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Determination of the solid fat content of commercial fats by pulsed nuclear magnetic resonance
Author(s) -
Madison B. L.,
Hill R. C.
Publication year - 1978
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/bf02669922
Subject(s) - tempering , instrumentation (computer programming) , analytical chemistry (journal) , materials science , sample (material) , temperature measurement , repeatability , nuclear magnetic resonance , chemistry , chromatography , thermodynamics , composite material , computer science , physics , operating system
A method and instrumentation for measuring the solid fat content is reported that is both accurate and precise. It involves using transient nuclear magnetic resonance (NMR) measurements for determining the percentage of solids in commercial shortenings and hydrogenated oils at selected temperatures. The incorporation of a tempering step at 26.7 C for all samples before measurement has improved the precision of the solids content actually measured (±0.2% solids) which approximates that of dilatometry. Duplicate measurements are not required to obtain this precision. The instrument is equipped with six 10‐mm sample holders in combination with a precise variable temperature accessory system which eliminates the temperature difference between the sample and sample holder. This improved and exact temperature conditioning of samples provides better sample stability and easier handling for routine conditions of analysis. A single temperature result can be made in less than 1 hr and typical 5 temperature results obtained in 2.5 hr. Our work also indicates that tempering does influence results, the net effect being to decrease the amount of solids at temperatures less than the tempering temperature. In comparing the pulsed NMR measured solids with these measured by dilatometry, differences between methods of measurement are minimized when samples have had the same tempering and temperature history. This method provides flexibility, speed, and increased sample throughput of up to 60 samples/day. The self‐contained equipment requires only 9 sq ft of space and is ready for measurements within 45 min after start‐up.