## 4 Results and Discussion  
Figure 1a shows a microphotograph of the thus obtained emulsion of dairy and palm fat in alcohol, which was obtained using the MIM-320 microscope in white light imaging mode. It should be noted that the visible image size of the drops in the photograph is greatly increased due to diffraction. Figure 1b-d show the OPD map in a vicinity of an emulsion drop, its cross-section along line 2-2 in Figure 2b, and a 2D distribution of OPD measured by the same microscope in OPD scanning mode, respectively. The relevance of the LPM measurements in the case of emulsion droplets is based on a comparison with the LPM data for suspensions of particles of a homogeneous material with a known refractive index and size, namely calibrated latex particles [25]. Figure 1: Measurements of an emulsion particle with laser phase microscope. (**a**) White-light microphotograph of the prepared emulsion B1-PO0, 65% PO; the size of the white square is \(8\times 8\) microns; (**b**) the phase shift map of a drop of the emulsion measured by LPM in OPD units; (**c**) phase shift profile of the drop; (**d**) 2D distribution of the phase shift \(\delta\) (X, Y) in OPD units. Figure 2: Intensity distribution of light scattered by fat droplets over their size in a sample of an emulsion made from a spread B2–PO1 consisting of 70% butter and 30% palm oil. The scattering angle is 45\({}^{\circ}\). These phase microscope results are only used to confirm that we are obtaining a real emulsion during sample preparation, and the measurement of the droplet sizes of the emulsion was carried out by the DLS method [26]. Figure 2 shows an example of such a distribution for a spread containing 70% butter and 30% of palm fat. The table under the distribution shows the average radius of the drops and the area of their peaks. Note that the intensity peak at radii values of the order of 10\({}^{5}\)-10\({}^{6}\) nm sometimes appears in the intensity distribution. This artifact peak should not be taken into account when interpreting the results, as there are no such large particles in the sample. Such particles with a radius of 0.1-1 mm would be visible in the cuvette with the naked eye. The appearance of such a peak is associated with the effect of the entry and exit of large dust particles from the scattering volume [30; 31]. In weakly scattering samples, a cycle mode of ACF accumulation was applied, which allows for getting rid of noises caused by dust. The decrease in the intensity of scattering in the samples occurs with an increase in the concentration of palm fat in the spread and a corresponding decrease in the milk fat content since pure palm fat does not dissolve in alcohol and does not form drops. However, the experiment showed that a mixture of palm oil with milk fat forms drops in the emulsion. Figure 3 presents the concentration dependence of droplet radius r on the weight percent of added palm fat \(C_{palm}\) in spreads. The drops of pure butter B1 and B2 emulsions have radii of 392 \(\pm\) 29 nm and 387 \(\pm\) 28 nm, respectively. The droplet radius grows as the content of the palm fat in the spread increases, and at a concentration of 65%, it reaches 705 nm. This growth is connected, apparently, with different surface tension on the border of alcohol with palm oil and butter. With a further increase in the content of palm fat in the spread, for example, with 80% palm fat, the size of the drops decreases sharply and becomes practically the same as in an emulsion with 20% palm fat content. Such a decrease is because pure palm oil does not form an emulsion in a solvent. In the spread, where the amount of palm fat is more than 65%, the amount of milk fat is not enough for the formation of drops with sizes corresponding to the curve in Figure 3. It is most likely that with an increase in the content of palm fat in the spread, the formation of drops of an alcohol emulsion becomes more difficult, these drops become unstable, their number and size decrease and the size distribution is greatly broadened.