Phosvitin-wheat gluten complex catalyzed by transglutaminase in the presence of Na2SO3: Formation, cross-link behavior and emulsifying properties

Insight into the solubilization mechanism of wheat gluten by protease modification from conformational change and molecular interaction perspective

The low solubility limits the utilization of other functional characteristics of wheat gluten (WG). This study effectively improved the solubility of WG through protease modification and explored the potential mechanism of protease modification to enhance the solubility of WG, further stimulating the potential application of WG in the food industry. Solubility of WG modified with alkaline protease, complex protease, and neutral protease was enhanced by 98.99%, 54.59%, and 51.68%, respectively. Notably, the content of β-sheet was reduced while the combined effect of hydrogen bond and ionic bond were increased after protease modification. Meanwhile, the reduced molecular size and viscoelasticity as well as the elevated surface hydrophobicity, thermostability, water absorption capacity, and crystallinity were observed in modified WG. Moreover, molecular docking indicated that protease was specifically bound to the amino acid residues of WG through hydrogen bonding, hydrophobic interaction, and salt bridge.

Unraveling the deterioration mechanism of dough during whole wheat flour processing: A case study of gluten protein containing arabinoxylan with different molecular weights

This study aims to the effect of arabinoxylan (AX) on gluten quality. Ultrasonic treatment is utilized to degrade water unextractable arabinoxylans (WUAX) from wheat bran, which obtains three molecular weights of AX. The results indicate that the shear viscosity and particle size of AX were decreased and the ζ-potential was increased after ultrasonic treatment. Analysis of the gluten shows that the free SH of gluten with 6% WUAX, SAX10, and SAX30 (ultrasound duration for 10 min and 30 min) was increased by 51.9%, 48.1%, and 17.0%, respectively, whereas the free SH of 2% SAX30-gluten was increased by 19.8%. Furthermore, WUAX impaired the viscoelasticity properties of gluten, while SAX30 improved the viscoelasticity of gluten. WUAX induced the open, fragile, and discontinuous structure of gluten. On the contrary, SAX30 promoted the formation of the compact and regular gluten structure. Overall, ultrasonic as a non-chemical treatment could be used to improve the quality of whole-wheat foods.

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.

Physicochemical and Structural Properties of Gluten-Konjac glucomannan Conjugates Prepared by Maillard Reaction

Gluten (Glu) is important to wheat products by forming a three-dimensional matrix. This study aimed to investigate the physicochemical and structural properties of gluten after conjugation with konjac glucomannan (KGM) through the Maillard reaction. The study revealed that the degree of graft increased with the prolonged reaction time. The Glu-KGM conjugates were possessed of increased β-sheet but decreased α-helix and β-turn, as well as unfolding and loose tertiary structures as the reaction proceeded. Among three different proportions, the Glu-KGM 1:1 conjugate was proved to have the most excellent foaming and emulsifying properties, and could form more rigid and firm gelation structures, which could be related to the decreased particle size and increased zeta potential of the conjugate. Overall, the physicochemical and structural properties of gluten were significantly related to the KGM ratios as well as the reaction period.

Plant Protein versus Dairy Proteins: A pH-Dependency Investigation on Their Structure and Functional Properties

Plant proteins are constantly gaining attention as potential substitutes for dairy proteins, due to their suitable functionality and nutritional value. This study was designed to compare the structural and functional responses of different plant protein isolates (soy, pea, lentil, and chickpea) with two commonly used dairy protein (whey protein isolates and sodium caseinate) under different pH treatments (pH 3.0, 5.0, 7.0, and 9.0). The results showed that pH had a different alteration on the structural, surface properties and functional properties of plant and dairy proteins. Plant protein generally possessed a darker color, lower solubility, emulsifying properties, and foaming capacity, whereas their foaming stability and water holding capacity were higher than those of dairy proteins. Soy protein isolates were characterized by its comparable proportion of β-turn and random coils, zeta-potential, emulsifying (30.37 m²/g), and water-holding capacity (9.03 g/g) at alkaline conditions and chickpea protein isolates showed good oil-holding capacity (3.33 g/g at pH 9) among plant proteins. Further analysis confirmed that pH had a greater influence on the structural and functional properties of proteins as compared to protein sources, particularly at acidic conditions. Overall, this study might help processors select the appropriate plant protein as dairy alternatives for their target application in plant-based food products.

