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In situ monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics
Author(s) -
Martini Silvana,
Bertoli Constantin,
Herrera Maria Lidia,
Neeson Ian,
Marangoni Alejandro
Publication year - 2005
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-005-1071-8
Subject(s) - ultrasonic sensor , analytical chemistry (journal) , crystallization , spectrometer , resolution (logic) , materials science , nuclear magnetic resonance , signal (programming language) , spectroscopy , mass spectrometry , chirp , chemistry , acoustics , chromatography , optics , laser , physics , organic chemistry , quantum mechanics , artificial intelligence , computer science , programming language
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).