Rheological Study on the Fractal Nature of the Protein Gel Structure

Ikeda, Shinya; Foegeding, E. Allen; Hagiwara, Takaaki

doi:10.1021/la9817415

Cited by 196 publications

(174 citation statements)

References 54 publications

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“…It should be noted that the fractal dimension remains unchanged upon projection, providing D ≤ 2 (Mandelbrot, 1983). Thus, the values of D in this study were close to the value that is expected for the cluster-cluster aggregation model (Weitz and Huang, 1984;Weitz and Huang, 1986;Meakin, 1998;Ikeda et al, 1999). The structure of opaque and particulate gels was previously analyzed in terms of the fractals using CLSM (Hagiwara et al, 1997;Doi and Tokita, 2005).…”

Section: Effects Of 2-me On Microstructures Of 11s and Spi Gelssupporting

confidence: 81%

Contribution of Disulfide Bonding to Viscoelastic Properties and Microstructures of 11S Globulin Gels from Soybeans: Magnesium Chloride-Induced Gels

Nagano

2013

FSTR

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The role of disulfide bonding in the structure of gels formed from soybean proteins was investigated. Heat-induced gels of 11S globulin (11S) and soybean protein isolate (SPI) were prepared using magnesium chloride as a coagulant, and the effects of 2-mercaptoethanol (2-ME), which prevents the formation of disulfide bonds, on the viscoelastic properties and microstructures of these gels were determined. The effects of 2-ME were quantified using dynamic viscoelastic measurement (DVM) and confocal laser scanning microscopy (CLSM). DVM indicated that 11S gels showed higher storage modulus (G') and lower mechanical loss tangent (tan δ ) than SPI gels. CLSM was used to examine microstructures of 11S and SPI gels, and to determine their fractal dimension and the average density of network structures. The 11S gels showed lower fractal dimension and denser gel networks than SPI gels. These characteristic viscoelastic properties and microstructures of the 11S gel were lost with increasing 2-ME concentration, suggesting that the characteristic properties of 11S gels are due to disulfide bonding.Keywords: 11S globulin, disulfide bond, heat-induced gel, dynamic viscoelastic measurement, confocal laser scanning microscopy *To whom correspondence should be addressed. E-mail: naganot@mw.kawasaki-m.ac.jp IntroductionTofu is a traditional soybean-based food that is especially popular in Asian countries. Tofu is a gel of soybean proteins that is produced by adding coagulants to heated soybean milk (Saio, 1979). Magnesium chloride (MgCl 2 ), calcium sulfate (CaSO 4 ), and glucono-δ-lactone (GDL) are common coagulants used on an industrial scale for the preparation of tofu (deMan et al., 1986). Although MgCl 2 is the most commonly used coagulant for tofu production in Japan (Toda et al., 2003), there is little information concerning MgCl 2 -induced gels of soybean proteins. Most studies on tofu formation and properties have used GDL or CaSO 4 as the coagulant because the rates of gel formation are relatively slow and more homogeneous gels are formed (Saio et al., 1969;Nishinari et al., 1991;Kohyama and Nishinari, 1993;Kohyama et al., 1995;Liu et al., 2004;Tay and Perera, 2004;Guo and Ono, 2005;Ono, 2008).The two dominant soybean storage proteins are 7S globulin (7S) and 11S globulin (11S), which together constitute approximately 70% of the total storage protein at maturity (Nielsen, 1985). Soybean protein isolate (SPI) is prepared from water-extracted soybean proteins by acidic precipitation and consists mainly of 7S and 11S. Rheological properties of heat-induced 7S, 11S, and SPI gels have been extensively studied (Saio et al., 1973;Hermansson, 1986;van Kleef, 1986;Nakamura et al., 1986;Yamauchi et al., 1991; Nagano et al., 1994ab;Renkema et al., 2001;Lakemond et al., 2003;Renkema, 2004). Most studies have reported that of all the soybean proteins, 11S has the greatest ability to form heatinduced gels. However, the reasons why 11S proteins form harder and stiffer gels than other soybean proteins remain unclear.The cross-link bond...

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Section: Effects Of 2-me On Microstructures Of 11s and Spi Gelssupporting

confidence: 81%

Contribution of Disulfide Bonding to Viscoelastic Properties and Microstructures of 11S Globulin Gels from Soybeans: Magnesium Chloride-Induced Gels

Nagano

2013

FSTR

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“…At neutral pH, heatinduced whey protein gels show transitions, with increasing concentration of monovalent ions in the systems, from transparent or translucent gels, composed of fine strands with a diameter of several nanometers, to opaque syneresing gels, consisting of particulate aggregates that could be some micrometers in size. 2,21,[35][36][37][38][39] Enormous efforts have been made to understand physical properties of whey protein gels but most of such studies deal only with final gels that had experienced rather severe heat-treatments. Relatively little experimental works have been done for investigating events occurring during gelation.…”

Section: Introductionmentioning

confidence: 99%

Mechanical characterization of network formation during heat-induced gelation of whey protein dispersions

2000

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“…Briefly, assuming the colloidal gel as a series of interconnected flocs, the storage modulus is related to the protein concentration in a power law manner with a scaling exponent containing information about the fractal dimension of the aggregates [75,77,98]. Depending on the type and flexibility of the network junction, the storage modulus is correlated either to the entropic or to the enthalpic elasticity [77].…”

Section: Biotechnology Journalmentioning

confidence: 99%

A multiscale view of therapeutic protein aggregation: A colloid science perspective

Nicoud

Owczarz

Arosio

et al. 2015

Biotechnology Journal

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The formation of aggregates in protein-based pharmaceuticals is a major issue that can compromise drug safety and drug efficacy. With a view to improving protein stability, considerable effort is put forth to unravel the fundamental mechanisms underlying the aggregation process. However, therapeutic protein aggregation is a complex multistep phenomenon that involves time and length scales spanning several orders of magnitude, and strategies addressing protein aggregation inhibition are currently still largely empirical in practice. Here, we review how key concepts developed in the frame of colloid science can be applied to gain knowledge on the kinetics and thermodynamics of therapeutic protein aggregation across different length scales. In particular, we discuss the use of coarse-grained molecular interaction potentials to quantify protein colloidal stability. We then show how population balance equations simulations can provide insights into the mechanisms of aggregate formation at the mesoscale, and we highlight the strength of the concept of fractal scaling to quantify irregular aggregate morphologies. Finally, we correlate the macroscopic rheological properties of protein solutions with the occupied volume fraction and the aggregate structure. Overall, this work illustrates the power and limitations of colloidal approaches in the multiscale description of the aggregation of therapeutic proteins.

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Rheological Study on the Fractal Nature of the Protein Gel Structure

Cited by 196 publications

References 54 publications

Contribution of Disulfide Bonding to Viscoelastic Properties and Microstructures of 11S Globulin Gels from Soybeans: Magnesium Chloride-Induced Gels

Contribution of Disulfide Bonding to Viscoelastic Properties and Microstructures of 11S Globulin Gels from Soybeans: Magnesium Chloride-Induced Gels

Mechanical characterization of network formation during heat-induced gelation of whey protein dispersions

A multiscale view of therapeutic protein aggregation: A colloid science perspective

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