Effect of cysteine on structural, rheological properties and solubility of wheat gluten by enzymatic hydrolysis

Mechanism for improving the in vitro digestive properties of coconut milk by modifying the structure and properties of coconut proteins with monosodium glutamate

In this paper, the effect of monosodium glutamate (MSG) on coconut protein (CP) solubility, surface hydrophobicity, emulsification activity, ultraviolet spectroscopy and fluorescence spectroscopy was investigated. Meanwhile, the changes in the in vitro digestive properties of coconut milk were also further analyzed. MSG treatment altered the solubility and surface hydrophobicity of CP, thereby improving protein digestibility. Molecular docking showed that CP bound to pepsin and trypsin mainly through hydrogen bonds and salt bridges. And MSG increased the cleavable sites of pepsin and trypsin on CP, thus further improving the protein digestibility. In addition, MSG increased the Na+ concentration in coconut milk, promoted flocculation and aggregation between coconut milk droplets, which prevented the binding of lipase and oil droplets and inhibited lipid digestion. These findings may provide new ideas and insights to improve the digestive properties of plant-based milk.

Effect of l-cysteine on functional properties and fibrous structure formation of 3D-printed meat analogs from plant-based proteins

The development of three-dimensional (3D) printed meat analogs with fiber, texture, and sensory resembling meat remains challenging. This study investigated the effect of l-cysteine on functionality enhancement and fibrous structure formation in mixtures of mung bean protein isolate (MBPI) and wheat gluten (WG) for meat analog production. 3D printing was used to construct fibrous filaments. Raw MBPI-WG mixtures decreased rheological properties when increasing l-cysteine contents (0.0%-0.6%), promoting ink extrudability. The cys-0.4% ink exhibited the highest printing resolution and structural stability, correlated with its higher mechanical strength and increased disulfide cross-links. After cooking, the cys-0.4% sample showed a pronounced fibrousness in agreement with its microstructure image. This meat analog displayed a muscle-meat-like structure, improved texture, and reduced beany odor and bitter taste. Excessive cysteine contents (0.5%-0.6%) negatively affected the functionality of meat analogs. This study provides guidance for optimizing the amount of l-cysteine in meat analogs to improve product quality.

Preparation and properties of high-soluble wheat gluten protein-based meat analogues

BACKGROUND

Wheat gluten protein (WGP) is poorly soluble and does not easily form fibrous structures. The meat analogues prepared from it have an unsatisfactory texture and poor water-holding capacity (WHC). Our previous work indicated that pH-shifting combined with heat treatment can significantly improve the solubility and emulsifiability of WGP. In this work, WGP was therefore treated by pH-cycling (m-WGP) to improve the solubility and then applied in the preparation of meat analogues by high moisture extrusion.

RESULTS

The results indicated that the addition of m-WGP improved the texture characteristics and WHC of the extrudates significantly (282.4) and made the extrudates show a tighter organizational structure, according to scanning electron microscope (SEM) images. Magnetic resonance imaging (MRI) analysis showed that the addition of m-WGP resulted in a more uniform moisture distribution in the extrudate. The free sulfhydryl group result showed that the addition of m-WGP significantly increased the free sulfhydryl group content, which was beneficial to the formation of disulfide bonds to enhance the tissue structure.

CONCLUSION

When the addition content of m-WGP was 10%, the gluten extrudate exhibited a good WHC and uniform moisture distribution but the excessive hardness and chewiness were not suitable for simulating meat. When the additional m-WGP content reached 50%, the gluten extrudate had textural characteristics that were closest to commercial plant-based meat and real meat, with the potential to be used as a raw material to simulate meat. Accordingly, this work improves the processing properties of WGP and explores plant-based ingredients for meat analogues. © 2023 Society of Chemical Industry.

