Complex Coacervation of Whey Proteins and Gum Arabic
TL;DR: A strong similarity is seen between the behavior of this system and a colloidal gas-liquid phase separation, and a "metastable" region delimited by a percolation line is seen.
About: This article is published in Biomacromolecules.The article was published on 2003-01-30. It has received 552 citations till now. The article focuses on the topics: Whey protein isolate & Whey protein.
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TL;DR: In this article, the essential molecular features of hydrocolloids having the ability to act as emulsifying agents and emulsion stabilizing agents are considered, and the criteria for effectiveness in protecting newly formed droplets against flocculation and coalescence are contrasted with the requirements to maintain long-term stability against aggregation, creaming and Ostwald ripening.
1,049 citations
TL;DR: The structure of the concentrated polymer phase seems to resemble a continuous polymer phase in which the protein can diffuse around, as well as the individual polysaccharide molecules, which resembles the behaviour of a (viscous) concentrated particle dispersion.
Abstract: Coacervation of proteins and anionic polysaccharides is both of practical and theoretical interest. From a large body of literature, it seems that the phase separation is mainly entropically driven, and may most probably be attributed to the delocalisation of the counter ions of the protein and the polysaccharide. The protein and polysaccharide appear to form complexes in solution, which can be viewed as new colloidal entities. These complex particles are neutral and exhibit an attractive interaction, which leads to a phase separation of the gas-liquid type in which a (very) dilute colloidal phase coexists with a very concentrated colloidal phase. In the case of strong poly-acids, usually, a precipitate is formed rather than a liquid coacervate phase. The structure of the concentrated polymer phase seems to resemble a continuous polymer phase in which the protein can diffuse around, as well as the individual polysaccharide molecules. Time scales of diffusion vary from milliseconds to days depending on the strength of the interaction. From a rheological point of view, the concentrated phase is much more viscous than elastic and the rheology resembles the behaviour of a (viscous) concentrated particle dispersion. Theoretical developments are limited probably due to the difficulty to describe the (correlated) charge distribution in the system. There is a strong interest in coacervates for the use of encapsulation. For the same reason, much attention is given to replacing the traditional gelatin by milk and plant proteins.
1,000 citations
TL;DR: A brief overview of the major bioactive lipids that need to be delivered within the food industry (for example, omega-3 fatty acids, carotenoids, and phytosterols) is provided, highlighting the main challenges to their current incorporation into foods.
Abstract: There is a pressing need for edible delivery systems to encapsulate, protect, and release bioactive lipids within the food, medical, and pharmaceutical industries. The fact that these delivery systems must be edible puts constraints on the type of ingredients and processing operations that can be used to create them. Emulsion technology is particularly suited for the design and fabrication of delivery systems for encapsulating bioactive lipids. This review provides a brief overview of the major bioactive lipids that need to be delivered within the food industry (for example, ω-3 fatty acids, carotenoids, and phytosterols), highlighting the main challenges to their current incorporation into foods. We then provide an overview of a number of emulsion-based technologies that could be used as edible delivery systems by the food and other industries, including conventional emulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems could be produced from food-grade (GRAS) ingredients (for example, lipids, proteins, polysaccharides, surfactants, and minerals) using simple processing operations (for example, mixing, homogenizing, and thermal processing). For each type of delivery system, we describe its structure, preparation, advantages, limitations, and potential applications. This knowledge can be used to facilitate the selection of the most appropriate emulsion-based delivery system for specific applications.
889 citations
TL;DR: This review focuses on the main research streams followed in this field during the last 12 years regarding: i) the parameters influencing the formation of complexes and coacervates in protein-polysaccharide systems; ii) the characterization of the kinetics of phase separation and multi-scale structure of the complexes andCoacervate; and iii) the investigation of the functional properties in food applications.
671 citations
TL;DR: The factors affecting the stability of emulsions using food proteins will be discussed and the use of polysaccharides to complex with proteins will also be explored in relation to enhancing emulsion stability.
607 citations
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TL;DR: The protein-polysaccharide complexes exhibit better functional properties than that of the proteins and polysaccharides alone, and could be attributed to the simultaneous presence of the two biopolymers, as well as the structure of the complexes.
Abstract: Food proteins and polysaccharides are the two key structural entities in food materials. Generally, interactions between proteins and polysaccharides in aqueous media can lead to one- or two-phase systems, the latter being generally observed. In some cases of protein-polysaccharide net attraction, mainly mediated through electrostatic interactions, complex coac-ervation or associative phase separation occurs, giving rise to the formation of protein-polysac-charide complexes. Physicochemical factors such as pH, ionic strength, ratio of protein to polysaccharide, polysaccharide and protein charge, and molecular weight affect the formation and stability of such complexes. Additionally, the temperature and mechanical factors (pressure, shearing rate, and time) have an influence on phase separation and time stability of the system. The protein-polysacchaide complexes exhibit better functional properties than that of the proteins and polysaccharides alone. This improvement could be attributed to the simultaneou...
782 citations
TL;DR: In this article, the authors describe the structure formation in the mixed systems in combination with rheological characterisation and make progress in the description of the mechanisms underlying the phase separation processes by the use of scattering techniques.
Abstract: Numerous investigations on protein–polysaccharide systems have recently been undertaken and are leading to a better understanding of the key parameters implied in protein–polysaccharide interactions. Microscopic methods are being developed to describe the structure formation in the mixed systems in combination with rheological characterisation. Progress is also being made in the description of the mechanisms underlying the phase separation processes by the use of scattering techniques.
627 citations
496 citations
TL;DR: In this article, the interaction between proteins and polysaccharides, as can be observed in food related systems, is systematically discussed by separating biopolymer interactions into respectively enthalpy- and entropy-dominated types.
469 citations
TL;DR: In this article, the authors studied the factors affecting the nature and strength of electrostatic protein-polysaccharide interactions and proposed a method to predict how solution conditions such as pH and ionic strength influence food macromolecular functional properties.
Abstract: Proteins and polysaccharides are the two kinds of biopolymers used by food technologists to control structure, texture and stability. In any particular situation, the constituent protein molecules may be attracted towards the polysaccharide molecules (complexation) or repelled apart (segregation). The polyelectrolyte character of milk proteins and hydrocolloid stabilizers like carrageenan and pectin means that electrostatic interactions play an important role in determining mixed biopolymer behaviour. In order to be able to predict how solution conditions such as pH and ionic strength influence food macromolecular functional properties, we need to understand the factors affecting the nature and strength of electrostatic protein–polysaccharide interactions.
382 citations