Study on starch-protein interactions and their effects on physicochemical and digestible properties of the blends

Incorporating maltitol regulates the gel properties and structural features of κ-carrageenan-corn starch-soy protein isolate based quaternary system and its application of low glycemic index gummies

This study investigated the structure and gel features of maltitol-κ-carrageenan-corn starch-soy protein isolate quaternary system under the different maltitol addition (5 %-25 %), and evaluated the glycemic index (GI), digestibility, sensory and texture properties of gummies prepared based on this system. As maltitol incorporation increased, gelatinization temperature raised from 69.87 °C to 97.77 °C but the enthalpy value decreased from 8.40 J/g to 2.39 J/g. The quaternary complexes also showed structural changes, and there was the highest uniform of the dense gel network structure, the highest content of the short-range ordering structure, and the lowest crystallinity degree after the 20 % incorporation of maltitol. However, the textural properties (e.g., hardness, chewiness, gumminess and cohesiveness) and gel strength of the quaternary gels decreased, resulting from the formation of the weaker gel. Additionally, gummies at 20 % maltitol incorporation exhibited a low GI (33.38) value, digestibility and the desired sensory and texture characteristics.

Comparison of annealing and heat-moisture modification on effects of Tartary buckwheat starch under plasma-activated water condition

This study investigated the effects of plasma-activated water (PAW) assisted annealing and heat-moisture treatment (HMT) on the physicochemical, structural properties, and in vitro digestibility of Tartary buckwheat starch (TBS). The results showed that there were much aggregates on the surface of starch granules under annealing and HMT conditions, it was more pronounced when subjected in PAW. The modified starches showed higher R1047/1022 and pasting temperature, which led to reducing digestibility of TBS. Notably, the highest resistant starch content (71.08 %) was observed with PAW-HMT under the moisture content of 30 %. In addition, all the modified starches remained A type pattern except HMT and PAW-HMT samples, which displayed an A + V type pattern. Therefore, TBS was more sensitive to the combined HMT and PAW treatment. These findings offered valuable insights into the application of PAW combined with thermal treatments to enhance the quality of TBS in the utilization of functional foods.

Study on the influence mechanism of raw potato flour on the stability of ketchup

Some raw potato flour has thickening properties, but its mechanisms and application in food systems are unclear. This study aims to investigate the difference between raw potato flour with thickening potential (RWT) and raw potato flour without thickening potential (RWOT) in application performance and the stability mechanism of RWT for ketchup. Results showed that the RWT has better rheological stability, less swelling power, lower amylose leakage (12.86-13.67 g/100 g), and higher solubility than RWOT. Water molecule movement results indicate that non-starch polysaccharides present in RWT compete water with starch and tomato pulp, enhancing the thermal stability of RWT during ketchup preparation and water retention of ketchup. This clarifies, improving ketchup's viscosity and stability. The application effect of adding RWT is comparable to that of incorporating modified starch into ketchup. Overall, RWT exhibit and can be effectively utilized in the ketchup.

Investigation of self-assembly mechanism of gluten protein amyloid fibrils and molecular characterization of structure units

The mechanism of peptides self-assembly into gluten amyloid fibrils was explored through bond-breaking experiments and molecular dynamics (MD) simulations, verified through fibrillation experiments using synthetic peptides. The disruption of hydrogen bonds reduced thioflavin T fluorescence intensity and average particle size of gluten amyloid fibrils by 24 % and 81 %, respectively, causing a breakdown of internal structure. Disruption of electrostatic and hydrophobic forces induced further aggregation of fibrils. MD simulation revealed that peptides transitioned from a dispersed state to aggregation, followed by changes in secondary structure, culminating in the formation of stacked β-sheets structure units. Hydrogen bonding emerged as the primary driver of self-assembly with contributions from hydrophobic and electrostatic interactions. The synthetic single or hybrid peptide systems selected by MD formed ribbon- or fiber-like amyloid fibrils with inter-strand distance of 4.7 Å and respective inter-sheet distances of 10.2 Å and 10.8 Å, suggesting that the structure and morphology of eventual amyloid fibrils were affected by the peptide sequence and cross β-sheet structure units.

The morphologies, physicochemical properties and sustained-release features of short amylose/WPI modified by DBD plasma-rutin nanocomplex

To further improve the sustained-release feature of whey protein isolate (WPI) modified by dielectric barrier discharge (DBD) plasma (DWPI) for rutin, short amylose (SA) was used to fabricate DWPI/SA-rutin ternary complex. The physicochemical properties of complexes with different DWPI/SA ratios were investigated and compared. The results showed that the ternary complex nanoparticles gradually tended to be spherical and increased in particle size with the increase of the SA addition. The primary interaction forces between DWPI and SA were hydrogen bond, electrostatic and hydrophobic interactions, which made the ΔH of ternary complex be increased by 649.71 % when the DWPI/SA ratio was 1:1, and the radical scavenging activities of rutin significantly be improved. The cumulative release rate of rutin in the ternary complex was only 27.11 % when the ratio of DWPI/SA was 1:4 after oral and stomach digestion. The research provided a new method for fabricating starch/protein nanocarriers with a sustained-release effect.

Effect of exogenous protein crosslinking on the physicochemical properties and in vitro digestibility of corn starch

Starch is a primary energy source of human diet. Its physicochemical properties and digestibility can be improved by incorporating exogenous protein. In this study, mung bean protein isolate was covalently crosslinked using transglutaminase and proanthocyanidin to create crosslinked mung bean protein isolate. This modified protein was combined with corn starch to form crosslinked mung bean protein isolate-corn starch composite samples. Results demonstrated that these composite samples exhibited superior physicochemical properties, including reduced swelling capacity, enhanced freeze-thaw stability, improved thermostability, and enhanced antioxidant properties. During in vitro digestion, the improved corn starch digestibility was attributed to two factors: first, hydrogen bonding and electrostatic interactions between crosslinked mung bean protein isolate and corn starch; and second, the synergistic crosslinking of transglutaminase and proanthocyanidin promoting the formation of a stable protein network of mung bean protein isolate, serving as a physical barrier to protect corn starch. After co-treatment with transglutaminase and proanthocyanidin, significant changes of mung bean protein isolate occurred in their secondary and tertiary structures, enhancing its protein network strength, thereby improving the physicochemical properties of corn starch. These findings propose a new strategy for reducing rapidly digestible starch and provide a theoretical foundation for developing low glycemic index starch foods.

Effect of endogenous protein on starch before and after post-harvest ripening of corn: Structure, pasting, rheological and digestive properties

This work revealed the effects of endogenous proteins on the structural, physicochemical, and digestive properties of starch in corn before and after ripening and explored the binding mechanism of proteins with starch. The microstructure showed that the postharvest ripening process resulted in a thinning of the protein layer on the surface of starch particle. After the removal of protein, the uniformity of the sample surface increased, with tiny pores. The proportion of double helix structure of starch were significantly reduced, while the proportion of amorphous structure and the thickness (da) of the amorphous region were significantly increased. The gelatinization enthalpy, gelatinization viscosity value, consistency coefficient, elasticity, and rapid digestibility of starch (RDS) were all significantly increased. Due to the weakening of the interaction between starch (including amylose and amylopectin) and protein in post-ripened corn, the effect of protein removal on the structure and properties of unripened samples was more significant.