Structure-activity relationship between gluten and dough quality of sprouted wheat flour based on air classification-induced component recombination

BACKGROUND

Air classification can separate sprouted wheat flour (SWF) into three types: coarse wheat flour (F1), medium wheat flour (F2) and fine wheat flour (F3). The gluten quality of SWF can be indirectly improved by removing inferior parts (F3). In order to reveal the underlying mechanism of this phenomenon, the composition and structural changes of gluten, as well as the rheological properties and fermentation characteristics of gluten in recombinant dough in the process of air classification of all three SWF types, were analyzed in this study.

RESULTS

Overall, sprouting significantly reduced the content of high-molecular-weight subunits, such as glutenin subunit and ω-gliadin. It also destroyed the structural content, such as disulfide bonds, α-helix and β-turn contents, which maintained the stability of gluten gel. Air classification made the above changes in F3 more severe but reversed them in F1. Moreover, rheological properties were more affected by gluten composition, whereas fermentation characteristics were more affected by gluten structure.

CONCLUSION

After air classification, particles rich in high molecular weight subunits from SWF are enriched in F1, and the gluten of F1 has more secondary structure that maintain gel stability, which ultimately lead to improved rheology properties and fermentation characteristics. F3 relatively exhibits the opppsite phenomenon. These results further reveal the potential mechanism of improvement of SWF gluten by air classification. Moreover, Thus, this study provides new perspectives for the utilization of SWF. © 2023 Society of Chemical Industry.

Effect of High-Molecular Weight Glutenin Subunits (HMW-GSs) on Gluten Polymerization during Biscuit Making: Insights from Experimental and Molecular Dynamics Simulation Study

The effect of high-molecular weight glutenin subunits (HMW-GSs) on gluten polymerization during biscuit making was investigated using a set of HMW-GS deletion lines. Results showed that the deletion of HMW-GSs improved the biscuit quality compared with the wild type (WT), especially in x-type HMW-GS deletion lines. Slight gluten depolymerization was observed during dough mixing, while progressive gluten polymerization occurred during biscuit baking. The deletion of HMW-GSs suppressed the polymerization of glutenin and gliadin compared with the WT during biscuit baking, especially in x-type HMW-GS deletion lines. These actions resulted in less elevation of the intermolecular β-sheet and ordered α-helix and altering the disulfide (SS) conformation to a less stable conformation in HMW-GS deletion lines compared with the WT during baking. Molecular dynamics simulation analysis further demonstrated that x-type HMW-GSs had higher thermal stability compared with y-type HMW-GSs during heating.

Enhancing the solubility and antimicrobial activity of cellulose through esterification modification using amino acid hydrochlorides

Most amino acid molecules have good water solubility and are rich in functional groups, which makes them a promising derivatizing agent for cellulose. However, self-condensation of amino acids and low reaction efficiency always happen during esterification. Here, amino acid hydrochloride ([AA]Cl) is selected as raw material to synthesize cellulose amino acid ester (CAE). Based on TG-MS coupling technology, a significantly faster reaction rate of [AA]Cl compared to raw amino acid can be observed visually. CAE with the degree of substitution 0.412-0.516 is facilely synthesized under 130-170 °C for 10-50 min. Moreover, the effects of amounts of [AA]Cl agent, temperature, and time on the esterification are studied. The CAE can be well dissolved in 7 wt% NaOH aq., resulting in a 7.5 wt% dope. The rheological test of the dope demonstrated a shear-thinning behavior for Newtonian-like fluid, and a high gel temperature (41.7 °C). Further, the synthesized products show distinct antibacterial activity and the bacteriostatic reduction rate against E. coli can reach 99.5 %.

The Consistency Factor and the Viscosity Exponent of Soybean-Protein-Isolate/Wheat-Gluten/Corn-Starch Blends by Using a Capillary Rheometry

Blends with different proportions of protein or starch show different rheological behaviors, which may be related to the fibrous structure formation of extruded textured plant proteins. The consistency factor K and the viscosity exponent n of soybean–protein–isolate (SPI)/wheat–gluten (WG)/corn–starch (CS) blends were investigated through capillary rheometry. All blends exhibited shear-thinning behavior at 80 °C and 50% moisture. The CS content in SPI/CS blends or WG content in SPI/WG blends showed a positive relation to the viscosity exponent n and a negative relation to the consistency factor K. However, there was no correlation between the CS content in WG/CS blends and n or K. The coefficient of determination of the linear relationship between K and mass fraction in SPI/CS, SPI/WG/CS, SPI/WG and WG/CS decreased from 0.872 to 0.073. SPI was more likely to form a non-interactive structure, while wheat-gluten was more likely to form a highly interactive structure. It turned out that the materials with globular morphology, such as soybean-protein-isolate and corn-starch, are likely to form a non-interactive structure.

