Rice starch and Co-proteins improve the rheological properties of zein dough

Influence of zein on viscoelastic properties and gluten network development during dough formation

This study investigated the effects of zein addition on the viscoelastic properties and gluten network of wheat dough. Results from Mixolab and dynamic rheometer showed that 2-3 % zein enhanced dough softness without affecting development time, stability, or creep recovery, while reducing pasting viscosity. Zein increased free water mobility, which decreased dough rigidity and facilitated deformation. Dough with 3 % zein showed a 26.50 % increase in free water relaxation time (T23). SE-HPLC revealed reduced gluten aggregation, increasing SDS-soluble polymeric and monomeric proteins and free sulfhydryl (SH) groups by 20 %. FTIR showed zein promoted antiparallel β-sheets and decreased β-sheet content. TGA indicated a 1.57 % increase in mass loss, and prolonged mixing lowered degradation temperature. CLSM confirmed zein weakened the gluten structure. These findings provided a better understanding of the interactions between zein and gluten in wheat dough, which could help optimize dough processing and improve product quality.

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.

Soy protein, zein, and rice starch for the development of improved plant protein-based products by high-moisture extrusion

The final characteristics of plant protein-based high moisture extrudates depend on the processing conditions and the composition of the raw materials. In this study, different soy protein-based formulations containing zein and rice starch were studied for the development of plant-based gluten-free high moisture extrudates. The physicochemical, rheological, textural, and microstructural characteristics of the final products were studied and related to the product formulation and the secondary structure of the participating proteins. Changes in the type and concentration of proteins had significant effects on the final rheological and microstructural properties of the resulting products, but these were not directly associated to changes on the secondary structure of proteins. The addition of rice starch generated softer products, while proteins' molecular associations and conformational arrangements defined the textural and microstructural characteristics. Products prepared with gluten (control) generated a layered and fibrous structure, but the study showed that gluten-free products with similar microstructural characteristics could be obtained from the addition of zein and rice starch. These results confirmed the key role of the formulation on the definition of the final characteristics of gluten-free products and that zein can be used for the generation of plant protein-based high moisture extrudates with desired textural properties.

Textural improvement of pea protein-based high-moisture extrudates with corn zein and rice starch

High moisture extrusion allows the production of plant protein-based products, including meat analogues. Building upon our previous findings showing that zein mixed with rice starch provides the necessary textural properties to formulations, different pea protein-based formulations with varying amounts of zein and rice starch or wheat gluten (as control) were produced using high moisture extrusion and the rheological, textural, and microstructural characteristics were evaluated and associated with the secondary structure of proteins. Samples containing wheat gluten presented desirable rheological and mechanical properties in terms of texturization, which was evidenced by the generation of a layered and three-dimensional viscoelastic network. The addition of rice starch to zein significantly increased the viscoelasticity of the samples due to enhanced development of non-covalent interactions that led to higher and more stable β-sheets content and to the formation of a fibrous and layered microstructure and a 3D network nearly like those obtained with gluten. The sole replacement of pea protein by zein was not enough to develop these desired characteristics, demonstrating the importance of the non-covalent interactions between rice starch and zein for the generation of these properties. Overall, zein and rice starch improved texturization of pea protein-based gluten-free analogues made by high moisture extrusion.

Impacts of ethanol-plasticization and extrusion on development of zein network and structure of zein-starch dough

To improve the viscoelasticity of zein in gluten-free dough, ethanol-plasticization and extrusion modification were employed. The peak viscosity of UZS (unextruded zein-starch) flour and EZS (extruded zein-starch) flour with ethanol (10 %, v/v) increased from 1340.0 to 1996.5 mPa·s and 1336.3 to 2291.5 mPa·s, and the bound bromophenol blue increased from 7.1 μg to 10.6 μg and 5.3 μg to 5.9 μg, respectively. Ethanol-plasticization enhanced zein's hydrophobic interactions and promoted zein network development, thus improving dough compatibility. However, the dense structure of the extruded zein made ethanol inaccessible to the interior, and the structural improvement on extruded zein-starch dough was limited. A model was developed to explain the influences of extrusion and ethanol-plasticization on the behavior of zein in the dough. Extrusion reduces the fiber-forming ability of zein, while ethanol-plasticization facilitates extensive fibrous network formation. This study provides a sound basis for the development of zein in gluten-free foods.

Breaking the temperature limitation of zein-rice starch dough by microwave pre-gelatinization: Morphological, structural and rheological properties of the dough

Zein has gluten-like viscoelasticity, but its use is limited due to high glass transition temperature (Tg). To break the temperature limitation of zein-starch dough, microwave heating was used to pre-gelatinize a partial of the starch with zein, and then the remaining was added and kneaded to form a dough. Pre-gelatinized doughs formed by rice starch (PRS), zein-starch (PUZS), and extruded zein-starch (PEZS) were included in this study. The thermal, morphological, rheological, and secondary structural properties of the dough were investigated. The results showed that zein and starch formed a composite gel network and firmly bound starch granules, which improved the dough properties with a smooth surface and compact internal structure, increased strain tolerance, and decreased stiffness. Unextruded zein was distributed uniformly and had strong interactions with the starch. Extruded zein tended to form large particles and had limited interaction with starch but improved dough extensibility. Microwave pre-gelatinization increased the stability of the secondary structure of zein and maintained the viscoelasticity of dough below zein's Tg, which provided a safe and effective way to break the temperature limitation of zein as a structural protein used in foods.