Mechanism of the effect of mixing guar gum and fish collagen peptide with rice on in vitro digestibility, gastric emptying and postprandial response

This study investigated the effects of adding guar gum (GG) and fish collagen peptide (FCP) during rice cooking on postprandial blood glucose and satiety of rice and the related mechanisms. The results showed that the combined intervention of GG and FCP (GG-FCP) significantly reduced the postprandial blood glucose levels. The GG increased the viscosity of the digesta, and the physical barrier of GG and FCP formed on the surface of the rice limited the disintegration of the rice granule. The chyme containing GG and FCP displayed a larger particle size and gastric emptying were delayed. GG-FCP alleviated the digestion rate of rice, with the rapidly digestible starch content decreasing from 77.68 % to 65.01 %. Low-field nuclear magnetic resonance (LF-NMR) analysis indicated the GG and FCP reduced the binding water content of starch. DSC analysis showed that the addition of GG and FCP reduced the enthalpy of gelatinization of rice flour from 5.87 to 3.13 J/g, and the gelatinization degree of the rice flour was reduced. This study investigated the mechanisms of exogenous additives in regulating rice digestion and postprandial response. The findings would provide evidence-based strategies for developing rice products with the potential to mitigate the effects of blood glucose.

Innovative use of camel whey proteins, quercetin, and starch as ternary complexes for emulsion stabilization at the Micro and Nano scale

Protein-polyphenol and polysaccharide complexes have gained ample research interest as natural emulsifiers. Covalent camel whey protein-quercetin (WQ) conjugates and their non-covalent complexes (WQS) with starch would enhance the stabilization of micron (ME) and nano-size emulsions (NE). Fabrication of WQ conjugates and WQS complexes was followed by their characterization using spectroscopic and electrophoretic techniques. Emulsions stabilized by these compounds were evaluated through microscopy, droplet size analysis, rheology, and oxidative stability assays. Production method and WQS incorporation were considered as variables in the experimental design. Results showed that WQ-conjugate-stabilized emulsions exhibited superior stability compared to control, regardless of the production method. WQS incorporation improved stability, especially in nano emulsions. Covalent-WQ-conjugates outperformed WQS in stabilizing micron emulsions. Starch concentration influenced oxidative stability, with higher concentrations in ternary complexes correlating with decreased stability. These findings underscore the potential of WQ covalent conjugates and WQS ternary complexes to enhance camel whey proteins' emulsifying properties for functional foods.

Molecular mechanism of taurine promotes the interaction between rice starch and soy lecithin

This study investigated how taurine zwitterions modulate the interaction between rice starch and soy lecithin in hydrothermal systems, aiming to overcome the low embedding efficiency observed in traditional methods. Significantly, we achieved a peak starch-soy lecithin complex index (CI) of 69.16 %, which was crucial in demonstrating the effectiveness of our approach. Through advanced analytical techniques like Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and 1H Nuclear Magnetic Resonance Spectra (1HNMR), we elucidated the molecular mechanism. It was revealed that taurine disrupted hydrogen bonds among starch molecules, leading to increased amylose dissolution. Consequently, the molecular interaction between rice starch and soy lecithin was enhanced. Moreover, the addition of taurine enhanced the thermal stability of the complex, increased the content of resistant starch (RS) by 16 % and slowly digestible starch (SDS) by 14 %, while reducing solubility and swelling 5.12 by % and 6.05 % respectively. These findings hold great promise for practical applications in the food industry, including the development of functional foods with improved nutritional profiles and enhanced stability during processing.

Freeze-thaw pretreatment improved the anti-digestibility and viscosity of corn starch/type-A gelatin complexes

Slowly digestible starches, known to confer health benefits, are often prepared via compounding with other substances. However, starch complexes often encounter problems such as low viscosity. This work aimed to develop a corn starch/type-A gelatin (CS/GA) complex that simultaneously exhibited rapidly digestible starch (RDS) reduction, and superior viscosity. The pH and drying temperature of the complexes were systematically optimized, and a novel freeze-thaw pretreatment (FTP) technique was innovatively introduced. This work investigated the effects of varying FTP cycles (ranging from 0 to 8) on the physicochemical properties of CS/GA complexes. Results showed that FTP significantly enhanced the viscosity of the complexes while effective RDS reduction. Notably, after six FTP cycles, the complexes attained optimal properties, characterized by the highest the complex index (CI), relative crystallinity (RC) and short-range molecular order, accompanied by the lowest RDS reduction of 46.24 %. The multivariate analysis revealed CI as the crucial parameter for altering the resistant starch (RS) content. Furthermore, FTP induced cracking on the surface of starch particles was observed. In conclusion, these results were of significance for developing CS-based food materials with RDS reduction, and high viscosity characteristics, such as noodles, corn porridge and sausage.

Impact of octenyl succinic anhydride esterification on Kodo millet starch-commercial protein blends functionality and Pickering emulsion properties

This study was designed to investigate the morphological, structural, rheological, functional, and emulsifying properties of native (NKS) and octenyl succinic anhydride (OSA)-esterified Kodo millet starch (EKS) blended with commercial pea protein (PP), soy protein (SP), and whey protein (WP). The effects of esterification and blending on the stabilization of oil-in-water Pickering emulsions were also evaluated. Morphological analysis revealed significant starch-protein interactions, causing deformation and surface irregularities in the NKS and EKS blends, with stronger interactions in the esterified blends due to hydrophilic and hydrophobic forces. Structural characterization revealed similar crystalline structures in starch-protein blends, with increased X-ray diffraction peaks after protein addition. However, esterification reduced the pasting temperature (PT) from 88.80 °C (NKS) to 83.25 °C (EKS), and protein addition further decreased the PT by 0.5-4.80 % for the NKS blends and 0.25-1.62 % for the EKS blends, indicating reduced swelling resistance and thermal stability. Rheological tests of starch-protein blend suspensions revealed shear-thinning flow and elastic-dominant (G' > G") behavior, with EKS-protein blends exhibiting stronger gel networks. NKS-protein blends had relatively high water absorption capacities (2.37-2.43 g/g), whereas EKS-protein blends showed higher oil absorption capacities (2.32-2.37 g/g). The emulsifying activity index (11.03 to 12.76-16.21) and emulsifying stability index (70.49 min to 93.85-99.62 min) increased after blending, with Pickering emulsions remaining stable for a minimum of two weeks. However, emulsion stability was highest for the EKS-SP blends, which remained stable for up to 25 days. Overall, the esterification of starch increased its compatibility with proteins, leading to improved emulsifying properties and more stable emulsions.

