By Cai Clemen Christensen, Business Unit Manager, Lipid & Fine Food Group Palsgaard A/S. This article discusses the characteristics and the use of emulsifiers for different food applications. The use of emulsifiers in different processed meat products is described in details including the results of different trials made with emulsifiers in frankfurter and liver sausages. Emulsifiers in food applications Multiphase systems consist of two or more distinctive phases; systems typical encountered in foods are water-in-oil (W/O), oil-in-water (O/W), solid-in-oil, gas-in-liquid, gas-, solidor oil-in-water and so on. These systems are often unstable due to the immiscibility and thus repulsion between the phases. Emulsifiers consist of molecules with ambiphilic properties; i.e. part of the structure is of hydrophilic and another of lipophilic nature. In the multiphase systems these emulsifiers will orientate themselves in the Table 1: Relationship between the HLB value and the aqueous solubility and food application.1 position which is favourable with respect to energy, and the emulsifiers will reduce the interfacial tension between the phases in the multiphase system; typically an O/W or W/O system. The lipophilic moiety of the emulsifier often consists of hydrocarbon chains of fatty acids and the hydrophilic part originates from more polar molecules such as glycerol, lactic acid, citric acid and polyglycerol. The types and sizes of the lipophilic and hydrophilic moieties determine the functional behaviour in multiphase systems. An estimate for this relationship is the hydrophilic to lipophilic balance (HLB value), which can be calculated or determined experimentally. A high HLB value (the hydrophilic moiety dominates the emulsifier) typically stabilises oil-in-water emulsions, whereas low HLB values will lead to water-in-oil type emulsion. The HLB value of certain emulsifiers such as citric acid esters can vary considerably (from 3 to 10) depending the type and amount of fatty acids, the amount of citric acid, the neutralisation degree and the pH in the final food application. A low pH in the food systems will render a neutralised citric acid ester to nonneutralised and vice versa. The selection of emulsifiers has to be defined from the process and the type of emulsion in the final application. Properties in water Non-dispersible Poor dispersibility Milky dispersion Stable milky dispersion Transparent, clear dispersion Clear, colloidal solution Field of application Anti-foaming agent Water-in-oil emulsifier Wetting agent Oil-in-water emulsifier Detergent Solubilizer HLB value 0-2 2-6 6-10 8-12 12-15 15-20 HLB value 1-3 3-6 7-9 8-18 13-15 15-18 Table 2: HLB values for emulsifiers typically used in food applications Emulsifier Glycerol dioleate Glycerol monooleate Citric acid esters of mono- and diglycerides of fatty acids. Calcium stearoyl-2-lactylate Glycerol monolaurate Lecithins Sodium stearoyl-2-lactylate Citric acid esters of mono- and diglycerides of fatty acids. (Neutralised) Polyoxyethylene (20) sorbitan monooleate E-number E-471 E-471 E-472c E-482 E-471 E-322 E-481 E-472c E-433 HBL value 1.8 3.4 3-4* 5 5.2 8 8 9-10* 15.0 *Citric acid ester contains unesterified citric acid chemical groups which can exist as acids or salts (neutralised). This greatly affects the HLB value. Palsgaard Technical Paper - August 2011 Emulsifiers used in food applications, focussing on the meat processing industry 2
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