Emulsifying and Structural Properties of β-Lactoglobulin at Different PHs

Shimizu, Makoto; Saito, Masayoshi; Yamauchi, Kunio

doi:10.1080/00021369.1985.10866680

Cited by 41 publications

(54 citation statements)

References 10 publications

(8 reference statements)

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“…The apparent relationship between protein hydrophobicity and emulsifying properties has been reviewed by Nakai. 86 However, the results obtained by Shimizu et al 84 were inconsistent with the correlations proposed by Kato and Nakai,87 indicating that factors other than hydrophobicity are important for the emulsifying properties of β-Lg. Haque and Kinsella 51 -52 observed that β-Lg formed finer, more stable emulsion droplets than the more hydrophobic caseins.…”

Section: β-Lactoglobulinmentioning

confidence: 90%

“…Shimizu et al 84 showed that the EAI of β-Lg was low at pH 3, but increased with an increasing in pH to pH 9.0. At pH 3, the amount of β-Lg in the adsorbed interfacial film layer was much less than at pH 9.…”

Section: β-Lactoglobulinmentioning

confidence: 98%

“…At acidic pH, the β-Lg assumes a more rigid, stable structure that is more resistant to unfolding and, hence, does not easily form films at the interface. 84 At alkaline pH values β-Lg is much more expanded and flexible 27 and forms good stable films. 85 During adsorption at an interface, proteins undergo significant conformational changes.…”

Section: β-Lactoglobulinmentioning

confidence: 99%

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Surface activity, film formation, and emulsifying properties of milk proteins

Leman

Kinsella

Kilara

1989

Critical Reviews in Food Science and Nutrition

101

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This overview indicates that simple, reliable standardized methods for measuring emulsifying activity and for determining ES are not yet available. One of the major shortcomings of most of the current methods is the inability to detect very small fat globules (less than 0.5 micron), which may be very important in stable emulsions. Several of the methods are time consuming and destructive. To minimize the time required to evaluate emulsions, techniques that monitor instability under the influence of accelerated aging (increased temperature and gravitational field) have been used with varying degrees of success. These methods, e.g., centrifugation, are useful, but processes occurring during centrifugation or heating may not be characteristic of those occurring in a stored emulsion. Generally, there is no method that simultaneously determines changes in emulsions due to the aggregation coalescence, flocculation, creaming, of the droplets and/or oiling off. No single criterion of emulsion instability is sufficient to characterize all the changes occurring in the system. A nonintrusive technique that can monitor dynamic changes in emulsions is needed. Ideally, it should be simple, rapid, inexpensive, and applicable to both diluted and concentrated emulsions. Scientists must continue research to develop such a standard universal method for determining ES, because data from different laboratories cannot currently be validly compared. Reliable methods are also required to elucidate relationships between the physical properties of proteins as emulsifiers and their performance in food emulsions. There is a need for opportunities for systematic research to determine the interfacial behavior of food emulsifiers, particularly food proteins. Research to describe the kinetics and thermodynamics of adsorption at an interface, the extent of unfolding, the degree of packing and polypeptide interactions in an interface during film formation, and information concerning the physical and mechanical properties of interfacial films is needed to describe emulsifying behavior of different proteins. The effects of components in the continuous and discontinuous phase, parameters of manufacture, and interactions between different types of surface-active materials that occur in food need to be studied.

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Section: β-Lactoglobulinmentioning

confidence: 90%

Section: β-Lactoglobulinmentioning

confidence: 98%

Section: β-Lactoglobulinmentioning

confidence: 99%

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Surface activity, film formation, and emulsifying properties of milk proteins

Leman

Kinsella

Kilara

1989

Critical Reviews in Food Science and Nutrition

101

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“…In contrast with other results, water layers at the bottom were very clean, and emulsion layers gelled after the emulsions had formed at pH 3.0 and had been heated at 85°C for 48 h. This indicated that the SP-SDS complex bound lipids more strongly in more alkaline or acidic media than the isoelectric point of SP. The pH can affect protein solubility and S 0 (25). ES values at pH 5.0 were lower owing to lower solubility and S 0 , and to the pH being close to the isoelectric point of the isolate.…”

