# Multiblock Analysis Applied to TD-NMR of Butters and Related Products
## 3 Results and Discussion  
### NMR Signal Description  
Figure 2 shows the mean signals for the three classes of product: butter, concentrated fat and margarine, for both sets of T\({}_{1}\) relaxation data, T\({}_{1L}\) and T\({}_{1S}\), and at both temperatures. All the signals have the same sigmoidal appearance. It can be noticed that, by increasing the temperature, the intensity of the T\({}_{1L}\) signals increases, while the intensity of the T\({}_{1S}\) signals decreases. This observation is coherent with the solid fat content of samples that is expected to decrease at higher temperatures due to fat crystal melting. The solid fat phase should be characterized by T\({}_{1S}\) whose intensity should decrease at 15 \({}^{\circ}\)C. As no material is lost during the NMR measurements, the solid signal decreases in favor of the liquid one, therefore the T\({}_{1L}\) signal intensity increases.  
Regarding T1L, it can be noticed that the margarine signals (in green) are below the butter signals (in red), and globally below the concentrated fat signals (in blue). This discrimination is clearer at 6 \({}^{\circ}\)C than at 15 \({}^{\circ}\)C. At high times (>3000 ms), the signal intensity of butters is the highest one, while for margarines the signal intensity is slightly lower, showing a clear increase with higher temperature. For both temperatures, the concentrated fat signal is the only one that presents a complete sigmoid with a clear plateau reached after 1000 ms. Butter signals also seem to be like a sigmoid with a plateau after 3000 ms. The margarine signals have a more crushed shape between 100 and 1000 ms and no plateau is reached for T1L. However, the signal intensity for margarines exceeds that of the concentrated fat signal after 1000 ms, and particularly at 15 \({}^{\circ}\)C. The crushed shape of the signal of margarines indicates the presence of proton pools with different T1L compared to the other butters. These protons may characterize emulsifiers or additives used in the margarine composition. They are, in general, lecithin or synthetic molecules that crystallize at 6 \({}^{\circ}\)C [26]. By increasing the temperature at 15 \({}^{\circ}\)C, the intensity of the margarine mean signal increases. This can be explained by the appearance of a new proton phase that should originate from the melting of these additives.  
Regarding T1S, the change in temperature does not induce any change in the form or order of the signals. The signals measured at 6 \({}^{\circ}\)C simply appear to be vertically expanded compared to those measured at 15 \({}^{\circ}\)C. The changes due to the increasing of temperature are only due to the proton quantity that only influences the signal intensity. However, expected changes in the signal shape due to the variations in relaxation time T1S were not observed. The signals of the three classes are very similar for times before 200 ms. For longer times, the signal intensities for butter are lower than for margarines, which in turn are lower compared to concentrated fats. This result agrees with the solid fat content  
Figure 2: Mean signal of each class of products. (**a**,**c**): T1L, (**b**,**d**): T1S, (**a**,**b**): T = 6 \({}^{\circ}\)C, (**c**,**d**): T = 15 \({}^{\circ}\)C. Vertical scale of (**b**,**d**) is different from that of (**a**,**c**). Horizontal scale is logarithmic.  
of concentrated fats. These samples are expected to be exclusively composed of fat. Margarines are expected to contain a higher content of dry matter compared to butters. As mentioned before, they contain added emulsifying agents that provide their special texture and which crystallized, in general, at 6 \({}^{\circ}\)C [26]. The fact that the T\({}_{\rm 1S}\) signal for margarines is higher than butters can be explained by this additional crystalline phase.