Influence of Polymorphism on the Solid Fat Content Determined by FID Deconvolution

Abstract

One of the most important quality parameters of a fat, is its solid fat content (SFC). The standard method to determine the SFC is pNMR using a f‐factor. This factor is determined with three standards. However, this contribution shows that SFC standards are not required when using deconvolution methods. At first, data acquisition is optimized. These experiments revealed that the deconvolution method worked better, if more sample is present in the detection zone of the NMR, due to a higher signal‐to‐noise ratio (SNR). Regarding deconvolution, a bi‐Gaussian model and a model combining a Gaussian and Abragamian function are compared. Both models are able to fit the free induction decay (FID) data. Furthermore, the corresponding SFC values are comparable with the SFC values of the f‐factor method when analyzing SFC standards or fats which are preprocessed using the AOCS tempering protocol. Upon evaluating the influence of the polymorphic states of cocoa butter, it became clear that the f‐factor standards resemble fats containing α‐polymorphs. As a further consequence, the f‐factor method fails when β‐polymorphs are present to a large extent. Overall this study shows that the deconvolution method is superior to the f‐factor method since it does not require any standards and is less affected by the polymorphic state. Practical Applications: This work shows that the solid fat content (SFC) of a fat can be calculated without the use of calibration standards. If deconvolution would replace the standard used pNMR method, it could potentially reduce the preparation time for the measurements, because no calibration is necessary. Next to this, it also lowers the cost of SFC determination, because no standards should be bought. Deconvolution also gives insight in the behavior of the different components present in the sample, for example, T2‐values. There above, research toward deconvolution of pNMR signals is necessary as it could potentially also determine the presence of different fat crystal polymorphs present in samples. One of the most important quality parameters of a fat, is its solid fat content (SFC). The standard method to determine the SFC is pNMR using a f‐factor. However, this contribution shows that SFC standards are not requires when using deconvolution methods. At first, data acquisition is optimized. These experiments revealed that the deconvolution method worked better, if more sample is present in the detection zone of the NMR, due to a higher signal‐to‐noise ratio (SNR). Regarding deconvolution, a bi‐Gaussian model and a model combining a Gaussian and Abragamian function are compared. Both models are able to fit the free induction decay (FID) data.

Water and oil signal assignment in low‐moisture mozzarella as determined by time‐domain NMR T2 relaxometry

“…The latter was assigned on the basis of the composition of mozzarella cheese with 54–60% water and 20–25% lipids. Whereas the relaxation time of solid fat protons is too short to be measured by a CPMG sequence, the protons of water and of the liquid fraction of the fat phase are supposed to be sufficiently mobile to contribute to the CPMG relaxation signal. At 5°C, a milk fat phase consists of only about 40% liquid oil protons .…”

“…Two NMR sequences were employed: the CPMG and the FID‐CPMG sequence. Short time scales of the relaxation decay (<50 μs) are only accessible using an FID sequence, which results in a T 2 * relaxation time distribution due to solid phase protons (e.g., protons of the solid fraction of the fat phase in cheese) . The CPMG sequence provides details about the T 2 relaxation time of protons from the liquid phase (i.e., T 2 > 100 μs).…”

“…Short time scales of the relaxation decay (<50 μs) are only accessible using an FID sequence, which results in a T 2 * relaxation time distribution due to solid phase protons (e.g., protons of the solid fraction of the fat phase in cheese). [23] The CPMG sequence provides details about the T 2 relaxation time of protons from the liquid phase (i.e., T 2 > 100 μs). Combining both sequences into one (FID-CPMG) sequence may yield the relaxation time distribution of solid phase and liquid phase protons.…”

Fat crystals: A tool to inhibit molecular transport in W/O/W double emulsions

“…Samples were measured after 1 day of storage at 5°C. A spacer of 3.0 cm was used to place the sample within the detection window …”

Production of reduced‐fat whipped toppings by solid fat‐based W/O/W double emulsions: proof of concept

“…A relaxation delay of 2 s was used. A bi‐Gaussian model was fitted to the FID data in order to estimate the SFC as described by Declerck et al (). Data processing was done using MATLAB R2018a software.…”