Section: Resultsmentioning

confidence: 96%

Enhancing storage stability of emulsions by binding detergents with soy protein isolate and its hydrolysates

Hettiarachchy

Rhee

1998

J Surfact & Detergents

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Sodium dodecyl sulfate (SDS) is a frequently used anionic detergent, and proteins are among the widely used minor ingredients in cosmetic products. Proteins may enhance the detergent functions and protect human skin from irritation caused by detergents. Soy protein hydrolysates (SPH) were prepared by modifying soy protein (SP) with papain. Varying concentrations of SP or SPH were mixed with various concentrations of SDS at different pH values to determine: (i) molecular characteristics, degree of hydrolysis (DH), and surface hydrophobicity (S 0 ) of SP and SPH; (ii) the effect of SDS concentrations on the S 0 of SP; (iii) the storage stabilities of oil-in-water emulsions formed by SDS, SP, SPH, SP-SDS, and SPH-SDS; and (iv) the effect of protein concentration (0.01 to 1.5%), DH (1.2 to 12.5%), and pH (3.0, 5.0, 7.0, and 9.0) on storage stabilities of emulsions formed by SP-SDS or SPH-SDS. An increase in emulsion stability (ES) with increasing protein concentration was observed. The ES values of emulsions formed by SPH-SDS complexes were significantly higher than those formed by SP-SDS at pH 7.0 and 9.0. The ES of emulsions formed by the complexes were low at pH 5.0 and increased with increasing pH. At pH 3.0 the emulsions formed by SP-SDS at 1 to 1.5% protein concentration and by SPH-SDS at 1.5% protein concentration were very stable. The results indicate that at least one-half of SDS content can be replaced by SP or SPH while maintaining emulsion stability. JSD 1, 387-392 (1998).KEY WORDS: Degree of hydrolysis, pH, protein concentration, protein hydrolysate, soy protein-SDS complex, storage stability of emulsion, surface hydrophobicity.The demand for natural personal-care products is increasing. Natural cosmetic ingredients have better biodegradability than synthetic products and provide good performance (1,2). Proteins and their derivatives are among the most widely used minor ingredients in cosmetic products (3). Collagen, a protein from animals, after many years of successful use in many different cosmetics, has achieved a connotation of quality and performance with the consumer (4). However, concern about certain communicable diseases such as the so-called mad cow disease and increasing support for animal rights have increased demand for plant sources of natural cosmetic ingredients (1,2,4,5). Native proteins with low water solubility and low hydrophobicity are not suitable for water-based cosmetic formulations. Protein hydrolysates have been shown to have higher water solubility, surface hydrophobicity, and emulsifying and foaming properties. However, fragmentation of such proteins into shorter peptides lowers their ability to protect the skin surfactant against irritation (3,6).Basic functions of detergents are to clean, disperse, emulsify, foam, and penetrate. However, detergents create increased dermatological problems, such as skin redness, roughness, and irritation. Sodium dodecyl sulfate (SDS), an anionic detergent frequently used in cosmetic products, can electrostatically and nonpolarly interact wit...

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“…It was reported that a heat-induced rise in SH was observed in milk proteins, and it was caused by the denaturation of their tertiary and secondary structures (Euston, Ur-Rehman, & Costello, 2007;Eynard, Iametti, Relkin, & Bonomi, 1992;Risso, Borraccetti, Araujo, Hidalgo, & Gatti, 2008;Sava, Van der Plancken, Claeys, & Hendrickx, 2005). When adjusting the pH of a milk protein solution, the change in SH value was observed to be closely linked with their solubility and functional properties (Alizadeh-Pasdar & Li-Chan, 2000;Shimizu, Saito, & Yamauchi, 1985;Voutsinas, Cheung, & Nakai, 1983). Hence, in the present case, the change in SH is not only caused by the thermal stress during drying, but also the structural characteristics of the casein clusters.…”

Section: Encapsulation Efficiency and Surface Hydrophobicitymentioning

confidence: 96%