Enhancing the texture and modulating digestive behavior of gluten-free quinoa sponge cakes via microwave-assisted alkaline amino acid treatment

This study investigated the effects of microwave treatment combined with lysine and arginine on gluten-free quinoa sponge cakes. The results indicated that the addition of these amino acids during microwave treatment significantly increased the cakes' specific volume by 49 %. X-ray diffraction analysis revealed that cake crystallinity reached 56.23 % and 49.17 % when lysine and arginine were used, respectively. Fourier Transform Infrared spectroscopy showed confirmed the absence of new functional groups or chemical bonds under different treatments, but the absorbance ratio at 1047 cm-1 to 1022 cm-1 was higher in microwave-treated cakes with lysine compared to traditionally steamed cakes. Simulated digestion experiments demonstrated that microwave-treated cakes, especially with added amino acids, exhibited higher protein digestibility but lower starch digestibility. Confocal Laser Scanning Microscopy observations further showed that proteins formed a denser network structure around starch granules during in vitro digestion, suggesting improved protein functionality and structure in microwave-treated quinoa sponge cakes.

Extrusion-aided interaction of rice starch with whey protein isolate: Synergistic influence on physicochemical properties and in vitro starch digestibility characteristics

Synergistic influence of extrusion conditions and whey protein isolate (WPI) incorporation on glycemic response and physicochemical characteristics of rice starch was studied. Box-Behnken Design was used to evaluate effect of process variables (rice starch:WPI ratio; feed moisture and barrel temperature) on quality characteristics of resistant starch-rich, low GI extruded snacks (RSLG-E). Optimum conditions for development of RSLG-E were WPI:18.30 %, feed moisture:20 % and barrel temperature:120 °C. FTIR spectroscopy showed maximum peaks at 1615 cm-1 and 1540 cm-1 corresponding to presence of amide group; however, such band was absent in control. Thermal analysis indicated significantly higher transition temperatures in RSLG-E than control. Expansion ratio (3.79 ± 0.17) and overall acceptability (4.48 ± 0.05) were found to be significantly lower in RSLG-E. In vitro digestibility indicated significantly lower very rapidly digestible starch (2.08 ± 0.03 %) and rapidly digestible starch (68.49 ± 1.07 %) in RSLG-E than control. Digestible starch (86.85 ± 0.97 %), starch hydrolysis rate (58.72 ± 0.97 %) and slowly digestible starch (72.61 ± 0.82 %) were lower in control.

Effects of rolling on eating quality, starch structure, and water distribution in cooked indica rice dough

BACKGROUND

Given the composition of rice and its lack of gluten proteins, rice flour fails to form a cohesive and elastic dough when mixed directly with water. Consequently, many rice products rely on rice sheets (RS) made by rolling cooked rice dough. Limited research exists on how the rolling process impacts the properties and structure of cooked indica rice dough.

RESULTS

This study investigated the effect of the number of rolling passes on the eating quality, starch structure, and water distribution of cooked fermented indica RS formed by dough. When the number of rolling passes reached six, the RS (RP-6) that was obtained exhibited the lowest cooking loss, the highest hardness, adhesiveness, and chewiness, and optimal stretchability. It also demonstrated the lowest water loss after freezing. Dense microstructures were observed on both the surface and cross-section of RP-6. More ordered starch crystal structures and double helix structures were formed. The relative peak area of tightly bound water significantly increased in RP-6, indicating a stronger bonding status between the starch and water molecules. However, excessive rolling passes (more than six) led to a partial disruption of the internal RS structure, resulting in a decline in eating quality.

CONCLUSION

The study demonstrated the importance of the rolling process in improving the performance of RS. It was found that a moderate number of rolling passes was conducive to producing excellent RS, providing a theoretical basis for the production of high-quality rice-based products such as rice noodles, dumplings, and cakes. © 2024 Society of Chemical Industry.

Leguminous proteins as beneficial baking emulsifiers: A comparative study with traditional sucrose ester

In recent years, pursuing healthier and more sustainable food ingredients has increased interest in plant-based alternatives to traditional synthetic emulsifiers. In this study, the properties of five legume proteins: soybean protein isolate (SPI), pea protein isolate (PPI), black bean protein isolate (BBPI), white Canavalia protein isolate (WCAI), and white kidney bean protein isolate (WKBPI) were compared with that of the conventional emulsifier sucrose ester (SE), and add them as emulsifiers to the cake making process. The centrifugal instability index of SPI stabilized emulsion (0.11) was close to that of SE stabilized emulsion (0.08). The foaming performance of WKBPI (85 %) and BBPI (82 %) is 4 times that of SE (20 %).In the simulated cake paste system, the gelatinization temperature of the cake paste with PPI was increased by 0.49 °C compared with that of the blank group and the gelatinization enthalpy decreased by 57.8 % compared with the blank cake paste system. As temperature increases, the viscoelastic curve of the batter with legume protein exhibits an initial decrease followed by a subsequent increase. The above changes are expected to have a positive impact on the quality characteristics of the final baked product. The findings of this study indicated that legume protein could potentially substitute the traditional emulsifier SE.

High moisture extrusion induced interaction of Tartary buckwheat protein and starch mitigating the in vitro starch digestion

This study investigated the effects of adding 4-20 % Tartary buckwheat protein (TBP, with a purity of 93.35 %) on the structural, thermal, and digestive properties of Tartary buckwheat starch (TBS) by high moisture (60 %) extrusion. The added TBP embedded and enwrapped the starch matrix, which formed protein-starch complexes. After adding 4 %-20 % TBP, the shear degradation of AP decreased. Conversely, the shear degradation of AM chains increased. The addition of TBP promoted the retrogradation of starch in extrudates, enhancing their short- and long-range ordered structures. Compared with extruded TBS, extrudates contained TBP showed a reduction of gelatinization enthalpy, a high content of resistant starch, and a lower starch digestibility. These findings provided an insight into the protein-starch interactions under high moisture extrusion, which would promote the advancement of starch-based foods with high TBP content.

The Effect of Protein-Starch Interaction on the Structure and Properties of Starch, and Its Application in Flour Products

Grains are an energy source for human beings, and the two main components-starch and protein-determine the application of grains in food. The structure and properties of starch play a decisive role in determining processing characteristics, nutritional properties, and application in grain-based foods. The interaction of proteins with starch greatly affects the structure, physicochemical, and digestive properties of the starch matrix. Scientists have tried to apply this effect to create foods tailored to specific needs. Therefore, studying the effect of protein on the structure and properties of starch in the starch-protein complexes will help in designing personalized and improved starch-based food. This paper reviews the latest research about the effects of endogenous and exogenous proteins on the structure and properties of starch, as well as factors influencing the interaction between protein and starch. This includes investigations of the chain and aggregation structure of proteins with starch, as well as assessments of impacts on thermal properties, rheology, gel texture properties, hydration properties, aging, and digestion. In addition, particular examples illustrating the effects of protein-starch interaction on starch properties in various foods are discussed, providing a reference for designing starch-protein foods that are rich in terms of nutrition and easier to process.