The effect of redox agents on conformation and structure characterization of gluten protein: An extensive review

Gluten protein as one of the plant resources is affected by redox agent. Chemical modifications by redox agent have myriad advantages mainly short reaction times, no requirement for specialized equipment, low cost, and highly clear modification impacts. The gluten network properties could be influenced through redox agents (oxidative and reducing agents) which are able to alter the strength of dough via different mechanisms for various purposes. The present review examined the impact of different redox compounds on gluten and its subunits based on their effects on their bonds and conformations and thus with their impacts on the physico-chemical, morphological, and rheological properties of gluten and their subunits. This allows for the use of gluten for different of purposes in the food and nonfood industry.

Effect of enzymatic hydrolysis on the formation and structural properties of peanut protein gels

The limited enzymatic hydrolysis gelation method was investigated using peanut protein isolate (PPI) without any coagulators. A peanut protein gel could be formed by enzyme treatment with Alcalase at low temperature (50–70 °C). The influence of enzymatic hydrolysis on the rheological and physicochemical properties was investigated. Structural changes in the PPI were characterized by analyzing the subunits, chemical forces, surface hydrophobicity, fluorescence spectra, and circular dichroism (CD) spectra. The results revealed that enzymatic hydrolysis significantly affected the conarachin II protein of PPI, and had little influence on conarachin I and the basic subunits of arachin. Hydrophobic interaction was the main chemical force active in the peanut protein gel. An increase in the surface hydrophobicity coupled with red-shifts of the fluorescence spectra indicated that inner hydrophobic regions were exposed after hydrolysis, resulting in gel formation via hydrophobic interactions. The CD spectra showed that significant changes occurred in the secondary structure of PPI, where the ordered PPI structure formed a more open structure after enzymatic hydrolysis.

Potential protective effect of L-cysteine against the toxicity of acrylamide and furan in exposed Xenopus laevis embryos: an interaction study

The embryo toxicities of two food-processing-induced toxic compounds, acrylamide and furan, with and without added L-cysteine were examined individually and in mixtures using the frog embryo teratogenesis assay-Xenopus (FETAX). The following measures of developmental toxicity were used: (a) 96 h LC50, the median concentration causing 50% embryo lethality; (b) 96 h EC50, the median concentration causing 50% malformations of the surviving embryos; and (c) teratogenic index (96 h LC50/96 h EC50), an estimate of teratogenic risk. Calculations of toxic units (TU) were used to assess possible antagonism, synergism, or response addition of several mixtures. The evaluated compounds demonstrated counterintuitive effects. Furan had lower than expected toxicity in Xenopus embryos and, unlike acrylamide, does not seem to be teratogenic. However, the short duration of the tests may not show the full effects of furan if it is truly primarily genotoxic and carcinogenic. L-Cysteine showed unexpected properties in the delay of hatching of the embryos. The results from the interaction studies between combination of two or three components (acrylamide plus L-cysteine; furan plus L-cysteine; acrylamide plus furan; acrylamide plus furan and L-cysteine) show that furan and acrylamide seem to have less than response addition at 1:1 toxic unit ratio in lethality. Acrylamide and L-cysteine show severe antagonism even at low 19 acrylamide/1 L-cysteine TU ratios. Data from the mixture of acrylamide, furan, and L-cysteine show a slight antagonism, less than would have been expected from binary mixture exposures. Bioalkylation mechanisms and their prevention are discussed. There is a need to study the toxicological properties of mixtures of acrylamide and furan concurrently formed in heat-processed food.