The science of beverage emulsions

Stabilising beverages poses a unique challenge for formulators because of their very dilute nature. Formulators have to find a way of stabilising sensitive ingredients like colours, flavours, or micronutrients, many of which may not even be soluble in water, down to microgram levels in litres of liquid.

Pepsi-Co’s Peter Given Jr. recently reviewed the options for encapsulating flavours in beverage emulsions and concluded that there is “a growing need for enhanced emulsion functionality in beverages, such as controlled release, protection, taste masking, and targeted delivery”​ (Current Opinion in Colloid & Interface Science​, 2009, Vol. 14, pp. 43-47).

However, to achieve these goals research and development must produce “more sophisticated dispersion technologies employing complex mixtures of biopolymers as well as low molecular weight surfactants, and novel multilayered interfacial structures”​.

Simple systems that use only one emulsifier, like gum acacia or modified starch, will produce simple beverages, he said. In his review, Given noted that “virtually all beverage flavour macroemulsions employ biopolymeric emulsifiers”​, and these can be either natural or chemically modified.

Various ingredient combinations are mentioned in the literatureas beverage emulsion stabilisers, with a range of enzyme modifed ingredients being tested. For example, patented amylase enzymes from Novozymes have been used to improve the functionality of modified starch. Another patent (EP332027B1) covers the beta-amylase modification of native starch to enhance their emulsifying action.

Modification of pectin has also produced a range of ingredients for use in emulsions, microencapsulation, foam stabilization, and film formation, said Given.

Finnish and USDA researchers are exploring the potential of galactoglucomannan (GGM) from spruce as stabilisers for beverage emulsions. Recent data (LWT - Food Science and Technology​, 2009, Vol 42, pp. 849-855) indicated that GGM was more effective at beverage stablisation than guar gum, Konjac glucomannan, and locust bean gum.

The potential of soybean soluble polysaccharide (SSPS) was recently investigated by Canadian and Japanese researchers, and found to form stable oil-in-water emulsions (J. Agric. Food Chem​., 2007, Vol. 55, pp. 502-509).

A recent development in this field was a hydrocolloid blend based principally on gellan gum from CP Kelco. Their Kelcogel PS ingredient, launched in 2004, reportedly forms “fluid gels”​ or a structured network formed at very low hydrocolloid concentrations. The concentration is too low to create a gel, but the gellan gum system still forms a weak network.

Health & wellness​

The move towards health and wellness, and adding in bioactive ingredients like vitamins and minerals, leads to an increase in the particle content of the beverage. Ingredients are then needed to help suspend and stabilise the functional ingredients.

Many hydrocolloids help solve these problems, but which hydrocolloid should be used? The challenge is to suspend and stabilise these micronutrients without thickening the beverage to the point where it becomes undrinkable.

Pectin is one such highly versatile solution. Ralph Appel, business unit leader,from Cargill Texturizing told this website in 2008: "In the production of health foods, pectins and hydrocolloids in general can play a significant role in creating good texture, mouthfeel and taste and so on, particularly if other elements such as salt, fat or sugar have been reduced."​

Korea’s Eugene Science Inc. patented an approach for plant sterol dispersal in a clear beverage by mixing with surfactants, including sucrose fatty acid esters, polyglycerol fatty acid esters, or sorbitan fatty acid esters prior to shearing. This reportedly led to an increase in the bioavailability of the sterols (WO/2002/028204).

Co-enzyme Q10 dispersion was achieved using of a “healthy diglyceride” containing high levels of linolenic acid. The Japanese patent (JP2004357538), held by Kao Corporation, “is noteworthy [because] this dispersion system remains stable after thermal treatment during sterile packaging,”​ said Pepsi-Co’s Given.

For omega-3, one of the nutrition industry’s big ish, several systems have been developed, said Given. These include complex coacervates, traditional emulsions, layer–by–layer emulsions, and microemulsions. Whey protein was recently reported as a means of encapsulating and stabilising omega-3 without degradation of the fatty acid (Food Hydrocolloids​, 2009, Vol. 23, pp. 1120-1126).

The topic of functional beverages, from formulation to success with health claims, will be addressed further at the upcoming Drinks Ingredients 2010 Virtual Conference and Expo​ on May 27th. For more information and to register, please click here​.