Different effects of polyphenols on hydration, pasting and rheological properties of rice starch under extrusion condition: From the alterations in starch structure

Effects of polyphenols including caffeic acid (CA), ferulic acid (FA), epigallocatechin gallate (EG), tannic acid (TA) and resveratrol (R) on physicochemical and structural properties of rice starch (RS) under the extrusion condition were investigated. Extrusion altered the hydration, pasting and rheological properties of rice starch. Adding FA exhibited the best improvement effect on hydration properties of extruded rice starch (E-RS). All polyphenols possessed different inhibitory effects on short-term retrogradation of E-RS following the order of TA > EG > CA > FA > R. The FA and CA enhanced the viscoelasticity of E-RS, whereas the other polyphenols had opposite influences. Polyphenols mainly interacted with starch via hydrogen bonds, which transformed the crystalline structure to V-type and increased the molecular weight of E-RS. Above different effects were due to polyphenols exhibited varied microstructure and phenolic hydroxyl group content. These findings provided valuable information for preparing extruded starchy foods rich in polyphenols.

New insights into rice starch-gallic acid-whey protein isolate interactions: Effects of multiscale structural evolution and enzyme activity on starch digestibility

In starch-based food where proteins and polyphenols coexist, the impact of protein on the inhibition of starch digestion by polyphenols is unclear. Therefore, the aim of this study was to investigate the impact of whey protein isolate (WPI) on the inhibition of rice starch digestion by gallic acid (GA) from the aspects of multiscale structure and enzyme activity. Rice starch-gallic acid-whey protein isolate complex (RS-GA-WPI) was formed predominantly by hydrogen bonding and hydrophobic interactions. Compared to rice starch-gallic acid complex (RS-GA), RS-GA-WPI exhibited higher short-range ordering and thermal stability, and lower relative crystallinity. Fluorescence spectra and molecular docking showed that the interactions between GA and WPI weakened the hydrogen bond between GA and enzyme active site, so that WPI significantly reduced the enzyme inhibitory activity of GA. The above factors led to the result that the presence of WPI weakened the inhibitory effect of GA on starch digestibility. RS-GA-WPI showed higher starch digestibility and lower resistant starch content compared to RS-GA. This study provided a new understanding of starch digestion mechanism in starch-polyphenol-protein coexistence system.

Effect of Superheated Steam Treatment on Rice Quality, Structure, and Physicochemical Properties of Starch

This study aimed to investigate the effect of superheated steam treatment on the cooking and eating quality of rice, and further explore the effect of superheated steam treatment on the structure, gel properties, and rheological behavior of rice starch. After superheated steam treatment, the optimal cooking time of rice was effectively reduced by 26.9%, and the taste value of rice was significantly improved, from 78.45 to 84.20, when treated at 155 °C for 10 s. Superheated steam treatment significantly reduced the amylose and protein content, and increased the average particle size of rice starch. Compared with the control, the enthalpy change (ΔH) in the superheated steam treatment rice starch decreased notably from 6.53 to 5.28 after treatment, the relative crystallinity of the starch was significantly reduced from 21.20 to 10.89, and the short-term order of the starch was enhanced owing to the rearrangement of starch molecules after gelatinization. The starch structure was more compact and orderly after the superheated steam treatment, which significantly improved the hardness, viscoelasticity, and strength of the gel. These results indicate that superheated steam treatment improves the quality of rice by changing the structure of rice starch.

High molecular weight soluble dietary fiber of corn bran exhibits stronger inhibitions in digestibility and short-term retrogradation of corn starch than low molecular weight soluble fiber

Starch-dietary fiber interactions regulate starch processing and digestion, though the effects of varying molecular weight dietary fibers remain insufficiently studied. This study investigates how corn bran-derived soluble dietary fibers (SDFs) with distinct molecular weights influence corn starch (CS) processing, retrogradation, and digestibility. Results revealed that adding 5 % (W/W, based on the dry weight of CS) high molecular weight soluble dietary fiber (HM-SDF) or low molecular weight soluble dietary fiber (LM-SDF) significantly reduced amylose leaching, peak viscosity, retrogradation value, and retrogradation enthalpy during CS pasting. HM-SDF and LM-SDF decreased the thixotropic ring area by 55.8 % and 16.5 %, respectively, and inhibited the formation of ordered structures in CS. The HM-SDF-CS complex contained the least rapidly digestible starch at 68.26 %, indicating it more effectively slows starch digestion. These findings enhance our understanding of how SDF molecular weight distribution modulates starch-based foods, offering insights into potential applications for improved food processing and digestibility.

Formulation and characterization of low-fat breakfast cream using conjugated whey protein and modified starch

This study investigates the impact of conjugating whey protein (WP) with modified starch (MS), utilizing the Maillard reaction, on the characteristics of low-fat breakfast cream. The combination of WP and MS is significant due to its potential to improve the nutritional profile and textural attributes of low-fat dairy products, in response to consumer demand for healthier options. Various cream formulations were prepared with different ratios and concentrations of WP-MS conjugates, and their texture, water holding capacity, and sensory attributes were systematically analyzed. Results showed that creams with a MS-to-WP ratio of 2:1 at concentrations of 3 % and 4.5 %, as well as a ratio of 3:1 at 3 % concentration, exhibited superior texture properties including enhanced firmness, springiness, and gumminess. Structural analyses confirmed effective conjugation between MS and WP in these optimal formulations. However, higher WP content generally led to lower viscosity and hardness, as well as undesirable color darkening, resulting in lower sensory scores. Overall, these findings highlight the potential of WP-MS conjugates to optimize cream properties, offering valuable insights for producers seeking to develop low-fat dairy products with enhanced qualities and improved consumer acceptance.

Yield, physicochemical properties and in vitro digestibility of starch isolated from defatted meal made from microwaved tigernut (Cyperus esculentus L.) tubers

In this work, the effects of microwave treatment (MDT) of tigernut tubers at 540 W for 140, 180, 220, 240 s on the yield, physicochemical properties and in vitro digestibility of tigernut starch (TS) were firstly investigated. MDT significantly reduced the crystallinity and double helix structures of the starch, without altering its native A-type crystal structure. After microwaving for 140 s and 180 s, the extraction yield of TS was significantly increased from 14.92 % to 16.68 %, and a dense gel network structure was found by rheological analysis. In vitro digestion results indicated that the microwaved TS contained more content of rapidly digestible starch (RDS, 76.10 %-80.74 %) but lower slowly digestible starch (SDS, 2.85 %-5.78 %) and resistant starch (RS, 14.94 %-18.12 %); in other words, microwaving increased the in vitro digestibility of TS. This work elucidated the essential features of the response of tigernut starch to microwave treatment, and provided a basic understand of the digestibility of tigernut starch under microwave treatment, making it more suitable for industrial applications.