Interaction mechanism between cereal phenolic acids and gluten protein: protein structural changes and binding mode

BACKGROUND

Phenolic acids are antioxidant nutrients in cereals and affect the quality of wheat products and the properties of gluten protein. Gallic acid (GA), caffeic acid (CA), syringic acid (SA), and p-coumaric acid (p-CA) were selected to study the interaction mechanism between cereal phenolic acids and gluten protein.

RESULTS

The results showed that adding GA significantly (P < 0.05) decreased the content of free sulfhydryl in gluten proteins by 70-87.26% compared with the control group. The aggregates' behavior of gluten protein induced by adding the phenolic acids would produce oversized particles (>5000 nm). Adding the selected phenolic acids changed the hydrogen-bond linkage of protein secondary structure. Zeta potential values of gluten protein increased significantly (P < 0.05) by 14.41%, 26.49%, 30.77%, and 57.93% for CA, p-CA, GA, and SA respectively added at 0.03 g kg^-1 . Moreover, the gluten protein surface hydrophobicity increased when the phenolic acids were added at 0.03 g kg^-1 , displaying the effect of the phenolic acid on the hydrophobic interaction of protein. Molecular docking results showed that the selected phenolic acids could interact with glutenin and gliadin using hydrogen-bond formation, and SA had the strongest binding with glutenin and gliadin.

CONCLUSION

The results demonstrated that the selected phenolic acids could interact with gluten protein via covalent cross-linking as well as by hydrogen bonding, thereby changing the structure of the gluten protein. This exploration is expected to provide theoretical support for the development and utilization of whole-grain foods. © 2022 Society of Chemical Industry.

Casein-hempseed protein complex via cross-link catalyzed by transglutaminase for improving structural, rheological, emulsifying and gelation properties

In present study, microbial transglutaminase (MTGase) was applied to strengthen the interaction between casein and hempseed protein (HPI) through crosslinking. The structural and functional characteristics of this heteropolymers were investigated. Both homologous and heterologous crosslinking were achieved by adding MTGase in casein-HPI system, and thus enhanced zeta potential, surface hydrophobicity, viscosity, emulsifying and gelation properties of the complex. However, HPI hindered the crosslinking due to unbalanced Lys/Gln ratios. Emulsifying and gelling properties were significantly correlated with the secondary structures. When MTGase activity was < 30 U/g or treatment time was < 2 h, the α-helix content decreased by 9% while the β-sheet content increased by 12%, respectively, with MTGase activity and treatment time increase. The structural alterations resulted in the better emulsifying activity, gel networks and water holding capacity of the complex. This work represents a novel interaction mode between casein and HPI via MTGase to elevate functional properties of complex.

Improving physicochemical properties of myofibrillar proteins from wooden breast of broiler by diverse glycation strategies

The effect of diverse glycation strategies on the physicochemical and structural properties of wooden breast myofibrillar protein (WBMP) were studied. The WBMP was mixed with D-ribose (RI), sodium alginate (SA), and glucosamine (GH) respectively in a weight ratio of 1:2 (w/w) at 70 °C, and was heated for 6 h. Atomic force microscopy and particle size results showed that the glycation reaction in the presence of RI made WBMP to be more evenly dispersed in the solution and had a significantly smaller particle size (78-955 nm, average 361.06 nm) (P < 0.05). There was an increase in WBMP-RI solubility (76.23 ± 0.56%) and α-helix content (51.23 ± 1.1%) than other groups. Compared with WBMP-RI, WBMP-SA and WBMP-GH have poor performance in particle distribution, solubility and emulsification. This study clarified the aldehyde group in aldose was more suitable for the glycation modification of WBMP than the ketone group in ketose.