Early stages of fat crystallisation evaluated by low‐field NMR and small‐angle X‐ray scattering

Abstract

Low‐field time‐domain nuclear magnetic resonance (NMR; 20 MHz) is commonly used in the studies of fats in the form of solid fat content (SFC) measurements. However, it has the disadvantage of low sensitivity to small amounts of crystalline material (0.5%), thus often incorrectly determining crystallisation induction times. From spin–lattice relaxation rate measurements (R1) during the isothermal crystallisation measurements of cocoa butter between 0.01 and 10 MHz using fast field cycling NMR, we learnt previously that the most sensitive frequency region is below 1 MHz. Thus, we focused on analysing our 10‐kHz data in detail, by observing the time dependence of R1 and comparing it with standard SFCNMR and SFC determinations from small‐angle X‐ray scattering (SFCSAXS). Although not reflecting directly the SFC, the R1 at this low frequency is very sensitive to changes in molecular aggregation and hence potentially serving as an alternative for determination of crystallisation induction times. Alongside R1, we also show that SFCSAXS is more sensitive to early stages of crystallisation, that is, standard SFCNMR determinations become more relevant when crystal growth starts to dominate the crystallisation process but fail to pick up earlier crystallisation steps. This paper thus demonstrates the potential of studying triacylglycerols at frequencies below 1 MHz for obtaining further understanding of the early crystallisation stages of fats and presents an alternative and complementary method to estimate SFC by SAXS.

Effect of Different Syrup Types on Turkish Delights (Lokum): A TD-NMR Relaxometry Study

“…At this point, the importance of low-field TD-NMR is revealed due to its power to determine the solid–liquid ratio in foods and solid fat content determination . In various studies, the basic FID pulse sequence was generally utilized to define solid–liquid fractions and the crystallization behavior of food systems. ,,, Unlike the classical FID approach, liquid fractions (%) of Turkish delight samples were found by using the MSE sequence as explained in detail in the study of Grunin et al (2019). Similar to the liquid fractions, second moment values ( M 2 ) which are related to the crystallinity of the samples were also found by using the same pulse sequence again by referring to the same study, as indicated in the oncoming sections.…”

Nuclear Magnetic Resonance with Fast Field-Cycling Setup: A Valid Tool for Soil Quality Investigation

“…FFC NMR relaxometry versatility makes the technique quite useful in many fields. As an example, it has been applied to monitor food quality [25,26], traceability [27][28][29], conservation [30], and transformation [31][32][33][34][35][36][37]; to evaluate the physical chemical characteristics of systems useful for drug delivery [38]; to design new contrast agents to be used in diagnostic imaging techniques [39][40][41]; to explore tumor development [42]; to monitor environmental quality [18,43,44], and many other different applications that can be found elsewhere [45,46]. The present review paper is intended to explore the suitability in soil science of FFC NMR relaxometry.…”

Crystal Memory near Discontinuous Triacylglycerol Phase Transitions: Models, Metastable Regimes, and Critical Points

“…This phenomenon has been studied for linear polymers [10][11][12], as well as for cocoa butter [13] and fatty acids [14]. Those papers addressed questions regarding the role played by polymer selfand mutual-entanglement in the kinetics of memory effects.Recently, TAG crystallization has been studied [15][16][17][18]. Coexistence of solid and liquid state TAGs were reported [16].…”