Partial gelatinization treatment affects the structural, gelatinization, and retrogradation characteristics of maize starch-dietary fiber complexes

The effect of partial gelatinization (PG) treatment on the structural, gelatinization, and retrogradation characteristics of maize starch (MS)-dietary fiber (pectin, PE; konjac glucomannan, KG) complex was conducted. The result suggests that PG treatment shows an obvious effect in improving thermal stability, decreasing the viscoelastic, inhibiting starch gelatinization and retrogradation of the MS-PE/KG complex. The decreased breakdown viscosity, storage modulus, apparent viscosity, setback value, and hardness value could confirm these results. Furthermore, PG treatment had a better effect on inhibiting the gelatinization and retrogradation of the MS-0.3 %PE complex than other complexes. This result was proved by reduced setback value (by 78.96 %) and hardness value (by 54.46 % and 44.00 % during cold storage at 1 and 14 days, respectively). 0.3 %PE interacts with starch molecules through hydrogen bonding and electrostatic forces during PG treatment forming a strong starch granule structure to impede starch gelatinization and retrogradation. Moreover, the lighter iodine staining, the obvious coating thin layer, and the thicker fluorescence layer have appeared in the MS-PE/KG complex. The relative crystallinity and the short-range order degree of the MS-PE/KG complex were significantly decreased. The current findings provide the theoretical basis for MS modification to improve the quality and prolong the shelf-life of starch-based foods.

Wheat Bread Supplemented with Egg Albumin: Structural Features, and In Vitro Starch and Protein Digestibility

This study aimed to explore the effects of egg albumin protein addition (5, 15 and 20 g/100 g db) on the textural characteristics, as well as in the in vitro digestibility of protein and starch of wheat bread. Egg albumin addition resulted in smoother bread loaves as compared to traditional wheat bread. Reduced hardness and increased cohesiveness were correlated to the protein secondary structure, mainly with the content of β-sheets. The in vitro protein digestibility decreased with the albumin addition, suggesting the mediation of protein-starch interactions. The in vitro starch digestibility was also decreased, reflected in a huge decrease of the slowly digestible starch fraction, but with non-significant changes in the rapidly digestible starch fraction. The supplemented albumin can form a physical barrier around the starch granules, which hampers the access of the amylolytic enzymes to the starch chains. Overall, the results of this study suggest that the addition of egg albumin is a viable alternative for producing wheat bread with reduced glycemic index and improved nutritional properties.

Mechanism underlying V-type structure formation in maize starch through glycerol-ethanol thermal substitution method

V-type starches have been widely used in food science, agriculture, and biomedical science, but their mechanism of formation in nonaqueous solvents remains unclear. This study performed glycerol-ethanol thermal substitution to prepare V-type starch at atmospheric pressure. Scanning electron microscopy and confocal laser scanning microscopy revealed that breakage of starch particles began in the hilum region and rapidly spread to the periphery with the temperature increased from 100 °C to 130 °C. The Maltese crosses of the starch disappeared and starch particles had the form of doughnut-shaped rings when the glycerol temperature was 140 °C. Glycerol temperature was not found to significantly affect the chain length of amylopectin, meaning that glycerol molecules may stabilize the conformation of amylose through hydrogen bonding, promoting the amylose to form a V-type spiral structure. Additionally, A-type crystallinity and double helix structure proportion of the samples significantly decreased from 30.81 % and 42.21 % to 5.70 % and 16.47 % as the temperature of glycerol was increased to 140 °C, whereas the V-type crystallinity and single helix structure proportion of the samples remarkably increased from 13.26 % and 1.05 % to 37.97 % and 25.09 %, respectively. This study provided a facile and versatile approach to effectively regulate the formation of V-type starch.

Sorghum starch review: Structural properties, interactions with proteins and polyphenols, and modification of physicochemical properties

Sorghum, a gluten-free carbohydrate source with high antioxidants and resistant starch, contains anti-nutrients like phytic acid, tannin, and kafirin. Interactions with starch and proteins result in polyphenol-starch, starch-kafirin, and tannin-protein complexes. These interactions yield responses such as V-type amylose inclusion complexes, increased hydrophobic residues, and enzyme resistance, reducing nutrient availability and elevating resistant starch levels. Factors influencing these interactions include starch composition, structure, and Chain Length Distribution (CLD). Starch structure is impacted by enzymes like ADP-glucose pyrophosphorylase, starch synthases, and debranching enzymes, leading to varied chain lengths and distributions. CLD differences significantly affect crystallinity and physicochemical properties of sorghum starch. Despite its potential, the minimal utilization of sorghum starch in food is attributed to anti-nutrient interactions. Various modification approaches, either direct or indirect, offer diverse physicochemical changes with distinct advantages and disadvantages, presenting opportunities to enhance sorghum starch applications in the food industry.

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.

Modification of microporous bionanocomposite films with visible light-activated photocatalytic antimicrobial TNT-CuO nanoparticles for active fruit packaging

Active packaging technologies are evolving to enhance the preservation of fresh produce by fighting against microbial contamination and controlling internal packaging atmospheres. This study introduced an active fruit packaging called MT film, created by modifying a microporous polyvinyl alcohol/chitosan/cellulose nanocrystal bionanocomposite film with CuO-doped titania nanotubes. The MT film, with an average micropore size of 2.4 μm, displayed excellent mechanical properties and hydrophobicity due to its crosslinked structure. When exposed to visible light, the MT film could produce reactive oxygen species, effectively inhibiting the growth of Staphylococcus aureus and Escherichia coli O157:H7. Moreover, experiments on blueberry preservation demonstrated that the MT film could remove excess CO2 and maintain a higher O2 level. Under visible light, this film significantly reduced total viable count (4.6 ± 0.2 log CFU/g) and mold colony count (2.6 ± 0.1 log CFU/g), with Bacillus and Ascochyta being the primary inhibited genera. These findings highlight the potential of MT film in utilizing visible light to prevent microbial growth on blueberries and regulating the gas exchange of food packaging. MT film holds promise as an active packaging solution to improve the quality and shelf life of fresh produce while reducing food losses in the supply chain.

Multi-scale structure and digestible process of wheat starch as affected by distribution behavior of rice glutelin amyloid fibril aggregates during gelatinization and digestion

The effect of distribution behaviors of rice glutelin amyloid fibril aggregates (RAFA) on the structures and digestible process of wheat starch was investigated, and the interaction was revealed by molecular dynamics simulations. Rice glutelin (RG)/RAFA enhanced the long-range ordered structure of starch, and the relative crystallinity of gelatinized RAFA-wheat starch reached 14.35 %. Moreover, the RAFA was more effective than RG in improving the short-range ordered structure of starch. Simultaneously, the RAFA exhibited higher cross-linking with starch than the RG, forming continuous and compact network structures that encapsulated the starch. After 180 min of in vitro pancreatic digestion, the residual RAFA encapsulating the starch was still observed in the chyme, hindering amylolytic enzyme action and alleviating the starch digestibility. Molecular dynamics simulations further confirmed that the RAFA, compared to the RG, bound more readily to the starch molecule and formed more stable complexing structure. And the RAFA formed hydrogen bonds with the hydroxyl groups of starch through polar amino acid residues (Gln and Asn) and nonpolar residues (Ala, Gly, and Ile) with binding free energy of -263.868 kJ/mol, while that of the RG-starch was -28.798 kJ/mol. The study enriches the theory of regulating starch digestion using food-derived protein amyloid fibril aggregates.

