Effect of thermomechanical treatment on the aggregation behaviour and colloidal functionality of β-Lactoglobulin at high concentrations

Quevedo, María Cristina Céspedes; Kulozik, Ulrich; Karbstein, Heike P.; Emin, M. Azad

doi:10.1016/j.idairyj.2020.104654

Cited by 9 publications

(10 citation statements)

References 41 publications

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“…Pommet et al [64] performed one of the first studies using a CCR for food biopolymers and investigated the aggregation/degradation behavior of wheat gluten/glycerol blends at elevated temperature under shear conditions. Further studies by our research group [43,[65][66][67][68][69][70][71] confirmed the applicability of this rheometer to study the reaction behavior of various protein and proteinpolysaccharide systems under defined extrusion-like conditions. To the best of our knowledge, however, the potentials of this rheometer in characterizing the complex rheological behavior of highly concentrated biopolymers have not yet been reported.…”

Section: Introductionmentioning

confidence: 53%

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

et al. 2020

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Highly concentrated biopolymers are used in food extrusion processing. It is well known that rheo-logical properties of biopolymers influence considerably both process conditions and product properties. Therefore, characterization of rheological properties under extrusion-relevant conditions is crucial to process and product design. Since conventional rheological methods are still lacking for this purpose, a novel approach is presented. A closed cavity rheometer known in the rubber industry was used to systematically characterize a highly concentrated soy protein, a very relevant protein in extruded meat analogues. Rheological properties were first determined and discussed in the linear viscoelastic range (SAOS). Rheo-logical analysis was then carried out in the non-linear viscoelastic range (LAOS), as high deformations in extrusion demand for measurements at process-relevant high strains. The protein showed gel behavior in the linear range, while liquid behavior was observed in the nonlinear range. An expected increase in elasticity through addition of methylcellulose was detected. The measurements in the non-linear range reveal significant changes of material behavior with increasing strain. As another tool for rheological characterization, a stress relaxation test was carried out which confirmed the increase of elastic behavior after methylcellulose addition.

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Section: Introductionmentioning

confidence: 53%

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

et al. 2020

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“…In contrast to the βLG used in previous studies [ 17 , 19 , 20 ], as already mentioned in the materials section, in this study a different lot of βLG powder was used, which was probably the cause of the observed aggregation behavior in these mixed systems. Due to the low ionic strength and, consequently, low buffering capacity of the solvent used during the purification step, a βLG lot with rather low pH (~4.7) was produced.…”

Section: Resultsmentioning

confidence: 97%

“…Pure bovine βLG was produced at the Chair of Food and Bioprocess Engineering of the Technical University Munich at Freising-Weihenstephan, Germany. The βLG powder used in our previous works [17,19,20] was isolated from whey protein solutions as described by [21]. The previously used lot of βLG was produced using water de-hardened by ion exchange, and it therefore had an ionic strength sufficient to stabilize the pH of the solution with distilled water as rehydration medium at pH 6.25.…”

Section: Methodsmentioning

confidence: 99%

“…Although the formation of non-covalent bonds was expected, since it is known that treatment below 80 • C of αLA and βLG in milk samples results mostly in non-covalent bond aggregation [30], it was not expected that it outweighed the formation of disulfide bonds at the treatment temperatures investigated. In [20], the aggregation behavior of βLG at concentrations above 50% was investigated, and it was shown that the aggregation between βLG molecules was mainly via disulfide bonds and non-disulfide covalent bonds. Additionally, thermal treatment of 70% αLA (w/w) at 80 and 100 • C resulted in a degree of disulfide bond aggregation of 30% and 85%, respectively (data not shown).…”

Section: Influence Of Thermomechanical Treatment On the Protein-protementioning

confidence: 99%

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Influence of Thermomechanical Treatment and Ratio of β-Lactoglobulin and α-Lactalbumin on the Denaturation and Aggregation of Highly Concentrated Whey Protein Systems

Quevedo

Kulozik

Karbstein

et al. 2020

Foods

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The influence of thermomechanical treatment (temperature 60 °C–100 °C and shear rate 0.06 s−1–50 s−1) and mixing ratio of β-lactoglobulin (βLG) and α-lactalbumin (αLA) (5:2 and 1:1) on the denaturation and aggregation of whey protein model systems with a protein concentration of 60% and 70% (w/w) was investigated. An aggregation onset temperature was determined at approx. 80 °C for both systems (5:2 and 1:1 mixing ratio) with a protein concentration of 70% at a shear rate of 0.06 s−1. Increasing the shear rate up to 50 s−1 led to a decrease in the aggregation onset temperature independent of the mixing ratio. By decreasing the protein concentration to 60% in unsheared systems, the aggregation onset temperature decreased compared to that at a protein concentration of 70%. Furthermore, two significantly different onset temperatures were determined when the shear rate was increased to 25 s−1 and 50 s−1, which might result from a shear-induced phase separation. Application of combined thermal and mechanical treatment resulted in overall higher degrees of denaturation independent of the mixing ratio and protein concentration. At the conditions applied, the aggregation of the βLG and αLA mixtures was mainly due to the formation of non-covalent bonds. Although the proportion of disulfide bond aggregation increased with treatment temperature and shear rate, it was higher at a mixing ratio of 5:2 compared to that at 1:1.

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“…At least a small reduction in die pressure would have been expected at SPI + 30% WPC; thus, this expected viscosity reduction must have been outweighed by some other effect. Whey proteins are known to be reactive and aggregate at extrusion conditions [ 46 , 47 ], leading to an increase in viscosity [ 48 ], which could be such an overlying effect. Reactivity could also be considered for the pressure increase at 133 °C in SPI.…”

Section: Resultsmentioning

confidence: 99%

Blending Proteins in High Moisture Extrusion to Design Meat Analogues: Rheological Properties, Morphology Development and Product Properties

Wittek

Karbstein

Emin

2021

Foods

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High moisture extrusion (HME) of meat analogues is often performed with raw materials containing multiple components, e.g., blends of different protein-rich raw materials. For instance, blends of soy protein isolate (SPI) and another component, such as wheat gluten, are used particularly frequently. The positive effect of blending on product texture is well known but not yet well understood. Therefore, this work targets investigating the influence of blending in HME at a mechanistic level. For this, SPI and a model protein, whey protein concentrate (WPC), were blended at three different ratios (100:0, 85:15, 70:30) and extruded at typical HME conditions (55% water content, 115/125/133 °C material temperature). Process conditions, rheological properties, morphology development, product structure and product texture were analysed. With increasing WPC percentage, the anisotropic structures became more pronounced and the anisotropy index (AI) higher. The achieved AI from the extrudates with a ratio of 70:30 (SPI:WPC) were considerably higher than comparable extrudates reported in other studies. In all extrudates, a multiphase system was visible whose morphology had changed due to the WPC addition. The WPC led to the formation of a much smaller dispersed phase compared to the overlying multiphase structure, the size of which depends on the thermomechanical stresses. These findings demonstrate that targeted mixing of protein-rich raw materials could be a promising method to tailor the texture of extruded meat analogues.

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Effect of thermomechanical treatment on the aggregation behaviour and colloidal functionality of β-Lactoglobulin at high concentrations

Cited by 9 publications

References 41 publications

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

Influence of Thermomechanical Treatment and Ratio of β-Lactoglobulin and α-Lactalbumin on the Denaturation and Aggregation of Highly Concentrated Whey Protein Systems

Blending Proteins in High Moisture Extrusion to Design Meat Analogues: Rheological Properties, Morphology Development and Product Properties

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