In-line Monitoring of Fats and Oils Structure Using Ultrasonic Spectroscopy

S. MARTINI, M. PIATKO, S. BERNET, I. NEESON, M.L. HERRERA, AND A.G. MARANGONI

Salt Lake City, Utah, USA

Congreso; 96th American Oil Chemists’ Society Annual Meeting & Expo; 2005

American Oil Chemists’ Society

Ultrasonic technology has been widely used to study the physical properties of food materials. Ultrasonics has been used to characterize emulsions and suspensions, to analyze the rheological properties of sugars, to determine the percentage of frozen material in foods and to determine solid fat content (SFC) in-line. Previous work in our lab showed that ultrasonic spectroscopy could be used in bulk fat systems to determine SFC in-line. The most important finding was that we could measure SFC up to 20% through 8 cm of crystallized fat. Based on our previous work, we used ultrasonic spectroscopy to study emulsions and foams. Time of flight was found to be highly correlated to the SFC of the fat within the emulsions droplets. We were able to measure SFC up to 30% without significant attenuation of the ultrasonic signal. Additionally, time of flight and integrated response, were correlated with the ideal whipping time of foams. We also used this technique to study the effect of chemical composition on the time of flight. We measured the time of flight of blends with different proportions of olein and stearin at 70°C. We found a linear relationship between these parameters, enabling a rapid determination of the composition of oil systems in terms of saturated and unsaturated triacylglycerols and therefore possibly predict the final SFC of these oils upon crystallization.