Mechanistic studies on the effect of endogenous proteins on the starch retrogradation characteristics of corn before and after postharvest ripening

The corn starch-protein complexes before postharvest ripening (JD-0) and after postharvest ripening (JD-40) were subjected to protease treatment, and the influence of protein on starch retrogradation was studied. Kinetic studies of starch retrogradation showed that protein reduced the retrogradation rate constant (k) of starch by 25.46 % (JD-0) and 7.48 % (JD-40), respectively. This was mainly reflected in the inhibition of short-range order, relative crystallinity and helix structure formation in the retrogradation process. In addition, low field strength nuclear magnetic resonance (LF-NMR) analyses also revealed that proteins inhibited starch retrogradation by isolating the precipitation of free water during retrogradation, causing the decrease in the viscoelasticity and firmness of the starch gel. Therefore, the inhibitory effect of proteins on starch retrogradation before postharvest ripening of corn-based food products was more relevant.

Controlling pea starch gelatinization behavior and rheological properties by modulating granule structure change with pea protein isolate

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.

Effect of four highland barley proteins on the retrogradation and in vitro digestion properties of highland barley starch

This study evaluated the effects of four highland barley proteins (HBPs), namely albumin, globulin, gliadin and glutenin, on the retrogradation and in vitro digestion properties of highland barley starch (HBS). The results showed globulin had the most significant effect on inhibiting short-term retrogradation of HBS, which was reflected in the reduction of G' and G". Compare with HBS, four HBPs could significantly inhibit long-term recrystallization process. For albumin, globulin, gliadin and glutenin, the degree of retrogradation reduced from 51.55 % to 48.20 %, 35.06 %, 42.22 % and 32.63 %, respectively, which was reflected in the decrease of water migration rate, crystal enthalpy, crystallinity and short-range order. It could be found that glutenin had the most significant effect on inhibiting long-term retrogradation of HBS. Moreover, the anti-digestion properties of retrograded HBS with HBPs intervention significantly increased, with glutenin most significantly. Compared with HBS, resistant starch (RS) content increased by 59.76 % at 28 d of retrogradation.

Modulation of Gut Microbiota by the Complex of Caffeic Acid and Corn Starch

To understand the impact of different types of polyphenol-starch complexes on digestibility and gut microbiota, caffeic acid (CA) and corn starch (CS) complexes were prepared by coheating and high-pressure homogenization. The resistant starch content in CS coheated with CA (HCS-CA) and HCS-CA after high-pressure homogenization (HCS-CA-HPH) was 47.75 and 56.65%, respectively. Fourier transform infrared spectroscopy and X-ray diffraction analysis revealed hydrogen bonding in coheated samples and enhanced V-complex formation with high-pressure homogenization. The in vitro-digested complexes were of the B + V type, with higher relative crystallinity and short-range ordering of HCS-CA-HPH. Fermentation of the digested complex with human feces increased the yield of acetate, butyrate, and total short-chain fatty acids (SCFAs), which was more pronounced for HCS-CA-HPH. HCS-CA increased torques-Ruminococcaceae abundance, while HCS-CA-HPH boosted Prevotella, Roseburia, Lachnospiraceae, and Lachnospiraceae-NK4A136. Overall, CA and CS complexes enhanced beneficial bacteria and increased SCFA production.

Effect of rice storage proteins on the physicochemical properties of indica rice during after-ripening

The processing quality of indica rice stabilizes after a period of post-harvest storage known as after-ripening, during which proteins play an important role according to our previous research. The present study investigated the effects of rice storage proteins (RSPs) on the physicochemical properties of after-ripening rice, employing protein analysis, rapid viscosity analyzer, hydration properties assessment, morphological analysis and fourier transform infrared spectroscopy (FTIR). The results indicated that the crude protein content remained relatively unchanged during after-ripening, while the band intensities of 13 kDa and 20 kDa protein subunits increased with increasing storage time. Removing RSPs decreased the setback viscosity, final viscosity and pasting temperature of after-ripening indica rice flour but led to an increase in its breakdown viscosity, especially by 93.45 % after storage at 36 °C for 90 d. Protein-removal also contributed to increasing the water solubility and swelling power of after-ripening indica rice flour by 31.66 % and 37.31 % for 90 d respectively. Morphological analysis revealed that RSPs had wrapped the starch granules, thus delaying the migration of water into the starch during heating. FTIR spectra indicated that the presence of RSPs enhanced the short-range ordered structure of starch. These findings will contribute to further elucidating the mechanisms underlying indica rice quality changes during storage.

Effect of 3D printing accuracy by wheat starch gel combined with canola oil

This study investigated the impact of canola oil (CO) on wheat starch (WS) in 3D printing, focusing on intermolecular interactions and gel characteristics. 3D printing performance, microstructure, rheology, texture, proton distribution, thermal properties, molecular structures, and crystal structure were used to analyze the properties of starch gels. The results showed that adding CO improved the similarity between printed products and their models, and facilitated smoother extrusion by enhancing the cohesiveness and adhesiveness of the WS-CO complex. Moreover, adding >6 % CO to the starch gels destabilized the 3D-printed structure, causing the top layer to collapse, which affected the aesthetics and printing accuracy. The WS-4%CO complex demonstrated superior printing performance and enhanced accuracy. FTIR (Fourier Transform Infrared) and NMR (Nuclear Magnetic Resonance) results indicated that the interaction between WS and CO involved non-covalent interactions, primarily hydrophobic interactions. SEM (scanning electron microscope) results further revealed the molecular structure, CO hindered the interaction between amylose and amylopectin, disrupting the ordered structure and increasing lamellar formation, thereby affecting the stability of the 3D printing structure. This experiment provides valuable insights for enriching the nutrition and improving the accuracy of 3D-printed food.

The influence of pulse cell wall structure and cellular protein matrix on the in vitro digestion kinetics of starch: A dual encapsulation mechanism

The intrinsic characteristics and extrinsic processing of whole-pulse food modulate the starch digestion rate and extent. This study investigated the dual encapsulation mechanism of cell wall structure and protein matrix on the in vitro digestion properties of intracellular starch, using an isolated whole-pulse food model of intact pea cotyledon cells subjected to alkaline buffer and enzymatic treatments. Results showed that intact cells with the maximum protein matrix content (18.9 %) exhibited the lowest peak temperature (71.4 °C, uncooked and 58.1 °C, cooked), enthalpy change (3.4 J/g, uncooked and 2.0 J/g, cooked), relative crystallinity (11.6 %), and starch digestion rate (0.0248 min-1) and extent (11.9 %) compared to alkaline buffer and enzymatic treatments. Even after enzymatic treatment, cells with minimal protein matrix content (1.8 %) exhibited a starch digestion rate (0.0387 min-1) and extent (39.7 %), which were still lower than those of isolated starch (0.0480 min-1 and 56.8 %). These findings indicate that the protein matrix and cell walls act as a dual encapsulation system to slow starch hydrolysis. This provides a theoretical basis and technical guidance for developing low-glycemic whole-pulse foods.

