and the weight loss rate of bananas.【Result】The HIU treatment （20 kHz,400 W,15 min） could effectively stretch the structure of zein.The particle size of the zein and the content of the α-helix were decreased to 1 013.3±6.9 nm,and 45.86%,respectively,and the content of the β-sheet increased to 12.20%.Compared with the zein-0 film,the ethylene adsorption capacity and oxygen resistance of the zein-15 film were increased by 9.486 mg·m -3 ·h -1 and 0.75×10 -16 kg·m·m -2 ·s -1 ·Pa -1 ,respectively.The results including the browning rate,the flesh hardness,and the weight loss rate of bananas indicated that the zein-15 film could effectively extend the shelf-life of bananas.【Conclusion】The HIU treatment （20 kHz,400 W,15 min） could effectively induce to stretch the zein structure and expose more functional groups,resulting in an improved ethylene adsorption performance of zein.The zein-15film presented a better ethylene adsorption capacity,oxygen permeability,and mechanical property,leading to an extended shelf life of bananas and its life as the ethylene scavenger.

Summary The objective of the study was to investigate the configurational changes and aggregation mechanism of wheat gluten induced by sodium chloride (NaCl) and sodium carbonate (Na 2 CO 3 ). The results showed that NaCl shielded surface charges of gluten, developed more hydrogen bonds with tyrosine, and stabilised the secondary structure, while Na 2 CO 3 promoted significant transition of the secondary structure from random coils and β‐turn to β‐sheet. Both NaCl and Na 2 CO 3 quenched tryptophan fluorescence and promoted the aggregation of gluten subunits, where Na 2 CO 3 induced covalent bond formation other than disulphides and facilitated gluten network development. Atomic force microscopy images confirmed different molecular surface features in gluten network. In conclusion, both NaCl and Na 2 CO 3 demonstrated the ability to promote rheology, aggregation, and network formation of gluten but different molecular mechanisms were involved. This work provides valuable insights for the processing of salted and alkaline noodles.

The frozen preservation quality of dough cannot meet the requirements of industrial production of fresh and wet noodles. To investigate the effect of the main dough components (gluten protein and starch) on the quality of the frozen dough, dough restructuring with high gluten wheat flour (50%) and different proportions of gluten and wheat starch, and the water distribution, rheological properties, pasting characteristics, gel strength, microstructure and hydrogen bond strength were analyzed after freezing storage at 18 ℃ for 20 days, with 100% raw wheat flour as the control group. The results showed that the water in the frozen reconstituted dough gradually migrated from bound water to free water, and the elastic modulus decreased from 125900 Pa to 73020 Pa as the ratio of gluten to wheat starch decreased from 4:1 to 1:4, the pasting parameters increased, andgel hardness from 114.30 g to 181.39 g. Scanning electron microscope showed that the lower the ratio of gluten to wheat starch, the more unfavorable the uniformity of the gluten protein network structure. The hydrogen bond strength in the reconstituted dough was greater than that in the control group after adding gluten and wheat starch, and it continued to increase as the ratio of gluten to wheat starch decreased. When the ratio of gluten to wheat starch was 4:1, the elastic modulus of the reconstituted dough frozen for 20 days was 49.95% higher than that of the control group, which delayed the quality deterioration of the dough during the frozen storage. Reconstituting the dough with a certain ratio of starch to gluten can improve the viscoelasticity of the dough, which was beneficial to its cryopreservation quality.

The purpose of this study was to evaluate the influence of reconstituted gluten fractions (RGF) with varied glutenin/gliadin (glu/gli) ratios on short-term and long-term retrogradation of wheat starch (WS). Adding RGF, irrespective of glu/gli ratio, effectively inhibited the retrogradation behavior of WS. Lower storage modulus and higher water mobility during storage at 4 degrees C for 8 h suggested that gliadin could restrain the short-term retrogradation of amylose more evidently than glutenin. During storage for 28 d, increasing glutenin could reduce the retrogradation enthalpy and relative crystallinity of starch. Retrogradation degree of gliadin alone-treated WS was 14.0% higher than that of glutenin alone-treated sample, indicating that glutenin was superior in retarding long-term retrogradation of amylopectin. Furthermore, glutenin produced a more disordered gel structure, which was attributed to its inhibition of amylopectin aggregation at the nanoscale. This study suggested that by adjusting glu/gli ratios in RGF, the shelf-life of wheat-based products during short-term and long-term storage could be prolonged.

Mungbean starch (MBS)-flaxseed protein (FP) composite gels were prepared to explore the feasibility of developing soft gel food products. The mixtures of 8% MBS with 1%-4% FP formed smooth and soft-textured gels. Elasticity modulus and hardness of gels decreased with the increase of FP content, e.g., the hardness value reduced from 2.39 N for MBS alone gel to 1.00 N for composite gel (8% MBS+4% FP). The MBS-FP composite gels exhibited a microstructure in which FP granules were imbedded within the continuous MBS network, and the cross section showed a rough and irregular structure. Furthermore, the composite gel of 8% MBS+4% FP had a higher digestibility (53.3%, 2 h) than the MBS-alone gel (30.5%, 2 h). Mechanistically, amylose was released from MBS when heated and formed a three-dimensional network when cooled. Meanwhile, partially unfolded FP molecules were encapsulated in starch network to form semi-interpenetrating gel network. Therefore, MBS-FP composite gels can be prepared as novel, gelled food with a range of soft texture to meet the demand of different consumers, especially for those with swallowing challenges.