RESUMO
The concept of critical micelle concentration (CMC) is an important principle for the application of emulsifiers in various fields, not least in the production of food emulsions. In general, the application of emulsifier concentrations > CMC, often 10-20 times CMC, is suggested, to ensure the generation of stable emulsions. Typically, the concept of CMC is only discussed for emulsions or foams, but not simultaneously for liquid emulsions that are to be foamed. This study investigates the CMC concept for aerosol whipping cream (AWC), a system in which emulsion stability has to be guaranteed during storage and foam build up and stability has to be enabled upon foaming. Model AWC (30 g·100 g-1 fat; 6/1 MPa) was processed in the presence of various concentrations of a medium chain saturated monoacylglyceride (cme-sMAG: 0 - 2.0 g·100 g-1). It was found that similarly to the CMC concept in emulsions, the application of me-sMAG in model AWC has to be divided into three sections: i) cme-sMAG < CMC; ii) cme-sMAG ≈ CMC; iii) cme-sMAG > CMC.
Assuntos
Emulsificantes , Micelas , Aerossóis , Emulsões , Fenômenos FísicosRESUMO
Mono- and diacylglycerol (MAG and DAG) emulsifiers (E 471) are widely applied to regulate techno-functional properties in different food categories, for example, in dairy products. A method for the determination of MAG and DAG in aerosol whipping cream by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) after derivatization with primuline was developed. For sample preparation, aerosol whipping cream was mixed with ethanol, followed by the addition of water and liquid-liquid extraction with tert-butyl methyl ether. The sample extracts were analyzed by HPTLC-FLD on silica gel LiChrospher plates with n-pentane/n-hexane/diethyl ether (22.5:22.5:55, v/v/v) as mobile phase, when interfering matrix like cholesterol and triacylglycerols were successfully separated from the E 471 food additives. For quantitation, an emulsifier with known composition was used as calibration standard and the fluorescent MAG and DAG were scanned at 366/> 400 nm. Limits of detection and quantitation of 4 and 11 mg/100 g aerosol whipping cream were obtained for both monostearin and 1,2-distearin, respectively, and allowed the reliable quantitation of MAG and DAG from E 471 far below commonly applied emulsifier amounts. Recoveries from model aerosol whipping cream with 400 mg E 471/100 g were determined in a calibration range of 200-600 mg E 471/100 g sample and ranged between 86 and 105% with relative standard deviations below 7%. In aerosol whipping creams from the German market, E 471 amounts ranged between 384 and 610 mg/100 g.