Mung bean protein enhances the expansion of corn starch during twin-screw extrusion

This study examined the effects of the inclusion of mung bean protein (MBP) on the direct expansion characteristics of corn starch during twin-screw extrusion. Six blends of corn starch and MBP isolate (0%, 5%, 10%, 15%, 20%, and 25% w/w) were hydrated to three different moisture contents (MCs) (16%, 19%, and 21% w.b.). The blends were extruded using a twin-screw extruder at three screw speeds (SSs) (300, 400, and 500 rpm). The resulting extrudates were evaluated for their water solubility index, water absorption index, expansion ratio (ER), true density, unit density, and porosity. As the protein content increased, the porosity of the extrudates increased. The ER of all extrudates ranged from 2.90 to 5.46, with the largest ER observed at an SS of 400 rpm, an MC of 19%, and 25% MBP inclusion. The porosity of the extrudates ranged from 1.79% to 11.42%. SS and protein content had a significant impact (p < 0.05) on the porosity and ER of the extrudate. PRACTICAL APPLICATION: This work provides valuable information for the industry on utilizing mung bean protein in direct expanded corn starch-based extruded snacks. The information could be useful in the development of high-protein extruded snacks and breakfast cereals.

Composition, Anti-Diabetic, and Antioxidant Potential of Raphanus sativus Leaves

Limiting and/or slowing down the starch digestion process and consequently the release of glucose can be an important strategy for the prevention of type 2 diabetes (T2D). The aim of the current in vitro study was to assess the anti-diabetic and antioxidant potential of red radish leaves of the Carmen, Jutrzenka, Saxa, and Warta cultivars. In the context of anti-diabetic activity, the effect of leaves on potato starch digestion and free glucose binding, as well as inhibitory effects of leaf extracts against α-amylase and α-glucosidase and non-enzymatic glycation (AGEs) were determined. The basic chemical composition, quantitative composition of phenolic compounds, and antioxidant activity of leaves were also estimated. This study showed that all radish leaves inhibited the breakdown of potato starch and showed their ability to bind glucose. This activity was correlated with the content of hydroxycinnamic acids, protein and dietary fiber while flavones was probably responsible for glucose binding. Leaf extracts inhibited α-glucosidase activity and formation of AGEs but were practically inactive towards α-amylase. Inhibition of α-glucosidase activity was related to the content of proanthocyanidins and inhibition of AGEs formation to flavonols. These results point to radish leaves, especially the Warta and Jutrzenka cultivars, as a potential natural remedy for treating T2D.

Novel mode of kafirin modification using combination of enzyme and thermal treatment to expand its food application

Kafirin in sorghum inhibits starch digestion and exhibits antioxidant properties, however its potential in food industry remains unexplored. Therefore, the study was aimed to explore and improve the potential of kafirin as natural carbohydrate blocker using papain (6 NFU/mL) and/or infrared treatment (220 °C/3 min). Results indicated that the combined treatment, PIR (infrared + papain) is the most efficient treatment to modify kafirin. PIR generated a new ∼37 kDa high molecular weight moiety in kafirin with a crystal size of 157.44 Å. All samples showed superior antioxidant activity post-treatments, with PIR exhibiting highest scavenging activity from 31.09 to 82.97%, 15.09 to 42.82%, and 25.92 to 38.58% for DPPH, FRAP, and ABTS, respectively. PIR-modified kafirin limited malondialdehyde production, and increased α-amylase and α-glucosidase inhibition. Incorporation of 7.5% kafirin in corn starch increased resistant starch from 5.09 to 21.04% after cooking, which suggests potential of kafirin in development of diabetic-friendly food formulations.

Amelioration of tiger nut insoluble dietary fiber as a partial substitute for fat in meat emulsions: Techno-functional properties and in vitro protein digestibility

The effects of tiger nut insoluble dietary fiber (TNF) (1%-3% w/w) on techno-functional properties and in vitro protein digestibility of low-fat meat emulsions were examined. The results showed that TNF (especially 2% and 3%) could improve techno-functional performances of low-fat meat emulsions in terms of water binding capacity and textural attributes, which were even preferable to the high-fat control. The improvements were associated with the attenuated fluidity of inner water within the gels, the increased storage modulus (G'), the formation of a well-joined gel network with uniformly-dispersed fat particles and the uncoiling of α-helix and the formation of β-sheet. The weakened water mobility, the heat-triggered conformational shift from α-helix to β-sheet, as well as less and evenly distributed fat particles ulteriorly led to elevated protein digestibility in meat emulsions. Therefore, TNF shows promise as a fat substitute to develop fat-reduced emulsified pork meat products with desirable quality and digestion behaviors.

Effect of maturity on the drying characteristics of lotus seed and molecular structure, gelation and digestive properties of its starch

Maturity and drying treatment are important factors affecting the processing characteristics of lotus seeds and its starch. This study aimed to investigate the effect of maturity (from low to high-M-1, M-2, M-3, M-4) on far-infrared drying kinetics of lotus seeds, and on the variation of structure, gelation and digestive properties of lotus seed starch (LSS) before and after drying. As the maturity increased, the drying time reduced from 5.8 to 1.0 h. The reduction of drying time was correlated with the decrease of initial moisture content, the increase of water freedom and the destruction of tissue structure during ripening. The increased maturity and drying process altered the multiscale structure of LSS, including an increase in amylose content, disruption of the short-range structure, and a decrease in relative crystallinity and molecular weight. The viscosity, pasting temperature and enthalpy of LSS decreased during ripening, and drying treatment caused the further decrease. The digestibility of LSS increased during ripening and drying. Lotus seeds at M-4 would be optimal for obtaining shorter drying time, lower pasting temperature and enthalpy, and higher digestibility. This study provided theoretical guidance for achieving effective drying process and screening LSS with suitable processing properties through maturity sorting.

Retrograded Resistant Starch Improves Emulsion Stability and Emulsion Gel Properties Stabilized by Myofibrillar Proteins Without Degrading In Vitro Protein Digestibility

The objective of this study was to investigate the effects of retrograded resistant starch (RS3) (0, 2%, 4% and 6%; w/v) on the emulsion gel properties stabilized by myofibrillar proteins (MPs) and in vitro protein digestibility of the gels. The RS3 was prepared from corn or potato starch using the gelatinization-ultrasound-retrogradation method. The results showed that the addition of RS3 decreased the surface hydrophobicity (p < 0.05) and increased the fluorescence intensity of MPs, indicating enhanced protein-protein interactions. More stable emulsions stabilized by MP/RS3 mixtures were formed, along with higher electronegativity, a smaller droplet size and reduced creaming index. These changes promoted the formation of better gel networks with the oil droplets evenly dispersed, thus improving gel strength, water holding capacity (WHC) and texture, especially at the concentration of 6% RS3 added. The gel force results indicated that the addition of RS3 enhanced the hydrophobic interaction and disulfide bonds between MPs. LF-NMR and MRI data further confirmed that RS3 addition facilitated the migration of free water to immobilized water. Furthermore, the incorporation of RS3 caused a relatively lower pepsin digestibility but did not change the overall in vitro protein digestibility of the gels. This paper provides a method to produce high-quality low-GI meat products without degrading protein digestibility.

