Food industry coacervation

Equation (7.8) does not hold for proteins of a more or less unfolded conformation the protein may then form a coacervate rather than a precipitate (Section 6.5.1). However, the trends would be the same. Another point is that extreme pH values may lead to unfolding, even at room temperature. The molecules then generally have such a high charge as to be well soluble, despite the exposure of apolar groups. Most proteins used in the food industry are soluble at pH >9. An additional cause would be disruption of —S—S— bridges at such a pH. 

In spite of these limitations, the development of microcapsules by complex coacervation remains a viable area of study today from both a fundamental understanding and a commercial application point of view. Polymers derived from plant or milk that are adaptable to the complex coacervation encapsulation protocols have been used to replace gelatin isolated from animals. Interest in capsules produced by complex coacervation for food-related applications remains high because a variety of GRAS polymers can be used to produce commercially viable capsules accepted by the food industry. New technically and commercially viable polymers are being developed to meet the increasing demand from various applications and to fulfill the regulatory requirements. 

Thies, C., Biopolymers and complex coacervation encapsulation procedures. Agro Food Industry Hi Tech, 24(4) (2013) 50-52. 

Zhang, W., C. Yan, J. May, and C. J. Barrow, Whey protein and gum arabic encapsulated omega-3 lipids—The effect of material properties on coacervation. Agro Food Industry Hi Tech, 20(4) (2009) 20-24. 

There are many ways to microencapsulate active components, such as spray drying, film coating, coacervation, carrageenan entrapment, molecular encapsulation using P-cyclodextrin, double emulsions, liposomes, and microemulsions (Vilstrup, 2001). Of these, spray drying is currently the best technology available to the food industry to produce stable, cost-effective, microencapsulated ingredients or products. Spray dryers, first constmcted in 1878 (Hayashi, 1989), are now widely used in the dairy industry and, in a modified form, by infant formulae manufacturers. 

The encapsulation of various essential oils has intrigued the food, cosmetic, and pharmaceutical industries for some time. Several encapsulation systems based on the complex coacervation of gelatin have been used to encapsulate a range of essential oils. However, variable results have been obtained, especially with citrus oils. 

To our knowledge, simple coacervation has essentially remained a technology described by academics and used for research rather than in pharmaceutical industry. Green first demonstrated the microencapsula-tion of oil droplets by simple coacervation of gelatin. In this study, gelatin coacervation was induced by sodium or ammonium sulfate. Since then, simple coacervation has been used to encapsulate foods, flavors, and pharmaceuticals. ... 

This technique employs a conventional three-phase system the manufacturing vehicle (solvent), the flavor carriers (wall materials), and the flavor (core material). While there are several types of coacervation, complex coacervation is most commonly used in the food/flavor industry. 

The primary considerations for the flavor industry are the use of any meat or meat byproduct in process flavors, gelatin in process flavors or coacervation processes, and the use of alcohol as a component on any basis in a flavoring are all prohibited. There are various organizations that oversee halal certification of foods. Unlike the kosher certification, halal certification is younger and thus less well organized. Two organizations that come up on a web search are IFANCA (The Islamic Food and Nutrition Council of America, 5901 N. Cicero Avenue, Suite 309 Chicago, IL, 60646) and Halal Transactions, Inc., P.O. Box 4546, Omaha, NE, 68104). 

Complexation has frequently been correlated with the hydrophobic character of one (or both) of the interacting ions [273-279]. Details of the interaction between a series of dyes and alkyltrimethylammonium bromides have been published [277], The structure of the dyes used, tartrazine (XXVI) amaranth (XXVII) carmoisine (XXVIII) and erythrosine (XXIX) are shown below. These are all important colours used in the food, drug and cosmetic industries. Phase separation diagrams were constructed to indicate the relationship between surfactant concentration and the anisotropic solution-coacervate boundary. Differences between the interactions of a hydrophilic dye, tartrazine and amaranth, carmoisine and erythrosine which have both hydrophobic and hydrophilic moieties were exhibited. Tartrazine appears to behave like a simple electrolyte interacting simply with the charged groups at the micellar surfaces while the other dyes complexed and were solubilized as a complex in addition to interacting with the micelle surface [277]. These dyes also induced the formation... 

---