In-situ Monitoring of Solid Fat Content by Means of p-NMR and Ultrasonics
Journal of Agricultural and Food Chemistry
An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC. TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r 2>0.9) in a linear fashion (v=2.601 SFC+1433.0).
Martini, S., Bertoli, C., Herrera, M.L., Neeson, I. and Marangoni, A.G. 2005. In-situ Monitoring of Solid Fat Content by Means of p-NMR and Ultrasonics. Journal of the American Oil Chemists’ Society 82:305-312 (Impact Factor: 1.504)