Lauric acid improved the quality of fresh noodles with/without sodium bicarbonate by altering physical properties and structure of wheat starch

To know the influence of lauric acid (LA) on wheat flour fresh noodles (WFN) quality and the latent mechanism, the effect of LA on cooking properties, digestibility and structure of WFN with/without sodium bicarbonate (SB) and the properties of wheat flour (WF) with/without SB were studied. The results indicated that LA reduced cooking loss and digestibility of WFN with SB and slightly decreased water adsorption and increased the free water binding ability and hardness of WFN without SB. Furthermore, LA increased the degree of short- and long-range order and molecular weight of starch in cooked WFN with/without SB and it had greater effect on the degree of short- and long-range order and molecular weight of starch in cooked WFN with SB than that without SB. Differential scanning calorimeter (DSC) and rapid viscosity analysis (RVA) displayed that WFN with LA and SB formed more starch-LA or/and starch-LA-protein complexes than WFN with LA. Additionally, the impact of LA on WFN quality and WF properties was influenced by SB concentration. This study will provide theoretical basis and new thoughts for the design of high-quality fresh noodles with low digestibility, low cooking loss and high hardness.

Influence of chickpea protein on the pH and temperature dependent viscosity of carboxymethylated starch

Proteins can significantly improve the elasticity and microstructure of starch gels in food. In this work, the influence of chickpea protein flour on the viscoelastic behaviour of carboxymethylated starch (CMS, 92.6 mmol COOH kg-1) gels was studied as function of pH and temperature. A weight ratio CMS:protein flour of 1:0.45 was investigated in the pH range of pH 2.5-8. Above pH 7 presence of 7.5 %w/w chickpea flour lead to an increase in complex viscosity of a 16.5 %w/w CMS solution by a factor of 10. The interaction between CMS and protein above pH 4 accelerates gelation at 37 °C, resulting in an increase in viscosity by a factor of 5, 10 and 120 at pH 5, pH 7 and pH 8 respectively. Model calculations for species dissociation of ammonium groups in basic amino acids and carboxylate groups in CMS indicate that electrostatic interactions led to the observed increase in viscosity. The results form a general model to explain the pH-dependent viscoelastic behaviour of polysaccharide-protein mixtures. The understanding of the mechanism of action between protein and polysaccharides is a condition for targeted analysis and explanation of many phenomena of texture, stability and coacervate formation in food processing.

Effect of adding various supplements on physicochemical properties and starch digestibility of cooked rice

This study investigated the physicochemical modifications of cooked rice caused by adding various supplements (rapeseed oil, dried wasabi powder, and dried chili pepper powder). The physicochemical and digestive properties of treated cooked rice were analyzed using multiple techniques to determine the impact of supplements on the rice quality, including its starch digestibility. All samples with added supplements showed an increase in surface firmness (0.77-0.95 kg·m/s2 (N)) and a decrease in thickness (2.23-2.35 mm) and surface adhesiveness (1.43-7.22 J/m3). Compared to the control group, two absorption peaks at 2856 and 1748 cm-1 and new signals at 1683 and 1435 cm-1 appeared in the Fourier transform infrared (FTIR) spectroscopy. Analysis of FTIR results revealed that the interaction force was mainly through noncovalent interactions. Moreover, adding supplements increased the resistant starch (RS) levels in all samples. Scanning electron microscopy (SEM) suggested that oil-enriched phases, proteins, and polyphenols could cause large agglomeration and loose gel structure. These results suggested the formation of amylose-guest molecule complexes, which may influence starch functionality. Our work could provide insight into the starch-supplement interactions and the key factors affecting starch digestibility.

Metabolic regulation mechanism of melatonin for reducing cadmium accumulation and improving quality in rice

Melatonin acts as a potential regulator of cadmium (Cd) tolerance in rice. However, its practical value in rice production remains unclear. To validate the hypothesis that melatonin affects Cd accumulation and rice quality, a series of experiments were conducted. The results showed that exogenous melatonin application was associated with reduced Cd accumulation (23-43%) in brown rice. Fourier transform infrared spectroscopy (FTIR) analysis showed that exogenous melatonin affected the rice protein secondary structure and starch short-range structure. Metabolomics based on LC-MS/MS revealed that exogenous melatonin altered the brown rice metabolic profile, decreased fatty acid metabolite content, but increased amino acid metabolite, citric acid, melatonin biosynthetic metabolite, and plant hormone contents. These findings indicate that exogenous melatonin can effectively reduced Cd accumulation and improve rice quality through metabolic network regulation, serving as an effective treatment for rice cultivated in Cd-contaminated soil.

Study on the Mechanism of Effect of Protein on Starch Digestibility in Fermented Barley

Previous studies have shown that fermented barley has a lower digestion rate. However, it remains unclear whether the antidigestibility of starch in fermented barley is affected by other nonstarch components. In this paper, the removal of protein, lipid, and β-glucan improved the hydrolysis rate of starch and the protein showed the greatest effect. Subsequently, the inhibitory mechanism of protein on starch digestion was elucidated from the perspective of starch physicochemical properties and structural changes. The removal of protein increased the swelling power of starch from 10.09 to 11.14%. The short-range molecular ordered structure and the helical structure content decreased. The removal of protein reduced the coating and particle size of the starch particles, making the Maltese cross more dispersed. In summary, protein in fermented barley enhanced the ordered structure of starch by forming a physical barrier around starch and prevented the expansion of starch, which inhibited the hydrolysis of starch.

Starch in Emulsion-Type Sausage Reduced the Gastric Digestibility of Meat Protein by Reducing the Stability and Increasing the Viscoelasticity of Gastric Digests

The effect of the addition of native starch (S) and modified starches (distarch phosphate (SP), acetylated distarch phosphate (AP), and starch acetate (SA)) in emulsion-type sausage on the digestion process of meat protein was studied in this work. The addition of native and modified starches reduced the release of -NH2 during the simulated gastric digestion stage, whereas the addition of SA increased the total release of -NH2 after the whole digestion. Peptidomic analysis revealed that the presence of starch decreased the release of peptides in the gastric digestion. The presence of starch reduced the stability of the digests but increased the viscosity of the gastric digestive fluid, which should largely be responsible for the decreased gastric digestibility of meat protein. These results highlighted the physical properties of digests as a key factor affecting the gastric digestion process of meat protein and provided guidance for the application of starches in meat products.