Analysis of food emulsifiers

Abstract

Analytical methods used to measure food emulsifiers are derived from lipid analysis (Firestone, 2001; Otles, 2004; Wood et al., 2004; Byrdwell, 2005a). Test Methods are of several types and are carried out for several reasons. Food additives are regulated by government agencies to ensure health and safety. Specifications may be set for starting materials, products, processing methods, and maximum use levels in foods. Tests may also be necessary to ensure the absence of degradation products, microorganisms and foreign materials. Composition of emulsifiers may be related to their functional performance in finished foods. Nongovernmental specifications for food emulsifiers may be negotiated between the supplier and the customer, usually a processed food producer. Tests nay be carried out in the manufacturer's processing line or control laboratory, after which the manufacturer may issue a certificate of analysis. The customer may check the analyses as part of the receiving process, and accept or reject the shipment. Disputes may be submitted to an independent testing laboratory for resolution. Standardized test methods have been developed by professional societies, such as, the Association of Official Analytical Chemists (AOAC) (Horvitz, 2005), the American Oil Chemists Society (AOCS) (Firestone, 2005a), the International Union of Pure and Applied Chemistry (IUPAC) (Paquot and Hauffen, 1987), Leatherhead Foods Research Association, and the National Academy of Sciences (Food Chemicals Codex) (Codex, 2004). To determine emulsifiers in intact food products, fats and emulsifiers must first be extracted. Fats and oils are soluble in nonpolar solvents, such as hexane and toluene. However, emulsifiers are amphiphilic and therefore, less soluble, particularly when emulsifier concentration is high compared to total lipid. Chloroform and chloroform/methanol have been effective for extraction of emulsifiers (Flor and Prager, 1980). Because these solvents are classified as hazardous waste, provisions should be made for recycling. In cases where the lipid concentration is high relative to emulsifier concentration, extraction with hot hexane, followed by acetonitrile was reported (Halverson and Qvist, 1974). Solid samples (e.g., cakes or powdered coffee whiteners) may be conveniently extracted in a Soxhlet extraction apparatus. Liquid samples (e.g., milk or ice cream mix) are generally extracted in a separatory funnel or countercurrent distribution apparatus. Another factor complicating extraction is that emulsifiers may be tightly complexed with starches or proteins, or may be encapsulated in a biopolymer matrix. Pretreatment with amylase enzyme may overcome this problem (Jodlbauer, 1976). © 2008 Springer New York.