A Study Of Food Oil-in-Water Emulsions Stability

The method evaluating the stability of food Oil-in-Water emulsions were investigated in this paper. The formula and process of powdered oil prepared by using maltodextrin, soybean oil and cocoa butter substitute as raw materials were investigated in this paper. Also, the effects of food components and environmental factors on the stability of food Oil-in-Water emulsions by the transmittance turbidity measurement were studied. The main results were as follows:1. The emulsification system of powdered oil was established. Among many varieties of emulsifiers, it was determined by experiments that the microencapsulation effect was best with starch fatty acid esters and sodium caseinate as emulsifier of powdered oil. The proportion and quantity of two kinds of emulsifiers were decided by single factor experiment. It was showed that the microencapsulation efficiency of product prepared by spray drying technique was highest when the emulsifier proportion was 1:1 and the additions were respectively 5% and 5%.The microencapsulation process was optimized. Applying two phase emulsification technique, the temperature of emulsification was 75℃, homogenizing pressure was 40Mpa and homogenizing twice.The optimum technological conditions of spray drying were as follows:inlet air temperature 195℃, outlet air temperature 95℃, feeding rate 25.0mL·min-1, air pressure 0.10Mpa.2. In order to determine the stability of food Oil-in-Water emulsions, evaluating indexes system with the transmittance turbidity was constructed. The stability in Cocoa butter substitute and soybean oil emulsions was analyzed by three methods, such as laser particle analyzer method, centrifugation method, the transmittance turbidity method. The results showed that:when the transmittance of Cocoa butter substitute and soybean oil emulsions are over 10%, they are stable with reference to 0.2 mol/L potassium bichromate solution by 450nm. The agreement between the two methods is excellent. The turbidimetric method is shown to be amore conservative estimate of emulsion stability. The simplicity of the method makes it useful for both product formulation and process control.3. The effects of temperature, metal ions, organic acid and inorganic acid on Cocoa butter substitute and soybean oil emulsions were investaged. The results showed that:Calcium and magnesium ions are were significant. The lowest concentrations were 0.04 mol/L and 0.05 mol/L. Soiumand and potassium ions wre feeble.4. The effects of food components and environmental factors on Cocoa butter substitute and soybean oil emulsions were investaged.