Wheat Flour Quality Assessment by Fundamental Non-Linear Rheological Methods: A Critical Review

Wheat quality assessment involves physical, physicochemical, chemical, and sensory characterization of wheat kernels and the resulting wheat flour, dough, and bread. The physical tests conducted on wheat flour dough are mostly based on empirical methods. Empirical methods have been useful in industry and research to relate wheat flour quality to baking performance. However, these methods have the disadvantage of providing data in arbitrary units, which makes the fundamental interpretation of results difficult. Therefore, this review focuses on the use of fundamental rheological methods to determine wheat flour quality in terms of processing performance. During the transition from wheat flour to bread, wheat flour dough is mostly exposed to large deformations, and the quality of wheat flour determines its response to these large deformations and its baking quality. For this reason, this review only focuses on the application of fundamental rheological tests that are conducted in the non-linear viscoelastic region where wheat flour dough experiences large deformations.

Effects of coarse cereals on dough and Chinese steamed bread - a review

Chinese steamed breads (CSBs) are long-established staple foods in China. To enhance the nutritional value, coarse cereals such as oats, buckwheat, and quinoa have been added to the formulation for making CSBs. This review presents the nutritional value of various coarse cereals and analyses the interactions between the functional components of coarse cereals in the dough. The addition of coarse cereals leads to changes in the rheological, fermentation, and pasting aging properties of the dough, which further deteriorates the appearance and texture of CSBs. This review can provide some suggestions and guidelines for the production of staple and nutritious staple foods.

Effect of Proofing on the Rheology and Moisture Distribution of Corn Starch-Hydroxypropylmethylcellulose Gluten-Free Dough

Dough rheology, mainly enabled by gluten in the traditional dough, determines the end-products' quality, particularly by affecting gas production and retention capacities during proofing. Gluten-free dough has quite different rheological performance compared with gluten-containing dough. To deepen the understanding of gluten-free dough, variations of rheology and moisture distribution of corn starch-hydroxypropylmethylcellulose (CS-HPMC) gluten-free dough in the process of proofing were studied. Significant differences were found in terms of soluble carbohydrate composition, moisture distribution, and rheology. Arabinose, glucose, fructose, and mannose were the main composition of soluble carbohydrates in CS-HPMC dough, out of which glucose was preferentially utilized during proofing. Non-freezable water content and third relaxation time decreased from 44.24% and 2171.12 ms to 41.39% and 766.4 ms, respectively, whereas the amplitudes of T₂₃ increased from 0.03% to 0.19%, indicating reduced bounded water proportion and improved water mobility with proofing time. Frequency dependence and the maximum creep compliance increased, whereas zero shear viscosity reduced, suggesting decreased molecular interactions and flowability, but improved dough rigidity. In conclusion, the reduced soluble carbohydrates and improved water mobility decreased molecular entanglements and hydrogen bonding. Furthermore, yeast growth restricted a large amount of water, resulting in declined flowability and increased rigidity.

Effect of soy protein isolate on physical properties of quinoa dough and gluten-free bread quality characteristics

BACKGROUND

Quinoa is a good gluten-free resource for food processing, especially bread making, and can improve and prevent the development of complications associated with celiac disease (CD). However, lack of gluten affects quinoa bread quality. Previous research showed that soy protein isolate (SPI) could improve gluten-free bread quality to some extent. Therefore, this study investigated the effects of SPI on the physical properties of quinoa dough and gluten-free bread quality characteristics.

RESULTS

Results showed that, with appropriate SPI substitution, the farinograph properties of quinoa flour significantly improved (P < 0.05). The sample with 8% SPI substitution showed a better development time (DT, 3.30 ± 0.20 min), stability time (ST, 8.80 ± 0.10 min) and softening degree (SD, 8.80 ± 0.10 FU), which were close to those of wheat flour, although more water absorption (WA, 76.40 ± 2.10%) was needed than for wheat flour (66.30 ± 3.10%). The extensograph properties of quinoa flour also significantly improved after 8% SPI substitution (P < 0.05). Furthermore, SPI substitution increased G' moduli of quinoa dough and decreased tan δ to some extent, providing better rheological properties closer to those of wheat dough. SPI substitution also improved the quality and texture of quinoa bread and reduced the gap with wheat bread. When SPI substitution was 8%, the specific volume, hardness and springiness of quinoa bread were 2.29 ± 0.05 mL g^-1 , 1496.47 ± 85.21 g and 0.71 ± 0.03%, respectively.

CONCLUSION

These results suggested that SPI substitution would be an effective way to develop higher-quality gluten-free bread. © 2022 Society of Chemical Industry.

Modification of zein dough functionality using kafirin as a coprotein

Kafirin, sorghum prolamin, was investigated as a coprotein for zein as visco-elastic masses and in starch-based model doughs. Regular kafirin and kafirins from waxy and high protein digestibility (HD) sorghum crosses were studied. HPLC revealed that waxy-HD kafirin was of smaller molecular size and low in β-kafirin. It also had greater surface hydrophobicity. Kafirin addition to zein increased visco-elastic mass elasticity up to ≈50% stress-recovery, similar to wheat gluten. Waxy-HD kafirin gave the highest elasticity, possibly due to its hydrophobicity. Kafirin inclusion at 2:8 parts zein increased the tensile strength of model doughs. Maximum strength was, however, only 60% that of gluten-based dough. Kafirin from regular sorghum gave the highest strength, possibly because of greater disulphide-bonded polymerisation. Confocal laser scanning microscopy showed that zein-kafirin copolymers formed fairly linear fibrils in stretched doughs, indicating excellent compatibility between the proteins. Future research should establish how kafirin-zein copolymer performs in non-wheat flour products.